scholarly journals Fast heterogeneous N<sub>2</sub>O<sub>5</sub> uptake and ClNO<sub>2</sub> production in power plant and industrial plumes observed in the nocturnal residual layer over the North China Plain

2017 ◽  
Vol 17 (20) ◽  
pp. 12361-12378 ◽  
Author(s):  
Zhe Wang ◽  
Weihao Wang ◽  
Yee Jun Tham ◽  
Qinyi Li ◽  
Hao Wang ◽  
...  
Keyword(s):  
North China Plain ◽  
North China ◽  
Northern China ◽  
Residual Layer ◽  
Tropospheric Chemistry ◽  
Aerosol Formation ◽  
The North ◽  
The North China Plain ◽  
Haze Pollution ◽  
Key Species

Abstract. Dinitrogen pentoxide (N2O5) and nitryl chloride (ClNO2) are key species in nocturnal tropospheric chemistry and have significant effects on particulate nitrate formation and the following day's photochemistry through chlorine radical production and NOx recycling upon photolysis of ClNO2. To better understand the roles of N2O5 and ClNO2 in the high-aerosol-loading environment of northern China, an intensive field study was carried out at a high-altitude site (Mt. Tai, 1465 m a.s.l.) in the North China Plain (NCP) during the summer of 2014. Elevated ClNO2 plumes were frequently observed in the nocturnal residual layer with a maximum mixing ratio of 2.1 ppbv (1 min), whilst N2O5 was typically present at very low levels (< 30 pptv), indicating fast heterogeneous N2O5 hydrolysis. Combined analyses of chemical characteristics and backward trajectories indicated that the ClNO2-laden air was caused by the transport of NOx-rich plumes from the coal-fired industry and power plants in the NCP. The heterogeneous N2O5 uptake coefficient (γ) and ClNO2 yield (ϕ) were estimated from steady-state analysis and observed growth rate of ClNO2. The derived γ and ϕ exhibited high variability, with means of 0.061 ± 0.025 and 0.28 ± 0.24, respectively. These values are higher than those derived from previous laboratory and field studies in other regions and cannot be well characterized by model parameterizations. Fast heterogeneous N2O5 reactions dominated the nocturnal NOx loss in the residual layer over this region and contributed to substantial nitrate formation of up to 17 µg m−3. The estimated nocturnal nitrate formation rates ranged from 0.2 to 4.8 µg m−3 h−1 in various plumes, with a mean of 2.2  ± 1.4 µg m−3 h−1. The results demonstrate the significance of heterogeneous N2O5 reactivity and chlorine activation in the NCP, and their unique and universal roles in fine aerosol formation and NOx transformation, and thus their potential impacts on regional haze pollution in northern China.

scholarly journals Fast heterogeneous N<sub>2</sub>O<sub>5</sub> uptake and ClNO<sub>2</sub> production in power plant plumes observed in the nocturnal residual layer over the North China Plain

2017 ◽  
Author(s):  
Zhe Wang ◽  
Weihao Wang ◽  
Yee Jun Tham ◽  
Qinyi Li ◽  
Hao Wang ◽  
...  
Keyword(s):  
North China Plain ◽  
North China ◽  
Northern China ◽  
Residual Layer ◽  
Tropospheric Chemistry ◽  
Aerosol Formation ◽  
The North ◽  
The North China Plain ◽  
Haze Pollution ◽  
Key Species

Abstract. Dinitrogen pentoxide (N2O5) and nitryl chloride (ClNO2) are key species in nocturnal tropospheric chemistry, and have significant effects on particulate nitrate formation and the following day’s photochemistry. To better understand the roles of N2O5 and ClNO2 in the high aerosol loading environment of northern China, an intensive field study was carried out at a high-altitude site (Mt. Tai, 1465 m a.s.l.) in the North China Plain (NCP) during the summer of 2014. Elevated ClNO2 plumes were frequently observed in the nocturnal residual layer with a maximum mixing ratio of 2.1 ppbv (1-min), whilst N2O5 was typically present at very low levels (<30 pptv), indicating fast heterogeneous N2O5 hydrolysis. Combined analyses of chemical characteristics and backward trajectories indicated that the ClNO2-laden air was caused by the transport of NOx-rich plumes from the coal-fired power plants in the NCP. The heterogeneous N2O5 uptake coefficient (γ) and ClNO2 yield (ϕ) during the campaign exhibited high variability, with means of 0.061 ± 0.025 and 0.27 ± 0.24, respectively. These derived values are higher than those derived from previous laboratory and field studies in other regions, and cannot be well characterized by model parameterizations. Fast heterogeneous N2O5 reactions dominated the nocturnal NOx loss in the residual layer over this region, and contributed to substantial nitrate formation of up to 17 μg m−3. The determined nocturnal nitrate formation rates ranged from 0.2 to 4.8 μg m−3 hr−1 in various plumes, with a mean of 2.2 ± 1.4 μg m−3 h−1. The results demonstrate the significance of heterogeneous N2O5 reactivity and chlorine activation in the NCP, and their unique and universal roles in fine aerosol formation and NOx transformation, and thus potential impacts on regional haze pollution in northern China.

scholarly journals Role of Ammonia on the Feedback Between AWC and Inorganic Aerosol Formation During Heavy Pollution in the North China Plain

2019 ◽  
Vol 6 (9) ◽  
pp. 1675-1693 ◽  
Author(s):  
Baozhu Ge ◽  
Xiaobin Xu ◽  
Zhiqiang Ma ◽  
Xiaole Pan ◽  
Zhe Wang ◽  
...  
Keyword(s):  
North China Plain ◽  
North China ◽  
Aerosol Formation ◽  
The North ◽  
The North China Plain ◽  
Heavy Pollution ◽  
Inorganic Aerosol

Explosive morning growth phenomena of NH3 on the North China Plain: Causes and potential impacts on aerosol formation

2020 ◽  
Vol 257 ◽  
pp. 113621 ◽  
Author(s):  
Ye Kuang ◽  
Wanyun Xu ◽  
Weili Lin ◽  
Zhaoyang Meng ◽  
Huarong Zhao ◽  
...  
Keyword(s):  
North China Plain ◽  
North China ◽  
Aerosol Formation ◽  
The North ◽  
The North China Plain

Hydrologic and Climatic Responses to Global Anthropogenic Groundwater Extraction

2017 ◽  
Vol 30 (1) ◽  
pp. 71-90 ◽  
Author(s):  
Yujin Zeng ◽  
Zhenghui Xie ◽  
Jing Zou
Keyword(s):  
North China Plain ◽  
North China ◽  
Supply And Demand ◽  
Northern China ◽  
Large Area ◽  
Deep Soil ◽  
Northern India ◽  
The North ◽  
The North China Plain ◽  
Climatic Responses

In this study, a groundwater (GW) extraction scheme was incorporated into the Community Earth System Model, version 1.2.0 (CESM1.2.0), to create a new version called CESM1.2_GW, which was used to investigate hydrologic and climatic responses to anthropogenic GW extraction on a global scale. An ensemble of 41-yr simulations with and without GW extraction (estimated based on local water supply and demand) was conducted and analyzed. The results revealed that GW extraction and water consumption caused drying in deep soil layers but wetting in upper layers, along with a rapidly declining GW table in areas with the most severe GW extraction, including the central United States, the north China plain, and northern India and Pakistan. The atmosphere also responded to GW extraction, with cooling at the 850-hPa level over northern India and Pakistan and a large area in northern China and central Russia. Increased precipitation occurred in the north China plain due to increased evapotranspiration from irrigation. Decreased precipitation occurred in northern India because the Indian monsoon and its transport of water vapor were weaker as a result of cooling induced by GW use. Additionally, the background climate change may complicate the precipitation responses to the GW use. Local terrestrial water storage was shown to be unsustainable at the current high GW extraction rate. Thus, a balance between reduced GW withdrawal and rapid economic development must be achieved in order to maintain a sustainable GW resource, especially in regions where GW is being overexploited.

scholarly journals Aerosol optical depth thresholds as a tool to assess diffuse radiation fertilization of the land carbon uptake in China

2017 ◽  
Vol 17 (2) ◽  
pp. 1329-1342 ◽  
Author(s):  
Xu Yue ◽  
Nadine Unger
Keyword(s):  
Aerosol Optical Depth ◽  
Optical Depth ◽  
North China Plain ◽  
North China ◽  
Carbon Uptake ◽  
The North ◽  
The North China Plain ◽  
Haze Pollution ◽  
Aerosol Pollution ◽  
Sky Conditions

Abstract. China suffers from frequent haze pollution episodes that alter the surface solar radiation and influence regional carbon uptake by the land biosphere. Here, we apply combined vegetation and radiation modeling and multiple observational datasets to assess the radiative effects of aerosol pollution in China on the regional land carbon uptake for the 2009–2011 period. First, we assess the inherent sensitivity of China's land biosphere to aerosol pollution by defining and calculating two thresholds of aerosol optical depth (AOD) at 550 nm, (i) AODt1, resulting in the maximum net primary productivity (NPP), and (ii) AODt2, such that if local AOD < AODt2, the aerosol diffuse fertilization effect (DFE) always promotes local NPP compared with aerosol-free conditions. Then, we apply the thresholds, satellite data, and interactive vegetation modeling to estimate current impacts of aerosol pollution on land ecosystems. In the northeast, observed AOD is 55 % lower than AODt1, indicating a strong aerosol DFE on local NPP. In the southeastern coastal regions, observed AOD is close to AODt1, suggesting that regional NPP is promoted by the current level of aerosol loading, but that further increases in AOD in this region will weaken the fertilization effects. The North China Plain experiences limited enhancement of NPP by aerosols because observed AOD is 77 % higher than AODt1 but 14 % lower than AODt2. Aerosols always inhibit regional NPP in the southwest because of the persistent high cloud coverage that already substantially reduces the total light availability there. Under clear-sky conditions, simulated NPP shows widespread increases of 20–60 % (35.0 ± 0.9 % on average) by aerosols. Under all-sky conditions, aerosol pollution has spatially contrasting opposite sign effects on NPP from −3 % to +6 % (1.6 ± 0.5 % on average), depending on the local AOD relative to the regional thresholds. Stringent aerosol pollution reductions motivated by public health concerns, especially in the North China Plain and the southwest, will help protect land ecosystem functioning in China and mitigate long-term global warming.

scholarly journals Aerosol–radiation feedback deteriorates the wintertime haze in the North China Plain

2019 ◽  
Vol 19 (13) ◽  
pp. 8703-8719 ◽  
Author(s):  
Jiarui Wu ◽  
Naifang Bei ◽  
Bo Hu ◽  
Suixin Liu ◽  
Meng Zhou ◽  
...  
Keyword(s):  
Solar Radiation ◽  
Air Pollutants ◽  
North China Plain ◽  
North China ◽  
Near Surface ◽  
The North ◽  
The North China Plain ◽  
Incoming Solar Radiation ◽  
Haze Pollution ◽  
Pm2.5 Concentration

Abstract. Atmospheric aerosols scatter or absorb a fraction of the incoming solar radiation to cool or warm the atmosphere, decreasing surface temperature and altering atmospheric stability to further affect the dispersion of air pollutants in the planetary boundary layer (PBL). In the present study, simulations during a persistent and heavy haze pollution episode from 5 December 2015 to 4 January 2016 in the North China Plain (NCP) were performed using the Weather Research and Forecasting model with Chemistry (WRF-Chem) to comprehensively quantify contributions of aerosol shortwave radiative feedback (ARF) to near-surface (around 15 m above the ground surface) PM2.5 mass concentrations. The WRF-Chem model generally performs well in simulating the temporal variations and spatial distributions of air pollutants concentrations compared to observations at ambient monitoring sites in the NCP, and the simulated diurnal variations of aerosol species are also consistent with the measurements in Beijing. Additionally, the model simulates the aerosol radiative properties, the downward shortwave flux, and the PBL height against observations in the NCP well. During the episode, ARF deteriorates the haze pollution, increasing the near-surface PM2.5 concentrations in the NCP by 10.2 µg m−3 or with a contribution of 7.8 % on average. Sensitivity studies have revealed that high loadings of PM2.5 attenuate the incoming solar radiation reaching the surface to cool the low-level atmosphere, suppressing the development of the PBL, decreasing the surface wind speed, further hindering the PM2.5 dispersion, and consequently exacerbating the haze pollution in the NCP. Furthermore, when the near-surface PM2.5 mass concentration increases from around 50 to several hundred µg m−3, ARF contributes to the near-surface PM2.5 by more than 20 % during daytime in the NCP, substantially aggravating the heavy haze formation. However, when the near-surface PM2.5 concentration is less than around 50 µg m−3, ARF generally reduces the near-surface PM2.5 concentration due to the consequent perturbation of atmospheric dynamic fields.

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