Assessment of ClNO2 as a missing oxidant in the UK atmosphere

在英国，硝基氯(ClNO2)是一种氯活化途径和强氯源，对对流层的组成和大气的氧化能力有很大影响吗？N2O5在含氯粒子上夜间反应生成的硝基氯(ClNO2)已被证明是一种非常有效的氯活化机制。最近对美国和德国海洋/沿海和大陆污染区域的高水平ClNO2(高达1 ppb)的观测有力地表明，ClNO2化学活动的规模比以前认为的要大得多，对空气成分和质量、公共和环境健康以及全球气候都有非常重要的影响。在这项建议中的工作通过协调测量和模拟的方式来探索在英国的情况下，ClNO2是否可以向对流层释放大量的活性氯(Cl)。这种化学物质对英国可能特别重要，因为英国被海洋包围，这为沿海地区和更远的内陆地区提供了源源不断的海盐。此外，燃煤发电厂的排放、冬季道路上砂砾的扩散以及游泳池、污水和水处理厂中氯化合物的使用，都可能提供重要的非海盐氯来源。ClNO2的另一个大气前体是N2O5。最近，在NERC资助的RONOCO行动期间，FAAM飞机首次对英国上空的N2O5进行了大范围测量。RONOCO航班发现高空N2O5浓度升高(高达1ppbv)，这通常与英国主要城市的污染羽流中的NOx(氮氧化物)的大气处理有关，例如伦敦流经英吉利海峡/北海。VOC、NOx和含氯颗粒物的大量来源共存意味着ClNO2化学在英国大部分地区应该是活跃的。由于大多数英国人居住在距离海洋约100公里的范围内，而且几个大城市(如伦敦、格拉斯哥、利物浦)都位于海岸附近，这种化学反应可能会对许多人的健康和生活质量产生重大影响

Is nitryl chloride (ClNO2) a chlorine activation pathway and a strong Cl source that substantially affects tropospheric composition and oxidative capacity of the atmosphere in the UK?The nocturnal formation of nitryl chloride (ClNO2) via reaction of N2O5 on Cl- containing particles has been shown to be a very efficient mechanism to activate chlorine. Recent observations of high levels of ClNO2 (up to 1 ppb) in marine/coastal and continental polluted regions in USA and Germany strongly suggests that ClNO2 chemistry is active on a much larger scale than previously thought, with very important consequences for air composition and quality, public and environmental health and global climate.The work in this proposal explores by way of concerted measurements and modelling whether in the UK context, ClNO2 can release large concentrations of reactive chlorine (Cl) into the troposphere. The chemistry could be especially important for the United Kingdom as the UK is surrounded by the ocean, which provides a continuous source of sea-salt in the coastal areas and further inland. In addition, emissions from coal-fired power stations, spread of grit on roads during winter and usage of chlorinated compounds in swimming pools, sewage and water treatment plants, can provide significant sources of non sea-salt Cl. The other atmospheric precursor to ClNO2 is N2O5. The first wide-scale measurements of N2O5 above the UK were recently conducted from the FAAM aircraft during the NERC-funded RONOCO campaigns. The RONOCO flights found elevated N2O5 concentrations aloft (up to 1 ppbv), typically associated with atmospheric processing of NOx (nitrogen oxides) in pollution plumes from major UK cities, such as the London outflow over the English Channel/North Sea. The co-location of large sources of VOC, NOx and Cl- containing particles means that ClNO2 chemistry should be active in large parts of the UK. Since most of the population in the UK lives within ca. 100 km from the ocean and several large metropolitan areas (e.g., London, Glasgow, Liverpool) are located near the coast, this chemistry is likely to have a significant impact on the health and life quality of many people