Sources and Potential Photochemical Roles of Formaldehyde in an Urban Atmosphere in South China

Wang, Chuan; Huang, Xiaofeng; Han, Yu; Zhu, Bo; He, Lingyan

doi:10.1002/2017jd027266

Cited by 63 publications

(32 citation statements)

References 105 publications

(217 reference statements)

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“…In addition to autumn, Ling et al (2017) showed strong photochemical activities in summer, but the prevailing southerly and southeasterly winds from the oceans alleviated carbonyls pollution during summer, whereas the northeasterly winds in autumn aggravated the pollution. Wang et al (2017a) investigated the source category contributions to HCHO in different seasons. They used the photochemical age-based parameterization method and found that the contributions of biogenic sources (including both primary and secondary biogenic sources) to HCHO were much higher during summer (41%) and autumn (39%) than during spring (26%) and winter (28%).…”

Section: Pearl River Deltamentioning

confidence: 99%

“…The collected data show that various aspects of carbonyls have been investigated. Analyses of the temporal and spatial distributions of carbonyls have been widely performed (Cheng et al, 2014;Dai et al, 2012;Guo et al, 2016;Ho et al, 2014a;Ho et al, 2015;Lui et al, 2017a;Lui et al, 2017c;Pang and Lee, 2010;Pang and Mu, 2006), but few studies have focused on the sources or photochemical mechanisms of carbonyls, or their influence on atmospheric chemistry, air quality, and human health (Ling et al, 2017;Liu et al, 2009;Wang et al, 2017a;Xue et al, 2016;Yang et al, 2018), so these aspects are relatively poorly understood. In addition, most studies have focused on the characteristics of gaseous carbonyls; observational data on high-molecular weight carbonyls are relatively scarce.…”

Section: Introductionmentioning

confidence: 99%

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Gaseous carbonyls in China's atmosphere: Tempo-spatial distributions, sources, photochemical formation, and impact on air quality

Zhang

Xue

Dong

et al. 2019

Atmospheric Environment

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Carbonyls are an important class of oxygenated volatile organic compounds that play a crucial role in tropospheric chemistry as intermediates in the formation of ozone (O3) and secondary organic aerosols. Over the last two decades, China's severe air pollution has led atmospheric chemists to devote substantial efforts to investigate the contribution of carbonyl compounds to the observed phenomena. This study reviews the major findings with regard to the gas-phase atmospheric chemistry of carbonyls in China, including their chemical compositions, temporal and spatial distributions, source apportionments, photochemical formation mechanisms, and impact on tropospheric oxidative capacity, air quality, and human health. Extremely high levels of carbonyls have frequently been observed in China's most rapidly developing regions, such as the North China Plain, the Yangtze River Delta, and the Pearl River Delta, but observational data from other regions are relatively scarce. Primary emissions and photochemical formation are major sources of carbonyls. Alkenes, aromatics, and isoprene have been identified as major precursors on a national scale. In addition, an increasing number of studies has focused on the effects of carbonyls on O3 formation, radical chemistry, the formation of secondary organic aerosols, and human health. The photolysis of oxygenated volatile organic compounds was recognized as a dominant pathway to ROx production, which further influences O3 formation, mainly via HO2+NO or RO2+NO. Dicarbonyls (such as glyoxal and methylglyoxal) make important contributions to secondary organic aerosol formation via irreversible uptake by aqueous particles. Indoor and outdoor carbonyls often pose a significant threat to human health. This review also includes recommendations from the perspective of emissions, observations, photochemical formation mechanisms, and the effects of carbonyls to guide future research and provide scientific support for the formulation of mitigation policies to address photochemical air pollution.

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Section: Pearl River Deltamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Gaseous carbonyls in China's atmosphere: Tempo-spatial distributions, sources, photochemical formation, and impact on air quality

Zhang

Xue

Dong

et al. 2019

Atmospheric Environment

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“…HCHO usually originates from the photochemical reactions of volatile organic compounds (VOCs) and can be used as a proxy for the total reactivity of VOCs 3 . The sources of VOCs include fire, vegetation and anthropogenic emissions 4 . VOCs are important precursors of secondary organic aerosols and ozone (O 3 ) 5 .…”

Section: Introductionmentioning

confidence: 99%

Satellite UV-Vis spectroscopy: implications for air quality trends and their driving forces in China during 2005–2017

et al. 2019

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Abundances of a range of air pollutants can be inferred from satellite UV-Vis spectroscopy measurements by using the unique absorption signatures of gas species. Here, we implemented several spectral fitting methods to retrieve tropospheric NO2, SO2, and HCHO from the ozone monitoring instrument (OMI), with radiative simulations providing necessary information on the interactions of scattered solar light within the atmosphere. We analyzed the spatial distribution and temporal trends of satellite-observed air pollutants over eastern China during 2005–2017, especially in heavily polluted regions. We found significant decreasing trends in NO2 and SO2 since 2011 over most regions, despite varying temporal features and turning points. In contrast, an overall increasing trend was identified for tropospheric HCHO over these regions in recent years. Furthermore, generalized additive models were implemented to understand the driving forces of air quality trends in China and assess the effectiveness of emission controls. Our results indicated that although meteorological parameters, such as wind, water vapor, solar radiation and temperature, mainly dominated the day-to-day and seasonal fluctuations in air pollutants, anthropogenic emissions played a unique role in the long-term variation in the ambient concentrations of NO2, SO2, and HCHO in the past 13 years. Generally, recent declines in NO2 and SO2 could be attributed to emission reductions due to effective air quality policies, and the opposite trends in HCHO may urge the need to control anthropogenic volatile organic compound (VOC) emissions.

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“…larger than direct emissions of HCHO, and will occur a few hours after the peak commuter time (e.g. Lin et al (2012); Wang et al (2017)). The early morning rush hour in Delhi starts after 0700 so we expect a 0930 overpass to also capture some fraction of the secondary HCHO production.…”

Section: Anthropogenic Hotspotsmentioning

confidence: 99%

Which processes drive observed variations of HCHO columns over India?

Surl¹,

Palmer²,

Abad³

2017

Preprint

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Abstract. We interpret HCHO column variations observed by the Ozone Monitoring Instrument (OMI), aboard the NASA Aura satellite, over India during 2014 using the GEOS-Chem atmospheric chemistry and transport model. We use a nested version of the model with a spatial resolution of approximately 25 km. HCHO columns are related to local emissions of volatile organic compounds (VOCs) with a spatial smearing that increases with the VOC lifetime. Over India, HCHO has bio-5 genic, pyrogenic, and anthropogenic VOC sources. Using a 0-D photochemistry model, we find that isoprene has the largest molar yield of HCHO that is typically realized within a few hours. We find that forested regions that neighbours major urban conurbations are exposed to high levels of nitrogen oxides. This results in depleted hydroxyl radical concentrations and a delay in the production of HCHO from isoprene oxidation. We find that propene is the only anthropogenic VOC emitted 10 in major Indian cities that produces HCHO at a comparable (slower) rate to isoprene. The GEOSChem model reproduces the broadscale annual mean HCHO column distribution observed by OMI (r=0.6), which is dominated by a distinctive meridional gradient in the northern half of the country, and by localized regions of high columns that coincide with forests. Major discrepancies are over the Indo-Gangetic Plain and Delhi. We find that the model has more skill at reproducing observations

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Sources and Potential Photochemical Roles of Formaldehyde in an Urban Atmosphere in South China

Cited by 63 publications

References 105 publications

Gaseous carbonyls in China's atmosphere: Tempo-spatial distributions, sources, photochemical formation, and impact on air quality

Gaseous carbonyls in China's atmosphere: Tempo-spatial distributions, sources, photochemical formation, and impact on air quality

Satellite UV-Vis spectroscopy: implications for air quality trends and their driving forces in China during 2005–2017

Which processes drive observed variations of HCHO columns over India?

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