Roadside measurements of particulate matter size distribution

Sturm, Peter; Baltensperger, Urs; Bacher, Michael; Lechner, Bernhard; Hausberger, Stefan; Heiden, Bernhard; Imhof, D.; Weingärtner, E.; Prévôt, Andrê S. H.; Kurtenbach, R.; Wiesen, Peter

doi:10.1016/j.atmosenv.2003.05.006

Cited by 59 publications

(27 citation statements)

References 7 publications

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“…Kittelson et al, 2004;Sturm et al, 2003;Zhu et al, 2002). Subsequently, physical processes will shape the size distribution of the vehicular emissions which has been the focus of a number of studies (e.g.…”

Section: Weekly Patternsmentioning

confidence: 99%

On the diurnal cycle of urban aerosols, black carbon and the occurrence of new particle formation events in springtime São Paulo, Brazil

Backman

Rizzo²,

Hakala

et al. 2012

Atmos. Chem. Phys.

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Abstract. Large conurbations are a significant source of the anthropogenic pollution and demographic differences between cities that result in a different pollution burden. The metropolitan area of São Paulo (MASP, population 20 million) accounts for one fifth of the Brazilian vehicular fleet. A feature of MASP is the amount of ethanol used by the vehicular fleet, known to exacerbate air quality. The study describes the diurnal behaviour of the submicron aerosol and relies on total particle number concentration, particle number size distribution, light scattering and light absorption measurements. Modelled planetary boundary layer (PBL) depth and air mass movement data were used to aid the interpretation. During morning rush-hour, stagnant air and a shallow PBL height favour the accumulation of aerosol pollution. During clearsky conditions, there was a wind shift towards the edge of the city indicating a heat island effect with implications on particulate pollution levels at the site. The median total particle number concentration for the submicron aerosol typically varied in the range 1.6 × 10 4 -3.2 × 10 4 cm −3 frequently exceeding 4 × 10 4 cm −3 during the day. During weekdays, nucleation-mode particles are responsible for most of the particles by numbers. The highest concentrations of total particle number concentrations and black carbon (BC) were observed on Fridays. Median diurnal values for light absorption and light scattering (at 637 nm wavelength) varied in the range 12-33 Mm −1 and 21-64 Mm −1 , respectively. The former one is equal to 1.8-5.0 µg m −3 of BC. The growth of the PBL, from the morning rush-hour until noon, is consistent with the diurnal cycle of BC mass concentrations. Weekday hourly median single-scattering albedo (ω 0 ) varied in the range 0.59-0.76. Overall, this suggests a top of atmosphere (TOA) warming effect. However, considering the low surface reflectance of urban areas, for the given range of ω 0 , the TOA radiative forcing can be either positive or negative for the sources within the MASP. On the average, weekend ω 0 values were 0.074 higher than during weekdays. During 11 % of the days, new particle formation (NPF) events occurred. The analysed events growth rates ranged between 9 and 25 nm h −1 . Sulphuric acid proxy concentrations calculated for the site were less than 5 % of the concentration needed to explain the observed growth. Thus, other vapours are likely contributors to the observed growth.

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Section: Weekly Patternsmentioning

confidence: 99%

On the diurnal cycle of urban aerosols, black carbon and the occurrence of new particle formation events in springtime São Paulo, Brazil

Backman

Rizzo²,

Hakala

et al. 2012

Atmos. Chem. Phys.

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“…Particles released directly from a source (primary PM) have a characteristic size and composition distribution that is determined by the generating mechanism (Hildemann et al 1991;Kleeman et al 1999;Kleeman et al 2000;Allen et al 2001;Wingfors et al 2001;McDonald et al 2003;Sturm et al 2003;Hays 2004;Laschober et al 2004;McDonald et al 2004;Shah et al 2004). Once in the atmosphere, the particle size and composition distribution can be modified by chemical reactions, condensation/evaporation of semi-volatile species, coagulation with other particles, activation during high humidity, wet deposition, and dry deposition.…”

Section: Introductionmentioning

confidence: 99%

Dominant Mechanisms that Shape the Airborne Particle Size and Composition Distribution in Central California

Herner

Ying

et al. 2006

Aerosol Science and Technology

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The size and composition of ambient airborne particulate matter is reported for winter conditions at five locations in (or near) the San Joaquin Valley in central California. Two distinct types of airborne particles were identified based on diurnal patterns and size distribution similarity: hygroscopic sulfate/ammonium/nitrate particles and less hygroscopic particles composed of mostly organic carbon with smaller amounts of elemental carbon. Daytime PM 10 concentrations for sulfate/ammonium/nitrate particles were measured to be 10.1 µg m −3 , 28.3 µg m −3 , and 52.8 µg m −3 at Sacramento, Modesto and Bakersfield, California, respectively. Nighttime concentrations were 10-30% lower, suggesting that these particles are dominated by secondary production. Simulation of the data with a box model suggests that these particles were formed by the condensation of ammonia and nitric acid onto background or primary sulfate particles. These hygroscopic particles had a mass distribution peak in the accumulation mode (0.56-1.0 µm) at all times. Daytime PM 10 carbon particle concentrations were measured to be 9.5 µg m −3 , 15.1 µg m −3 , and 16.2 µg m −3 at Sacramento, Modesto, and Bakersfield, respectively. Corresponding nighttime concentrations were 200-300% higher, suggesting that these particles are dominated by primary emissions. The peak in the carbon particle mass distribution varied between 0.2-1.0 µm. Carbon particles emitted directly from combustion sources typically have a mass distribution peak diameter between 0.1-0.32 µm. Box model calculations suggest that the formation of secondary organic aerosol is negligible under cool winter conditions, and that the observed shift in the carbon particle mass distribution results from coagulation in the heavily polluted concentrations experienced during the current study. The analysis suggests that carbon particles and sulfate/ammonium/nitrate particles exist separately in the atmosphere

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“…Measurements of particle emissions from motor vehicles have been accomplished via dynamometer source testing (Chase et al 2000;Kwon et al 2003;Sakurai et al 2003aSakurai et al , 2003bSchauer et al 1999Schauer et al , 2002Suess and Prather 2002), roadway tunnel sampling (Allen et al 2001;Fraser et al 1998;Laschober et al 2004;McGaughey et al 2004), on-road chase experiments (Shah et al 2004;Vogt et al 2003), and roadside measurements Sturm et al 2003;Zhu et al 2002aZhu et al , 2002bZhu et al , 2004. In general, particles directly emitted from motor vehicles are in the size range from 20 to 130 nm in aerodynamic diameter for diesel engines and from 20 to 60 nm for gasoline engines (Ristovski et al 1998).…”

Section: Introductionmentioning

confidence: 99%

Physical and Chemical Characteristics and Volatility of PM in the Proximity of a Light-Duty Vehicle Freeway

Kühn¹,

Biswas

Fine

et al. 2005

Aerosol Science and Technology

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Roadside measurements of particulate matter size distribution

Cited by 59 publications

References 7 publications

On the diurnal cycle of urban aerosols, black carbon and the occurrence of new particle formation events in springtime São Paulo, Brazil

On the diurnal cycle of urban aerosols, black carbon and the occurrence of new particle formation events in springtime São Paulo, Brazil

Dominant Mechanisms that Shape the Airborne Particle Size and Composition Distribution in Central California

Physical and Chemical Characteristics and Volatility of PM in the Proximity of a Light-Duty Vehicle Freeway

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