Temporal variations and source apportionment of volatile organic compounds at an urban site in Shijiazhuang, China

Guan, Yanan; Wang, Lei; Wang, Shujuan; Zhang, Yihao; Xiao, Jianjun; Wang, Xiaoli; Duan, Erhong; Hou, Li’an

doi:10.1016/j.jes.2020.04.022

Cited by 26 publications

(6 citation statements)

References 43 publications

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“…The PMF model is based on the fundamental principle of mass conservation to identify and apportion source contributions from a given data matrix using Eq. ( 2 ) (Assan et al 2018 ; Guan et al 2020 ; Paatero and Tapper 1994 ). where X ij represents the VOC concentration matrix with i number of samples and j number of measured VOCs, which are resolved by the PMF to provide p number of possible source factors with the source profile f of each source and mass g contributed by each factor to each sample, leaving the residuals e for each sample (Sarkar et al 2017 ).…”

Section: Methodsmentioning

confidence: 99%

Important revelations of different degrees of COVID-19 lockdown on improving regional air quality: a case study of Shijiazhuang, China

Guan

Shen

Liu

et al. 2022

Environ Sci Pollut Res

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To control the spread of COVID-19, Shijiazhuang implemented two lockdowns of different magnitudes in 2020 (lockdown I) and 2021 (lockdown II). We analyzed the changes in air quality index (AQI), PM 2.5 , O 3 , and VOCs during the two lockdowns and the same period in 2019 and quantified the effects of anthropogenic sources during the lockdowns. The results show that AQI decreased by 13.2% and 32.4%, and PM 2.5 concentrations decreased by 12.9% and 42.4% during lockdown I and lockdown II, respectively, due to the decrease in urban traffic mobility and industrial activity levels. However, the sudden and unreasonable emission reductions led to an increase in O 3 concentrations by 160.6% and 108.4%, respectively, during the lockdown period. To explore the causes of the O 3 surge, the major precursors NO x and VOCs were studied separately, and the main VOCs species affecting ozone formation during the lockdown period and the source variation of VOCs were identified, and it is important to note that the relationship between diurnal variation characteristics of VOCs and cooking became apparent during the lockdown period. These findings suggest that regional air quality can be improved by limiting production, but attention should be paid to the surge of O 3 caused by unreasonable emission reductions, clarifying the control priorities for urban O 3 management.

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Section: Methodsmentioning

confidence: 99%

Important revelations of different degrees of COVID-19 lockdown on improving regional air quality: a case study of Shijiazhuang, China

Guan

Shen

Liu

et al. 2022

Environ Sci Pollut Res

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“…To illustrate regional pollution levels on a broader scale, Figure 5 (Guan et al, 2020;Guo et al, 2022). Figure 3 illustrates that alkanes, alkenes, and aromatic were substantially underpredicted due to inadequate prediction of industrial areas with high VOCs emissions in the MEIC.…”

Section: Adjusting Vocs Emissions and Their Impacts On O3 Predictionsmentioning

confidence: 99%

“…These compounds undergo complex chemical reactions that form ozone (O3) and secondary organic aerosols (SOA) (Sillman, 1999;Kroll and Seinfeld, 2008). While biogenic VOCs (BVOCs) are the primary source of VOCs worldwide (Guenther et al, 2006), urban areas are predominantly influenced by anthropogenic sources (Guan et al, 2020;Guo et al, 2022;Li et al, 2022a). Anthropogenic VOCs (AVOCs) emission inventories are typically developed by estimating the total VOCs emissions using emission factors (EFs) and activity rates from different sources.…”

Section: Introductionmentioning

confidence: 99%

Current status of model predictions on volatile organic compounds and impacts on surface ozone predictions during summer in China

She

Lyu

et al. 2023

Preprint

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Abstract. Volatile organic compounds (VOCs) play a crucial role in the formation of tropospheric ozone (O3) and secondary organic aerosols. VOC emissions are generally considered to have larger uncertainties compared to other pollutants, such as sulphur dioxide and fine particulate matter (PM2.5). Although predictions of O3 and PM2.5 have been extensively evaluated in air quality modelling studies, there has been limited reporting on the evaluation of VOCs, mainly due to a lack of routine VOCs measurements at multiple sites. In this study, we utilized VOCs measurements from the ATMSYC project at 28 sites across China and assessed the predicted VOCs concentrations using the Community Multiscale Air Quality (CMAQ) model with the widely used Multi-resolution Emission Inventory for China (MEIC). The ratio of predicted to observed total VOCs was found to be 0.74 ± 0.40, with underpredictions ranging from 2.05 to 50.61 ppbv (5.77 % to 85.40 %) at 24 sites. A greater bias in VOCs predictions was observed in industrial cities in the north and southwest, such as Jinan, Shijiazhuang, Lanzhou, Chengdu, and Guiyang. In terms of different VOC components, alkanes, alkenes, non-naphthalene aromatics (ARO2MN), and alkynes were consistently underpredicted, with prediction to observation ratios of 0.53 ± 0.38, 0.51 ± 0.48, 0.31 ± 0.38, and 0.41 ± 0.47, respectively. Sensitivity experiments were conducted to assess the impact of the VOCs prediction bias on O3 predictions. While emission adjustments improved the model performance for VOCs, resulting in a ratio of total VOCs to 0.86 ± 0.47, they also exacerbated O3 overprediction relative to the base case by 0.62 % to 6.27 % across the sites. This study demonstrates that current modelling setups and emission inventories are likely to underpredict VOCs concentrations, and this underprediction of VOCs contributes to lower O3 predictions in China.

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“…It is also an important site in the southwest transport channel of air pollutants in the North China Plain (NCP) 19 . Guan et al 20 investigated the characteristics and sources of summertime VOCs in Shijiazhuang using an offline sampling method. They found that oxygenated VOCs (OVOCs) accounted for 37.9% of the total VOCs, followed by alkanes (33.9%), unlike the results in Beijing 21 , 22 , Chengdu 6 , etc., where alkanes had the highest contribution (42.6–44.5%) to total VOCs.…”

Section: Introductionmentioning

confidence: 99%

“…They found that oxygenated VOCs (OVOCs) accounted for 37.9% of the total VOCs, followed by alkanes (33.9%), unlike the results in Beijing 21 , 22 , Chengdu 6 , etc., where alkanes had the highest contribution (42.6–44.5%) to total VOCs. Meanwhile, petrochemical (24.2%) and other industrial sources (15.2%) were the main emission sources of VOCs in SJZ 20 . However, less attention has been paid to O 3 pollution in SJZ at present although it is an urgent issue from the perspective of both regional transport of air pollutants and local photochemistry.…”

Section: Introductionmentioning

confidence: 99%

The contribution of industrial emissions to ozone pollution: identified using ozone formation path tracing approach

Zhan

Song

et al. 2023

npj Clim Atmos Sci

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Wintertime meteorological conditions are usually unfavorable for ozone (O3) formation due to weak solar irradiation and low temperature. Here, we observed a prominent wintertime O3 pollution event in Shijiazhuang (SJZ) during the Chinese New Year (CNY) in 2021. Meteorological results found that the sudden change in the air pressure field, leading to the wind changing from northwest before CNY to southwest during CNY, promotes the accumulation of air pollutants from southwest neighbor areas of SJZ and greatly inhibits the diffusion and dilution of local pollutants. The photochemical regime of O3 formation is limited by volatile organic compounds (VOCs), suggesting that VOCs play an important role in O3 formation. With the developed O3 formation path tracing (OFPT) approach for O3 source apportionment, it has been found that highly reactive species, such as ethene, propene, toluene, and xylene, are key contributors to O3 production, resulting in the mean O3 production rate (PO3) during CNY being 3.7 times higher than that before and after CNY. Industrial combustion has been identified as the largest source of the PO3 (2.6 ± 2.2 ppbv h−1), with the biggest increment (4.8 times) during CNY compared to the periods before and after CNY. Strict control measures in the industry should be implemented for O3 pollution control in SJZ. Our results also demonstrate that the OFPT approach, which accounts for the dynamic variations of atmospheric composition and meteorological conditions, is effective for O3 source apportionment and can also well capture the O3 production capacity of different sources compared with the maximum incremental reactivity (MIR) method.

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Temporal variations and source apportionment of volatile organic compounds at an urban site in Shijiazhuang, China

Cited by 26 publications

References 43 publications

Important revelations of different degrees of COVID-19 lockdown on improving regional air quality: a case study of Shijiazhuang, China

Important revelations of different degrees of COVID-19 lockdown on improving regional air quality: a case study of Shijiazhuang, China

Current status of model predictions on volatile organic compounds and impacts on surface ozone predictions during summer in China

The contribution of industrial emissions to ozone pollution: identified using ozone formation path tracing approach

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