Modeling the impact of chlorine emissions from coal combustion and prescribed waste incineration on tropospheric ozone formation in China

Abstract

Abstract. Chlorine radicals can enhance atmospheric oxidation which potentially increase tropospheric ozone concentration.However, few studies have been done to quantify the impact of chlorine emissions on ozone formation in China due to lack of chlorine emission inventory used in air quality model with sufficient resolution. In this study, Anthropogenic Chlorine Emissions Inventory for China (ACEIC) was developed for the first time, including emissions of hydrogen chloride (HCl) and molecular chlorine (Cl 2 ) from coal combustion and prescribed waste incineration (waste incineration plant). The HCl 15and Cl 2 emissions from coal combustion in China in 2012 were estimated to be 232.9 and 9.4 Gg, respectively, while HCl emission from prescribed waste incineration was estimated to be 2.9 Gg. Spatially high chlorine emissions were found in the North China Plain, the Yangtze River Delta and the Sichuan Basin. Air quality model simulations with the Community Multiscale Air Quality (CMAQ) modeling system were performed for November 2011 and the modeling results derived with and without chlorine emissions were compared. The magnitude of the simulated HCl, Cl 2 and ClNO 2 agreed reasonably with 20 the observation when anthropogenic chlorine emissions were included in the model. The inclusion of the ACEIC increased the concentration of fine particulate Cl -, leading to enhanced heterogeneous reactions between Cl -and N 2 O 5 which resulted in the higher production of ClNO 2 . Photolysis of ClNO 2 and Cl 2 in the morning and the reaction of HCl with OH in the afternoon produced chlorine radicals which accelerated tropospheric oxidation. When anthropogenic chlorine emissions were included in the model, the monthly mean concentrations of fine particulate Cl -, daily maximum 1-h ClNO 2 and Cl 25 radicals were estimated to increase by up to about 2.0 μg m -3 , 773 pptv and 1.5×10 3 molecule cm -3 in China, respectively.Meanwhile, the monthly mean daily maximum 1-h O 3 concentration was found to increase by up to 2.2 ppbv (3.8%), while the monthly mean NO x concentration decreased by up to 0.5 ppbv (6.1%). The anthropogenic chlorine emissions potentially increased the 1-h O 3 concentration by up to 7.7 ppbv in China. This study highlights the need for the inclusion of anthropogenic chlorine emission on air quality modeling and demonstrated its importance on tropospheric ozone formation. 30Atmos. Chem. Phys. Discuss., https://doi

Large Daytime Molecular Chlorine Missing Source at a Suburban Site in East China

“…Anthropogenic activities, such as coal combustion, water treatment (usage of chlorine‐containing disinfectants), waste water treatment, waste incineration, and industrial processes, have been proposed as potential sources of Cl 2 in the atmosphere, though their emission fluxes are not well known (Chang et al., 2002; Liu et al., 2018; Riedel et al., 2012, 2013; Tanaka et al., 2000; Yi et al., 2021). Riedel et al.…”

Status and quality evaluation of precursor emission inventories for PM<sub>2.5</sub> and ozone in China

“…增加到了 2021 年的 43 种 [55] 。除了 VOCs 和 PM 2.5 组分清单，我国学者也开始关注 S/IVOCs (semi-volatile and intermediate VOCs) 、氯和气态亚硝酸(HONO)等排放清单 [56-58] [43, 59] ，但 目前相关研究还相对较少。Wu 等人 [57,58] 先后采用了 POA 比值法建立了珠三角和中国 IVOCs 和 SVOCs 排放清单，但由于缺乏直接观测的 IVOCs 和 SVOCs 排放因子，IVOC 和 SVOCs 排放清 单依然存在较大的不确定性；我国现阶段建立的氯排放清单大部分为国家尺度 [7,60] ，主要关注 气态 Cl 2 、HCl 和二氯甲烷等有机氯以及颗粒氯 [61] ； HONO 排放清单主要为船舶 [34] 和机动车 [30] 等重点源排放清单，还缺乏综合 HONO 排放清单。…”

Anthropogenic Impacts on Tropospheric Reactive Chlorine Since the Preindustrial

“…Formation of HCl through acid displacement on SSA is thought to be the largest (85%) source of Cl y in the troposphere (X. Wang et al., 2019), and is influenced by anthropogenic emissions of acid gas precursors such as sulfur dioxide (SO 2 ) and nitrogen oxides (NO x = NO + NO 2 ). HCl is also emitted directly from combustion, mainly coal (Fu et al., 2018; Keene et al., 1999; Kolesar et al., 2018; Y. Liu et al., 2018; McCulloch, Aucott, Benkovitz et al., 1999; McCulloch, Aucott, Graedel et al., 1999). HCl contributes to acid deposition, causing damage to lakes and ecosystems, altering atmospheric acidity (Evans et al., 2011), and leads to severe haze and fog through cocondensation on aerosol (Gunthe et al., 2021).…”

“…Wang et al, 2019), and is influenced by anthropogenic emissions of acid gas precursors such as sulfur dioxide (SO 2 ) and nitrogen oxides (NO x = NO + NO 2 ). HCl is also emitted directly from combustion, mainly coal (Fu et al, 2018;Keene et al, 1999;Kolesar et al, 2018;Y. Liu et al, 2018;McCulloch, Aucott, Benkovitz et al, 1999;.…”