上海地区大气中氯化氢和颗粒氯排放源清单初步研究

氯自由基对于臭氧和二次气溶胶的生成贡献不容忽视.夜间颗粒相氯(Cl~-)可以通过与N_2O_5的复杂反应转化生成ClNO_2,其光解产生的氯自由基将显著影响大气污染的形成机制.本文以上海地区为案例,以2017年为基准年,收集了人为源活动水平数据,采用排放系数估算方法,首次建立了上海地区人为源氯化氢(HCl)和颗粒氯(Cl~-)的排放清单;并进一步结合模型计算海盐气溶胶排放的颗粒氯(Cl~-).结果表明,2017年上海市人为源和天然源排放的HCl和Cl~-分别为1207 t和820 t,其中,燃煤、工业、垃圾焚烧和秸秆燃烧产生的HCl排放量分别为327、134、722和24 t.燃煤源中的燃煤电厂和其它行业燃烧约占燃煤源排放的80%;工业源中水泥为HCl的最大排放源,约占工业源排放的51%;垃圾焚烧厂排放约占总HCl排放的60%,为最大的HCl排放源.燃煤、工业源、垃圾焚烧、秸秆焚烧、烹饪源和海盐的颗粒Cl~-排放量分别为82、153、498、47、39和0.6 t,燃煤源中的燃煤电厂占燃煤Cl~-排放的40%,供热、其他行业和家庭燃烧分别占燃煤Cl~-排放的24%、22%和14%;钢铁行业为工业源的主要Cl~-排放源,约占工业源排放的90%,垃圾焚烧厂占全部Cl~-排放的61%,烹饪源中餐饮企业为最主要排放源,占烹饪源的70%;天然源海盐的排放量极少,未占到总排放的1%.从空间分布来看,浦东新区、宝山、普陀、松江和金山排放的HCl和Cl~-占到全市人为源总排放的80%,为主要的HCl和Cl~-排放区域.本文研究建立的上海地区大气中氯化氢和颗粒氯排放源清单,对于深入研究氯化学机制对二次污染的影响提供了重要的数据参考.

Preliminary study on the inventory of sources of hydrogen chloride and particulate chlorine in the atmosphere in Shanghai

Chlorine radicals contribute to the generation of ozone and secondary aerosols. At night, particulate chlorine (Cl^-) reacts with nitrogen pentoxide (N₂O₅) to form chlorine nitrite (ClNO₂), which could further produce chlorine radical under sunlight. Taking Shanghai as an example, this study collected anthropogenic activities data in year 2017 and calculated emissions of hydrogen chloride (HCl) and Cl^- from anthropogenic sources based on the emission factor method. Natural Cl^- emitted as sea salt was simulated using an offline oceanic emission model. The results show that HCl and Cl^- emissions from both anthropogenic sources and natural sources in 2017 were 1207 t and 819 t, respectively. With respect to HCl, waste incineration plants are the largest source of HCl emissions (722 t), followed by coal combustion (327 t), industrial sources (134 t), and straw burning (24 t). Coal-burning of power plants and other industries account for 80% of total HCl emissions from coal^- burning sources with cement production being the largest source of HCl of all industrial sources. With respect to Cl^- emissions, top five emission sources are waste incineration (498 t, accounting for 61%), industry (153 t), coal burning (82 t), straw burning (47 t) and cooking sources (39 t). Natural Cl^- emissions as sea salt are negligible (~0.6 t). Coal^- fired power plants account for 40% of all coal-fired Cl^- emissions, while heating, other industries and household combustion account for 24%, 22% and 14%, respectively. Steel industry is the dominant source of Cl^- emissions (90%) among all industrial sources while commercial catering is the dominant source (70%) of Cl^- from all cooking sources. Spatially, Pudong, Baoshan, Putuo, Songjiang and Jinshan were the main HCl and Cl^- emitting regions, together accounting for 80% of the total anthropogenic emissions. This study established a comprehensive bottom-up emission inventory of both hydrogen chloride and particulate chlorine in Shanghai, which is an important input dataset for further studies on the effects of chlorine chemistry on the formation of secondary air pollutants.