On the nature and origins of visibility-reducing aerosols in the los angeles air basin

White, William M.; Roberts, Paul T.

doi:10.1016/0004-6981(77)90042-7

Cited by 225 publications

(116 citation statements)

References 16 publications

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“…It is also worth estimating the amount of organic matter (OM), accounting for heteroatoms in the organic compounds such as oxygen and nitrogen, by applying suitable OM / OC conversion factors. In the case of aerosols measured downwind of biomass burning activities, OM / OC conversion factors of more than 1.4 have been suggested in literature for organic aerosols in urban areas (e.g., White and Roberts, 1977;Turpin and Lim, 2001). When applying a factor of 1.4 to the OC levels detected during the haze period, the content of OM in TSP was found to be extremely high (50 % on average), while it was only around 25 % during clear days.…”

Section: Tsp Mass Balancementioning

confidence: 99%

Assessing the regional impact of indonesian biomass burning emissions based on organic molecular tracers and chemical mass balance modeling

Engling

Betha

et al. 2014

Atmos. Chem. Phys.

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Abstract. Biomass burning activities commonly occur in Southeast Asia (SEA), and are particularly intense in Indonesia during the dry seasons. The effect of biomass smoke emissions on air quality in the city state of Singapore was investigated during a haze episode in October 2006. Substantially increased levels of airborne particulate matter (PM) and associated chemical species were observed during the haze period. Specifically, the enhancement in the concentration of molecular tracers for biomass combustion such as levoglucosan by as much as two orders of magnitude and the diagnostic ratios of individual organic compounds indicated that biomass burning emissions caused a regional smoke haze episode due to their long-range transport by prevailing winds. With the aid of air mass backward trajectories and chemical mass balance modeling, large-scale forest and peat fires in Sumatra and Kalimantan were identified as the sources of the smoke aerosol, exerting a significant impact on air quality in downwind areas, such as Singapore.

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Section: Tsp Mass Balancementioning

confidence: 99%

Assessing the regional impact of indonesian biomass burning emissions based on organic molecular tracers and chemical mass balance modeling

Engling

Betha

et al. 2014

Atmos. Chem. Phys.

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“…Accurate determination of the OM/OC ratio is also needed to achieve closure between gravimetric PM mass and the sum of measured PM species, for air quality management planning, and to link OC measurements with air quality models. A multiplication factor of 1.4 (OM/OC) has typically been used to convert from OC to OM (Grosjean and Friedlander 1975;White and Roberts 1977). Turpin and Lim (2001) argued that as an aerosol ages the enhanced contribution of more oxidized organic species (i.e., formed through photochemistry and oxidation reactions) results in higher OM/OC ratios.…”

Section: Introductionmentioning

confidence: 99%

Organic PM_2.5: Fractionation by Polarity, FTIR Spectroscopy, and OM/OC Ratio for the Pittsburgh Aerosol

Polidori

Turpin

Davidson

et al. 2008

Aerosol Science and Technology

108

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A polarity-based extraction/fractionation method validated with standard compounds was used to characterize organic aerosol samples collected during the Pittsburgh Air Quality Study (PAQS). Organic extracts were separated into 5 polarity classes by sequential elution with hexane, dichloromethane, ethyl acetate, acetone, and methanol. Organic mass (OM) and carbon mass (OC) were measured in samples, their extracts, and their corresponding fractions yielding OM/OC ratios and the contribution of each polarity fraction to total OM. The study average OM/OC ratio for each fraction [(OM/OC) fraction ] varied from 1.37 for the hexane fraction to 2.25 for the methanol fraction. OM/OC ratios for "nonextractable" organics ((OM/OC) N-E ) were also predicted; the study average (OM/OC) N -E was 2.54, consistent with ratios of 2.1-3.2 for water-soluble organic aerosol species. Annual average ratios with and without the contributions of the "non-extractable" material [(OM/OC) total and (OM/OC) extract , respectively] were 2.05 ± 0.18(1σ ) and 1.91 ± 0.24(1σ ), similar to OM/OC of atmospherically relevant oligomers and aged aerosols measured elsewhere. Ratios were somewhat higher during summer/winter than spring/fall, probably because of a greater contribution of oxidized species such as dicarboxylic acids (summer), levoglucosan (winter and/or summer), and humic-like-substances (HULIS; winter and/or summer). We hypothesize that the OM/OC of atmospheric aerosols approaches a value of 1.9-2.1 as it ages and oligomerizes in the atmosphere. The annual-average contributions of each fraction to Received 23 September 2007; accepted 1 February 2008. We gratefully acknowledge the hospitality and assistance of our Carnegie Mellon University (CMU) hosts. We appreciated the encouragement of PAQS' neighbor, Mr. Fred Rogers, and wish to thank the CMU students, staff, and faculty for their continued assistance in and out of the field. This work was supported in part by the US Department of Energy, US Environmental Protection Agency, the Electric Power Research Institute (EPRI), and the NJ Agricultural Experiment Station. This research has not been subjected to Agency review and therefore does not necessarily reflect the views of DOE or EPA; no official endorsement should be inferred.Address correspondence to Barbara J. Turpin, Department of Environmental Sciences, Rutgers University, 14 College Farm Rd., New Brunswick, NJ 08901, USA. E-mail: turpin@envsci.rutgers.edu the total collected OM mass were, 16.8, 14.0, 11.7, 11.5, 19.3, and 26.7% for the hexane-, dichloromethane-, ethyl acetate-, acetone-, methanol-, and "non-extractable" fractions, respectively. Thus non-polar and very polar species dominated the OM mass throughout the year. Fourier transformed infrared (FTIR) spectroscopy was used to further characterize the composition of extracts and fractions. This method can be used to fractionate organic PM for toxicological studies as well as organic aerosol characterization.

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“…This is important because ammonium nitrate containing aerosols account for a significant fraction of local and regional visibility problems, particularly in Los Angeles and Denver (White and Roberts, 1977;Cass, 1979;Groblicki et al, 1981 Environmental Protection Agency (1973, 1978 et seq.). PAN was measured by electron capture gas chromatography, and NO and N0 2 were measured by chemiluminescence by researchers at the University of California at Riverside (UCR).…”

Section: Introductionmentioning

confidence: 99%

Acquisition of regional air quality model validation data for nitrate, sulfate, ammonium ion and their precursors

Russell

Cass

1984

Atmospheric Environment (1967)

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An intensive field study was conducted throughout California's South Coast Air Basin to acquire air quality model validation data for use with aerosol nitrate formation models. Aerosol nitrate, sulfate, ammonium, other major ionic aerosol species, nitric acid gas and ammonia were measured concurrently at ten sites for forty-eight consecutive hours during the period August [30][31] 1982. Ozone, NO and NO were measured at all locations, and PAN was measured at Pasadena an~ Riverside, completing a nitrogen balance on the air masses studied.The product of the meas~red nitric acid and ammon~a concentrations ranged from less than 1 ppbv to greater than 300 ppbv during the experiment, providing a wide range of conditions over which comparisons can be drawn between chemical equilibrium calculations and experimental results. The ionic material in the aerosol phase was chemically more complex than is assumed by present theoretical models for the equilibrium between NH 3 , HNOa and the aerosol phase, and included . .f. f N + ++ ++ + d Cl-. dd . . NH+ s1gn1 1cant amounts o a , a , Mg , K an 1n a 1t1on to 4 , so4 and NO)· Results of the experiment showed that aerosol nitrate levels in excess of 20 ~g m-3 accumulated in near-coastal locations in the morning of August 31, followed by subsequent transport across the air basin. Trajectory analysis showed that the afternoon aerosol nitrate peak observed inland at Rubidoux near Riverside was associated with the same air mass that contained the high morning nitrate levels near the coast, indicating that description of both transport and atmospheric chemical reactions is important in understanding regional nitrate dynamics. + Mechanical Engineering Department and Environmental Quality Laboratory * Environmental Engineering Science Department and EnvironmentalQuality Laboratory IntroductionAmmonia and nitric acid vapor react to form ammonium nitrate aerosol. This is important because ammonium nitrate containing aerosols account for a significant fraction of local and regional visibility problems, particularly in Los Angeles and Denver (White and Roberts, 1977;Cass, 1979;Groblicki et al., 1981 Environmental Protection Agency (1973, 1978 et seq.). PAN was measured by electron capture gas chromatography, and NO and N0 2 were measured by chemiluminescence by researchers at the University of California at Riverside (UCR). PAN also was measured by the same principle at Caltech in Pasadena.The aerosol, nitric acid and ammonia sampling apparatus for this experiment is shown schematically in Figure 2. Aerosol nitrate and nitric acid concentrations were measured both by dual filter methods and by the denuder difference method. Gaseous ammonia was measured by a dual filter method using oxalic acid impregnated filters as a sink for NH 3 • Filter holders were of open-faced design so that any large particle nitrates would be collected. The sampling apparatus was surrounded by a bug screen and shaded by a sun shield to prevent nitrate volatilization through over-heating. Nine of the ten sa...

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On the nature and origins of visibility-reducing aerosols in the los angeles air basin

Cited by 225 publications

References 16 publications

Assessing the regional impact of indonesian biomass burning emissions based on organic molecular tracers and chemical mass balance modeling

Assessing the regional impact of indonesian biomass burning emissions based on organic molecular tracers and chemical mass balance modeling

Organic PM_2.5: Fractionation by Polarity, FTIR Spectroscopy, and OM/OC Ratio for the Pittsburgh Aerosol

Acquisition of regional air quality model validation data for nitrate, sulfate, ammonium ion and their precursors

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On the nature and origins of visibility-reducing aerosols in the los angeles air basin

Cited by 225 publications

References 16 publications

Assessing the regional impact of indonesian biomass burning emissions based on organic molecular tracers and chemical mass balance modeling

Assessing the regional impact of indonesian biomass burning emissions based on organic molecular tracers and chemical mass balance modeling

Organic PM2.5: Fractionation by Polarity, FTIR Spectroscopy, and OM/OC Ratio for the Pittsburgh Aerosol

Acquisition of regional air quality model validation data for nitrate, sulfate, ammonium ion and their precursors

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Resources

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Organic PM_2.5: Fractionation by Polarity, FTIR Spectroscopy, and OM/OC Ratio for the Pittsburgh Aerosol