Assessment of ClNO2 as a missing oxidant in the UK atmosphere

硝酰氯（ClNO 2）是一种氯活化途径和强氯源，对英国对流层成分和大气氧化能力有重大影响吗？夜间通过N2 O 5与含氯颗粒反应生成硝酰氯（ClNO 2）已被证明是一种非常有效的活化氯的机制。最近观察到高浓度的ClNO 2在美国和德国的海洋/沿海和大陆污染区，ClNO 2的浓度（高达1 ppb）强烈表明，ClNO 2的化学活性比以前认为的要大得多，对空气成分和质量有非常重要的影响，公众和环境健康以及全球气候。本提案中的工作通过协调一致的测量和建模方式探索英国是否ClNO 2可以释放大量的活性氯（Cl）到对流层中。这种化学物质对英国来说尤其重要，因为英国被海洋包围，海洋为沿海地区和内陆地区提供了持续的海盐来源。此外，燃煤发电站的排放，冬季道路上砂砾的传播以及游泳池，污水和水处理厂中氯化化合物的使用，可以提供非海盐Cl的重要来源。ClNO 2的另一种大气前体是N2 O 5。最近，在NERC资助的RONOCO活动期间，FAAM飞机对英国上空的N2 O 5进行了首次大规模测量。RONOCO的飞行发现高空中N2 O 5浓度升高（高达1 ppbv），通常与英国主要城市污染羽流中NOx（氮氧化物）的大气处理有关，例如伦敦在英吉利海峡/北海的外流。大量VOC、NOx和含氯颗粒的来源共存意味着ClNO 2化学在英国的大部分地区应该是活跃的。由于英国的大部分人口都生活在加州。距离海洋和几个大都市区100公里（例如，伦敦、格拉斯哥、利物浦）都位于海岸附近，这种化学物质很可能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.