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Measurement of ambient aerosol characteristics for receptor modeling with special emphasis on fine particles
J. AcmsolSci. Vol. 29. Suppl. I, pp. S301-S302, 1998 8 1998 Publishedby ElsevierScienceLtd. All rightsreserved Printedin Great Britain CO21-85OZ98$19.00 + 0.00
Pergamon
Measurement
of ambient aerosol characteristics for receptor modeling with special emphasis on fine particles G. Pohlmann”, W. Koch”, M. The&n*, and R. NieBner*
OFraunhofer Institute for Toxicologyand Aerosol Research,NikobiiFuchs-Str.1.30625 l
Hannover, Gemrany Institute for Hydrochemistry,TechnicalUnivenity of Munich, Ma rchioninistr.17.81377 Miinchen, Germany
KEYWORDS Receptor Modeling, Fine Particles,Ambient Aerosol, Aerosol Measurement, Aerosol Suing
An increasing number of reports on adverse health effects of fine particles raisesthe demand on a more detailed characterization of these ambient particulates and the major contributing sources. A mechanistic toxicological explanation of the epidemiological finding of increased morbidity and mortality associated with an even small increase in the concentration of airborne particles is still in an early stage. The role of chemical composition as well as particle size and morphology is discussedin this context. Even the choice of the correct dose measure, i.e. number or mass concentration to characterize the exposure is still uncertain. To improve the knowledge on the exposure situation we initiated a study to comprehensively characterize the aerosol in the urban atmosphere with respect to size selective chemical composition and various physical aerosol quantities. Special attention is paid to fine and ultra fine particles and to a high time resolution. Emission-ambientconcentration-relationship can be established via dispersion or receptor modeling. Since an emission inventory is not available we use receptor modeling in this study. Two types of receptor models are in use: Chemical mass balance models which require the knowledge of almost all contributing sourcesand their profiles, and models based on factorial analysis of time series of ambient concentration data. In the United States emission factors and emission inventories have long been fundamental tools for air quality management, but in Europe there exists only fragmentary information about type and origin of inhalable particles. Therefore in our case we decided to use factor analysis (FA) for the identification of emissionsources.
Ii--L
PM 10 PM 2.5 Sack-up
-U
-U
-.U
4
flowmeter
v
In order to be consistent with today’s standard 15 mV7 definitions for inhalable particles we sample :igure 1: lmpactor setup used for organic and inorparticles with aerodynamic diameters up to 10 ganic analysis pm as can be seen in Figure 1. For chemical analysisthis PM10 fraction is further subdivided into two fractions: bigger and smaller than 2.5 pm. Factor analysisrequires time resolution as high as possible.Taking into account the expected loading of the sampling device and the detection limit of the chemical analysis6 hours were chosen as sampling time. Due to analysisrequirements two impactors were operated in parallel: one equipped with cellulose acetate for inorganic analysis and one equipped with quartz fibre filters for organic analysis. As inorganic part of the analysisanions are determined with ion-chromatography (conductivitydetection) and selected s301
$302
Abstracts of the 5th International Aerosol Conference 1998
elements with total reflection x-ray fluorescence spectrometry. The organic part consists of the measurement of PAHs with HPLC (fluorescence detection) and of elemental carbon and organic carbon with coulometry. Every 6 hours the airflow is switched over to a new pair of impactors. All 8 impactors are reloaded with new substrates every day. Filters are pre- and post-weighed. AIthou~lh a higher time resolution would be desirable low filter loading and instrumentation expenses limit the number of PM 10 -Inlet 7 r---7 r-impactor samples per day. aethaloI Simultaneously an on-line monitoring meter system measures various physical paI CNC rameters of the aerosol. A scheme of this setup is shown in Figure 2. The air I ~CO/NO,- I epiphaniois sucked in through a PMIO inlet with analyser meter a flow rate of approximately 15 m~/h. PAHB-dustSeveral probes for the different analyzI sensor meter ers are placed down-stream of the 10 I i~m impaction stage. The remaining I I aerosol is sampled on a back-up filter. This filter is changed every day and pretube fu~ace and post-weighed. This allows to compare the impactor data with the results of the on-line monitoring.
_/ a k-up
The B-dust-meter monitors the time dependent variation of the aerosol mass concentration, the epiphaniometer the time dependent variation of the Fuchs surface of the aerosol and the CNC the variation of total number concentration. 15 m3/h An aethalometer is used for comparison with elemental carbon analysis. Addi- I Figure 2: Schematic of the on-line monitoring system tional on-line information obtained from the PAH-sensor can be compared with selected PAH's found on the impactor samples. The CO and NOx analyzers are used for the detection of gases correlating with combustion sources. Since small, insoluble particles are regarded as exceptionally harmful it was our attempt to discriminate on-line between soluble and insoluble particles. This is accomplished using two differential mobility analyzers (DMA's) in parallel. A furnace with a quartz tube is placed at the entrance of one of the two DMA's heating the incoming air to about 400°C. This leads to the evaporation of ammonium nitrate and sulfate. The difference in number concentration at the outlet of the two different DMA's is regarded as the ratio of soluble and insoluble particles in the respective size class. Using this equipment a first measuring campaign will be carried out at 3 places characterized by different air quality levels in the city of Hannover/Germany. Results of these measurements will be presented.
Pergamon
Measurement
of ambient aerosol characteristics for receptor modeling with special emphasis on fine particles G. Pohlmann”, W. Koch”, M. The&n*, and R. NieBner*
OFraunhofer Institute for Toxicologyand Aerosol Research,NikobiiFuchs-Str.1.30625 l
Hannover, Gemrany Institute for Hydrochemistry,TechnicalUnivenity of Munich, Ma rchioninistr.17.81377 Miinchen, Germany
KEYWORDS Receptor Modeling, Fine Particles,Ambient Aerosol, Aerosol Measurement, Aerosol Suing
An increasing number of reports on adverse health effects of fine particles raisesthe demand on a more detailed characterization of these ambient particulates and the major contributing sources. A mechanistic toxicological explanation of the epidemiological finding of increased morbidity and mortality associated with an even small increase in the concentration of airborne particles is still in an early stage. The role of chemical composition as well as particle size and morphology is discussedin this context. Even the choice of the correct dose measure, i.e. number or mass concentration to characterize the exposure is still uncertain. To improve the knowledge on the exposure situation we initiated a study to comprehensively characterize the aerosol in the urban atmosphere with respect to size selective chemical composition and various physical aerosol quantities. Special attention is paid to fine and ultra fine particles and to a high time resolution. Emission-ambientconcentration-relationship can be established via dispersion or receptor modeling. Since an emission inventory is not available we use receptor modeling in this study. Two types of receptor models are in use: Chemical mass balance models which require the knowledge of almost all contributing sourcesand their profiles, and models based on factorial analysis of time series of ambient concentration data. In the United States emission factors and emission inventories have long been fundamental tools for air quality management, but in Europe there exists only fragmentary information about type and origin of inhalable particles. Therefore in our case we decided to use factor analysis (FA) for the identification of emissionsources.
Ii--L
PM 10 PM 2.5 Sack-up
-U
-U
-.U
4
flowmeter
v
In order to be consistent with today’s standard 15 mV7 definitions for inhalable particles we sample :igure 1: lmpactor setup used for organic and inorparticles with aerodynamic diameters up to 10 ganic analysis pm as can be seen in Figure 1. For chemical analysisthis PM10 fraction is further subdivided into two fractions: bigger and smaller than 2.5 pm. Factor analysisrequires time resolution as high as possible.Taking into account the expected loading of the sampling device and the detection limit of the chemical analysis6 hours were chosen as sampling time. Due to analysisrequirements two impactors were operated in parallel: one equipped with cellulose acetate for inorganic analysis and one equipped with quartz fibre filters for organic analysis. As inorganic part of the analysisanions are determined with ion-chromatography (conductivitydetection) and selected s301
$302
Abstracts of the 5th International Aerosol Conference 1998
elements with total reflection x-ray fluorescence spectrometry. The organic part consists of the measurement of PAHs with HPLC (fluorescence detection) and of elemental carbon and organic carbon with coulometry. Every 6 hours the airflow is switched over to a new pair of impactors. All 8 impactors are reloaded with new substrates every day. Filters are pre- and post-weighed. AIthou~lh a higher time resolution would be desirable low filter loading and instrumentation expenses limit the number of PM 10 -Inlet 7 r---7 r-impactor samples per day. aethaloI Simultaneously an on-line monitoring meter system measures various physical paI CNC rameters of the aerosol. A scheme of this setup is shown in Figure 2. The air I ~CO/NO,- I epiphaniois sucked in through a PMIO inlet with analyser meter a flow rate of approximately 15 m~/h. PAHB-dustSeveral probes for the different analyzI sensor meter ers are placed down-stream of the 10 I i~m impaction stage. The remaining I I aerosol is sampled on a back-up filter. This filter is changed every day and pretube fu~ace and post-weighed. This allows to compare the impactor data with the results of the on-line monitoring.
_/ a k-up
The B-dust-meter monitors the time dependent variation of the aerosol mass concentration, the epiphaniometer the time dependent variation of the Fuchs surface of the aerosol and the CNC the variation of total number concentration. 15 m3/h An aethalometer is used for comparison with elemental carbon analysis. Addi- I Figure 2: Schematic of the on-line monitoring system tional on-line information obtained from the PAH-sensor can be compared with selected PAH's found on the impactor samples. The CO and NOx analyzers are used for the detection of gases correlating with combustion sources. Since small, insoluble particles are regarded as exceptionally harmful it was our attempt to discriminate on-line between soluble and insoluble particles. This is accomplished using two differential mobility analyzers (DMA's) in parallel. A furnace with a quartz tube is placed at the entrance of one of the two DMA's heating the incoming air to about 400°C. This leads to the evaporation of ammonium nitrate and sulfate. The difference in number concentration at the outlet of the two different DMA's is regarded as the ratio of soluble and insoluble particles in the respective size class. Using this equipment a first measuring campaign will be carried out at 3 places characterized by different air quality levels in the city of Hannover/Germany. Results of these measurements will be presented.