scholarly journals Secondary Organic Aerosol Formation from Gasoline and Diesel Vehicle Exhaust under Light and Dark Condition

2021 ◽  
Author(s):  
Yu Morino ◽  
Ying Li ◽  
Yuji Fujitani ◽  
Kei Sato ◽  
Satoshi Inomata ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Atmospheric Particulate Matter ◽  
Urban Air ◽  
Dark Condition ◽  
Aerosol Formation ◽  
Vehicle Exhaust ◽  
Atmospheric Particulate ◽  
Diesel Vehicle

Secondary organic aerosol (SOA) formed from vehicle exhaust contributes substantially to the atmospheric particulate matter in urban air but there still remain uncertainties in the simulation of the SOA by...

scholarly journals Secondary Organic Aerosol Formation Enhanced by Organic Seeds of Similar Polarity at Atmospherically Relative Humidity

2015 ◽  
Vol 1 (2) ◽  
pp. 6-10 ◽  
Author(s):  
Catherine A. Gordon ◽  
Jianhuai Ye ◽  
Arthur W.H. Chan
Keyword(s):  
Climate Models ◽  
Secondary Organic Aerosol ◽  
Phase Particle ◽  
Organic Aerosol ◽  
Atmospheric Particulate Matter ◽  
Oxidation Products ◽  
Tetraethylene Glycol ◽  
Aerosol Formation ◽  
Volatile Oxidation Products ◽  
Low Humidity

Secondary Organic Aerosol (SOA) forms in the atmosphere when semi-volatile oxidation products from biogenic and anthropogenic hydrocarbons condense onto atmospheric particulate matter. Climate models assume that oxidation products and preexisting organic aerosol form a well-mixed particle and enhance condensation, and, as a result, predict that future increases in anthropogenic primary organic aerosol (POA) will cause a significant increase in SOA. However, recent experiments performed at low humidity (<10%) demonstrate a single-phase particle does not always form, challenging the validity of model assumptions. In this work, we investigate the formation of SOA at atmospherically relevant humidities (55 - 65%) and examine this mixing assumption. We hypothesized that humidity leads to decreased viscosity and shorter mixing timescales, which is favorable for aerosol mixing. Here, α-pinene, a biogenic volatile organic compound is oxidized with ozone in a flow tube reactor in the presence of different organic aerosol seeds. Increased humidity did not enhance SOA formation with erythritol or squalane seed as hypothesized, implying that these compounds do not mix with α-pinene SOA in the range of humidities studied (55 – 65%). Yield enhancements were observed with tetraethylene glycol seed, demonstrating interaction between the SOA and seed. These observations suggest increased humidity does not promote mixing between the oxidation products and POA and highlight the need to fully understand the aerosol phase state in the atmosphere in order to better parameterize SOA formation and accurately predict future changes in air quality.

scholarly journals Characterisation of solvent extractable organic constituents in atmospheric particulate matter: an overview

2008 ◽  
Vol 80 (1) ◽  
pp. 21-82 ◽  
Author(s):  
Célia A. Alves
Keyword(s):  
Particulate Matter ◽  
Organic Compounds ◽  
Atmospheric Aerosols ◽  
Current Knowledge ◽  
Atmospheric Particulate Matter ◽  
Aerosol Formation ◽  
Atmospheric Particulate ◽  
Organic Constituents ◽  
Geochemical Parameters ◽  
The Impact

In spite of accounting for 10-70% of the atmospheric aerosol mass, particulate-phase organic compounds are not well characterised, and many aspects of aerosol formation and evolution are still unknown. The growing awareness of the impact of particulate aerosols on climate, and the incompletely recognised but serious effects of anthropogenic constituents on air quality and human health, have conducted to several scientific studies. These investigations have provided information about the behaviour of atmospheric particulate matter and the description of the character of its carbonaceous content. The compilation of such results is important as they append to the emergent global-wide dataset of the organic composition of atmospheric aerosols. The contribution of the major emission sources to regional particulate pollution can be diagnosed by using specific molecular markers. This overview is mainly focused on results obtained with gas chromatography coupled with mass spectrometry, since it is the analytical method of choice in elucidating the solvent-extractable organic compounds in atmospheric particulate matter. A synopsis of the selection of organic tracers and the application of geochemical parameters to the analysis of organic constituents as a tool for source apportionment is shown here. Besides the assessment of current knowledge, this paper also presents the identification of further areas of concern.

scholarly journals Secondary organic aerosol formation exceeds primary particulate matter emissions for light-duty gasoline vehicles

2013 ◽  
Vol 13 (9) ◽  
pp. 23173-23216 ◽  
Author(s):  
T. D. Gordon ◽  
A. A. Presto ◽  
A. A. May ◽  
N. T. Nguyen ◽  
E. M. Lipsky ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Secondary Organic Aerosol ◽  
Cold Start ◽  
Organic Aerosol ◽  
Smog Chamber ◽  
Aerosol Formation ◽  
Gas Emissions ◽  
Light Duty ◽  
Gasoline Vehicles ◽  
Diesel Trucks

Abstract. The effects of photochemical aging on emissions from 15 light-duty gasoline vehicles were investigated using a smog chamber to probe the critical link between the tailpipe and ambient atmosphere. The vehicles were recruited from the California in-use fleet; they represent a wide range of model years (1987 to 2011), vehicle types and emission control technologies. Each vehicle was tested on a chassis dynamometer using the unified cycle. Dilute emissions were sampled into a portable smog chamber and then photochemically aged under urban-like conditions. For every vehicle, substantial secondary organic aerosol (SOA) formation occurred during cold-start tests, with the emissions from some vehicles generating as much as 6 times the amount of SOA as primary particulate matter after three hours of oxidation inside the chamber at typical atmospheric oxidant levels. Therefore, the contribution of light duty gasoline vehicle exhaust to ambient PM levels is likely dominated by secondary PM production (SOA and nitrate). Emissions from hot-start tests formed about a factor of 3–7 less SOA than cold-start tests. Therefore, catalyst warm-up appears to be an important factor in controlling SOA precursor emissions. The mass of SOA generated by photo-oxidizing exhaust from newer (LEV1 and LEV2) vehicles was only modestly lower (38%) than that formed from exhaust emitted by older (pre-LEV) vehicles, despite much larger reductions in non-methane organic gas emissions. These data suggest that a complex and non-linear relationship exists between organic gas emissions and SOA formation, which is not surprising since SOA precursors are only one component of the exhaust. Except for the oldest (pre-LEV) vehicles, the SOA production could not be fully explained by the measured oxidation of speciated (traditional) SOA precursors. Over the time scale of these experiments, the mixture of organic vapors emitted by newer vehicles appear to be more efficient (higher yielding) in producing SOA than the emissions from older vehicles. About 30% of the non-methane organic gas emissions from the newer (LEV1 and LEV2) vehicles could not be speciated, and the majority of the SOA formed from these vehicles appears to be associated with these unspeciated organics. These results for light-duty gasoline vehicles contrast with the results from a companion study of on-road heavy-duty diesel trucks; in that study late model (2007 and later) diesel trucks equipped with catalyzed diesel particulate filters emitted very little primary PM, and the photo-oxidized emissions produced negligible amounts of SOA.

scholarly journals Secondary organic aerosol formation from photochemical aging of light-duty gasoline vehicle exhausts in a smog chamber

2015 ◽  
Vol 15 (15) ◽  
pp. 9049-9062 ◽  
Author(s):  
T. Liu ◽  
X. Wang ◽  
W. Deng ◽  
Q. Hu ◽  
X. Ding ◽  
...  
Keyword(s):  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Smog Chamber ◽  
Atmospheric Conditions ◽  
Aerosol Formation ◽  
Vehicle Exhaust ◽  
Molar Ratios ◽  
Passenger Vehicles ◽  
Light Duty ◽  
Oxidation Chemistry

Abstract. In China, a rapid increase in passenger vehicles has led to the growing concern of vehicle exhaust as an important source of anthropogenic secondary organic aerosol (SOA) in megacities hard hit by haze. In this study, the SOA formation of emissions from two idling light-duty gasoline vehicles (LDGVs) (Euro 1 and Euro 4) operated in China was investigated in a 30 m3 smog chamber. Five photo-oxidation experiments were carried out at 25 °C with relative humidity at around 50 %. After aging at an OH exposure of 5 × 106 molecules cm−3 h, the formed SOA was 12–259 times as high as primary organic aerosol (POA). The SOA production factors (PF) were 0.001–0.044 g kg−1 fuel, comparable with those from the previous studies at comparable OH exposure. This quite lower OH exposure than that in typical atmospheric conditions might however lead to the underestimation of the SOA formation potential from LDGVs. Effective SOA yields in this study were well fit by a one-product gas-particle partitioning model but quite lower than those of a previous study investigating SOA formation from three idling passenger vehicles (Euro 2–4). Traditional single-ring aromatic precursors and naphthalene could explain 51–90 % of the formed SOA. Unspeciated species such as branched and cyclic alkanes might be the possible precursors for the unexplained SOA. A high-resolution time-of-flight aerosol mass spectrometer was used to characterize the chemical composition of SOA. The relationship between f43 (ratio of m/z 43, mostly C2H3O+, to the total signal in mass spectrum) and f44 (mostly CO2+) of the gasoline vehicle exhaust SOA is similar to the ambient semi-volatile oxygenated organic aerosol (SV-OOA). We plot the O : C and H : C molar ratios of SOA in a Van Krevelen diagram. The slopes of ΔH : C / ΔO : C ranged from −0.59 to −0.36, suggesting that the oxidation chemistry in these experiments was a combination of carboxylic acid and alcohol/peroxide formation.

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 Reducing secondary organic aerosol formation from gasoline vehicle exhaust

2017 ◽  
Vol 114 (27) ◽  
pp. 6984-6989 ◽  
Author(s):  
Yunliang Zhao ◽  
Rawad Saleh ◽  
Georges Saliba ◽  
Albert A. Presto ◽  
Timothy D. Gordon ◽  
...  
Keyword(s):  
Los Angeles ◽  
Atmospheric Chemistry ◽  
Urban Areas ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Peroxy Radicals ◽  
Oxides Of Nitrogen ◽  
Aerosol Formation ◽  
Vehicle Exhaust ◽  
Gasoline Vehicles

On-road gasoline vehicles are a major source of secondary organic aerosol (SOA) in urban areas. We investigated SOA formation by oxidizing dilute, ambient-level exhaust concentrations from a fleet of on-road gasoline vehicles in a smog chamber. We measured less SOA formation from newer vehicles meeting more stringent emissions standards. This suggests that the natural replacement of older vehicles with newer ones that meet more stringent emissions standards should reduce SOA levels in urban environments. However, SOA production depends on both precursor concentrations (emissions) and atmospheric chemistry (SOA yields). We found a strongly nonlinear relationship between SOA formation and the ratio of nonmethane organic gas to oxides of nitrogen (NOx) (NMOG:NOx), which affects the fate of peroxy radicals. For example, changing the NMOG:NOxfrom 4 to 10 ppbC/ppbNOxincreased the SOA yield from dilute gasoline vehicle exhaust by a factor of 8. We investigated the implications of this relationship for the Los Angeles area. Although organic gas emissions from gasoline vehicles in Los Angeles are expected to fall by almost 80% over the next two decades, we predict no reduction in SOA production from these emissions due to the effects of rising NMOG:NOxon SOA yields. This highlights the importance of integrated emission control policies for NOxand organic gases.

scholarly journals Measurement report: Distinct Emissions and Volatility Distribution of Intermediate Volatility Organic Compounds from on-road Chinese Gasoline Vehicle: Implication of High Secondary Organic Aerosol Formation Potential

2020 ◽  
Author(s):  
Rongzhi Tang ◽  
Quanyang Lu ◽  
Song Guo ◽  
Hui Wang ◽  
Kai Song ◽  
...  
Keyword(s):  
Organic Compounds ◽  
Secondary Organic Aerosol ◽  
Volume Ratio ◽  
Organic Aerosol ◽  
Aerosol Formation ◽  
Vehicle Exhaust ◽  
Test Cycle ◽  
Yield Data ◽  
Formation Potential ◽  
Exhaust Purification

Abstract. In the present work, we performed chassis dynamometer experiments to investigate the emissions and secondary organic aerosol (SOA) formation potential of intermediate volatility organic compounds (IVOCs) from an on-road Chinese gasoline vehicle. High IVOCs emission factors (EFs) and distinct volatility distribution were recognized. The IVOCs EFs for the China V vehicle ranged from 12.1 to 226.3 mg · kg-fuel−1, with a median value of 83.7 mg · kg-fuel−1, which is higher than that from US vehicles. Besides, large discrepancy in volatility distribution and chemical composition of IVOCs from Chinese gasoline vehicle exhaust is discovered, with larger contributions of B14-B16 compounds and higher percentage of n-alkanes. Further we investigated the possible reasons that influence the IVOCs EFs and volatility distribution and found that fuel type, starting mode, operating cycles and acceleration rates could have an impact on the IVOCs EF. When using E10 (ethanol volume ratio of 10 %, v / v) as fuel, the IVOCs EF of the tested vehicle was lower than that using commercial China standard V fuel. Cold-start operation has higher IVOCs EF than hot-start operation. Chinese Light vehicles Test Cycle (CLTC) produced 70 % higher IVOCs than those from the World-wide harmonized Light-duty Test Cycle (WLTC). We found that vehicle emitted more IVOCs at lower acceleration rates, which leads to high EFs under CLTC. The only factor that may influence the volatility distribution and compound composition is the engine-aftertreatment system, which has compound and volatility selectivity in exhaust purification. These distinct characteristics in EFs and volatility may result in higher SOA formation potential in China. Using published yield data and surrogate equivalent method, we estimated SOA formation under different OA loading and NOx conditions. Results showed that under low and high NOx conditions at different OA loadings, IVOCs contributes more than 80% of the predicted SOA. Furthermore, we built up a parameterization method to simply estimate the vehicular SOA based on our bottom-up measurement of VOCs and IVOCs, which would provide another dimension of information when considering the vehicular contribution to the ambient OA. Our results indicate that vehicular IVOCs contribute significantly to SOA, implying that the importance of reducing IVOCs when making air pollution controlling policies in urban area of China.

scholarly journals Gasoline aromatics: a critical determinant of urban secondary organic aerosol formation

2017 ◽  
Vol 17 (17) ◽  
pp. 10743-10752 ◽  
Author(s):  
Jianfei Peng ◽  
Min Hu ◽  
Zhuofei Du ◽  
Yinhui Wang ◽  
Jing Zheng ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Urban Areas ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Urban Atmosphere ◽  
Aerosol Formation ◽  
Vehicle Exhaust ◽  
Aromatic Content ◽  
Volatile Organic

Abstract. Gasoline vehicle exhaust is an important contributor to secondary organic aerosol (SOA) formation in urban atmosphere. Fuel composition has a potentially considerable impact on gasoline SOA production, but the link between fuel components and SOA production is still poorly understood. Here, we present chamber experiments to investigate the impacts of gasoline aromatic content on SOA production through chamber oxidation approach. A significant amplification factor of 3–6 for SOA productions from gasoline exhausts is observed as gasoline aromatic content rose from 29 to 37 %. Considerably higher emission of aromatic volatile organic compounds (VOCs) using high-aromatic fuel plays an essential role in the enhancement of SOA production, while semi-volatile organic compounds (e.g., gas-phase PAHs) may also contribute to the higher SOA production. Our findings indicate that gasoline aromatics significantly influence ambient PM2. 5 concentration in urban areas and emphasize that more stringent regulation of gasoline aromatic content will lead to considerable benefits for urban air quality.

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