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peroxyacetyl nitrate at a rural site in Beijing based on continuous observations from 2015 to 2019 and the WRF-Chem

Yulu Qiu, Zhiqiang Ma, Weili Lin, Weijun Quan, Weiwei Pu, Yingruo Li, Liyan Zhou, Qingfeng Shi

《环境科学与工程前沿(英文)》 2020年 第14卷 第4期 doi: 10.1007/s11783-020-1250-0

摘要: Abstract •PAN concentrations at a rural site near Beijing were monitored from 2015 to 2019. •PAN concentrations exhibited high values in spring and low values in winter. •Anomalously southerlies induced extreme high PAN concentration in spring 2018. Peroxyacetyl nitrate (PAN) is one of the most important photochemical pollutants and has aroused much concern in China in recent decades. However, few studies described the long-term variations in PAN in China. In this study, we continuously monitored the PAN, O3 and NOx concentrations at a regional background site near Beijing from August 2015 to February 2019. Based on the observed concentrations and climate data, we analyzed the seasonal PAN variations. The results revealed that the monthly mean PAN concentration ranged from 0.33–2.41 ppb, with an average value of 0.94 ppb. The PAN concentration exhibited a distinct seasonal variation, with high values in spring and low values in winter. After analyzing the corresponding meteorological data, we found that stronger ultraviolet (UV) radiation, a relatively longer lifetime and a higher background PAN concentration contributed to the high PAN concentrations in spring. In addition, with the utilization of the WRF-Chem (Weather Research and Forecasting with Chemistry) model, the cause of the extremely high PAN concentration in spring 2018 was determined. The model results demonstrated that an anomalously low pressure and the southwesterly winds in northern China might be the main causes of the increased PAN concentration in Beijing and its surrounding area in spring 2018.

关键词: PAN     Ozone     Beijing     WRF-Chem    

Improving simulations of sulfate aerosols during winter haze over Northern China: the impacts of heterogeneous oxidation by NO

Meng Gao,Gregory R. Carmichael,Yuesi Wang,Dongsheng Ji,Zirui Liu,Zifa Wang

《环境科学与工程前沿(英文)》 2016年 第10卷 第5期 doi: 10.1007/s11783-016-0878-2

摘要: Incorporating the missing heterogeneous oxidation of S(IV) by NO into the WRF-Chem model. Sulfate production is not sensitive to increase in SO emission. The newly added reaction reproduces sulfate concentrations well during winter haze. We implemented the online coupled WRF-Chem model to reproduce the 2013 January haze event in North China, and evaluated simulated meteorological and chemical fields using multiple observations. The comparisons suggest that temperature and relative humidity (RH) were simulated well (mean biases are -0.2K and 2.7%, respectively), but wind speeds were overestimated (mean bias is 0.5 m?s ). At the Beijing station, sulfur dioxide (SO ) concentrations were overpredicted and sulfate concentrations were largely underpredicted, which may result from uncertainties in SO emissions and missing heterogeneous oxidation in current model. We conducted three parallel experiments to examine the impacts of doubling SO emissions and incorporating heterogeneous oxidation of dissolved SO by nitrogen dioxide (NO ) on sulfate formation during winter haze. The results suggest that doubling SO emissions do not significantly affect sulfate concentrations, but adding heterogeneous oxidation of dissolved SO by NO substantially improve simulations of sulfate and other inorganic aerosols. Although the enhanced SO to sulfate conversion in the HetS (heterogeneous oxidation by NO ) case reduces SO concentrations, it is still largely overestimated by the model, indicating the overestimations of SO concentrations in the North China Plain (NCP) are mostly due to errors in SO emission inventory.

关键词: Sulfate aerosols     Winter haze     WRF-Chem     Northern China    

How aerosol direct effects influence the source contributions to PM

Litao Wang, Joshua S. Fu, Wei Wei, Zhe Wei, Chenchen Meng, Simeng Ma, Jiandong Wang

《环境科学与工程前沿(英文)》 2018年 第12卷 第3期 doi: 10.1007/s11783-018-1014-2

摘要: Beijing-Tianjin-Hebei area is the most air polluted region in China and the three neighborhood southern Hebei cities, Shijiazhuang, Xingtai, and Handan, are listed in the top ten polluted cities with severe PM pollution. The objective of this paper is to evaluate the impacts of aerosol direct effects on air quality over the southern Hebei cities, as well as the impacts when considering those effects on source apportionment using three dimensional air quality models. The WRF/Chem model was applied over the East Asia and northern China at 36 and 12 km horizontal grid resolutions, respectively, for the period of January 2013, with two sets of simulations with or without aerosol-meteorology feedbacks. The source contributions of power plants, industrial, domestic, transportation, and agriculture are evaluated using the Brute-Force Method (BFM) under the two simulation configurations. Our results indicate that, although the increases in PM concentrations due to those effects over the three southern Hebei cities are only 3%–9% on montly average, they are much more significant under high PM loadings (~50 μg·m when PM concentrations are higher than 400 μg m ). When considering the aerosol feedbacks, the contributions of industrial and domestic sources assessed using the BFM will obviously increase (e.g., from 30%–34% to 32%–37% for industrial), especially under high PM loadings (e.g., from 36%–44% to 43%–47% for domestic when PM >400 μg·m ). Our results imply that the aerosol direct effects should not be ignored during severe pollution episodes, especially in short-term source apportionment using the BFM.

关键词: Aerosol direct effect     PM2.5     Southern Hebei     WRF/Chem     Haze    

标题 作者 时间 类型 操作

peroxyacetyl nitrate at a rural site in Beijing based on continuous observations from 2015 to 2019 and the WRF-Chem

Yulu Qiu, Zhiqiang Ma, Weili Lin, Weijun Quan, Weiwei Pu, Yingruo Li, Liyan Zhou, Qingfeng Shi

期刊论文

Improving simulations of sulfate aerosols during winter haze over Northern China: the impacts of heterogeneous oxidation by NO

Meng Gao,Gregory R. Carmichael,Yuesi Wang,Dongsheng Ji,Zirui Liu,Zifa Wang

期刊论文

How aerosol direct effects influence the source contributions to PM

Litao Wang, Joshua S. Fu, Wei Wei, Zhe Wei, Chenchen Meng, Simeng Ma, Jiandong Wang

期刊论文