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Indoor and outdoor air pollution in Tokyo and Beijing supercities
Pergamon
Atmospheric
Environment Vol. 30, No. 5, pp. 695-702, 1996 Copyright 0 1996 Elsevier Science Ltd Pnnted in Great Britain. All rights reserved 1352-2310/96 $15.00 + 0.00
1352-2310(94)00216-9
INDOOR AND OUTDOOR AIR POLLUTION AND BEIJING SUPERCITIES M. ANDO, K. KATAGIRI, K. TAMURA, and M. MATSUMOTO
IN TOKYO
S. YAMAMOTO,
National Institute for Environmental Studies, Tsukuba, Ibaraki 305, Japan
and Y. F. LI, S. R. CAO, R. D. JI and C. K. LIANG Institute of Environmental Health and Engineering, Beijing 100050, China (First received 15 October 1992 and in final form 1 July 1994)
Abstract-Since automobile exhaust and coal combustion exhaust are the major sources of suspended particulate matter (SPM) and airborne pollutants in many countries, SPM and polycyclic aromatic hydrocarbons (PAH) in indoor and outdoor air were measured using the new portable samplers (AND sampler) around a main road and in residential areas of Tokyo and Beijing. The results showed that the relationship between the airborne particle concentration in indoor air and outdoor air varied with the aerodynamic diameter of the particles. The concentration of SPM in indoor air increased in proportion to that in outdoor air. The concentration of PAH and mutagenic activity in air also varied with the aerodynamic diameter of the particles. Fine particles exhibiting an aerodynamic diameter of =L2 pm contained high concentrations of PAH and mutagens. The concentrations of benzo(k)fluoranthene, benzo(a)pyrene [B(a)P], and benzo(ghi)perylene in indoor air increased in proportion to those in outdoor air around a main road and in residential areas of Tokyo and Beijing. The results showed that fine particles seemed to be more harmful to humans than coarse ones. In the winter season, the SPM and sulfur dioxide concentration in indoor and outdoor air in residential areas of Beijing was approximately 4 to 5 times higher than that around a main road of Tokyo. The B(a)P concentration in outdoor air in residential areas of Beijing was approximately 15 times higher than that in residential areas around a main road of Tokyo. Since the concentration of SPM and PAH in indoor air increases in proportion to that in outdoor air, it is reasonable to make efforts to reduce SPM and PAH generated by automobile exhaust in Tokyo and coal
combustion exhaust in Beijing. Key word index: Air pollution, particulate, benzo(a)pyrene, mutagen, indoor pollution.
INTRODUCTION
There are many sources of airborne particles and gaseous pollutants, such as automobile exhaust, industries, and many combustion processes (Peterson and Junge, 1971; Gartrell and Friedlander, 1975; Heicklein, 1976; Spengler et al., 1990; UNEP/WHO, 1993). Among them, automobile exhaust is one of the major sources of airborne particles and gaseous pollutants in many countries, including Japan (Schuetzle, 1980; Ishinishi et al., 1986; Ando and Tamura, 1988; Ando et al,, 1991). On the other hand, combustion processes of coal are also one of the major sources of air pollutants in many countries, including China (Cao et al., 1988). Automobile exhaust and combustion exhaust contains a huge number of airborne particles which
consist of thousands of chemical components (Levsen et al., 1987; Matsushita, 1987; Naikwadi et al., 1987). These chemicals have a potential toxicological significance, and some of them produce mutagenic and carcinogenic effects (Goldsmith, 1980, Schuetzle et al., 1981; Ross et al., 1987). Therefore, it is necessary that quantative assessments of human health risks associated with exposure to these chemicals, such as polycyclic aromatic hydrocarbons (PAH) and mutagens, has to be carried out (Yocom et al., 1977; Repace and Lowrey, 1980; Yocom, 1982; Stock et al., 1985; Sinclair and Psota-Kelty, 1988; Liang et al., 1988). Since high concentrations of airborne particles, especially suspended particulate matter (SPM) that measures less than 10 pm in aerodynamic diameter have been detected in outdoor air in the Tokyo and Beijing supercities, the potential exposure of the population to
695
696
M. AND0 et al.
these substances has been a matter of great concern in Japan and China. In the present study, changes in the concentrations of SPM, PAH, and gaseous pollutants in indoor and outdoor air were measured in residential areas around a main road of Tokyo and in residential areas of Beijing.
MATERIALS
AND METHODS
Study sites
The areas studied were located around a main road, in residential areas in the Tokyo metropolitan area, and in residential areas of the Beijingmetropolitan area. In 1986, the mean daily traffic on the main road and at the main crossroad studied were about 88,000 and 230,000 cars, respectively. Measurements of SPM and gaseous pollutants were carried out in the homes of non-smoking participants in Tokyo from 1985 to 1991. In Beijing, measurements of air pollutants were also carried out in the homes of non-smoking participants whose fuel energy sources were coal, coal gas, and natural gas in 1991.
Sampling methods
Analytical methods
To study changes in concentrations of SPM and PAH in indoor/outdoor air and personal exposure, the new portable sampler (AND sampler; Shibata Sci. Tech. Ltd., Tokyo) was designed as shown in Fig. 1. The sampler could separately collect particles exhibiting aerodynamic diameters of > 10 pm, 2-10 pm, and <2pm. The sampler was positioned in a sound-proof box to keep the pumping noise at < 40dB at a distance of 1m. Concentrations of SPM and PAH in indoor and outdoor air were measured using the AND samplers. Low-volume Andersen cascade impactors (Dylec Co., Tokyo), Marple personal cascade impactors (Sierra Inst. Inc., Carmel Valley), and portable desital dust monitors (PCD-1; Shibata Sci. Tech. Ltd.) were also used. For the measurement of sulfur dioxide (SO,) and nitrogen dioxide (NO,), the personal passive samplers were used.
The filter (19 and 35 mm T6OA20; Pallflex Prod. Corp., Putnam) was washed completely with methylene chloride to decrease background contamination and then dried in a room for 24 h at 20°C and 50% relative humidity before use. At the end of each measurement, the filter of the sampler was removed, dried for 24 h at 20°C and 50% relative humidity, weighed, and analyzed as follows. The PAH on the filter was extracted with 20 ml methylene chloride in the ultrasonic generator according to the method of Schuetzle et al. (1981) and Ando et al. (1991).The extracted solvent was filtered using a 0.5 pm filter (Millex-SR; Millipore Co., Bedford) and concentrated under nitrogen flow. The extracted PAH was dissolved in acetonitrile and then assayed using a HPLC system (Shimadzu Co., Kyoto equipped with a supersensitive fluorometric detector (RF-550;
(b) Fig. 1. (a) Schematic diagram of AND sampler designed to collect airborne particles. Filter 1: an impactor cut point measuring 10 pm (100% efficiency); Filter 2: an impactor cut point measuring 2 pm (100% efficiency); Filter 3: a filter collecting particles measuring < 2 pm. (b) A view of AND sampler as used to measure airborne particles in outdoor/indoor air and personal exposure.
Indoor and outdoor air pollution in Tokyo and Beijing Shimadzu Co., Kyoto; Ex 366 nm; Em 403 nm) using Zorbax ODS C-18 (5 pm; Du Pont, Wilmington). Acetonitrile/water (80:20 v/v) was used as the mobile phase at a flow rate 1.0 mlmin-’ (Furuta and Otsuki, 1983). NIST 1647 (NIST, Washington, DC) was used as the standard for PAH. Methylene chloride was sufficiently effective in extracting PAH, such as benzo&)fluoranthene EWc)Fl, benzo(a)pyrene [B(a)P], and benz&&)perylene [IyB‘h@] from the T60A20 filter. Sulfur dioxide and nitrogen dioxide were analyzed using ion chromatography -(CDD-6A; Shimadzu Co., Kyoto) and UV-Spectrophotometer, respectively. The mutagenicity of airborne particles was evaluated by the microsuspension procedure (Kado et al., 1986) Using Salmonella typhimurium strain TA98 (Ames et al., 1975).Since the mutagenic activity of airborne particles in Tokyo was higher in the absence of rat liver S9 than that in the presence., the mutation assay was performed without metabolic activation. The mutagens were extracted by sonication using methylene chloride. After filtering the extracted solution, the filtrate was reduced to a few ml by a rotary evaporator and dried under nitrogen flow at room temperature. The residue was dissolved in dimethyl sulfoxide prior to mutation assay (Matsumoto et al., 1993).
697
120n^ $ C 0
80-
.E h
40-
00 6
4
10
8
I1 calendar
2 month
Fig. 2. The monthly mean concentration change of SPM at monitoring stations around main roads of the Tokyo metropolitan area ((0) 1986; (0) 1991).
RESULTS
Figure 2 shows the variation in the monthly mean of SPM in outdoor air at the monitoring stations around main roads of the Tokyo
concentration
metropolitan area in 1986 and in 1991. The SPM concentration around main roads in 1991 was slightly higher than that in 1986. The maximal mean monthly concentration of SPM was observed in December. Figure 3 shows the seasonal variation of the SPM concentration in outdoor air in a residential area and in an industrial area of Beijing. The maximum concentration of SPM was also observed in the winter season. Figure 4 displays the typical instantaneous variation in the concentration of SPM in outdoor air in Tokyo and Beijing in the winter season. The SPM concentrations in a residential area of Beijing varied remarkably and extremely high concentrations were measured during nighttime. (Fig. 4a). Figure 4b shows the instantaneous variation in the SPM concentration around a main road and in a residential area of Tokyo. High concentrations of SPM were measured around a main road, whereas those determined in a residential area decreased significantly. The concentration of SPM also varied remarkably and high concentrations were measured during nighttime. The size distribution of airborne particles in outdoor air in Tokyo and Beijing in the winter season is shown in Fig. 5. A high SPM concentration was observed in particles exhibiting aerodynamic diameters of 3.3-7.0, 0.65-1.1, and < 0.43 pm. The relationship between the aerodynamic diameter of the particles and their B(a)P concentration in outdoor air in the Tokyo and Beijing supercities in the winter season is shown in Fig. 6. The concentration of B(u)P in outdoor air was high in particles whose aerodynamic diameters measured < 2 pm.
0)
I
‘85
APT
I
‘3s JUl
t
‘85 Ott
1
1
‘86 Jan
Fig. 3. The seasonal variation of the SPM concentration in Beijing ((Cl) residential area; (6) indus-
trial area).
Figure 7 demonstrates the relationship between the aerodynamic diameter of the particles and their mutagenic activity in outdoor air around a main road and in residential areas of Tokyo. The mutagenic activity in outdoor air was high in particles whose aerodynamic diameters measured < 2 pm. Figure 8 shows the relationship between the B(a)P concentration in outdoor air and that in indoor air in Tokyo. The B(a)P concentration in indoor air increased in proportion to that in outdoor air (Fig. 8a). There were significant correlations between the concentration of B(k)F, B(a)P, and B(ghi)P in air. The personal exposure to B(a)P also increased in proportion to that in indoor air (Fig. 8b). Figure 9 shows the relationship between the B(a)P concentration and mutagenic activity in outdoor air in Tokyo. The mutagenic activity in air increased in proportion to the concentration of PAH, such as B(a)P, B(k)F, and B(ghi)P in air. Figure 10 shows the relationship between the B(u)P concentration in indoor air and that in outdoor air in residential areas of Beijing. The B(u)P concentration in indoor air also increased in proportion to that in outdoor air. The variation in the monthly mean concentration of SO, and NO, in outdoor air at the monitoring
M. AND0 et al.
698
4-a
1000 -
800 2
4-b A-
E
800
2 3
600
z 3
400
8
16
12
20
4
24
8
o’clock
Fig. 4. The instantaneous variation of the SPM concentration in the winter season. (a) In a residential area of Beijing. (b) Around a main road (MR) and in a residential area (RA) of Tokyo. stations around main roads of the Tokyo metropolitan area is shown in Fig. 11. The maximal mean monthly concentration of SO, and NO, was observed in December. In Beijing, coal, coal gas, and natural gas are used as fuel energy source. The air pollutants such as SOz, SPM, and B(a)P were significantly different among the three kinds of fuel combustion exhaust. As shown in Fig. 12, the highest concentration of SO,, SPM, and B(a)P was observed in indoor air of coal burning families.
DISCUSSION
0.5 1.0 Particle
2.0
5.0
10
size ( pm )
Fig. 5. The size distribution of airborne particles around a main road (A) and in a residential area (0) of Tokyo and in a residential area (0) of Beijing.
Automobile exhaust is one of the major sources of SPM, PAH, and gaseous pollutants in many countries, including Japan (Schuetzle, 1980; Ishinishi et al., 1986; Spengler et al., 1990; Lioy et al., 1990; Ando et al., 1991), and combustion processes of coal are also one of their major sources in many countries, including China (Cao et al., 1988). These air pollutants have a potential toxicological significance, and some of
Indoor and outdoor air pollution in Tokyo and Beijing
699
5-
4 a-
“6 ;*
3 -
i
2-
6.5 .e 7% 5 m
4-
l-
0'
O
(a)
2-
1
I
’
B(a)P
I
2
in outdoor
I
3
air ( ng/m3)
I
4
5
4 0-
r
Particle size ( pm ) Fig. 6. The relationship between the aerodynamic diameter of the particles and their B(a)P concentration around a main road (A) and in a residential area (0) of Tokyo and in a residential area (0) of Beijing.
4m
(b)
300
2
1
’
3
4
B(a)P in indoor air ( ng/mz)
Fig. 8. The relationship between B(a)P concentration in outdoor/indoor air and persona) exposure in Tokyo. (a) B(a)P in outdoor air (x) and B(a)P in indoor air (y) Cy=O.535x+O.777; n=41; r=0.73@ P < 0.01) and (b) B(a)P in indoor air(x) and personal exposure to B(a)P (y) (y = 0.742x + 0.201; n = 39; r = 0.632; P < 0.01).
2oi)
100
4cK
0 0.5
1.0
2.0
Particle size
5.0
IO
302
( pm ) 200
Fig. 7. The relationship between the aerodynamic diameter of the particles and their mutagenic activity around a main road ((A) winter; (A) summer) and in a residential area (( 0) winter; (0) summer)of Tokyo.
them have mutagenic and carcinogenic effects (Goldsmith, 1980; Schuetzle et al., 1981; Liang et al., 1988; Matsushita et al., 1992). To study the quantitative assessment of human health risks associated with exposure to SPM, PAH,
100
oc 0.0
B(a)P
0.5
1.0
concentration
2.0
1.5
in sir
( nglm3
)
Fig. 9. The relationship between the B(a)P concentration (x) and mutagenic activity (y) in airborne particles in Tokyo (y=184x+9;
n=36; r=0.896; PcO.01).
M. AND0 et al.
700
m
01
0
20 B(a)P
40 concentration
80
60 in outdoor
air
(rip/m 3,
Fig. 10. The relationship between the B(a)P concentration in outdoor air (x) and that in indoor air (y) in residential areas
of Beijing (y=O.532x+2.94; n=36; r=0.755; PiO.01).
n”
s
3
3cQi
T
T
T
(b)
calendar
month
Fig. 11. The monthly mean concentration change of SO, and NO2 at monitoring stations around main roads of the Tokyo metropolitan area ((0) SO,; (0) NO,).
and mutagens, the new portable sampler (AND sampler) was used. The sampler was capable of collecting particles exhibiting aerodynamic diameters of > 10 pm, between 2 and 10 pm, and < 2 pm. The SPM concentration using the sampler coincided closely with results obtained using the Marple personal cascade impactor. The linear equation was:
(cl
Cd
cods=
Natural @IS
Fig. 12. (a) The concentrations of SO, in indoor (=)/outdoor (0) air and personal exposure to SO2 (@). The concentration of(b) SPM and (c) B(a)P in indoor air ( ?? ) and outdoor air (c1) in coal burning, coal gas burning, and natural gas burning families.
Y = 0.976x + 3.88 @g m- ‘) (n = 21, r = 0.95, P < O.Ol), where x and y represent the SPM concentration measured using the AND sampler and the Marple personal cascade impactor, respectively. In Tokyo and Beijing, a high SPM concentration was observed in airborne particles exhibiting aerodynamic diameters of 3.3-7.0 pm, 0.65-1.1 pm, andc0.43 pm. The concentration of PAH, such as B(k)F, B(a)P, and B(ghi)P in outdoor air was high in particles whose aerodynamic diameters measured <2 pm. The mutagenic activity in outdoor air was also high in particles whose aerodynamic diameters measured c 2 pm.
Since the respiratory absorption of airborne particles is markedly different according to their aerodynamic diameter (Task group on lung dynamics, 1966; McClellan and Henderson, 1989), it is necessary that fine particles exhibiting an aerodynamic diameter of <2 pm and coarse particles whose diameter ranges between 2 and 10 pm should be measured separately. There were significant correlations between the concentration of B(k)F, B(a)P, and B(ghi)P in air. The concentration of PAH in indoor air increased in proportion to that in outdoor air in both of the residential areas of Tokyo and Beijing. The personal
Indoor and outdoor air pollution in Tokyo and Beijing
701
to that
hydrocarbons in indoor and outdoor air. Int. Archs enuir.
There were significant correlations between the mutagenic activity and PAH concentration in air-
Cao S. R., Chen Y. Y., Ren G. Y. and Li S. M. (1988) Analysis of organic and inorganic components of inhalable particles in the atmosphere. Biomed. envir. Sci. 1, 130-137. Furuta N. and Otsuki A. (1983) Time-resolved fluorometry in detection of ultratrace polycyclic aromatic hydrocarbons in lake waters by liquid chromatography. Analyt.
exposure to PAH also increased in proportion in indoor
borne
Hlth 63, 297-301.
air.
particles.
Since mutagens
and PAH
conoen-
trated more in airborne particles exhibiting an aerodynamic diameter of < 2 pm, fine particles seem to be more harmful
to humans
than coarse ones.
In the winter season, the mean concentration of SPM and B(a)P in outdoor air in residential areas of Tokyowas57.61t21.6/*gm-3and2.25+0.81 ngmm3, respectively. In this study, the SPM concentration in outdoor air in residential areas of Beijing in the winter season was 217.0 f 94.3 /*gmW3 and approximately four times higher than that in residential areas around a main road of Tokyo. The B(a)P concentration in outdoor air in residential areas of Beijing was 33.7 + 17.9 ngm-3 and approximately 15 times higher than that in residential areas of Tokyo. In December in 1991, the monthly mean concentration of SO2 and NO, at the monitoring stations around main roads of the Tokyo metropolitan area was 46.8k8.8 pgrnd3 and 111 f4.2 ngm-3, respectively. In Beijing, coal, coal gas, and natural gas are used as fuel energy source. The air pollutants such as SOz, SPM, and B(a)P were significantly different among the three kinds of fuel combustion exhaust. The highest concentration of SOz, SPM, and B(a)P was observed in indoor air of coal burning families. In this study, the concentration of SO, in outdoor air in residential areas of Beijing in December in 1991 was 232.7 f 73.7 pgrnm3 and approximately five times higher than that around main roads of Tokyo. On the other hand, the concentration of NO1 in outdoor air in residential areas of Beijing was 68.2) 11.2pgme3 and approximately 60% of that around main roads of Tokyo. Since the concentration of SPM, PAH, and mutagens in indoor air increases in proportion to that in outdoor air, it is reasonable to make efforts to reduce SPM, PAH, and mutagens generated by automobile exhaust in Tokyo and coal combustion processes in Beijing. Acknowledgements-This research was supported by the grants from Japan Environment Agency, Japan Science and Technology Agency, and Institute of Environmental Health and Engineering in China. REFERENCES Ames
B. N., McCann J. and Yamazaki E. (1975) Methods for mutagen with the carcinogen and detecting Salmone~la/mammalian microsome mutagenicity test. Mutation Res. 31, 347-364.
Ando M. and Tamura K. (1988) Study on the suspended particulate matter and polycyclic aromatic hydrocarbons in indoor and outdoor air environment along the main road. J. Jap. Sot. Air Pollut. 23, 342-348. Ando M., Tamura K. and Katagiri K. (1991) Study on suspended particulate matter and polycyclic aromatic
Chem. SS, 2407-2413.
Gartrell G. and Friedlander S. K. (1975) Relating particulate pollution to source: the 1972 California aerosol characterization study. Atmospheric Environment 9, 279-289. Goldsmith J. R. (1980) The urban factor in cancer: smokina. . industrial exposures, and air pollution as possible explanations. J. envir. path. Toxicol. 3, 205-212. Heicklein J. (1976) Atmospheric Chemistry. Academic Press, New York. Ishinishi N., Koizumi A., McClellan R. 0. and Stober W. (1986) Carcinogenic and Mutagenic Efects ofDiesel Engine Exhaust. Elsevier, Amsterdam. Kado N. Y., Guirsius G. N., Flessel C. P., Chan R. C., Chang K. and Wesolowski J. (1986) Mutagenicity of fine (< 2.5 pm) airborne particles: diurnal variation in community air determined by Salmonella micro preincubation (microsuspension) procedure. Envir. Mutag. 8, 53-66. Levsen K., Schilhabel J. and Puttins U. (1987) Progress in the analysis ofdiesel soot particles. J. Aerosol Sci. 18,845-848. Liang C. K., Quan N. Y., Cao S. R., He X. 2. and Ma F. (1988) Natural inhalation exposure to coal smoke and wood smoke induces lung cancer in mice and rats. Biomed. enoir. Sci. 1, 42-50. Lioy P. J., Waldman J. M., Buckley T., Butler J. and Pietarinen C. (1990) The personal indoor and outdoor concentrations of PM-10 measured in an industrial community during the winter. Atmospheric Environment 248, -I
57-66.
Matsumoto M., Ando M. and Tamura K. (1993) Differences of mutagenic activity of airborne particulates by particle size: assay by the Salmonella microsuspension procedure. Jap. J. Toxicol. Envir. Hlth 39, 139-147.
Matsushita H. (1987) Analytical methods for monitoring polycyclic aromatic hydrocarbons in the environment. In: Polycyclic Hydrocarbons and Cancer (edited by Gelboin, H. V. and Tso P. 0. P.), pp. 71-81. Academic Press, New York. Matsushita H., Endo O., Goto S., Shimizu H., Matsumoto H., Tamakawa K., Endo T., Sakabe Y., Tokiwa H. and Ando M. (1992) Collaborative study using the preincubation Salmonella typhimurium mutation assay for airborne particulate matter in Japan. A trial to minimize interiaboratory variation. Mu&t. Res. 271, 1-12. McClellan R. 0. and Henderson R. F. (1989) ConceDts in * Inhalation Toxicology. Hemisphere, New York. Naikwadi K. P., Charbonneau G. M. and Karasek F. W. (1987) Separation and identification of organic compounds in air particulate extracts by high performance liquid chromatography and gas chromatography-mass spectrometry. J. Chromatogr. 398, 227-237. Peterson J. T. and Junge C. E. (1971) Sources of particulate matter in the atmosphere. In Man’s impact on the Climate (edited by Matthews. W. H. et al.), pp. 310-320. MIT Press, Boston. Repace J. L. and Lowrey A. H. (1980) Indoor air pollution, tobacco smoke, and public health. Science 208, 464-472. Ross D. S., Hum G. P. and Schmitt R. J. (1987) Diesel exhaust and pyrene nitration. Envir. Sci. Technol. 21, 1130-l 131. &hue&e D. (1980) Air pollutants. In Biochemistry Applications of Mass Spectrometry (edited by Wager G. R. and Dermer 0. C.), pp. 970-1001. Wiley-Interscience, New York. Schuetzle D., Lee F. S. and Prater T. J. (1981) The identification of polynuclear aromatic hydrocarbon (PAH) derivat-
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ives in mutagenic fractions of diesel particulate extracts. Int. J. envir. analyt. Chem. 9, 93-144. Sinclair J. D. and Psota-Kelty L. A. (1988) Indoor/outdoor ratios and indoor surface accumulations of ionic substances at Newark, New Jersey. Atmospheric Environment 22,461-469. Spengler J. D., Brauer M. and Koutrakis P. (1990) Acid air and health. Envir. Sci. Technol. 24, 946-956. Stock T. H., Kotchmar D. J., Contant C. F., Buffler P. A., Holguin A. H., Gehan B. M. and Noel L. M. (1985) The estimation of personal exposures to air pollutants for a community-based study of health effects in ashmatics-
design
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Task group on lung dynamics (1966) Deposition and retention models for internal dosimetry of the human respiratory tract. Hlth Phys 12, 173-207. UNEPWHO (1993) Urban Air Pollution in Megacities of The World. World Health Organization, Geneva. Yocom J. E., Cote W. A. and Benson F. B. (1977) Effects on indoor air quality. In Air Pollution (edited by Stern A. C.), pp. 117-157. Academic Press, New York. Yocom J. E. (1982) Indoor-outdoor air quality relationships, A critical review. JAPCA 32, W-519.
Atmospheric
Environment Vol. 30, No. 5, pp. 695-702, 1996 Copyright 0 1996 Elsevier Science Ltd Pnnted in Great Britain. All rights reserved 1352-2310/96 $15.00 + 0.00
1352-2310(94)00216-9
INDOOR AND OUTDOOR AIR POLLUTION AND BEIJING SUPERCITIES M. ANDO, K. KATAGIRI, K. TAMURA, and M. MATSUMOTO
IN TOKYO
S. YAMAMOTO,
National Institute for Environmental Studies, Tsukuba, Ibaraki 305, Japan
and Y. F. LI, S. R. CAO, R. D. JI and C. K. LIANG Institute of Environmental Health and Engineering, Beijing 100050, China (First received 15 October 1992 and in final form 1 July 1994)
Abstract-Since automobile exhaust and coal combustion exhaust are the major sources of suspended particulate matter (SPM) and airborne pollutants in many countries, SPM and polycyclic aromatic hydrocarbons (PAH) in indoor and outdoor air were measured using the new portable samplers (AND sampler) around a main road and in residential areas of Tokyo and Beijing. The results showed that the relationship between the airborne particle concentration in indoor air and outdoor air varied with the aerodynamic diameter of the particles. The concentration of SPM in indoor air increased in proportion to that in outdoor air. The concentration of PAH and mutagenic activity in air also varied with the aerodynamic diameter of the particles. Fine particles exhibiting an aerodynamic diameter of =L2 pm contained high concentrations of PAH and mutagens. The concentrations of benzo(k)fluoranthene, benzo(a)pyrene [B(a)P], and benzo(ghi)perylene in indoor air increased in proportion to those in outdoor air around a main road and in residential areas of Tokyo and Beijing. The results showed that fine particles seemed to be more harmful to humans than coarse ones. In the winter season, the SPM and sulfur dioxide concentration in indoor and outdoor air in residential areas of Beijing was approximately 4 to 5 times higher than that around a main road of Tokyo. The B(a)P concentration in outdoor air in residential areas of Beijing was approximately 15 times higher than that in residential areas around a main road of Tokyo. Since the concentration of SPM and PAH in indoor air increases in proportion to that in outdoor air, it is reasonable to make efforts to reduce SPM and PAH generated by automobile exhaust in Tokyo and coal
combustion exhaust in Beijing. Key word index: Air pollution, particulate, benzo(a)pyrene, mutagen, indoor pollution.
INTRODUCTION
There are many sources of airborne particles and gaseous pollutants, such as automobile exhaust, industries, and many combustion processes (Peterson and Junge, 1971; Gartrell and Friedlander, 1975; Heicklein, 1976; Spengler et al., 1990; UNEP/WHO, 1993). Among them, automobile exhaust is one of the major sources of airborne particles and gaseous pollutants in many countries, including Japan (Schuetzle, 1980; Ishinishi et al., 1986; Ando and Tamura, 1988; Ando et al,, 1991). On the other hand, combustion processes of coal are also one of the major sources of air pollutants in many countries, including China (Cao et al., 1988). Automobile exhaust and combustion exhaust contains a huge number of airborne particles which
consist of thousands of chemical components (Levsen et al., 1987; Matsushita, 1987; Naikwadi et al., 1987). These chemicals have a potential toxicological significance, and some of them produce mutagenic and carcinogenic effects (Goldsmith, 1980, Schuetzle et al., 1981; Ross et al., 1987). Therefore, it is necessary that quantative assessments of human health risks associated with exposure to these chemicals, such as polycyclic aromatic hydrocarbons (PAH) and mutagens, has to be carried out (Yocom et al., 1977; Repace and Lowrey, 1980; Yocom, 1982; Stock et al., 1985; Sinclair and Psota-Kelty, 1988; Liang et al., 1988). Since high concentrations of airborne particles, especially suspended particulate matter (SPM) that measures less than 10 pm in aerodynamic diameter have been detected in outdoor air in the Tokyo and Beijing supercities, the potential exposure of the population to
695
696
M. AND0 et al.
these substances has been a matter of great concern in Japan and China. In the present study, changes in the concentrations of SPM, PAH, and gaseous pollutants in indoor and outdoor air were measured in residential areas around a main road of Tokyo and in residential areas of Beijing.
MATERIALS
AND METHODS
Study sites
The areas studied were located around a main road, in residential areas in the Tokyo metropolitan area, and in residential areas of the Beijingmetropolitan area. In 1986, the mean daily traffic on the main road and at the main crossroad studied were about 88,000 and 230,000 cars, respectively. Measurements of SPM and gaseous pollutants were carried out in the homes of non-smoking participants in Tokyo from 1985 to 1991. In Beijing, measurements of air pollutants were also carried out in the homes of non-smoking participants whose fuel energy sources were coal, coal gas, and natural gas in 1991.
Sampling methods
Analytical methods
To study changes in concentrations of SPM and PAH in indoor/outdoor air and personal exposure, the new portable sampler (AND sampler; Shibata Sci. Tech. Ltd., Tokyo) was designed as shown in Fig. 1. The sampler could separately collect particles exhibiting aerodynamic diameters of > 10 pm, 2-10 pm, and <2pm. The sampler was positioned in a sound-proof box to keep the pumping noise at < 40dB at a distance of 1m. Concentrations of SPM and PAH in indoor and outdoor air were measured using the AND samplers. Low-volume Andersen cascade impactors (Dylec Co., Tokyo), Marple personal cascade impactors (Sierra Inst. Inc., Carmel Valley), and portable desital dust monitors (PCD-1; Shibata Sci. Tech. Ltd.) were also used. For the measurement of sulfur dioxide (SO,) and nitrogen dioxide (NO,), the personal passive samplers were used.
The filter (19 and 35 mm T6OA20; Pallflex Prod. Corp., Putnam) was washed completely with methylene chloride to decrease background contamination and then dried in a room for 24 h at 20°C and 50% relative humidity before use. At the end of each measurement, the filter of the sampler was removed, dried for 24 h at 20°C and 50% relative humidity, weighed, and analyzed as follows. The PAH on the filter was extracted with 20 ml methylene chloride in the ultrasonic generator according to the method of Schuetzle et al. (1981) and Ando et al. (1991).The extracted solvent was filtered using a 0.5 pm filter (Millex-SR; Millipore Co., Bedford) and concentrated under nitrogen flow. The extracted PAH was dissolved in acetonitrile and then assayed using a HPLC system (Shimadzu Co., Kyoto equipped with a supersensitive fluorometric detector (RF-550;
(b) Fig. 1. (a) Schematic diagram of AND sampler designed to collect airborne particles. Filter 1: an impactor cut point measuring 10 pm (100% efficiency); Filter 2: an impactor cut point measuring 2 pm (100% efficiency); Filter 3: a filter collecting particles measuring < 2 pm. (b) A view of AND sampler as used to measure airborne particles in outdoor/indoor air and personal exposure.
Indoor and outdoor air pollution in Tokyo and Beijing Shimadzu Co., Kyoto; Ex 366 nm; Em 403 nm) using Zorbax ODS C-18 (5 pm; Du Pont, Wilmington). Acetonitrile/water (80:20 v/v) was used as the mobile phase at a flow rate 1.0 mlmin-’ (Furuta and Otsuki, 1983). NIST 1647 (NIST, Washington, DC) was used as the standard for PAH. Methylene chloride was sufficiently effective in extracting PAH, such as benzo&)fluoranthene EWc)Fl, benzo(a)pyrene [B(a)P], and benz&&)perylene [IyB‘h@] from the T60A20 filter. Sulfur dioxide and nitrogen dioxide were analyzed using ion chromatography -(CDD-6A; Shimadzu Co., Kyoto) and UV-Spectrophotometer, respectively. The mutagenicity of airborne particles was evaluated by the microsuspension procedure (Kado et al., 1986) Using Salmonella typhimurium strain TA98 (Ames et al., 1975).Since the mutagenic activity of airborne particles in Tokyo was higher in the absence of rat liver S9 than that in the presence., the mutation assay was performed without metabolic activation. The mutagens were extracted by sonication using methylene chloride. After filtering the extracted solution, the filtrate was reduced to a few ml by a rotary evaporator and dried under nitrogen flow at room temperature. The residue was dissolved in dimethyl sulfoxide prior to mutation assay (Matsumoto et al., 1993).
697
120n^ $ C 0
80-
.E h
40-
00 6
4
10
8
I1 calendar
2 month
Fig. 2. The monthly mean concentration change of SPM at monitoring stations around main roads of the Tokyo metropolitan area ((0) 1986; (0) 1991).
RESULTS
Figure 2 shows the variation in the monthly mean of SPM in outdoor air at the monitoring stations around main roads of the Tokyo
concentration
metropolitan area in 1986 and in 1991. The SPM concentration around main roads in 1991 was slightly higher than that in 1986. The maximal mean monthly concentration of SPM was observed in December. Figure 3 shows the seasonal variation of the SPM concentration in outdoor air in a residential area and in an industrial area of Beijing. The maximum concentration of SPM was also observed in the winter season. Figure 4 displays the typical instantaneous variation in the concentration of SPM in outdoor air in Tokyo and Beijing in the winter season. The SPM concentrations in a residential area of Beijing varied remarkably and extremely high concentrations were measured during nighttime. (Fig. 4a). Figure 4b shows the instantaneous variation in the SPM concentration around a main road and in a residential area of Tokyo. High concentrations of SPM were measured around a main road, whereas those determined in a residential area decreased significantly. The concentration of SPM also varied remarkably and high concentrations were measured during nighttime. The size distribution of airborne particles in outdoor air in Tokyo and Beijing in the winter season is shown in Fig. 5. A high SPM concentration was observed in particles exhibiting aerodynamic diameters of 3.3-7.0, 0.65-1.1, and < 0.43 pm. The relationship between the aerodynamic diameter of the particles and their B(a)P concentration in outdoor air in the Tokyo and Beijing supercities in the winter season is shown in Fig. 6. The concentration of B(u)P in outdoor air was high in particles whose aerodynamic diameters measured < 2 pm.
0)
I
‘85
APT
I
‘3s JUl
t
‘85 Ott
1
1
‘86 Jan
Fig. 3. The seasonal variation of the SPM concentration in Beijing ((Cl) residential area; (6) indus-
trial area).
Figure 7 demonstrates the relationship between the aerodynamic diameter of the particles and their mutagenic activity in outdoor air around a main road and in residential areas of Tokyo. The mutagenic activity in outdoor air was high in particles whose aerodynamic diameters measured < 2 pm. Figure 8 shows the relationship between the B(a)P concentration in outdoor air and that in indoor air in Tokyo. The B(a)P concentration in indoor air increased in proportion to that in outdoor air (Fig. 8a). There were significant correlations between the concentration of B(k)F, B(a)P, and B(ghi)P in air. The personal exposure to B(a)P also increased in proportion to that in indoor air (Fig. 8b). Figure 9 shows the relationship between the B(a)P concentration and mutagenic activity in outdoor air in Tokyo. The mutagenic activity in air increased in proportion to the concentration of PAH, such as B(a)P, B(k)F, and B(ghi)P in air. Figure 10 shows the relationship between the B(u)P concentration in indoor air and that in outdoor air in residential areas of Beijing. The B(u)P concentration in indoor air also increased in proportion to that in outdoor air. The variation in the monthly mean concentration of SO, and NO, in outdoor air at the monitoring
M. AND0 et al.
698
4-a
1000 -
800 2
4-b A-
E
800
2 3
600
z 3
400
8
16
12
20
4
24
8
o’clock
Fig. 4. The instantaneous variation of the SPM concentration in the winter season. (a) In a residential area of Beijing. (b) Around a main road (MR) and in a residential area (RA) of Tokyo. stations around main roads of the Tokyo metropolitan area is shown in Fig. 11. The maximal mean monthly concentration of SO, and NO, was observed in December. In Beijing, coal, coal gas, and natural gas are used as fuel energy source. The air pollutants such as SOz, SPM, and B(a)P were significantly different among the three kinds of fuel combustion exhaust. As shown in Fig. 12, the highest concentration of SO,, SPM, and B(a)P was observed in indoor air of coal burning families.
DISCUSSION
0.5 1.0 Particle
2.0
5.0
10
size ( pm )
Fig. 5. The size distribution of airborne particles around a main road (A) and in a residential area (0) of Tokyo and in a residential area (0) of Beijing.
Automobile exhaust is one of the major sources of SPM, PAH, and gaseous pollutants in many countries, including Japan (Schuetzle, 1980; Ishinishi et al., 1986; Spengler et al., 1990; Lioy et al., 1990; Ando et al., 1991), and combustion processes of coal are also one of their major sources in many countries, including China (Cao et al., 1988). These air pollutants have a potential toxicological significance, and some of
Indoor and outdoor air pollution in Tokyo and Beijing
699
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i
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(a)
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I
’
B(a)P
I
2
in outdoor
I
3
air ( ng/m3)
I
4
5
4 0-
r
Particle size ( pm ) Fig. 6. The relationship between the aerodynamic diameter of the particles and their B(a)P concentration around a main road (A) and in a residential area (0) of Tokyo and in a residential area (0) of Beijing.
4m
(b)
300
2
1
’
3
4
B(a)P in indoor air ( ng/mz)
Fig. 8. The relationship between B(a)P concentration in outdoor/indoor air and persona) exposure in Tokyo. (a) B(a)P in outdoor air (x) and B(a)P in indoor air (y) Cy=O.535x+O.777; n=41; r=0.73@ P < 0.01) and (b) B(a)P in indoor air(x) and personal exposure to B(a)P (y) (y = 0.742x + 0.201; n = 39; r = 0.632; P < 0.01).
2oi)
100
4cK
0 0.5
1.0
2.0
Particle size
5.0
IO
302
( pm ) 200
Fig. 7. The relationship between the aerodynamic diameter of the particles and their mutagenic activity around a main road ((A) winter; (A) summer) and in a residential area (( 0) winter; (0) summer)of Tokyo.
them have mutagenic and carcinogenic effects (Goldsmith, 1980; Schuetzle et al., 1981; Liang et al., 1988; Matsushita et al., 1992). To study the quantitative assessment of human health risks associated with exposure to SPM, PAH,
100
oc 0.0
B(a)P
0.5
1.0
concentration
2.0
1.5
in sir
( nglm3
)
Fig. 9. The relationship between the B(a)P concentration (x) and mutagenic activity (y) in airborne particles in Tokyo (y=184x+9;
n=36; r=0.896; PcO.01).
M. AND0 et al.
700
m
01
0
20 B(a)P
40 concentration
80
60 in outdoor
air
(rip/m 3,
Fig. 10. The relationship between the B(a)P concentration in outdoor air (x) and that in indoor air (y) in residential areas
of Beijing (y=O.532x+2.94; n=36; r=0.755; PiO.01).
n”
s
3
3cQi
T
T
T
(b)
calendar
month
Fig. 11. The monthly mean concentration change of SO, and NO2 at monitoring stations around main roads of the Tokyo metropolitan area ((0) SO,; (0) NO,).
and mutagens, the new portable sampler (AND sampler) was used. The sampler was capable of collecting particles exhibiting aerodynamic diameters of > 10 pm, between 2 and 10 pm, and < 2 pm. The SPM concentration using the sampler coincided closely with results obtained using the Marple personal cascade impactor. The linear equation was:
(cl
Cd
cods=
Natural @IS
Fig. 12. (a) The concentrations of SO, in indoor (=)/outdoor (0) air and personal exposure to SO2 (@). The concentration of(b) SPM and (c) B(a)P in indoor air ( ?? ) and outdoor air (c1) in coal burning, coal gas burning, and natural gas burning families.
Y = 0.976x + 3.88 @g m- ‘) (n = 21, r = 0.95, P < O.Ol), where x and y represent the SPM concentration measured using the AND sampler and the Marple personal cascade impactor, respectively. In Tokyo and Beijing, a high SPM concentration was observed in airborne particles exhibiting aerodynamic diameters of 3.3-7.0 pm, 0.65-1.1 pm, andc0.43 pm. The concentration of PAH, such as B(k)F, B(a)P, and B(ghi)P in outdoor air was high in particles whose aerodynamic diameters measured <2 pm. The mutagenic activity in outdoor air was also high in particles whose aerodynamic diameters measured c 2 pm.
Since the respiratory absorption of airborne particles is markedly different according to their aerodynamic diameter (Task group on lung dynamics, 1966; McClellan and Henderson, 1989), it is necessary that fine particles exhibiting an aerodynamic diameter of <2 pm and coarse particles whose diameter ranges between 2 and 10 pm should be measured separately. There were significant correlations between the concentration of B(k)F, B(a)P, and B(ghi)P in air. The concentration of PAH in indoor air increased in proportion to that in outdoor air in both of the residential areas of Tokyo and Beijing. The personal
Indoor and outdoor air pollution in Tokyo and Beijing
701
to that
hydrocarbons in indoor and outdoor air. Int. Archs enuir.
There were significant correlations between the mutagenic activity and PAH concentration in air-
Cao S. R., Chen Y. Y., Ren G. Y. and Li S. M. (1988) Analysis of organic and inorganic components of inhalable particles in the atmosphere. Biomed. envir. Sci. 1, 130-137. Furuta N. and Otsuki A. (1983) Time-resolved fluorometry in detection of ultratrace polycyclic aromatic hydrocarbons in lake waters by liquid chromatography. Analyt.
exposure to PAH also increased in proportion in indoor
borne
Hlth 63, 297-301.
air.
particles.
Since mutagens
and PAH
conoen-
trated more in airborne particles exhibiting an aerodynamic diameter of < 2 pm, fine particles seem to be more harmful
to humans
than coarse ones.
In the winter season, the mean concentration of SPM and B(a)P in outdoor air in residential areas of Tokyowas57.61t21.6/*gm-3and2.25+0.81 ngmm3, respectively. In this study, the SPM concentration in outdoor air in residential areas of Beijing in the winter season was 217.0 f 94.3 /*gmW3 and approximately four times higher than that in residential areas around a main road of Tokyo. The B(a)P concentration in outdoor air in residential areas of Beijing was 33.7 + 17.9 ngm-3 and approximately 15 times higher than that in residential areas of Tokyo. In December in 1991, the monthly mean concentration of SO2 and NO, at the monitoring stations around main roads of the Tokyo metropolitan area was 46.8k8.8 pgrnd3 and 111 f4.2 ngm-3, respectively. In Beijing, coal, coal gas, and natural gas are used as fuel energy source. The air pollutants such as SOz, SPM, and B(a)P were significantly different among the three kinds of fuel combustion exhaust. The highest concentration of SOz, SPM, and B(a)P was observed in indoor air of coal burning families. In this study, the concentration of SO, in outdoor air in residential areas of Beijing in December in 1991 was 232.7 f 73.7 pgrnm3 and approximately five times higher than that around main roads of Tokyo. On the other hand, the concentration of NO1 in outdoor air in residential areas of Beijing was 68.2) 11.2pgme3 and approximately 60% of that around main roads of Tokyo. Since the concentration of SPM, PAH, and mutagens in indoor air increases in proportion to that in outdoor air, it is reasonable to make efforts to reduce SPM, PAH, and mutagens generated by automobile exhaust in Tokyo and coal combustion processes in Beijing. Acknowledgements-This research was supported by the grants from Japan Environment Agency, Japan Science and Technology Agency, and Institute of Environmental Health and Engineering in China. REFERENCES Ames
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