The Formation and Characterisation of Secondary Organic Aerosol and its Contribution to PM10 Concentrations in the UK Atmosphere

空气污染对公众的健康有严重的不利影响。其中包括过早死亡、额外入院以及哮喘等呼吸道疾病患者症状恶化。许多污染物是造成这些影响的原因，但影响最大的污染物是颗粒物。这个术语描述了漂浮在空气中的肉眼不可见的微小颗粒，这些颗粒可以被吸入肺部。这些颗粒物来自一系列来源，最著名的是道路交通。然而，排放源并不是颗粒物的唯一来源，越来越重要的贡献来自于气体化学反应在大气中形成的颗粒物。这些物质包括被称为硫酸盐和硝酸盐的化学物质，它们是由二氧化硫和氮氧化物的排放形成的，其形成途径相当清楚。此外，空气中的颗粒物中还有一类化学物质，称为次生有机化合物。这些气体是由人造来源（如汽油蒸气）和天然来源（特别是树木释放的化合物）产生的有机蒸气在大气中经过化学处理而形成的。这些次生有机化合物的化学组成非常多样化，它们对空气中颗粒物质量的贡献还不清楚。该项目涉及测量英国大气中的次级有机化合物，以估计它们对空气中颗粒物总量的贡献。此外，该项目还将测量这些颗粒的化学成分，并以此来了解它们是由哪些有机蒸气形成的。通过这些研究，将有可能推断出次生有机化合物质量的哪些部分可以通过减少人为来源来控制，哪些部分来自植物释放的天然化合物，这是不容易控制的。

Air pollution has important adverse effects on the health of the public. These include premature mortality, additional hospital admissions and worsening symptoms for people with respiratory diseases such as asthma. A number of pollutants are responsible for these effects but the one with the biggest impact is known as particulate matter. This term describes tiny particles invisible to the naked eye floating in the air, which can be breathed into the lungs. These particles arise from a range of sources, the best known being road traffic. However, emission sources are not the only source of particles and a contribution of growing importance is from particles which form in the atmosphere from chemical reactions of gases. These include chemical substances known as sulphates and nitrates, which form from emissions of sulphur dioxide and oxides of nitrogen by pathways that are reasonably well understood. In addition, there is a class of chemical substances within airborne particles known as secondary organic compounds. These are formed through chemical processing in the atmosphere of organic vapours arising from both manmade sources (e.g. petrol vapour) and natural sources, especially from compounds released by trees. These secondary organic compounds are very diverse in their chemical composition and their contribution to the mass of particles in the air is not well understood. This project is concerned with measuring secondary organic compounds in the atmosphere of the UK, so as to estimate their contribution to the total amount of airborne particles. In addition, the project will measure the chemical composition of such particles, and use this to understand which organic vapours they are formed from. Through such studies it will be possible to infer which parts of the secondary organic compound mass can be controlled through abatement of anthropogenic sources, and which part arises from natural compounds released from vegetation, which is not readily amenable to control.