Seasonal and diurnal variations of atmospheric peroxyacetyl nitrate, peroxypropionyl nitrate, and carbon tetrachloride in Beijing

Zhang, Gen; Mu, Yujing; Liu, Junfeng; Zhang, Chenglong; Zhang, Yuanyuan; Zhang, Yujie; Zhang, Hongxing

doi:10.1016/s1001-0742(13)60382-4

Cited by 36 publications

(12 citation statements)

References 57 publications

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“…These results could be attributed to the considerably high-water solubility of HAHs, despite their high vapor pressures. This occurrence is consistent with the results of numerous studies conducted outside Korea [43][44][45].…”

Section: Classificationsupporting

confidence: 93%

Geographical Distribution and Risk Assessment of Volatile Organic Compounds in Tributaries of the Han River Watershed

Cho

Noh

et al. 2021

Agronomy

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Volatile organic compounds (VOCs), with negative impacts on the aquatic ecosystem, are increasingly released into the environment by anthropogenic activities. Water samples were collected from five areas of the Han River Watershed (HRW) tributaries, South Korea, to detect 11 VOCs, which were classified as halogenated aliphatic hydrocarbons (HAHs) and aromatic hydrocarbons (AHs). Among the 11 VOCs, 1,1-dichloroethylene, 1,1,1-trichloroethane, and vinyl chloride were undetected. The highest concentration compounds were chloroform (0.0596 ± 0.1312 µg/L), trichloroethylene (0.0253 ± 0.0781 µg/L), and toluene (0.0054 ± 0.0139 µg/L). The mean concentration (0.0234 µg/L) and detection frequency (37.0%) of HAHs were higher than those of AHs (0.0036 µg/L, 21.0%, respectively). The Imjin Hantan River area exhibited the highest mean concentration (0.2432 µg/L) and detection frequency (22.9%), because it is located near industrial complexes, thus, highlighting their role as important VOC sources. However, the detected VOCs had lower concentrations than those permitted by the EU, WHO, USA, and South Korea drinking water guidelines. Ecological risks associated with the VOCs were estimated by risk quotient (RQ); consequently, the predicted no-effect concentration was 0.0029 mg/L, and the toluene and styrene RQ values were >1 and >0.5, respectively. The findings may facilitate policymakers in designing pollution control strategies.

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Section: Classificationsupporting

confidence: 93%

Geographical Distribution and Risk Assessment of Volatile Organic Compounds in Tributaries of the Han River Watershed

Cho

Noh

et al. 2021

Agronomy

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“…1. PAN was measured by a modified gas chromatograph (Agilent 7890B, USA) equipped with an electron capture detector, which has been described in our previous studies in detail (G. Zhang et al, 2014Zhang et al, , 2015. Trace gases including O 3 , SO 2 , NO x , and CO were detected by a set of commercial trace gas analyzers (Thermo Environmental Instruments Inc., USA, i-series 49i, 43i, 42i, and 48i, respectively; Zhang et al, 2018).…”

Section: Observationsmentioning

confidence: 99%

Exploring the inconsistent variations in atmospheric primary and secondary pollutants during the 2016 G20 summit in Hangzhou, China: implications from observations and models

Zhang

Wang

et al. 2020

Atmos. Chem. Phys.

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Abstract. Complex aerosol and photochemical pollution (ozone and peroxyacetyl nitrate, PAN) frequently occur in eastern China, and mitigation strategies to effectively alleviate both kinds of pollution are urgently needed. Although the effectiveness of powerful control measures implemented by the Chinese State Council has been comprehensively evaluated in terms of reducing atmospheric primary pollutants, the effectiveness in mitigating photochemical pollution is less assessed and therefore the underlying mechanisms are still poorly understood. The stringent emission controls implemented from 24 August to 6 September 2016 during the summit for the Group of Twenty (G20) provide us a unique opportunity to address this issue. Surface concentrations of atmospheric O3, PAN, and their precursors including volatile organic compounds (VOCs) and nitrogen dioxides (NOx), in addition to the other trace gases and particulate matter, were measured at the National Reference Climatological Station (NRCS) (30.22∘ N, 120.17∘ E, 41.7 m a.s.l) in urban Hangzhou. We found significant decreases in atmospheric PAN, NOx, total VOCs, PM2.5, and sulfur dioxide (SO2) under the unfavorable meteorological conditions during G20 (DG20) relative to the adjacent period before and after G20 (BG20 and AG20), indicating that the powerful control measures were effective in reducing the pollutant emissions in Hangzhou. Unlike with the other pollutants, daily maximum 8 h average (DMA8) O3 exhibited a slight increase and then decrease from BG20 to AG20, which was mainly attributed to the variation in the solar irradiation intensity and regional transport in addition to the contribution from the implementation of stringent control measures. Results from an observation-based chemical model (OBM) indicated that acetaldehyde and methylglyoxal (MGLY) were the most important second-generation precursors of PAN, accounting for 37.3 %–51.6 % and 22.8 %–29.5 % of the total production rates including the reactions of OVOCs, propagation of other radicals, and other minor sources. Moreover, we confirmed the production of PAN and O3 was sensitive to VOCs throughout the whole period, specifically dominated by aromatics in BG20 and DG20 but by alkenes in AG20. These findings suggested that reducing emissions of aromatics, alkenes, and alkanes would mitigate photochemical pollution including PAN and O3. Source appointment results attributed the reductions of VOC source and ozone formation potentials (OFPs) during G20 to the effective emission controls on traffic (vehicle exhaust) and industrial processes (solvent utilization and industrial manufacturing). However, fuel combustion and biogenic emissions both weakened such an effect with a sizable contribution to the VOC mixing ratios (18.8 % and 20.9 %) and OFPs (25.6 % and 17.8 %), especially during the latter part of G20 (G20 II) when anthropogenic VOCs were substantially reduced. This study highlights the effectiveness of stringent emission controls in relation to traffic and industrial sources, but a coordinated program related to controlling fuel combustion and biogenic emissions is also required to address secondary pollution.

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“…PAN is easily decomposed under high temperatures (Seinfeld & Pandis, 2006), while O 3 production rate increases with temperature (Sillman & Samson, 1995). In a conventional view, the winter PAN levels are low due to weak solar radiation (G. Zhang et al, 2014), and in summer, observed PAN pollution events are usually accompanied by O 3 pollution episodes (B. Zhang et al, 2017). However, recent studies in China found that PAN concentrations on winter haze days could be as high as those observed in summer photochemical smog (Liu et al, 2018; Qiu, Ma, et al, 2019; G. Zhang, Xia, et al, 2020; B. Zhang et al, 2019), suggesting potential contributions from unfavorable meteorological conditions and local photochemical reactions (Qiu, Ma, et al, 2019; J. Zhang, Guo, et al, 2020).…”

Section: Introductionmentioning

confidence: 99%

Markedly Enhanced Levels of Peroxyacetyl Nitrate (PAN) During COVID‐19 in Beijing

Qiu

et al. 2020

Geophysical Research Letters

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High levels of secondary air pollutants during COVID-19 in China have aroused great concern. In Beijing, measured daily mean peroxyacetyl nitrate (PAN) concentrations reached 4 ppb over the lockdown period (24 January to 15 February), whose averages were 2-3 times that before lockdown (1-23 January). The lockdown PAN levels also reached a high historical record based on our long-term measurements (2016-2019). Unlike ozone and PM 2.5 , PAN formation depends on less complex photochemistry between NO x and volatile organic compounds (VOCs), providing a novel approach to investigate the wintertime photochemistry during COVID-19. The GEOS-Chem simulations suggest a markedly enhanced photochemistry by a factor of 2 during the lockdown. Change of meteorology featuring with anomalous wind convergence under higher temperatures is the main reason for enhanced photochemical formation of PAN, while chemically nonlinear feedbacks also play a role. Our results suggest implementing targeted VOC emission controls in the context of increasing photochemical pollution over this complex polluted region. Plain Language Summary Outbreaks of the COVID-19 pandemic caused immediate implementation of lockdown policy in China, which drastically decreased emissions of primary air pollutants. Peroxyacetyl nitrate (PAN), as an important photochemical product, is controlled by reactions between NO x and volatile organic compounds (VOCs) that were reduced substantially due to the lockdown. However, observed PAN levels in Beijing during the lockdown were markedly enhanced and were even much higher than the concentrations during the same periods in 2016-2019. Modeling results prove that this increase in PAN is driven by enhanced photochemistry, resulting from anomalous wind convergence under higher temperature and enhanced radical level in response to NO x reduction. Our results suggest the necessity of reducing VOC emissions in controlling photochemical pollution even in the wintertime over China.

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Seasonal and diurnal variations of atmospheric peroxyacetyl nitrate, peroxypropionyl nitrate, and carbon tetrachloride in Beijing

Cited by 36 publications

References 57 publications

Geographical Distribution and Risk Assessment of Volatile Organic Compounds in Tributaries of the Han River Watershed

Geographical Distribution and Risk Assessment of Volatile Organic Compounds in Tributaries of the Han River Watershed

Exploring the inconsistent variations in atmospheric primary and secondary pollutants during the 2016 G20 summit in Hangzhou, China: implications from observations and models

Markedly Enhanced Levels of Peroxyacetyl Nitrate (PAN) During COVID‐19 in Beijing

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