TOTAL ORGANIC AEROSOL CONCENTRATIONS: RELATIVE CONTRIBUTIONS OF BIOGENIC AND ANTHROPOGENIC AND PRIMARY AND SECONDARY AEROSOL

2001 ◽  
Vol 32 ◽  
pp. 957-958
Author(s):  
R.J. BARTHELMIE ◽  
S.C. PRYOR
Keyword(s):  
Organic Aerosol ◽  
Secondary Aerosol

scholarly journals In situ vertical profiles of aerosol extinction, mass, and composition over the southeast United States during SENEX and SEAC<sup>4</sup>RS: observations of a modest aerosol enhancement aloft

2015 ◽  
Vol 15 (12) ◽  
pp. 7085-7102 ◽  
Author(s):  
N. L. Wagner ◽  
C. A. Brock ◽  
W. M. Angevine ◽  
A. Beyersdorf ◽  
P. Campuzano-Jost ◽  
...  
Keyword(s):  
United States ◽  
Mixed Layer ◽  
Transition Layer ◽  
Southeastern United States ◽  
Vertical Mixing ◽  
Organic Aerosol ◽  
Vertical Profiles ◽  
Free Troposphere ◽  
Secondary Aerosol

Abstract. Vertical profiles of submicron aerosol from in situ aircraft-based measurements were used to construct aggregate profiles of chemical, microphysical, and optical properties. These vertical profiles were collected over the southeastern United States (SEUS) during the summer of 2013 as part of two separate field studies: the Southeast Nexus (SENEX) study and the Study of Emissions and Atmospheric Composition, Clouds, and Climate Coupling by Regional Surveys (SEAC4RS). Shallow cumulus convection was observed during many profiles. These conditions enhance vertical transport of trace gases and aerosol and create a cloudy transition layer on top of the sub-cloud mixed layer. The trace gas and aerosol concentrations in the transition layer were modeled as a mixture with contributions from the mixed layer below and the free troposphere above. The amount of vertical mixing, or entrainment of air from the free troposphere, was quantified using the observed mixing ratio of carbon monoxide (CO). Although the median aerosol mass, extinction, and volume decreased with altitude in the transition layer, they were ~10 % larger than expected from vertical mixing alone. This enhancement was likely due to secondary aerosol formation in the transition layer. Although the transition layer enhancements of the particulate sulfate and organic aerosol (OA) were both similar in magnitude, only the enhancement of sulfate was statistically significant. The column integrated extinction, or aerosol optical depth (AOD), was calculated for each individual profile, and the transition layer enhancement of extinction typically contributed less than 10 % to the total AOD. Our measurements and analysis were motivated by two recent studies that have hypothesized an enhanced layer of secondary aerosol aloft to explain the summertime enhancement of AOD (2–3 times greater than winter) over the southeastern United States. The first study attributes the layer aloft to secondary organic aerosol (SOA) while the second study speculates that the layer aloft could be SOA or secondary particulate sulfate. In contrast to these hypotheses, the modest enhancement we observed in the transition layer was not dominated by OA and was not a large fraction of the summertime AOD.

scholarly journals Sources and processes that control the submicron organic aerosol in an urban Mediterranean environment (Athens) using high temporal resolution chemical composition measurements

2018 ◽  
Author(s):  
Iasonas Stavroulas ◽  
Aikaterini Bougiatioti ◽  
Despina Paraskevopoulou ◽  
Georgios Grivas ◽  
Eleni Liakakou ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Biomass Burning ◽  
Volatile Component ◽  
Organic Aerosol ◽  
Urban Environments ◽  
High Temporal Resolution ◽  
Organic Fraction ◽  
Scanning Mobility Particle Sizer ◽  
Secondary Aerosol ◽  
Combustion Sources

Abstract. Submicron aerosol chemical composition has been studied during a year-long period (26/07/2016–31/07/2017) and two winter-time intensive campaigns (18/12/2013–21/02/2014 and 23/12/2015–17/02/2016), at a central site in Athens, Greece, using an Aerosol Chemical Speciation Monitor (ACSM). Concurrent measurements include a Particle-Into-Liquid Sampler (PILS-IC), a Scanning Mobility Particle Sizer (SMPS), an AE-33 Aethalometer and Ion Chromatography analysis on 24 or 12 hour filter samples. Quality of the ACSM data was assured by comparison versus the above mentioned measurements. The aim of the study was to characterize the seasonal variability of the main fine aerosol constituents and decipher the sources of organic aerosol (OA). Organics were found to contribute almost half of the submicron mass, with concentrations during wintertime reaching up to 200 μg m−3, on occasions. During this season, the primary sources contribute about 34 % of the organic fraction, comprising of biomass burning (10 %), fossil fuel combustion (16 %) and cooking (8 %), while the remaining 66 % is attributed to secondary aerosol. The semi-volatile component of the oxidized organic aerosol (SV-OOA; 31 %) was found to be clearly linked to combustion sources and in particular biomass burning, and even a part of the very oxidized, low-volatility component (LV-OOA; 35 %) could also be attributed to the oxidation of emissions from these primary combustion sources. These results highlight the rising importance of biomass burning in urban environments during wintertime, as revealed through this characteristic example of Athens, Greece, where the economic recessions led to an abrupt shift to biomass burning for heating purposes in winter. During summer, when concentrations of fine aerosols are considerably lower, more than 80 % of the organic fraction is attributed to secondary aerosol (SV-OOA 30 % and LV-OOA 53 %). In contrast to winter, SV-OOA appears to result from a well-mixed type of aerosol, linked to fast photochemical processes and the oxidation of primary traffic and biogenic emissions. Finally, LV-OOA presents a more regional character in summer, owing to the oxidation, within a few days, of organic aerosol.

scholarly journals Synergetic formation of secondary inorganic and organic aerosol: Influence of SO<sub>2</sub> and/or NH<sub>3</sub> in the heterogeneous process

2016 ◽  
Author(s):  
Biwu Chu ◽  
Xiao Zhang ◽  
Yongchun Liu ◽  
Hong He ◽  
Yele Sun ◽  
...  
Keyword(s):  
Secondary Organic Aerosol ◽  
Synergistic Effects ◽  
Particle Growth ◽  
Organic Aerosol ◽  
Interactive Effects ◽  
Aerosol Formation ◽  
Secondary Aerosol ◽  
Heterogeneous Process ◽  
So2 Concentration ◽  
Inorganic And Organic

Abstract. The effects of SO2 and NH3 on secondary organic aerosol formation have rarely been investigated together, while the interactive effects between inorganic and organic species under highly complex pollution conditions remain uncertain. Here we studied the effects of SO2 and NH3 on secondary aerosol formation in the photooxidation system of toluene/NOx in the presence or absence of Al2O3 seed aerosols in a 2 m3 smog chamber. The presence of SO2 increased new particle formation and particle growth significantly, regardless of whether NH3 was present or not. Sulfate, organic aerosol, nitrate and ammonium were all found to increase linearly with increasing SO2 concentrations. The increases in these four species were more obvious under NH3-rich conditions, and the generation of nitrate, ammonium and organic aerosol increased more significantly than sulfate with respect to SO2 concentration, while sulfate was the most sensitive species under NH3-poor conditions. The synergistic effects between SO2 and NH3 in the heterogeneous process contributed greatly to secondary aerosol formation. Specifically, the generation of NH4NO3 was found to be highly dependent on the surface area concentration of suspended particles, and increased most significantly among the four species with respect to SO2 concentration under ammonia-rich conditions. Meanwhile, the absorbed NH3 might provide a liquid surface layer for the absorption and subsequent reaction of SO2 and organic products, and therefore, enhance sulfate and secondary organic aerosol (SOA) formation. This effect mainly occurred in the heterogeneous process and resulted in a significantly higher growth rate of seed aerosols compared to that without NH3. By applying positive matrix factorization (PMF) analysis to the AMS data, two factors were identified for the generated SOA. One factor, assigned to less-oxidized organic aerosol and some oligomers, increased with increasing SO2 under NH3-poor conditions, mainly due to the well-known acid catalytic effect of the acid products on SOA formation in the heterogeneous process. The other factor, assigned to the highly oxidized organic component and some nitrogen-containing organics (NOC), increased with SO2 under a NH3-rich environment, with NOC (organonitrates and NOC with reduced N) contributing most of the increase.

Effect of aqueous-phase processing on aerosol chemistry and size distributions in Fresno, California, during wintertime

2012 ◽  
Vol 9 (3) ◽  
pp. 221 ◽  
Author(s):  
Xinlei Ge ◽  
Qi Zhang ◽  
Yele Sun ◽  
Christopher R. Ruehl ◽  
Ari Setyan
Keyword(s):  
Aqueous Phase ◽  
Fine Particles ◽  
Organic Aerosol ◽  
Size Distributions ◽  
Aerosol Chemistry ◽  
Aerosol Composition ◽  
Secondary Aerosol ◽  
Organic Species ◽  
Secondary Species ◽  
Aerosol Properties

Environmental contextAqueous-phase processes in fogs and clouds can significantly alter atmospheric fine particles with consequences for climate and human health. We studied the influence of fog and rain on atmospheric aerosol properties, and show that aqueous-phase reactions contribute to the production of secondary aerosol species and change significantly the composition and microphysical properties of aerosols. In contrast, rains effectively remove aerosols and reduce their concentrations. AbstractSubmicrometre aerosols (PM1) were characterised in situ with a high resolution time-of-flight aerosol mass spectrometer and a scanning mobility particle sizer in Fresno, CA, from 9 to 23 January 2010. Three dense fog events occurred during the first week of the campaign whereas the last week was influenced by frequent rain events. We thus studied the effects of aqueous-phase processing on aerosol properties by examining the temporal variations of submicrometre aerosol composition and size distributions. Rains removed secondary species effectively, leading to low loadings of PM1 dominated by primary organic species. Fog episodes, however, increased the concentrations of secondary aerosol species (sulfate, nitrate, ammonium and oxygenated organic aerosol). The size distributions of these secondary species, which always showed a droplet mode peaking at ~500 nm in the vacuum aerodynamic diameter, increased in mode size during fog episodes as well. In addition, the oxygen-to-carbon ratio of oxygenated organic species increased in foggy days, indicating that fog processing likely enhances the production of secondary organic aerosol as well as its oxidation degree. Overall, our observations show that aqueous-phase processes significantly affect submicrometre aerosol chemistry and microphysics in the Central Valley of California during winter, responsible for the production of secondary inorganic and organic aerosol species and the formation of droplet mode particles, thus altering the climatic and health effects of ambient aerosols in this region.

scholarly journals Aerosol composition and sources during the Chinese Spring Festival: fireworks, secondary aerosol, and holiday effects

2015 ◽  
Vol 15 (11) ◽  
pp. 6023-6034 ◽  
Author(s):  
Q. Jiang ◽  
Y. L. Sun ◽  
Z. Wang ◽  
Y. Yin
Keyword(s):  
Chinese Spring ◽  
Fine Particles ◽  
Nitrogen Monoxide ◽  
Primary Source ◽  
Organic Aerosol ◽  
Aerosol Composition ◽  
Secondary Aerosol ◽  
Particulate Pollution ◽  
Spring Festival ◽  
The Impact

Abstract. Aerosol particles were characterized by an Aerodyne aerosol chemical speciation monitor along with various collocated instruments in Beijing, China, to investigate the role of fireworks (FW) and secondary aerosol in particulate pollution during the Chinese Spring Festival of 2013. Three FW events, exerting significant and short-term impacts on fine particles (PM2.5), were observed on the days of Lunar New Year, Lunar Fifth Day, and Lantern Festival. The FW were shown to have a large impact on non-refractory potassium, chloride, sulfate, and organics in submicron aerosol (PM1), of which FW organics appeared to be emitted mainly in secondary, with its mass spectrum resembling that of secondary organic aerosol (SOA). Pollution events (PEs) and clean periods (CPs) alternated routinely throughout the study. Secondary particulate matter (SPM = SOA + sulfate + nitrate + ammonium) dominated the total PM1 mass on average, accounting for 63–82% during nine PEs in this study. The elevated contributions of secondary species during PEs resulted in a higher mass extinction efficiency of PM1 (6.4 m2 g-1) than during CPs (4.4 m2 g-1). The Chinese Spring Festival also provides a unique opportunity to study the impact of reduced anthropogenic emissions on aerosol chemistry in the city. Primary species showed ubiquitous reductions during the holiday period with the largest reduction being in cooking organic aerosol (OA; 69%), in nitrogen monoxide (54%), and in coal combustion OA (28%). Secondary sulfate, however, remained only slightly changed, and the SOA and the total PM2.5 even slightly increased. Our results have significant implications for controlling local primary source emissions during PEs, e.g., cooking and traffic activities. Controlling these factors might have a limited effect on improving air quality in the megacity of Beijing, due to the dominance of SPM from regional transport in aerosol particle composition.

Particulate matter emissions over the oil sands regions in Alberta, Canada

2017 ◽  
Vol 25 (4) ◽  
pp. 432-443 ◽  
Author(s):  
Zhenyu Xing ◽  
Ke Du
Keyword(s):  
Particulate Matter ◽  
Oil Sands ◽  
Secondary Organic Aerosol ◽  
Ambient Air ◽  
Organic Aerosol ◽  
Open Pit ◽  
Open Pit Mining ◽  
Formation Mechanisms ◽  
Aerosol Formation ◽  
Secondary Aerosol

Particulate matter (PM) emissions from the expanded oil sands development in Alberta are becoming a focus among the aerosol science community because of its significant negative impact on the regional air quality and climate change. Open-pit mining, petroleum coke (petcoke) dust, and the transportation of oil sands and waste materials by heavy-duty trucks on unpaved roads could release PM into the air. Incomplete combustion of fossil fuels by engines and stationary boilers leads to the formation of carbonaceous aerosols. In addition, wildfire and biogenic emissions surrounding the oil sands regions also have the potential to contribute primary PM to the ambient air. Secondary organic aerosol formation has been revealed as an important source of PM over nearby and distant areas from the oil sands regions. This review summarizes the primary PM sources and some secondary aerosol formation mechanisms that are linked to oil sands development. It also reviews the approaches that can be applied in aerosol source apportionment. Meteorological condition is an important factor that may influence the primary PM emission and secondary aerosol formation in Alberta’s oil sands regions. Current concern should not be limited to the primary emission of atmospheric PM. Secondary formation of aerosols, especially secondary organic aerosol originating from photochemical reaction, should also be taken into consideration. To obtain a more comprehensive understanding of the sources and amount of PM emissions based on the bottom-up emission inventory approach, investigations on how to reduce the uncertainty in determination of real-world PM emission factors for the variable sources are needed. Long-range transport trajectories of fine PM from Alberta’s oil sands regions remain unknown.

scholarly journals Significant source of secondary aerosol: formation from gasoline evaporative emissions in the presence of SO<sub>2</sub> and NH<sub>3</sub>

2019 ◽  
Vol 19 (12) ◽  
pp. 8063-8081 ◽  
Author(s):  
Tianzeng Chen ◽  
Yongchun Liu ◽  
Qingxin Ma ◽  
Biwu Chu ◽  
Peng Zhang ◽  
...  
Keyword(s):  
Organic Aerosol ◽  
Scientific Basis ◽  
Significant Source ◽  
Anthropogenic Source ◽  
Aerosol Formation ◽  
High Concentration ◽  
Secondary Aerosol ◽  
Evaporative Emissions ◽  
Size Growth ◽  
High Concentrations

Abstract. Gasoline evaporative emissions have become an important anthropogenic source of urban atmospheric volatile organic compounds (VOCs) and secondary organic aerosol (SOA). These emissions have a significant impact on regional air quality, especially in China where car ownership is growing rapidly. However, the contribution of evaporative emissions to secondary aerosol (SA) is not clear in an air pollution complex in which a high concentration of SO2 and NH3 was present. In this study, the effects of SO2 and NH3 on SA formation from unburned gasoline vapor were investigated in a 30 m3 indoor smog chamber. It was found that an increase in SO2 and NH3 concentrations (0–151 and 0–200 ppb, respectively) could linearly promote the formation of SA, which could be enhanced by a factor of 1.6–2.6 and 2.0–2.5, respectively. Sulfate was most sensitive to the SO2 concentration, followed by organic aerosol, which was due not only to the acid catalytic effect, but was also related to the formation of organic sulfur-containing compounds. In the case of an increasing NH3 concentration, ammonium nitrate increased more significantly than organic aerosol, and nitrogen-containing organics were also enhanced, as revealed by the results of positive matrix factorization (PMF) analysis. New particle formation (NPF) and particle size growth were also significantly enhanced in the presence of SO2 and NH3. This work indicates that gasoline evaporative emissions will be a significant source of SA, especially in the presence of high concentrations of SO2 and NH3. Meanwhile, these emissions might also be a potential source of sulfur- and nitrogen-containing organics. Our work provides a scientific basis for the synergistic emission reduction of secondary aerosol precursors, including NOx, SO2, NH3, and particularly VOCs, to mitigate particulate matter (PM) pollution in China.

scholarly journals Comparison of primary and secondary particle formation from natural gas engine exhaust and of their volatility characteristics

2017 ◽  
Author(s):  
Jenni Alanen ◽  
Pauli Simonen ◽  
Sanna Saarikoski ◽  
Hilkka Timonen ◽  
Oskari Kangasniemi ◽  
...  
Keyword(s):  
Natural Gas ◽  
Organic Aerosol ◽  
Liquid Fuels ◽  
Aerosol Formation ◽  
Engine Exhaust ◽  
Gas Engine ◽  
Secondary Aerosol ◽  
Formation Potential ◽  
Natural Gas Engine ◽  
Catalyst Temperature

Abstract. Natural gas usage in traffic and energy production sector is a growing trend worldwide, thus an assessment of its effects on air quality, human health and climate is required. Engine exhaust is a source of primary particulate emissions and secondary aerosol precursors that both contribute to air quality and can cause adverse health effects. Technologies, such as cleaner engines or fuels, that produce less primary and secondary aerosol could potentially significantly decrease the atmospheric particle concentrations and their adverse effects. In this study, we used a potential aerosol mass (PAM) chamber to investigate the secondary aerosol formation potential of natural gas engine exhaust. The PAM chamber was used with a constant UV-light voltage that resulted in an equivalent atmospheric age of 11 days at a maximum. The studied passenger car engine, retrofitted to run with natural gas, was observed to have a low or moderate secondary particle formation potential, although the simulated atmospheric ages were relatively long. The secondary organic aerosol (SOA) formation potential was measured to be 8–18 mg kgfuel−1. However, the mass of total aged particles, i.e. particle mass measured downstream the PAM chamber, was 6–184 times as high as the mass of the emitted primary exhaust particles. The total aged particles consisted mainly of nitrate, organic matter, sulfate and ammonium, the fractions depending on exhaust after-treatment and used engine parameters. Also the volatility, composition and concentration of the total aged particles were found to depend on the engine operating mode, catalyst temperature and catalyst type. For example, a high catalyst temperature promoted the formation of sulfate particles, whereas a low catalyst temperature promoted nitrate formation. However, especially the concentration of nitrate needed a long time, more than half an hour, to stabilize, which complicated the conclusions but also indicates the sensitivity of nitrate measurements on experimental parameters such as emission source and system temperatures. Sulfate was measured to have the highest evaporation temperature and nitrate the lowest. The evaporation temperature of ammonium depended on the fractions of nitrate and sulfate in the particles. The average volatility of the total aged particles was measured to be lower than that of primary particles, indicating better stability of the aged natural gas engine emitted aerosol in the atmosphere. According to the results of this study, the shift from traditional liquid fuels to natural gas can have a decreasing effect on total particle pollution in the atmosphere; in addition to the very low primary particle emissions, also the secondary organic aerosol formation potential of natural gas exhaust is lower or on the same level as the SOA formation potential measured on liquid fuels in previous studies.

scholarly journals Significant source of secondary aerosol: formation from gasoline evaporation emissions in the presence of SO<sub>2</sub> and NH<sub>3</sub>

2019 ◽  
Author(s):  
Tianzeng Chen ◽  
Yongchun Liu ◽  
Qingxin Ma ◽  
Biwu Chu ◽  
Peng Zhang ◽  
...  
Keyword(s):  
Organic Aerosol ◽  
Scientific Basis ◽  
Significant Source ◽  
Anthropogenic Source ◽  
Aerosol Formation ◽  
High Concentration ◽  
Secondary Aerosol ◽  
Size Growth ◽  
High Concentrations ◽  
Gasoline Evaporation

Abstract. Gasoline evaporation emissions have become an important anthropogenic source of urban atmospheric VOCs and secondary organic aerosol (SOA). These emissions have a significant impact on regional air quality, especially in China where car ownership is growing rapidly. However, the contribution of evaporation emissions on the secondary aerosol (SA) is not clear in air pollution complex in which high concentration of SO2 and NH3 was present. In this study, the effects of SO2 and NH3 on SA formation from unburned gasoline vapors were investigated in a 30 m3 indoor smog chamber. It was found that increase in SO2 and NH3 concentrations could promote linearly the formation of SA, which could be enhanced by a factor of 1.6–2.6 and 2.0–2.5, respectively. Sulfate was most sensitive to the SO2 concentration, followed by organic aerosol, which was due not only to the well-known acid catalytic effect, but also related to the formation of organic sulfur-containing compounds. In the case of increasing NH3 concentration, ammonium nitrate increased more significantly than organic aerosol, and nitrogen-containing organics were also enhanced, as revealed by the results of positive matrix factorization (PMF) analysis. Meanwhile, new particle formation (NPF) and particle size growth were significantly enhanced in the presence of SO2 and NH3. This work indicates that gasoline evaporation emissions will be a significant source of SA, especially in the presence of high concentrations of SO2 and NH3. Meanwhile, these emissions might also be a potential source of sulfur- and nitrogen-containing organics. Our work provides a scientific basis for the synergistic emission reduction of secondary aerosol precursors, including NOx, SO2, NH3 and particularly VOCs, to mitigate PM pollution in China.

scholarly journals Cloud condensation nuclei (CCN) activity of aliphatic amine secondary aerosol

2014 ◽  
Vol 14 (12) ◽  
pp. 5959-5967 ◽  
Author(s):  
X. Tang ◽  
D. Price ◽  
E. Praske ◽  
D. N. Vu ◽  
K. Purvis-Roberts ◽  
...  
Keyword(s):  
Hydroxyl Radical ◽  
Aliphatic Amine ◽  
Secondary Organic Aerosol ◽  
Cloud Condensation Nuclei ◽  
Organic Aerosol ◽  
Nitrate Radical ◽  
Condensation Nuclei ◽  
Primary Aliphatic Amine ◽  
Secondary Aerosol ◽  
Ccn Activity

Abstract. Aliphatic amines can form secondary aerosol via oxidation with atmospheric radicals (e.g., hydroxyl radical and nitrate radical). The particle can contain both secondary organic aerosol (SOA) and inorganic salts. The ratio of organic to inorganic materials in the particulate phase influences aerosol hygroscopicity and cloud condensation nuclei (CCN) activity. SOA formed from trimethylamine (TMA) and butylamine (BA) reactions with hydroxyl radical (OH) is composed of organic material of low hygroscopicity (single hygroscopicity parameter, κ, ≤ 0.25). Secondary aerosol formed from the tertiary aliphatic amine (TMA) with N2O5 (source of nitrate radical, NO3) contains less volatile compounds than the primary aliphatic amine (BA) aerosol. As relative humidity (RH) increases, inorganic amine salts are formed as a result of acid–base reactions. The CCN activity of the humid TMA–N2O5 aerosol obeys Zdanovskii, Stokes, and Robinson (ZSR) ideal mixing rules. The humid BA + N2O5 aerosol products were found to be very sensitive to the temperature at which the measurements were made within the streamwise continuous-flow thermal gradient CCN counter; κ ranges from 0.4 to 0.7 dependent on the instrument supersaturation (ss) settings. The variance of the measured aerosol κ values indicates that simple ZSR rules cannot be applied to the CCN results from the primary aliphatic amine system. Overall, aliphatic amine aerosol systems' κ ranges within 0.2 < κ < 0.7. This work indicates that aerosols formed via nighttime reactions with amines are likely to produce hygroscopic and volatile aerosol, whereas photochemical reactions with OH produce secondary organic aerosol of lower CCN activity. The contributions of semivolatile secondary organic and inorganic material from aliphatic amines must be considered for accurate hygroscopicity and CCN predictions from aliphatic amine systems.

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