Spatiotemporal patterns and source implications of aromatic hydrocarbons at six rural sites across China's developed coastal regions

Zhang, Zhou; Zhang, Yanli; Wang, Xinming; Lu, Shaoping; Huang, Zhi‐Zhen; Huang, Xinyu; Yang, Weiqiang; Wang, Yuesi; Zhang, Qiang

doi:10.1002/2016jd025115

Cited by 110 publications

(43 citation statements)

References 96 publications

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“…It is worth noting that recent chamber studies revealed that aromatic hydrocarbons and traditional VOCs could not fully explain the SOA formed during atmospheric aging of source emissions (Zhao et al, 2014(Zhao et al, , 2015Deng et al, 2017;Fang et al, 2017), particularly for emissions from diesel vehicles or biomass burning (Zhao et al, 2015;Deng et al, 2017;Fang et al, 2017). Therefore the discussion on the SOAFP in this study is limited to traditional anthropogenic SOA precursor species (mainly aromatic hydrocarbons), and intermediate-volatility organic compounds (IVOCs), which are important SOA precursors (Zhao et al, 2014), should be further considered in order to fully understand the influence of control measures on ambient SOA.…”

Section: Source Contributions To the Soafpmentioning

confidence: 99%

Volatile organic compounds at a rural site in Beijing: influence of temporary emission control and wintertime heating

et al. 2018

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Abstract. While residential coal/biomass burning might be a major and underappreciated emission source for PM2.5, especially during winter, it is not well constrained whether burning solid fuels contributes substantially to ambient volatile organic compounds (VOCs), which are precursors to secondary organic aerosols (SOAs) that typically have a higher contribution to particulate matter during winter haze events. In this study, ambient air samples were collected in 2014 from 25 October to 31 December at a rural site on the campus of the University of Chinese Academy of Sciences (UCAS) in northeastern Beijing for the analysis of VOCs. Since temporary intervention measures were implemented on 3–12 November to improve the air quality for the Asian-Pacific Economic Cooperation (APEC) summit held on 5–11 November in Beijing, and wintertime central heating started on 15 November in Beijing after the APEC summit, this sample collection period provided a good opportunity to study the influence of temporary control measures and wintertime heating on ambient VOCs. As a result of the temporary intervention measures implemented during 3–12 November (period II), the total mixing ratios of non-methane hydrocarbons averaged 11.25 ppb, approximately 50 % lower than the values of 23.41 ppb in period I (25 October–2 November) and 21.71 ppb in period III (13 November–31 December). The ozone and SOA formation potentials decreased by ∼50 % and ∼70 %, respectively, during period II relative to period I, with the larger decrease in SOA formation potentials attributed to more effective control over aromatic hydrocarbons mainly from solvent use. Back trajectory analysis revealed that the average mixing ratios of VOCs in southerly air masses were 2.3, 2.3 and 2.9 times those in northerly air masses during periods I, II and III, respectively; all VOC episodes occurred under the influence of southerly winds, suggesting much stronger emissions in the southern urbanized regions than in the northern rural areas. Based on a positive matrix factorization (PMF) receptor model, the altered contributions from traffic emissions and solvent use could explain 47.9 % and 37.6 % of the reduction in ambient VOCs, respectively, during period II relative to period I, indicating that the temporary control measures on vehicle emissions and solvent use were effective at lowering the ambient levels of VOCs. Coal/biomass burning, gasoline exhaust and industrial emissions were among the major sources, and they altogether contributed 60.3 %, 78.6 % and 78.7 % of the VOCs during periods I, II and III, respectively. Coal/biomass burning, mostly residential coal burning, became the dominant source, accounting for 45.1 % of the VOCs during the wintertime heating period, with a specifically lower average contribution percentage in southerly air masses (38.2 %) than in northerly air masses (48.8 %). The results suggest that emission control in the industry and traffic sectors is more effective in lowering ambient reactive VOCs in non-heating seasons; however, during the winter heating season reducing emissions from residential burning of solid fuels would be of greater importance and would have health co-benefits from lowering both indoor and outdoor air pollution.

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Section: Source Contributions To the Soafpmentioning

confidence: 99%

Volatile organic compounds at a rural site in Beijing: influence of temporary emission control and wintertime heating

et al. 2018

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“…Toluene is the most abundant aromatic hydrocarbon (Calvert et al, 2002;Zhang et al, 2016), and SOA yields from the photooxidation of toluene on dry or wet ammonium sulfate (AS) seeds have been studied by varying the RH in smog chambers. Kamens et al (2011) observed higher yields of SOA from toluene at higher RHs.…”

Section: Introductionmentioning

confidence: 99%

Comparison of secondary organic aerosol formation from toluene on initially wet and dry ammonium sulfate particles at moderate relative humidity

Liu

Huang

et al. 2018

Atmos. Chem. Phys.

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Abstract. The formation of secondary organic aerosol (SOA) has been widely studied in the presence of dry seed particles at low relative humidity (RH). At higher RH, initially dry seed particles can exist as wet particles due to water uptake by the seeds as well as the SOA. Here, we investigated the formation of SOA from the photooxidation of toluene using an oxidation flow reactor in the absence of NO x under a range of OH exposures on initially wet or dry ammonium sulfate (AS) seed particles at an RH of 68 %. The ratio of the SOA yield on wet AS seeds to that on dry AS seeds, the relative SOA yield, decreased from 1.31 ± 0.02 at an OH exposure of 4.66 × 10 10 molecules cm −3 s to 1.01 ± 0.01 at an OH exposure of 5.28 × 10 11 molecules cm −3 s. This decrease may be due to the early deliquescence of initially dry AS seeds after being coated by highly oxidized toluene-derived SOA. SOA formation lowered the deliquescence RH of AS and resulted in the uptake of water by both AS and SOA. Hence the initially dry AS seeds contained aerosol liquid water (ALW) soon after SOA formed, and the SOA yield and ALW approached those of the initially wet AS seeds as OH exposure and ALW increased, especially at high OH exposure. However, a higher oxidation state of the SOA on initially wet AS seeds than that on dry AS seeds was observed at all levels of OH exposure. The difference in mass fractions of m/z 29, 43 and 44 of SOA mass spectra, obtained using an aerosol mass spectrometer (AMS), indicated that SOA formed on initially wet seeds may be enriched in earliergeneration products containing carbonyl functional groups at low OH exposures and later-generation products containing acidic functional groups at high exposures. Our results suggest that inorganic dry seeds become at least partially deliquesced particles during SOA formation and hence that ALW is inevitably involved in the SOA formation at moderate RH. More laboratory experiments conducted with a wide variety of SOA precursors and inorganic seeds under different NO x and RH conditions are warranted.

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“…Carbon monoxide (CO) in the ambient air samples were also analyzed with an Agilent model 6890 gas chromatography equipped with a FID and a packed column (5Å Molecular Sieve 60/80 mesh, 3 m1/8 inch). CO was first separated by packed column, then converted to CH4 by Ni-based catalyst and finally detected by FID (Zhang et al, 2016a).…”

Section: Sampling Site and Field Samplingmentioning

confidence: 99%

“…previous study demonstrated that levels of aromatic hydrocarbons and carbonyls increased significantly under haze days in urban Beijing from 2008 to 2010 (Zhang et al, 2014b), yet few reports are available about wintertime precursor VOCs in Beijing. In urban areas, vehicle exhausts are important sources of SOA precursors (McDonald et al, 2015;Liu et al, 2015a;Ortega et al, 2016;Deng et al, 2017;Gentner et al, 2017). However, biomass/biofuel burning and coal burning may also contribute substantially to SOA precursors (Yokelson et al, 2008;Shrivastava et al, 2015;Fang et al, 2017), particularly in north China in wintertime when raw coal and biofuels are widely used for household heating (Liu et al, 2016;Zhang et al, 2016a;. In fact, a study by in 2011-2012 revealed that even at an urban site in Beijing coal combustion could account for 28-39% of VOCs observed in ambient air.…”

Section: Introductionmentioning

confidence: 99%

Volatile organic compounds at a rural site in Beijing: Influence of temporary emission control and wintertime heating

Yang¹,

Zhang²,

Wang³

et al. 2018

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Spatiotemporal patterns and source implications of aromatic hydrocarbons at six rural sites across China's developed coastal regions

Cited by 110 publications

References 96 publications

Volatile organic compounds at a rural site in Beijing: influence of temporary emission control and wintertime heating

Volatile organic compounds at a rural site in Beijing: influence of temporary emission control and wintertime heating

Comparison of secondary organic aerosol formation from toluene on initially wet and dry ammonium sulfate particles at moderate relative humidity

Volatile organic compounds at a rural site in Beijing: Influence of temporary emission control and wintertime heating

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