Particle and volatile organic emissions from the combustion of a range of building and furnishing materials using a cone calorimeter

Fire Safety Journal 69 (2014) 76–88

Contents lists available at ScienceDirect

Fire Safety Journal journal homepage: www.elsevier.com/locate/firesaf

Particle and volatile organic emissions from the combustion of a range of building and furnishing materials using a cone calorimeter Fabienne Reisen a,b,n, Mahendra Bhujel a, Justin Leonard b,c a

CSIRO Oceans and Atmosphere Flagship, VIC, Australia Bushfire CRC, Melbourne, VIC, Australia c CSIRO Land & Water Flagship, VIC, Australia b

art ic l e i nf o

a b s t r a c t

Article history: Received 12 December 2013 Received in revised form 13 August 2014 Accepted 16 August 2014 Available online 14 September 2014

A series of experimental small-scale fire tests using a cone calorimeter were conducted. The objective of the tests was to provide a comparative assessment of particle and volatile organic compound emissions from the combustion of 10 commonly used types of building and furnishing materials relative to radiata pine, a dominant construction material. The materials tested included wood-based products (particle board, particle board with melamine surface finishes, medium-density fibreboard, painted pine), wool/ nylon carpet, polyester insulation, two types of polyurethane (PUR) foams, high density polystyrene with cladding material and plasterboard. Tests were run at two irradiance levels, 25 kW m
2 and 50 kW m
2 under well-ventilated conditions. Samples were collected for analysis of gravimetric mass, particulate organic and elemental carbon, polycyclic aromatic hydrocarbons (PAHs), carbonyls and volatile organic compounds along with continuous measurements of carbon monoxide (CO), carbon dioxide (CO2) and fine particles (PM2.5). Under the tested conditions of flaming combustion of 11 materials, the highest pollutant concentrations per mass of specimen burnt resulted from the combustion of polyester insulation, polystyrene with cladding material, PUR foam and a wool/nylon carpet. Among wood-based materials, medium-density fibreboard and particle board with melamine surface ranked highest in emissions, with pine ranking lowest. However, wood-based products make up the majority of mass in building structures so that emissions from wood-based products may contribute more significantly to total emissions and hence to exposures than emissions from the polymeric materials. & 2014 Elsevier Ltd. All rights reserved.

Keywords: Wood-based materials Polymeric materials Elemental carbon Organic carbon PAHs VOCs

1. Introduction The impacts of large bushfires on air quality and health have been studied in a number of research studies worldwide [1–9]. The impact on air quality from bushfires into urbanised areas however has received less attention. Wildfires at the rural/urban interface (RUI) continue to impact on communities in bushfire-prone areas such as south-eastern Australia, California and southern Europe and can result in losses of life and property [10–12]. Once bushfires extend into urbanised areas, a different mix of fuel is available. Combustible materials from house structures, house contents, vehicles, sheds, garages and other objects around a structure will burn and release potentially toxic chemicals into the air which may cause an increased health risk to firefighters, emergency service workers and community members in the vicinity of the fire.

n Corresponding author at: CSIRO Oceans and Atmosphere Flagship, Private Bag 1, Aspendale, VIC 3195, Australia. Tel.: þ61 3 9239 4435; fax: þ 61 3 9239 4444. E-mail address: [email protected] (F. Reisen).

http://dx.doi.org/10.1016/j.firesaf.2014.08.008 0379-7112/& 2014 Elsevier Ltd. All rights reserved.

Combustible materials at the RUI range from natural to synthetic products. Wood and manufactured wood-based products such as particleboard, medium density fibreboards (MDF) and plywood are widely used in building structure, flooring, shelving and cabinetry and make up a large proportion of combustible materials [13]. Another important class of combustible materials is the polymeric materials or plastics which have a wide range of properties and therefore play a significant and ubiquitous role in everyday life. They are commonly used as furnishings, construction materials, textiles and in vehicles. Other products likely to be present include paper, clothing, appliances, paints, solvents, insecticides, pesticides, petrol, oil, rubber and other chemicals used in household items or stored in sheds and garages. Burning materials, either natural or man-made, release a complex mixture of combustion products into the atmosphere. Many are linked to adverse acute or chronic health effects, including asphyxia, eye, nose, throat, lung or skin irritation, shortness of breath, exacerbation of existing respiratory or cardiovascular conditions, effects on the central nervous system and cancer [14,15]. Major factors that play a role in the composition

F. Reisen et al. / Fire Safety Journal 69 (2014) 76–88

and yield of potentially toxic combustion products released into the atmosphere are the nature of the combustible material and the physical conditions of the fire (e.g. fire ventilation and fire intensity) [16,17]. During prescribed burning and bushfire operations firefighters are exposed to a range of hazardous pollutants in particular fine particles, carbon monoxide (CO), formaldehyde and volatile organic compounds (VOCs) such as benzene, toluene, xylenes and phenol [18–20]. Previous studies have also investigated exposures at structural fires [21–24], and have found air pollutants of concern to be CO, formaldehyde, acrolein, hydrogen chloride, hydrogen cyanide (HCN), hydrogen sulphide, hydrogen fluoride, benzene, nitrogen dioxide, sulphur dioxide and polycyclic aromatic hydrocarbons (PAHs). A recent study has assessed firefighters personal exposures during vehicle fire suppression [25]. In this particular case, formaldehyde was the only air pollutant measured at concentrations exceeding occupational exposure standards. The predominant contributors to the hazard index for respiratory effects were formaldehyde, acrolein, CO, benzene and isocyanates. Additionally studies were conducted to assess emissions from a range of burning materials under well-controlled conditions during small bench-scale experiments [26–38], emissions from largescale simulated room fires which were set up with a variety of furnishing materials [39–42] and emissions from vehicle fires [43]. These studies provide essential information on air pollutants released during combustion of materials. The most extensively studied class of combustion products was inorganic gases. A small number of studies also investigated other pollutants including VOCs [27,31,32,35,39,44], PAHs [27–29,31,33,37,38,45–48], dioxins and/or other persistent organic pollutants [33,40,47,49–52] and particle size distribution [45,53]. Organic compounds were considered to be a potential hazard, but in most studies individual compounds have not been identified or quantified. Although total emissions of CO and carbon dioxide (CO2) dominate, hydrocarbons and VOCs are important contributor to the total emissions and likely to impact on health. Furthermore as for any combustion sources particles are likely to constitute a major proportion of emissions from fires that extend into RUI areas, but information on their emissions and composition is limited. Exposures to elevated fine particle concentrations have been linked to respiratory and cardiovascular health impacts, including increased morbidity and mortality rates [54–56]. There has also been an increased focus on the chemical composition of particles to assess whether any particular components of a particle are responsible for the adverse health impacts [57]. Carbonaceous material can make up a substantial proportion of the total PM mass and has gained increased interest due to its potential implications for human health [58,59]. Based on the current knowledge, the experimental tests were carried out to enhance our understanding on emissions of particles, aldehydes and speciated VOCs from the combustion of selected combustible materials commonly found in urbanised areas. A number of these compounds are strong irritants and probable carcinogens and may add to the toxic effects of other toxic gases present in the smoke such as CO, HCN, nitrogen oxides and ammonia. The small-scale fire tests conducted in this study aim to provide an initial comparative assessment of particle and gaseous emissions from the combustion of a range of common structural and furnishing materials against emission from the combustion of radiata pine, a predominant construction material. The tests are not able to provide an exhaustive investigation of the production of combustion products under varying fire conditions, but nevertheless will enable a better understanding of differences in particle and organic emissions among major combustible materials during well-ventilated conditions.

77

2. Methods 2.1. Cone calorimeter test: Experimental set-up The tests were conducted under well-ventilated conditions using a cone calorimeter according to ISO 5660-1:1993 [60]. The cone calorimeter is a well known and well documented standardised fire test that allows for quantitative collection of smoke gases. All test specimens were exposed in the horizontal orientation with the standard pilot ignitor operating. The nominal exhaust system flow rate from the combustion chamber was 0.024 m3 s
1 for all tests. Specimens were tested at irradiance levels of 25 kW m
2 and 50 kW m
2. A heated jacket was installed on the exhaust duct to maintain a duct surface temperature of approximately 180–200 1C and prevent gas condensation onto the duct surfaces. Sampling was carried out from two sampling ports that were mounted in the 150 mm diameter horizontal exhaust duct at 0.4 and 0.6 m respectively from the combustion chamber, which was sealed by toughened glass doors. The sample ports consisted of 6.35 mm diameter stainless steel tubes, which diagonally reached the centre of the duct. A schematic of the experimental design is shown in Fig. 1. The custom aerosol sampling line comprised of approximately one metre of copper tubing of 6.35 mm diameter, passing into a stainless steel cylinder (d ¼0.15 m; L ¼0.33 m). The cylinder was equipped with 5 outlets distributing sample air to a vacuum pump, a particle monitor (DustTrak, TSI Inc., USA), a MicroVol-1100 (Ecotech Pty Ltd, Australia), a PAH sampling system and a CO/ CO2 monitoring device (QTrak, TSI Inc, USA) (Fig. 1). In order to prevent water saturation of instruments, reduce humidity and cool the hot air, the sampling air was diluted with zero grade air (1:5). The dilution ratio was determined by measuring CO concentrations both at the exhaust duct and at the end of the dilution line. Spot samples of VOCs and integrated samples of carbonyls were taken directly from the port in the exhaust duct. The port was fitted with cleaned silanised glass wool to prevent soot entering onto the sorbent tubes or carbonyl cartridges. Except for VOCs, sampling was conducted over the complete test periods which ranged from 5 to 25 min depending on the ignitability of the material resulting in variable sampling times for the different materials. 2.2. Materials tested The materials tested were selected to represent common combustible materials used in structural and furnishing components of houses. Information on the tested materials is given in Table 1. All materials were cut into 100 by 100 mm samples preconditioned to standard temperature of 23 72 1C and moisture conditions of 507 5% relative humidity. All test specimens were held in an edge frame sample holder. For some materials such as polyester insulation, PUR foams and carpet, a restraining grid was added to the top of the sample holder to avoid the materials to lift out of the sample holder. 2.3. Sampling and analysis methods CO and CO2 were measured continuously in the exhaust duct of the cone calorimeter using gas infrared spectroscopy. For aerosol measurements, a QTrak IAQ Monitor (model 7575, TSI Inc, USA) was used to continuously measure CO via an electrochemical sensor and CO2 via a dual-wavelength non-dispersive infrared sensor at the end of the dilution line. The CO and CO2 readings were calibrated each day using standard gas cylinders.

78

F. Reisen et al. / Fire Safety Journal 69 (2014) 76–88

0.4 m

0.6m 0.4 m

Laser smoke monitor Fan Soot filter Temperaturemonitor Pump

CO/CO2 analyser O2 analyser

Cold trap Carbonyls

VOCs (sorbent tubes)

Fig. 1. Schematic of the experimental set-up to monitor particle (top) and gaseous emissions (bottom) from the combustion of materials using a cone calorimeter.

Analyses for aerosol mass were carried out on particles collected on pre-weighed 47 mm fluoropore filters (Millipore, FALP04700, 1 μm pore size) using a low-volume aerosol sampler (Microvol1100, Ecotech Pty Ltd, Knoxfield, Australia) and operated at a constant flow of 3 L min
1 using a mass flow meter in the unit. Gravimetric mass measurements on the pre-exposed and exposed filters were made using an ultra-microbalance (Model UMT2, Mettler Toledo, USA) with a specialty filter pan in a temperature and humidity controlled environment. Analyses of elemental (EC) and organic (OC) carbon were carried out on particles collected on 47 mm quartz filters using a

DRI Model 2001A Thermal-Optical Carbon Analyzer and the IMPROVE-A temperature protocol [61]. Laser reflectance was used to correct for charring, since reflectance has been shown to be less sensitive to the composition and extent of primary organic carbon. Prior to analysis of filter samples, the sample oven was baked to 910 1C for 10 min to remove residual carbon. Sampling of PAH species was made using a 32 mm quartz filter followed by a pre-cleaned polyurethane foam (PUF) plug (ORBO1000 22 mm  76 mm, Supelco) mounted in a pyrex glass holder directly behind the filter attached to an air sampling pump. The sampling rate was nominally 4.5 L min
1 giving a typical

F. Reisen et al. / Fire Safety Journal 69 (2014) 76–88

79

Table 1 Elemental composition of materials tested in the experimental burns.

Materials

Radiata Pine Painted pine (100% acrylic self priming exterior white paint) Particle board (PB) Particle board w/ melamine Medium density fibreboard (MDF) Carpet (wool/nylon blend) Polyester insulation PUR foam 23/130 PUR Foam 36/130 CMb Polystyrene (high density) with cladding Plasterboard

Thickness (mm)

20 20 16 16 15 12 35–40 30 30–32 30 10

Elemental composition (%)a

Weight (g)

123.5 7 1.7 127.8 7 2.6 104.77 2.0 108.7 7 3.6 111.5 7 1.6 18.6 7 0.7 6.2 7 1.3 4.9 7 0.1 11.0 7 0.3 35.0 7 0.9 67.6 7 0.5

C

H

O

53 51 50 50 50 50 62 62 56 91 4

6 6 6 6 6 7 4 8 8 8 0.1

41 40 41 41 40 19 33 22 29 0.7 o5

N

S

Cl

Ash

0.01 2.6 2.6 3.8 5.4

0.01 0.04 0.03 0.01 0.17 0.02 0.02 0.02 0.10 19

0.02 0.01 0.01 0.01 0.02 0.01 0.02 0.08 0.05 0.07 0.02

0.18 4.1 0.34 1.0 0.31 19.2 0.37 1.8 3.2 0.17 91

6.7 3.6 0.3

a

    

The elemental composition analysis was carried out by HRL Technology Pty Ltd as follows. Carbon (C), hydrogen (H) and nitrogen (N) were determined using a LECO CHN analyser (LECO Australia Pty Ltd); sulphur (S) was determined according to AS1038.6.3.1, with measurement by Inductively Coupled Plasma Optical Emission Spectrometry (ICP–OES); chlorine (Cl) was determined according to AS1038.8.1 with measurement by ICP–OES; oxygen (O) content was estimated by difference (i.e. O ¼ 100
(Cþ Hþ N þorganic Sþash)); ash yield was determined by combustion at 815 1C.

b

The first number indicates ‘density’, the second number indicates hardness; CM is combustion modified.

collected volume of 23-110L. PUF plugs and quartz filters were extracted in 8 mL and 5 mL of acetonitrile by ultrasonication for 30 min in glass vials. PAH concentrations in the extract were determined using high performance liquid chromatography (HPLC) gradient elution, with a mobile phase consisting of a water–acetonitrile mixture pumped by a Dionex GP-40 gradient pump. A standard 16-PAH calibration mix (Supelco) was used to quantify individual PAHs. Continuous measurements of PM2.5 were made using a laser light-scattering detector (DustTrak model 8250, TSI Inc, USA), operated with a PM2.5 impactor. Zeroing of the DustTrak was performed before and after each test. PM2.5 concentrations determined by the DustTrak were calibrated against gravimetric mass measurements of PM made on samples collected using a MicroVol 1100. All particle concentrations are reported as gravimetric measurements with DustTrak data being corrected by the response factor of the light-scattering particle monitor to ambient particles. For gaseous measurements, aldehydes and ketones were collected onto 2,4-dinitrophenylhydrazine (DNPH) impregnated cartridge (LpDNPH, Sigma-Aldrich) attached to an air sampling pump at a flow rate of 0.7 to 1.5 L min
1 leading to sampling volumes of 8 to 18 L. The stable derivatives formed on the cartridge from the reaction of 2,4-DNPH were analysed using High Performance Liquid Chromatography (HPLC) according to OSHA Method 64 Modified (WorkCover, Chemical Analysis Branch Handbook, 6th Ed, 2006). VOC species were collected onto stainless steel sorbent tubes packed with Tenax TA (Markes International Ltd.). Samples of 200 mL were drawn onto the sorbent tube using a gas syringe over approximately 1-minute period. The VOC species were analysed using gas chromatography (GC) with flame ionisation detection (FID) and mass spectrometry detection (MSD). The tubes were thermally desorbed at 250 1C for 5 min onto a 30 m DB5MS column (0.32 mm, 0.25 μm film thickness) temperature programmed as follows: 10 min at 35 1C, 8 1C min
1 up to 250 1C, 20 1C min
1 up to 280 1C and 5 min at 280 1C. Individual species were identified by MS (using the NIST database) and quantified by FID, calibrated for selected VOCs using a standard gas mixture and using the effective carbon number concept to calculate FID relative response factors [62].

3. Results and discussion Eleven materials were tested under well-ventilated conditions at 2 irradiance levels. For CO, CO2 and PM2.5 time-resolved measurements were conducted at 5 or 10-second intervals. For the remaining pollutants, either integrated samples (PAHs, EC, OC, carbonyls) or spot samples (VOCs) were collected. The emission yields for CO, CO2, PM2.5, EC, OC, PAHs and carbonyls expressed as mass of compound generated per mass of material combusted are shown in Tables 2 and 3. 3.1. CO and CO2 emissions Fires can be classified into different fire stages that can range from non-flaming to well-ventilated flaming and under-ventilated flaming. ISO has classified fire stages based on heat flux, temperature, oxygen availability, CO2 to CO ratio and combustion efficiency [63]. The CO to CO2 ratios measured for most materials in this study fitted into fire stage 2, well-ventilated flaming as defined in ISO/TS 19706:2004 [63]. Exception was the combustion of plasterboard that fitted the profile of a non flaming self-sustaining (smouldering) fire type (Table 2). At 25 kW m
2, highest CO emission yields were observed for polystyrene, followed by plasterboard, polyester insulation and particle boards (Table 2). Statistically significant differences in CO emission yields (p o0.05) were observed between pine and woodbased and polymeric materials. CO emission yields for polystyrene, polyester and particle board with melamine were also statistically different from CO emission yields for MDF, carpet and PUR foams. At 50 kW m
2, wood-based materials had generally lower CO and higher CO2 emission yields, suggesting a more complete combustion. Polyester showed higher CO and CO2 emission yields, while polystyrene and plasterboard had similar CO but higher CO2 emission yields. 3.2. Particle emissions Sedimentation, diffusion and thermophoresis are the main processes that can lead to losses of particle concentration during transport [64]. The transport efficiency for gravitational deposition was calculated to be 0.92, 0.98 and 1.0 for particle sizes of 2.5,

80

F. Reisen et al. / Fire Safety Journal 69 (2014) 76–88

Table 2 Emission yields of CO, CO2, PM, OC, EC and PAHs for combustion of various materials (averaged over burn time). Top: Values are mean 7 stdev at irradiance level of 25 kW m
2 (n ¼7 for CO and CO2, n¼ 3 for PM, OC and EC. Bottom: Values are mean 7 stdev at irradiance level of 50 kW m
2 (n ¼2). Material

Pine Painted Pine Particle board (PB) PB with melamine MDF Carpet Polyester insulation PUR foam 23/130 PUR Foam 36/130 CM Polystyrene with cladding Plasterboard

CO/CO2a

CO (kg kg
1)

CO2 (kg kg
1)

PM (g kg
1)

OC (g C kg
1)

EC (g C kg
1)

0.010 0.014 0.011 0.007 0.021 0.009 0.026 0.007 0.021 0.009 0.020 0.021 0.073 0.088 0.017 0.023 0.015 0.014 0.075 0.035 0.54 0.24

0.0087 0.002 0.0097 0.004 0.0097 0.003 0.006 7 0.001 0.0177 0.003 0.0087 0.003 0.020 7 0.005 0.0057 0.001 0.0147 0.002 0.004 7 0.001 0.0137 0.003 0.0157 0.001 0.020 7 0.002 0.039 7 0.004 0.0157 0.004 0.029 7 0.001 0.0137 0.002 0.0117 0.001 0.025 7 0.007 0.028 7 0.002 0.020 7 0.009 0.029 7 0.003

1.05 70.04 1.18 70.05 1.08 70.07 1.12 70.01 0.98 70.05 0.95 70.00 0.91 70.07 0.93 70.01 0.89 70.04 0.94 70.06 1.36 70.12 1.51 70.01 0.6770.08 0.94 70.01 1.71 70.16 1.37 70.13 1.83 70.10 1.34 70.04 0.52 70.29 1.60 70.01 0.06 70.06 0.12 70.01

3.577 0.11 12.8 3.86 7 3.16 11.4 7 0.71 3.23 7 0.86 5.43 7 0.75 3.56 7 0.99 5.517 0.04 3.99 7 0.94 4.91 70.25 34.6 7 6.9 38.4 7 5.7 57.7 711.5 59.0 7 1.2 16.8 74.1 69.2 718.3 12.8 74.5 15.7 7 2.9 51.1 720.0 44.8 7 0.9 26.5 7 8.7 14.8 7 0.4

0.617 0.03 0.54 0.65 7 0.16 0.55 7 0.19 1.317 0.27 0.29 7 0.02 2.277 1.76 0.447 0.15 1.38 7 0.16 0.34 70.01 2.87 71.53 2.147 0.15 9.89 7 2.11 15.9 74.8 1.29 7 1.83 10.2 75.8 0.777 0.51 2.167 0.14 21.4 7 8.7 3.077 0.01 19.5 10.6

2.60 70.67 9.56 4.337 3.14 9.86 7 0.19 2.46 7 0.49 4.247 1.23 2.21 70.90 3.83 7 0.38 2.577 0.38 3.55 70.47 28.3 75.9 37.3 7 8.5 36.6 74.8 40.5 7 10.4 7.80 70.64 17.5 7 0.02 7.56 7 4.87 10.6 7 0.2 8.86 7 6.00 36.5 73.8 0.39 0.59

PAHsb (g kg
1)

0.056 0.040 70.007 0.0097 0.002 0.011 70.001 0.0087 0.0008 0.0977 0.016 0.340 7 0.041 0.045 70.007 0.026 7 0.005 0.209 7 0.052 0.052

a

CO/CO2 ratios less than 0.05 represent well ventilated flaming conditions. CO/CO2 ratios between 0.1 and 1 represent non- flaming, self sustained smouldering conditions. b Results of PAHs represent the combined gas- and particle-phase emissions. Table 3 Emission yields of selected carbonyls and total carbonyls for combustion of various materials. Top: Values are mean 7 stdev at irradiance level of 25 kW m
2 (n ¼2). Bottom: Values at irradiance level of 50 kW m
2. Material

Pine Painted Pine Particle board (PB) PB with melamine MDF Carpet Polyester insulation PUR foam 23/130 PUR Foam 36/130 CM Polystyrene with cladding Plasterboard

Formaldehyde (mg g
1)

Acetaldehyde (mg g
1)

Acrolein (mg g
1)

Benzaldehyde (mg g
1)

Methyl glyoxal (mg g
1)

Total carbonyls (mg g
1)

0.217 0.07 0.028 0.167 0.02 0.040 0.22 7 0.03 0.133 0.25 7 0.07 0.262 0.2470.02 0.154 0.25 7 0.02 0.247 1.167 0.36 0.817 0.93 7 0.17 0.155 0.23 7 0.05 1.40 1.46 7 0.59 0.408 4.22 1.51

0.067 0.03 0.006 0.0770.004 0.023 0.23 7 0.13 0.036 0.247 0.11 0.067 0.18 70.01 0.066 0.197 0.01 0.114 1.45 7 0.47 1.21 1.217 0.26 0.512 1.47 70.35 1.82 6.11 7 0.01 1.67 1.50 0.60

0.013 70.002 ND 0.0147 0.001 0.002 0.038 7 0.003 0.002 0.0447 0.009 0.004 0.025 70.004 0.002 0.007 ND ND ND ND ND ND ND ND ND 0.67 0.213

0.0027 0.003 0.002 o 0.001 0.002 0.0117 0.007 ND 0.004 70.0002 0.001 0.0037 0.0002 o 0.001 0.145 70.005 0.046 ND 0.011 ND 0.011 0.0067 0.002 0.005 13.81 7 3.73 0.48 0.325 0.050

0.2047 0.043 0.001 0.185 7 0.047 0.018 0.1757 0.049 0.029 0.220 70.027 0.049 0.1027 0.017 0.010 0.116 70.002 0.033 0.984 7 0.480 0.53 1.12 70.24 0.005 0.025 7 0.010 1.11 0.011 70.003 0.023 5.61 2.06

0.60 7 0.17 0.052 0.54 7 0.08 0.109 0.91 70.13 0.236 1.03 7 0.67 0.432 0.737 0.03 0.278 0.95 7 0.03 0.555 4.7071.71 3.34 4.20 7 0.88 0.741 1.82 70.39 5.38 26.79 7 3.29 3.61 16.06 5.49

1.0 and 0.1 μm, respectively. No particle losses by diffusion were observed for particles larger than 0.01 μm. For particles smaller than 0.01 μm, the transport efficiency with diffusive particle loss decreased to 0.92. No particle loss due to thermophoretic deposition was observed in the exhaust duct. Potential particle losses of up to 25% may have occurred for submicron particles in the sampling line which had a temperature gradient of approximately 300 K. Particle losses were minimised by the short residence time ( o1 s). At 25 kW m
2 highest particle emission yields were measured for polyester and polystyrene, both materials emitting about 20 times more particles compared to pine. This is likely linked to the

aromatic rings in their structure which has been shown to increase particle production [29,30,65,66]. Wood-based products had the lowest PM2.5 yields ranging from 3.2 to 4.0 g kg
1, with no statistically significant differences between the various woodbased materials. These emission yields were similar to those measured in a previous study [26]. Particle emission yields from the combustion of carpet and plasterboard were approximately 10 times higher than those measured for wood-based products. At 50 kW m
2, PM emission yields from the combustion of wood-based materials were 1.2 to 3.6 times higher, with a more significant increase observed for pine compared to manufactured wood products. No significant increases in PM emission yields

F. Reisen et al. / Fire Safety Journal 69 (2014) 76–88

81

60

35 Elemental carbon Organic carbon EC:OC ratio EC:OC ratio of 1

-1

30

25 40 20 30 15

EC:OC ratio

Emission yield (mg C g )

50

20 10 10

5

Plasterboard 25

Plasterboard 50

Polystyrene w/ cladding 50

PUR foam (36/130 CM) 50

Polystyrene w/ cladding 25

PUR foam (23/130) 50

PUR foam (36/130 CM) 25

Polyester 50

PUR foam (23/130) 25

Carpet 50

Polyester 25

MDF 50

Carpet 25

MDF 25

PB w/ melamine 50

Particleboard 50

PB w/ melamine 25

Particleboard 25

Painted Pine 25

Painted Pine 50

Pine 25

0

Pine 50

0

Fig. 2. Elemental and organic carbon emitted during combustion of materials at irradiance levels of 25 kW m
2 and 50 kW m
2.

were observed for carpet, polyester, polystyrene and combustion modified PUR foam. The elemental and organic carbon composition of particles is shown in Fig. 2. Wood-based materials had the lowest carbon emission yields (3–5 g C kg
1), while polyester, carpet and polystyrene had the highest carbon emission yields (30–62 g C kg
1). Most of the particle mass (470%) was carbonaceous. In general there was a larger fraction of EC compared to OC, with the exception of plasterboard and polystyrene where we observed a significant OC fraction (70–98%). At 50 kW m
2, the EC fraction was significantly higher than the OC fraction, except for polyester. We also observed some significant differences between the woodbased materials. At 25 kW m
2, pine had an EC:OC ratio of approximately 4, while both particle board and MDF had a lower EC:OC ratio of approximately 2. The differences are likely due to the presence of glues and resins in manufactured wood products, which increases the organic fraction of particles. Adding melamine reduced the EC:OC ratio to approximately 1. While in the small-scale tests in this study EC dominates, studies on residential wood combustion and biomass burning emissions have shown a larger contribution of OC compared to EC. For combustion of pine in residential woodheaters EC to OC ratios varied from 0.025 to 0.25 [67,68], while EC to OC ratios measured during emissions of biomass burning ranged from 0.06 to 0.29 [69]. The higher EC:OC ratios measured in this study were attributed to the higher temperatures of a flaming combustion which is known to produce more EC [70]. 3.3. Polycyclic aromatic hydrocarbons PAH formation during combustion processes is very complex. Many variables including scale of the experiment, combustion and flame temperature, oxygen supply and residence time play a significant role in the amount of PAH emissions and as a result may explain the large variability in reported emission yields for individual PAHs [27,29,31,32,38,45]. Previous studies have shown that pyrosynthesis of PAHs is promoted during vitiated conditions

and high temperatures, with highest yields of PAHs obtained at temperatures between 850 1C and 950 1C [38,65,66,71–73]. Proposed routes by which PAHs are formed during combustion include the HACA method [74], polymerisation of pyrolysis fragments [75] and deoxygenation of oxygenated aromatic compounds. The presence of oxygen significantly reduces PAH yields due to the two competing effects, (1) the radical enhancement effect by which higher oxygen concentrations lead to increased number of free radicals and yields of pyrolysis products and (2) oxidative destruction effect by which an increase in oxygen results in increased rates of pyrolysis product oxidation and a decrease in pyrolysis product yields [76]. These effects are highly temperature dependent. At low temperatures (400 1C), yields of PAHs are low but increase significantly with increasing pyrolysis temperatures [77]. At high temperatures ( 4900 1C), PAH yields decrease due to oxidisation of PAHs and condensation to form larger structures (i.e. soot) [71]. At the lower irradiance level of 25 kW m
2, PAHs were not detected, whereas measurable concentrations of PAHs were observed during combustion of the 11 materials at the higher irradiance level of 50 kW m
2. A higher irradiance level leads to more fully developed fire which may have promoted the formation of PAHs. Further the higher pyrolysis temperatures at the higher irradiance level would have favoured PAH formation over oxidative destruction [77]. The sum of the emission yields for the 16 priority PAHs is shown in Table 2. Highest PAH yields were observed for polyester (0.34 g kg
1) and polystyrene (0.21 g kg
1), consistent with the higher particle emission yields observed for both materials. The formation of PAHs is likely facilitated by the presence of an aromatic ring [78]. For polystyrene, PAH emission yields from this study were much lower than those reported in previous studies [28,29,37,78] which were conducted at varying temperatures ranging from 600 1C to 1000 1C. Although PAH emissions are very temperature-dependent, this may not explain the significant difference in PAH emission yields. Previous studies combusted pure polystyrene pellets unlike this study that used high density

82

F. Reisen et al. / Fire Safety Journal 69 (2014) 76–88

polystyrene with an added layer of cladding material. The layer of cladding material did not burn and may have altered the combustion conditions and thereby limited PAH formation. Additionally combustion in a cone calorimeter is always well ventilated which would also limit PAH formation. Panagiotou et al. showed a 15-fold increase in PAH emission yields from the combustion of polystyrene when the bulk equivalence ratio was increased from 0.8 (wellventilated flaming) to 1.0 (less-ventilated and more vitiated conditions) [79]. Pine and painted pine showed higher PAH yields than the other wood-based products, but similar to those measured during combustion of plasterboard. The wood-based products had the lowest PAH yields among all materials tested. Due to the complexity of PAH formation during combustion, it is difficult to compare reported emission yields of PAHs with those determined in this study, as experimental conditions can vary considerably. A number of studies have looked at PAH emissions from wood combustion with significant differences among the studies. PAH yields from combustion of pine determined in this study were in close agreement with those reported by McDonald et al. [67] but significantly lower than those reported in other studies [29,68,71,80]. Apart from naphthalene and benzo(b)fluoranthene, yields of individual PAHs from combustion of pine measured in this study were significantly higher than those measured by Bhargava et al. [81]. In their study, they measured higher PAH emission yields for manufactured wood compared to untreated pine. This study showed that manufactured wood products had the lowest emission yields of PAHs. Manufactured wood products used in this study had a higher content of nitrogen compared to the ones studied by Bhargava [81] and may have a urea-formaldehyde based resin rather than a phenol-formaldehyde based resin. For MDF, Bhargava [81] had significantly higher

emission yields for naphthalene, with emission yields of the remaining PAHs being comparable with this study. Differences in the resins used for the MDF may explain the difference in PAH emissions observed between both studies. The total PAH yields of 0.009 g kg
1 from the combustion of particle board agreed fairly well with the total PAH yield of 0.004 g kg
1 from combustion of wood board measured under well-ventilated conditions in a recent study by Blomqvist et al. [45]. This clearly shows that the binders and adhesives used in wood-based products can have a significant impact on emission yields. The distribution among the individual PAHs is shown in Fig. 3. Naphthalene made up the majority of the total PAH yields (31–90%). Other PAHs with significant contributions included phenanthrene (1.4–29%), fluoranthene (0–23%) and pyrene (1–14%). Benzo(a) pyrene (B(a)P), a known human carcinogen, contributed between 0 and 4.5% to the total PAH yields. The highest contribution of B(a)P was observed from the combustion of polyester. In their study on combustion of wood wastes, Khalfi [71] reported high amounts of light PAHs such as naphthalene, acenaphthylene, phenanthrene, fluoranthene and pyrene and low amounts or non-detectable amount of heavy PAHs such as benzo (a)anthracene, benzo(b) and benzo(k)fluoranthenes, benzo(a)pyrene and dibenzo(a,h)anthracene. This is consistent to the results obtained in this study that showed emission yields of heavy PAHs being an order of magnitude lower than emission yields of 3- and 4-ring PAHs. Ruokojarvi [46] and Gras [80] also reported that the most abundant particle-bound PAHs emitted during simulated room fires were phenanthrene, fluoranthene and pyrene, consistent with our study. Under the tested conditions, CO and PAH emission yields correlated very well (r2 ¼0.94) with the exception of combustion of plasterboard and PUR foam (23/130) (Fig. 4). Plasterboard and

Fig. 3. Distribution of individual PAHs emitted during combustion of various materials.

F. Reisen et al. / Fire Safety Journal 69 (2014) 76–88

83

0.4

Polyester

-1

PAHs (g kg )

0.3

y = 0.009x–0.0033 r2 = 0.94

Polystyrene 0.2

Wood-based materials

0.1

Carpet PUR foam and Plasterboard PUR foam

0.0 0

10

20

30

40

50

-1

CO (g kg ) Fig. 4. Distribution of individual carbonyls emitted during combustion of various materials.

Carbonyl distribution (%)

100 Formaldehyde Acetaldehyde Acrolein Acetone Propionaldehyde Crotonaldehyde Methacrolein Methyl Ethyl Ketone Butyraldehyde Benzaldehyde Glyoxal Valeraldehyde m-Tolualdehyde Methyl glyoxal Hexaldehyde

80

60

40

20

Pine 25 Pine 50 Painted Pine 25 Painted Pine 50 Particleboard 25 Particleboard 50 PB w/ melamine 25 PB w/ melamine 50 MDF 25 MDF 50 Carpet 25 Carpet 50 Polyester 25 Polyester 50 PUR foam (23/130) 25 PUR foam (23/130) 50 PUR foam (36/130 CM) 25 PUR foam (36/130 CM) 50 Polystyrene w/ cladding 25 Polystyrene w/ cladding 50 Plasterboard 25 Plasterboard 50

0

Fig. 5. Gas chromatograms (FID results) showing distinctive patterns of VOCs for combustion of wood-based materials at 25 kW m
2 (left panels) and at 50 kW m
2 (right panels): (a) Pine, (b) Painted Pine, (c) Particleboard, (d) Particleboard with melamine, (e) MDF.

PUR foam produced less PAHs as would be expected from the linear correlation. This indicates that PAH emissions could be estimated from CO emissions for well-ventilated scenarios. A linear correlation between CO and PAH emissions was also observed in a study by Khalfi et al. [71] that tested combustion of wood waste furniture.

3.4. Volatile organic carbon emissions The emission yields for total carbonyls are shown in Table 3. At 25 kW m
2, carbonyls were emitted at highest concentrations during combustion of polystyrene, with emission yields for total carbonyls being approximately 45 times higher than those for pine. Other materials with high emissions of carbonyls were plasterboard, polyester and PUR foams. Emissions of carbonyls

from combustion of particleboards were higher than those from combustion of MDF and pine. At 50 kW m
2, total carbonyl emission yields were 1.4 to 12 times lower, except for the combustion modified PUR foam which emitted approximately 3 times more carbonyls at the higher irradiance level and had one of the highest emission yield for total carbonyls. Other materials with elevated yields included plasterboard, polystyrene and polyester. Lowest carbonyl emission yields were measured for pine with an approximately 100 fold difference between emissions from pine and plasterboard. The relative distribution of individual carbonyls for each material at the two irradiance levels is shown in Fig. 5. For the majority of materials, formaldehyde and acetaldehyde, known and possible human carcinogens, were the dominant carbonyls contributing 29–93% to the total emissions of carbonyls. Acetone and methyl glyoxal also contributed significantly to the total carbonyl

84

F. Reisen et al. / Fire Safety Journal 69 (2014) 76–88

Fig. 6. Gas chromatograms (FID results) showing distinctive patterns of VOCs for combustion of wood-based materials at 25 kW m-2 (left panels) and at 50 kW m-2 (right panels): (a) Pine, (b) Painted Pine, (c) Particleboard, (d) Particleboard with melamine, (e) MDF.

emissions. For the combustion modified PUR foam, acetaldehyde was the dominant carbonyl (70–80%). Polystyrene, plasterboard and carpet were the only materials with significant emissions of benzaldehyde. Acrolein, a strong irritant, was emitted at high concentrations during combustion of plasterboard as well during combustion of wood-based products. About 2 to 4 fold higher emissions were observed for manufactured wood products compared to pine. At 50 kW m
2, wood-based products emitted proportionally more formaldehyde and less acrolein and methyl glyoxal. Combustion of carpet and polystyrene released proportionally less benzaldehyde at 50 kW m
2, but more formaldehyde for carpet and acetaldehyde for polystyrene. The GC chromatograms obtained from the combustion of wood-based products at 25 kW m
2 showed a number of dominant peaks including benzene, toluene, naphthalene, acetic and benzoic acid, furfural and phenol (Fig. 6, left panel). The major distinction between pine and manufactured wood products was the presence of nitrogen-containing compounds such as pyrrole, methyl-pyrrole and benzonitrile. Manufactured wood products also formed furan derivatives during their combustion. Proportionally higher amounts of methoxyphenol relative to pine were also observed for MDF and particle board with melamine. At 50 kW m
2, emissions from the combustion of wood-based products were dominated by aromatic hydrocarbons, e.g. benzene, toluene, benzene derivatives and naphthalene (Fig. 6, right panel). The GC chromatograms obtained from the combustion of polymeric materials were quite different from those obtained from the combustion of wood-based products (Fig. 7). They were dominated by benzene at both 25 and 50 kW m
2, with the exception of polystyrene which was dominated by styrene. The dominating presence of benzene, toluene and naphthalene was also observed during measurements at municipal structural

fires [21] and experimental fires burning different combustible materials [39]. The common toxic compounds detected in exposure monitoring at structural fires (e.g. benzene, toluene, naphthalene, formaldehyde) are also consistent to what has been measured in this study [21–24,39]. As highlighted in this study and other studies [21,39], the combustion of different materials does not seem to form any unknown toxic compounds. However we observed specific VOC fingerprints for various materials. For example, styrene was primarily emitted during combustion of materials containing an aromatic structure (e.g. polystyrene and polyester), furfural, pinene, camphene and limonene were only emitted during combustion of wood-based materials and pyrrole and methylpyrrole were only emitted during combustion of particleboards and MDF. Benzonitrile was emitted from combustion of any nitrogen-rich material (e.g. particleboards, MDF, carpet, polyester and PUR foams) and benzoic acid was prevalent during the combustion of PUR foams. While all materials emitted benzene, toluene, naphthalene and phenol during their combustion, the concentrations varied among materials. Emission yields for selected individual VOCs were calculated using CO2 as a reference compound as follows: EFVOC ¼ ERVOC=CO2 

MWVOC EFCO2 MWCO2

The results are shown in Table 4. At 25 kW m
2 emissions of VOCs were lowest from the combustion of pine compared to combustion of the other woodbased and polymeric materials. At 50 kW m
2, emissions of benzene and toluene from the combustion of pine were higher than those from the combustion of manufactured wood products but lower than those from the combustion of polymeric materials. Combustion of pine also resulted in significant emissions of

F. Reisen et al. / Fire Safety Journal 69 (2014) 76–88

85

Fig. 7. Gas chromatograms showing distinctive patterns of VOCs for combustion of polymeric materials at 25 kW m
2 (left panels) and at 50 kW m
2 (right panels): (a) Polyester, (b) PUR foam (23/130), (c) PUR foam (36/130 CM), (d) Carpet (wool/nylon blend), (e) Polystyrene with cladding Table 4 Emission yields (mg g
1) of selected VOCs for combustion of various materials. Top and bottom values represent irradiance level of 25 kW m
2 and 50 kW m
2, respectively. Benzene Toluene Ethylbenzene Xylenes Styrene Indene Naphthalene Phenol

Pine Painted Pine Particleboard PB with melamine MDF Carpet Polyester PUR foam 23/130 PUR foam 36/130 CM Polystyrene with cladding

0.006 0.152 0.032 0.081 0.023 0.124 0.177 0.061 0.201 0.034 1.173 10.45 3.284 1.245 4.897 12.67 0.087 0.646 0.972 9.604

0.003 0.075 0.010 0.010 0.010 0.009 0.121 0.013 0.132 0.049 0.102 0.709 0.263 0.115 0.459 1.353 0.010 0.074 0.893 9.360

0.005 0.007 0.006 0.004

0.037 0.022

0.432

0.008

0.003 0.054 0.018 0.008

0.056 0.025

0.446 2.233

0.120

0.039 0.007

0.010 0.133 0.061 0.019

0.053 0.829 0.117 0.071

0.227

19.077 24.004

0.124 1.210 2.530

naphthalene. Only polystyrene and carpet had higher emissions of naphthalene. A number of the organic compounds that were identified from the combustion of the various structural and furnishing materials are of particular interest due to their adverse health impacts (Table 5). Benzene and formaldehyde are known human carcinogens and repeated exposures to elevated levels of these compounds may increase the risk of cancer. Higher emissions of these two

0.104 0.010 0.035 0.003 0.006 0.103 0.007 0.039 0.012 0.043 1.072 0.040 0.040 0.390 0.000 0.033 0.061 0.109 0.513

0.004 0.003 0.003 0.005 0.004 0.005 0.016 0.006 0.006 0.234 0.026 0.028 0.143 2.276 0.012 0.020 0.207 0.326

Benzoic acid 0.172 0.124 0.128 0.092 0.104 0.147 0.286 0.094 0.239 0.124 0.315 3.799 0.208 0.224 7.648 76.58 0.613 0.656 0.408 2.008

Furfural Benzonitrile Pyrrole

0.007 0.010 0.012 0.005 0.059 0.000 0.909 0.007 0.381 0.010

1-Methyl-1-Hpyrrole

0.006 0.011 0.040 0.014 0.006 0.007 0.599

0.294

0.262

0.141

0.307

0.011 0.406 2.758 0.048 0.146

compounds were measured during combustion of polyester, PUR foam and polystyrene. Other VOCs such as acetaldehyde, ethylbenzene, furan, naphthalene and styrene are possibly carcinogenic to humans and their emissions were highest during combustion of polystyrene. A large number of VOCs identified are known to cause irritation to the eyes, nose, throat and respiratory tract. In general, their emissions were higher during combustion of polymeric materials and wood-based materials compared to pine.

86

F. Reisen et al. / Fire Safety Journal 69 (2014) 76–88

Table 5 Major VOCs identified during combustion of structural and furnishing materials and their health effects. Volatile organic compound

OESa TWA (STEL) in mg m
3

Health effects/symptomsb

36 (91)

Irritating to eyes, nose, throat and skin, aggravation of respiratory conditions, nausea, headaches, dizziness; possibly carcinogenic to humans Irritating to eyes and skin Irritating to eyes, nose and throat, aggravation of respiratory conditions Irritating to eyes, nose and throat Carcinogenic to humans; irritating to eyes, respiratory tract and skin, nausea, headaches, dizziness Irritating to eyes, headache, breathing difficulties Irritating to eyes and skin, headache Irritating to eyes, nose, throat and lungs, shortness of breath Possibly carcinogenic to humans; irritating to eyes, nose and upper respiratory tract, fatigue, drowsiness Carcinogenic to humans; irritating to eyes, nose and throat, aggravation of respiratory conditions Possibly carcinogenic to humans Irritating to eyes, skin and respiratory system Irritating to skin Irritating to eyes, nose and throat, coughing, wheezing Irritating to eyes Irritating to eyes, nose, throat and respiratory tract, headache, dizziness, drowsiness Irritating to eyes, nose and throat, headache, dizziness, drowsiness, nausea Irritating to nose and throat

Acetaldehyde Acetic acid Acrolein Benzaldehyde Benzene Benzonitrile Biphenyl Crotonaldehyde Ethylbenzene Formaldehyde Furan Furfural Hexane Indene 4-Methoxyphenol 1-Methoxypropan-2-ol Methyl ethyl ketone 2-Methylphenol (cresol) Naphthalene Phenol Pyrrole Styrene Toluene Xylene

25 (37) 0.23 (0.69) 3.2 1.3 5.7 434 (543) 1.2 (2.5) 7.9 72 48 5 369 (553) 445 (890) 22 52 (79) 4

Possibly carcinogenic to humans Irritating to eyes, nose and throat Irritating to eyes, throat and skin Possibly carcinogenic to humans; irritating to eyes and upper respiratory tract, headache, fatigue Drowsiness, headache, dizziness, irritating to nose, throat and respiratory tract Headache, dizziness, nausea, irritating to nose and throat

213 (426) 191 (574) 350 (655)

a Occupational exposure standard: TWA- 8-hour time-weighted average concentration, STEL-short-term exposure limit. No Australian standard exists where no figure is listed. b Carcinogenic classifications as defined by the International Agency for Research on Cancer.

Table 6 Normalised scoring of pollutant emissions on a relative scale of 0 to 100, with 0 being the lowest measured value and 100 being the highest measured value. 25 kW m
2

50 kW m
2

Material

CO

PM

TC

Carbonyls

Benzene

Toluene

CO

PM

TC

PAHs

Carbonyls

Benzene

Toluene

Pine Painted Pine Particle board (PB) PB with melamine MDF Carpet Polyester insulation Foam Foam (CM) Polystyrene cladding Plasterboard

0 5.9 52.9 70.6 35.3 29.4 70.6 41.2 29.4 100 70.6

0.6 1.2 0 0.6 1.4 57.6 100 24.9 17.6 87.9 42.7

0 4.1 1.3 2.9 1.7 64.6 100 13.6 11.8 62.5 38.5

0.2 0 1.4 1.8 0.7 1.5 15.8 13.9 4.9 100 59.1

0 0.5 0.4 3.5 4.0 23.9 67.0 100 1.7 19.8

0 0.7 0.7 13.2 14.5 11.2 29.3 51.2 0.7 100

14.3 5.7 11.4 2.9 0 31.4 100 71.4 20 68.6 71.4

12.3 10.1 0.8 0.9 0 52.1 84.1 100 16.8 62.1 15.4

11.8 12.4 1.2 0.7 0 67.7 100 45.3 16.9 68.0 13.9

14.5 9.6 0.3 0.9 0 26.8 100 11.1 5.4 60.5 13.3

0 1.1 3.4 7.0 4.2 9.3 98.1 60.4 12.7 65.5 100

0.9 0.4 0.7 0.2 0 82.5 9.6 100 4.8 75.8

0.7 0.02 0 0.04 0.4 7.5 1.1 14.4 0.7 100

3.5. Comparative assessment To enable a better comparison between the various materials, Table 6 represents the normalised emissions for CO, particle mass, total carbon, PAHs, total carbonyls, benzene and toluene for each irradiance level on a relative scale of 0 to 100, with 0 being the lowest value and 100 being the highest value. The results clearly show that polystyrene with cladding material, polyester insulation, PUR foam and a wool/nylon carpet ranked high in most categories at both irradiance levels. Peak particle emissions were also significantly higher when burning polyester insulation and carpet and PM emissions were dominated by elemental carbon, which made up 70–95% of the PM mass. For polystyrene organic carbon was dominant. Previous studies have also shown high emissions of hydrogen cyanide, an asphyxiant gas, from the combustion of polyester, wool and nylon [82].

It is also interesting to note that polymeric materials ranked much higher in terms of hazardous emissions relative to woodbased products. Among wood-based products, MDF and particle board with melamine surface finish ranked highest at 25 kW m
2, with pine ranking lowest. However at 50 kW m
2, combustion of pine resulted in higher emissions of pollutants compared to combustion of wood-based products. The comparative assessment of gaseous and particle emissions from the combustion of various materials is based on wellventilated flaming conditions and is not applicable to underventilated smouldering conditions. 4. Conclusion A number of commonly used structural and furnishing materials were combusted under well-ventilated conditions in a cone

F. Reisen et al. / Fire Safety Journal 69 (2014) 76–88

calorimeter at 2 irradiance levels, 25 and 50 kW m
2, with the aim to assess their particle and gaseous emissions. The results have shown that polystyrene with cladding material, polyester insulation, PUR foam and a wool-nylon carpet produced the most emissions in terms of pollutants emitted per mass of material burned. However as wood-based products make up the majority of mass in total combustible materials in a house, these materials are likely to contribute more significantly to emissions and hence exposures. The material-based small-scale fire tests in this study were carried out at controlled and well-defined flaming conditions and are not representative of real fire scenarios [83], where a fire undergoes various stages from well-ventilated flaming conditions to under-ventilated smouldering conditions. Under-ventilated conditions lead to increased emission yields of CO, PM and PAHs, as shown in a recent study by Blomqvist et al. [45]. These conditions were not investigated in this study and present a limitation in the assessment of potential health hazards from RUI fires. A future study using the controlled-atmosphere cone calorimeter [60] will enable to determine emission yields under reduced oxygen conditions and complement the current study. The tests however were able to provide a comparative analysis of particles and speciated volatile organic compounds emitted from radiata pine, a dominant construction material, relative to manufactured wood products and polymeric materials under welloxygenated flaming conditions and as such provided additional information on the potential hazardous emissions from burning building and furnishing materials. As the emission yields were determined under well-ventilated conditions on single materials careful considerations need to be taken into account when using these yields to assess potential exposures to firefighters, emergency service workers and residents from fires extending into the RUI. The elemental composition of materials can also have a significant impact on emission yields, in particular the presence of various glues, resins and fire-retardants. Acknowledgements The authors wish to acknowledge the support received from the Bushfire CRC in undertaking this research. The authors wish to thank Kathleen Boast and Paul Selleck from CSIRO Oceans and Atmosphere Flagship for sampling preparation and analysis. References [1] L.J. DeBell, R.W. Talbot, J.E. Dibb, J.W. Munger, E.V. Fischer, S.E. Frolking, A major regional air pollution event in the northeastern United States caused by extensive forest fires in Quebec, Canada, J. Geophys. Res. Atmos. 109 (D19) (2004) (p.). [2] V.A. Dutkiewicz, L. Husain, U.K. Roychowdhury, K.L. Demerjian, Impact of Canadian wildfire smoke on air quality at two rural sites in NY State, Atmos. Environ. 45 (12) (2011) 2028–2033. [3] S.C. Emmanuel, Impact to lung health of haze from forest fires: the Singapore experience, Respirology 5 (2000) 175–182. [4] E. Frankenberg, D. McKee, D. Thomas, Health consequences of forest fires in Indonesia, Demography 42 (1) (2005) 109–129. [5] N. Kunzli, E. Avol, J. Wu, W.J. Gauderman, E. Rappaport, J. Millstein, J. Bennion, R. McConnell, F.D. Gilliland, K. Berhane, F. Lurmann, A. Winer, J.M. Peters, Health effects of the 2003 Southern California wildfires on children, Am. J. Respir. Crit. Care Med. 174 (11) (2006) 1221–1228. [6] Phuleria, H.C., Fine, P.M., Zhu, Y.F., Sioutas, C., Air quality impacts of the October 2003 Southern California wildfires. J. Geophys. Res. Atmos., 2005. 110 (D7): p. -. [7] S. Vedal, S.J. Dutton, Wildfire air pollution and daily mortality in a large urban area, Environ. Res. 102 (1) (2006) 29–35. [8] T.C. Wegesser, K.E. Pinkerton, J.A. Last, California wildfires of 2008: coarse and fine particulate matter toxicity, Environ. Health Perspect. 117 (6) (2009) 893–897. [9] J. Wu, A.M. Winer, R.J. Delfino, Exposure assessment of particulate matter air pollution before, during, and after the 2003 Southern California wildfires, Atmos. Environ. 40 (18) (2006) 3333–3348.

87

[10] J. Beringer, Community fire safety at the urban/rural interface: the bushfire risk, Fire Saf. J. 35 (1) (2000) 1–23. [11] R. Blanchi, C. Lucas, J. Leonard, K. Finkele, Meteorological conditions and wildfire-related house loss in Australia, Int. J. Wildland Fire 19 (7) (2010) 914–926. [12] A.M. Gill, S.L. Stephens, Scientific and social challenges for the management of fire-prone wildland-urban interfaces, Environ. Res. Lett. 4 (2009) 3. [13] Reisen, F., Toxic Emissions from Fires at the Rural Urban Interface—Desktop Study, 2011, Report to Bushfire CRC. [14] Y. Alarie, Toxicity of fire smoke, Crit. Rev. Toxicol. 32 (4) (2002) 259–289. [15] G.E. Hartzell, Overview of combustion toxicology, Toxicology 115 (1-3) (1996) 7–23. [16] T.R. Hull, A.A. Stec, K. Lebek, D. Price, Factors affecting the combustion toxicity of polymeric materials, Polym. Degrad. Stab. 92 (12) (2007) 2239–2246. [17] A.A. Stec, T.R. Hull, K. Lebek, J.A. Purser, D.A. Purser, The effect of temperature and ventilation condition on the toxic product yields from burning polymers, Fire Mater. 32 (1) (2008) 49–60. [18] F. Reisen, S.K. Brown, Australian firefighters’ exposure to air toxics during bushfire burns of autumn 2005 and 2006, Environ. Int. 35 (2) (2009) 342–352. [19] F. Reisen, D. Hansen, C.P. Meyer, Exposure to bushfire smoke during prescribed burns and wildfires: firefighters’ exposure risks and options, Environ. Int. 37 (2) (2011) 314–321. [20] F. Reisen, C.P. Meyer, Smoke Exposure Management on the Fire Ground: A Reference Guide, Bushfire CRC, East Melbourne, VIC (2009) 72. [21] C.C. Austin, D. Wang, D.J. Ecobichon, G. Dussault, Characterization of volatile organic compounds in smoke at municipal structural fires, J. Toxicol. Environ. Health Part A 63 (6) (2001) 437–458. [22] D.M. Bolstad-Johnson, J.L. Burgess, C.D. Crutchfield, S. Storment, R. Gerkin, Wilson Jr., Characterization of firefighter exposures during fire overhaul, Am. Ind. Hyg. Assoc. J. 61 (5) (2000) 636–641. [23] P.W. Brandt-Rauf, L.F.J. Fallon, T. Tarantini, C. Idema, L. Andrews, Health hazards of fire fighters: exposure assessment, Br. J. Ind. Med. 45 (1988) 606–612. [24] J. Jankovic, W. Jones, J. Burkhart, G. Noonan, Environmental study of firefighters, Ann. Occup. Hyg. 35 (6) (1991) 581–602. [25] K.W. Fent, D.E. Evans, Assessing the risk to firefighters from chemical vapors and gases during vehicle fire suppression, J. Environ. Monit. 13 (3) (2011) 536–543. [26] P. Blomqvist, T. Hertzberg, M. Dalene, G. Skarping, Isocyanates, aminoisocyanates and amines from fires—a screening of common materials found in buildings, Fire Mater. 27 (6) (2003) 275–294. [27] P. Blomqvist, T. Hertzberg, H. Tuovinen, K. Arrhenius, L. Rosell, Detailed determination of smoke gas contents using a small-scale controlled equivalence ratio tube furnace method, Fire Mater. 31 (8) (2007) 495–521. [28] S.K. Durlak, P. Biswas, J. Shi, M.J. Bernhard, Characterization of polycyclic aromatic hydrocarbon particulate and gaseous emissions from polystyrene combustion, Environ. Sci. Technol. 32 (15) (1998) 2301–2307. [29] M. Elomaa, E. Saharinen, Polycyclic aromatic hydrocarbons (PAHs) in soot produced by combustion of polystyrene, polypropylene, and wood, J. Appl. Polym. Sci. 42 (10) (1991) 2819–2824. [30] T. Fabian, J.L. Borgerson, S.I. Kerber, P.D. Gandhi, C.S. Baxter, C.C. Ross, J. E. Lockey, J.M. Dalton, M. Arch, Firefighter Exposure to Smoke Particulates, Underwriters Laboratories Inc, Northbrook, IL., 2010. [31] R. Font, I. Aracil, A. Fullana, I. Martin-Gullon, J.A. Conesa, Semivolatile compounds in pyrolysis of polyethylene, J. Anal. Appl. Pyrolysis 68-9 (2003) 599–611. [32] J.M. Hoerning, M.A. Evans, D.J. Aerts, K.W. Ragland, Organic emissions from combustion of pine, plywood, and particleboard, Energy Fuels 10 (2) (1996) 299–304. [33] J. Molto, R. Font, J.A. Conesa, Study of the organic compounds produced in the pyrolysis and combustion of used polyester fabrics, Energy Fuels 20 (5) (2006) 1951–1958. [34] T. Morikawa, E. Yanai, T. Okada, T. Watanabe, Y. Sato, Toxic gases from house fires involving natural and synthetic polymers under various conditions, Fire Saf. J. 20 (3) (1993) 257–274. [35] M. Risholm-Sundman, E. Vestin, Emissions during combustion of particleboard and glued veneer, Holz Als Roh-Und Werkstoff 63 (3) (2005) 179–185. [36] Stec, A.A., Rhodes, J., Smoke and hydrocarbon yields from fire retarded polymer nanocomposites. Polym. Degrad. Stab., 2010. [37] A. Valavanidis, N. Iliopoulos, G. Gotsis, K. Fiotakis, Persistent free radicals, heavy metals and PAHs generated in particulate soot emissions and residue ash from controlled combustion of common types of plastic, J. Hazard. Mater. 156 (1-3) (2008) 277–284. [38] J. Wang, Y.A. Levendis, H. Richter, J.B. Howard, J. Carlson, Polycyclic aromatic hydrocarbon and particulate emissions from two-stage combustion of polystyrene: the effect of the primary furnace temperature, Environ. Sci. Technol. 35 (17) (2001) 3541–3552. [39] C.C. Austin, D. Wang, D.J. Ecobichon, G. Dussault, Characterization of volatile organic compounds in smoke at experimental fires, J. Toxicol. Environ. Health Part A 63 (3) (2001) 191–206. [40] P. Blomqvist, L. Rosell, M. Simonson, Emissions from fires Part II: Simulated room fires, Fire Technol. 40 (1) (2004) 59–73. [41] R.G. Gann, J.D. Averill, E.L. Johnsson, M.R. Nyden, R.D. Peacock, Fire effluent component yields from room-scale fire tests, Fire Mater. 34 (6) (2010) 285–314. [42] M.M. Hirschler, Analysis of work on smoke component yields from room-scale fire tests, Fire Mater. 29 (5) (2005) 303–314.

88

F. Reisen et al. / Fire Safety Journal 69 (2014) 76–88

[43] A. Lonnermark, P. Blomqvist, Emissions from an automobile fire, Chemosphere 62 (7) (2006) 1043–1056. [44] M. Bijloos, G.D. Lougheed, Smoldering of a Flexible Polyurethane Foam Sofa, National Research Council Canada, Ottawa, Canada, 2009. [45] P. Blomqvist, M.S. McNamee, A.A. Stec, D. Gylestam, D. Karlsson, Detailed study of distribution patterns of polycyclic aromatic hydrocarbons and isocyanates under different fire conditions, Fire Mater. 38 (2014) 125–144. [46] P. Ruokojarvi, M. Aatamila, J. Ruuskanen, Toxic chlorinated and polyaromatic hydrocarbons in simulated house fires, Chemosphere 41 (6) (2000) 825–828. [47] D.L. Wang, X.B. Xu, M.H. Zheng, C.H. Chiu, Effect of copper chloride on the emissions of PCDD/Fs and PAHs from PVC combustion, Chemosphere 48 (8) (2002) 857–863. [48] Z.L. Wang, J. Wang, H. Richter, J.B. Howard, J. Carlson, Y.A. Levendis, Comparative study on polycyclic aromatic hydrocarbons, light hydrocarbons, carbon monoxide, and particulate emissions from the combustion of polyethylene, polystyrene, and poly(vinyl chloride), Energy Fuels 17 (4) (2003) 999–1013. [49] W.F. Carroll, The relative contribution of wood and poly(vinyl chloride) to emissions of PCDD and PCDF from house fires, Chemosphere 45 (8) (2001) 1173–1180. [50] N.J. Farrar, K.E.C. Smith, R.G.M. Lee, G.O. Thomas, A.J. Sweetman, K.C. Jones, Atmospheric emissions of polybrominated diphenyl ethers and other persistent organic pollutants during a major anthropogenic combustion event, Environ. Sci. Technol. 38 (6) (2004) 1681–1685. [51] H. Muto, T. Sugawara, Polychlorinated dibenzo-p-dioxins and dibenzofurans in plywood combustion gas, Chemosphere 45 (2) (2001) 145–150. [52] A.A. Stec, J. Readman, P. Blomqvist, D. Gylestam, D. Karlsson, D. Wojtalewicz, B. Z. Dlugogorski, Analysis of toxic effluents released from PVC carpet under different fire conditions, Chemosphere 90 (1) (2013) 65–71. [53] T. Hertzberg, P. Blomqvist, Particles from fires—a screening of common materials found in buildings, Fire Mater. 27 (6) (2003) 295–314. [54] R.D. Brook, S. Rajagopalan, C.A. Pope III, J.R. Brook, A. Bhatnagar, A.V. DiezRoux, F. Holguin, Y. Hong, R.V. Luepker, M.A. Mittleman, A. Peters, D. Siscovick, S.C. Smith Jr., L. Whitsel, J.D. Kaufman, E. Amer Heart Assoc Council, D. Council Kidney Cardiovasc, M. Council Nutr Phys Activity, Particulate matter air pollution and cardiovascular disease an update to the scientific statement from the American Heart Association, Circulation 121 (21) (2010) 2331–2378. [55] B. Brunekreef, S.T. Holgate, Air pollution and health, Lancet 360 (9341) (2002) 1233–1242. [56] C.A. Pope, R.T. Burnett, M.J. Thun, E.E. Calle, D. Krewski, K. Ito, G.D. Thurston, Lung cancer, cardiopulmonary mortality, and long-term exposure to fine particulate air pollution, J. Am. Med. Assoc. 287 (9) (2002) 1132–1141. [57] R.M. Harrison, J.X. Yin, Particulate matter in the atmosphere: which particle properties are important for its effects on health? Sci. Total Environ. 249 (1-3) (2000) 85–101. [58] N.A.H. Janssen, G. Hoek, M. Simic-Lawson, P. Fischer, L. van Bree, H. ten Brink, M. Keuken, R.W. Atkinson, H.R. Anderson, B. Brunekreef, F.R. Cassee, Black carbon as an additional indicator of the adverse health effects of airborne particles compared with PM10 and PM2.5, Environ. Health Perspect. 119 (12) (2011) 1691–1699. [59] A.C. Rohr, R.E. Wyzga, Attributing health effects to individual particulate matter constituents, Atmos. Environ. 62 (2012) 130–152. [60] J.E. Leonard, P.A. Bowditch, V.P. Dowling, Development of a controlledatmosphere cone calorimeter, Fire Mater. 24 (3) (2000) 143–150. [61] J.C. Chow, J.G. Watson, L.W. Chen, M.C. Chang, N.F. Robinson, D. Trimble, S. Kohl, The IMPROVE_A temperature protocol for thermal/optical carbon analysis: maintaining consistency with a long-term database, J. Air Waste Manage. Assoc. 57 (9) (2007) 1014–1023. [62] J.T. Scanlon, D.E. Willis, Calculation of flame ionization detector relative response factors using the effective carbon number concept, J. Chromatogr. Sci. 23 (1985) 333–340.

[63] ISO/TS 19706:2004(E), Guidelines for Assessing the Fire Threat to People, ISO, 2004. [64] K.M. Butler, G.W. Mulholland, Generation and transport of smoke components, Fire Technol. 40 (2) (2004) 149–176. [65] R.A. Hawley-Fedder, M.L. Parsons, F.W. Karasek, Products obtained during combustion of polymers under simulated incinerator conditions. II. Polystyrene, J. Chromatogr. 315 (1984) 201–210. [66] L. Wheatley, Y.A. Levendis, P. Vouros, Exploratory-study on the combustion and pah emissions of selected municipal waste plastics, Environ. Sci. Technol. 27 (13) (1993) 2885–2895. [67] J.D. McDonald, B. Zielinska, E.M. Fujita, J.C. Sagebiel, J.C. Chow, J.G. Watson, Fine particle and gaseous emission rates from residential wood combustion, Environ. Sci. Technol. 34 (11) (2000) 2080–2091. [68] J.J. Schauer, M.J. Kleeman, G.R. Cass, B.R.T. Simoneit, Measurement of emissions from air pollution sources. 3. C-1-C-29 organic compounds from fireplace combustion of wood, Environ. Sci. Technol. 35 (9) (2001) 1716–1728. [69] M.O. Andreae, P. Merlet, Emission of trace gases and aerosols from biomass burning, Global Biogeochem. Cycles 15 (4) (2001) 955–966. [70] M. Posfai, R. Simonics, J. Li, P.V. Hobbs, P.R. Buseck, Individual aerosol particles from biomass burning in southern Africa: 1. Compositions and size distributions of carbonaceous particles, J. Geophys. Res. Atmos. 108 (D13) (2003). [71] A. Khalfi, G. Trouve, R. Delobel, L. Delfosse, Correlation of CO and PAH emissions during laboratory-scale incineration of wood waste furnitures, J. Anal. Appl. Pyrolysis 56 (2) (2000) 243–262. [72] F.J. Mastral, E. Esperanza, P. Garcia, M. Juste, Pyrolysis of high-density polyethylene in a fluidised bed reactor. Influence of the temperature and residence time, J. Anal. Appl. Pyrolysis 63 (1) (2002) 1–15. [73] S. Salvador, M. Quintard, C. David, Combustion of a substitution fuel made of cardboard and polyethylene: influence of the mix characteristicsexperimental approach, Fuel 83 (4-5) (2004) 451–462. [74] H. Richter, J.B. Howard, Formation of polycyclic aromatic hydrocarbons and their growth to soot—a review of chemical reaction pathways, Prog. Energy Combust. Sci. 26 (4-6) (2000) 565–608. [75] E.M. Fitzpatrick, A.B. Ross, J. Bates, G. Andrews, J.M. Jones, H. Phylaktou, M. Pourkashanian, A. Williams, Emission of oxygenated species from the combustion of pine wood and its relation to soot formation, Process. Saf. Environ. Prot. 85 (B5) (2007) 430–440. [76] S. Thomas, M.J. Wornat, The effects of oxygen on the yields of polycyclic aromatic hydrocarbons formed during the pyrolysis and fuel-rich oxidation of catechol, Fuel 87 (6) (2008) 768–781. [77] T.E. McGrath, W.G. Chan, M.R. Hajaligol, Low temperature mechanism for the formation of polycyclic aromatic hydrocarbons from the pyrolysis of cellulose, J. Anal. Appl. Pyrolysis 66 (1-2) (2003) 51–70. [78] B.E. Shemwell, Y.A. Levendis, Particulates generated from combustion of polymers (plastics), J. Air Waste Manage. Assoc. 50 (1) (2000) 94–102. [79] Panagiotou, T., Levendis, Y.A., Carlson, J., Vouros, P. The effect of bulk equivalence ratio on the PAH emissions from the combustion of PVC, poly (styrene) and poly(ethylene), in: Twenty-Sixth Symposium (International) on Combustion, Proceedings of the Combustion Institute, 1996. [80] Gras, J.L., Meyer, C.P., Weeks, I., Gillett, R., Galbally, I.E., Todd, J., Carnovale, F., Joynt, R., Hinwood, A., Berko, H., Brown, S.K., Emissions from Domestic Solid Fuel Burning Appliances, 2002, Technical Report No. 5. [81] A. Bhargava, B.Z. Dlugogorski, E.M. Kennedy, Emission of polyaromatic hydrocarbons, polychlorinated biphenyls and polychlorinated dibenzo-pdioxins and furans from fires of wood chips, Fire Saf. J. 37 (7) (2002) 659–672. [82] D. Wesolek, R. Kozlowski, Toxic gaseous products of thermal decomposition and combustion of natural and synthetic fabrics with and without flame retardant, Fire Mater. 26 (4-5) (2002) 215–224. [83] B. Schartel, T.R. Hull, Development of fire-retarded materials—Interpretation of cone calorimeter data, Fire Mater. 31 (5) (2007) 327–354.