Understanding the atmospheric chemistry of biomass burning emissions and their impact on air quality and climate

大规模的生物质燃烧事件，包括野火、农业焚烧和居民燃料燃烧，向大气中释放了大量的有机碳。然后，这些排放会发生化学变化，产生广泛的二次气体和颗粒产品，对气候和空气质量产生重大影响。空气质量和气候变化是我们这个时代最重要的两个环境问题，影响着人类健康、生态系统和经济。世界卫生组织估计，全球每年有880万人死于直接暴露在空气污染中。暴露在糟糕的空气质量中对健康有一系列的短期和长期影响，包括一系列心血管和呼吸系统疾病、癌症、糖尿病和与痴呆症有关的疾病。过去十年，美国、巴西和澳大利亚的野火频率和强度显著增加，由于火灾/土地管理做法和气候变化，这一趋势可能会继续下去。因此，了解这些排放的气体和气溶胶相产物的形成变得越来越重要，以便量化它们的影响并限制它们的有害影响。在这个项目中，我们将设计一系列实验，在约克郡建造的流动反应器中进行大气化学研究，以了解一系列生物质燃烧排放的气体和气溶胶相产物的最重要形成途径。这些重点将集中在含氧芳香挥发性有机化合物(VOC)上，如呋喃和酚类化合物。首先，流动反应器将通过在芳香体系上进行的一系列实验来描述，这些体系的化学机理已在主化学机理(MCM：mcm.york.ac.uk)中提供。使用在线和离线质谱学技术，包括气相物种的质子转移反应质谱仪(PTR-MS)和选择离子流管质谱仪(SIFT-MS)，以及与Orbitrap质谱仪耦合的超高压液相色谱(UPLC)，将测量前体物种的损失和各种气体和气溶胶产物的形成。实验将使用基于MCM中可用详细化学成分的盒子模型来设计，并针对流动反应器的条件进行优化。新开发和评估的用于排放生物质燃烧化合物的化学机制将随后被纳入MCM。

Large scale biomass burning events, including wildfires, agricultural burn-off and residential fuel combustion, release large quantities of organic carbon to the atmosphere. These emissions can then undergo chemical transformations leading to a wide range of secondary gas and particulate products which can have a significant impact upon climate and air quality.Air quality and climate change are two of the most important environmental issues of our time, impacting human health, ecosystems, and the economy. The World Health Organisation has estimated that globally 8.8 million people die each year as a direct result of exposure to air pollution. Exposure to poor air quality has a range of short and long term impacts on health including a wide range of cardiovascular and respiratory diseases, cancer, diabetes and links to dementia.The frequency and intensity of wildfires in the US, Brazil and Australia have notably increased over the last decade, and this trend is likely to continue owing to fire/land management practises and climate change. Therefore, it is becoming increasingly important to understand the formation of gas and aerosol phase products from these emissions in order to quantify their impacts and limit their detrimental effects.In this project we will design a series of experiments to be carried out in a flow reactor built in York to study atmospheric chemistry, in order to understand the most important formation pathways of gas and aerosol phase products from a range of biomass-burning emissions. These will focus on oxygenated aromatic volatile organic compounds (VOC), such as furans and phenolic compounds. First, the flow reactor will be characterised through a set of experiments carried out on aromatic systems whose chemical mechanisms are already available in the Master Chemical Mechanism (MCM: mcm.york.ac.uk). The loss of the precursor species and the formation of wide range of gas and aerosol phase products will be measured using on and off-line mass spectrometric techniques including PTR-MS (Proton Transfer Reaction mass spectrometry) and SIFT-MS (Selected Ion Flow Tube mass spectrometry) for gas phase species, and UPLC (ultra-high pressure liquid chromatography) coupled to Orbitrap mass spectrometry for investigating secondary organic aerosol composition. Experiments will be designed using box models based around the detailed chemistry available in the MCM, optimised for the conditions of the flow reactor. Newly developed and evaluated chemical mechanisms for emitted biomass burning compounds will subsequently be incorporated into the MCM.