The Effect of Particle Phase State on Multiphase Hydroxyl Radical (OH) Oxidation Kinetics and Products of Biomass Burning Aerosol

颗粒相态对生物质燃烧气溶胶多相羟基氧化动力学和产物的影响

• 批准号: 1446286
• 负责人: Daniel Knopf
• 金额: $ 32.15万
• 依托单位: SUNY at Stony Brook
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-07-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1446286&HistoricalAwards=false
• 关键词: Effect; Particle; Phase; State; Multiphase

Biomass burning aerosols (BBA) are ubiquitous throughout the global atmosphere. BBA source strength is believed to be of similar magnitude to the fossil fuel burning aerosols. Biomass burning plumes can affect the atmosphere on local to global scales, and BBAs can have a significant impact on visibility, and on the radiative forcing due to the direct scattering and absorption of radiation. By altering the properties of clouds, BBA also exert indirect effects on the radiation balance. Organic aerosols, representing a major mass fraction of the submicron size fraction, are implicated in human health effects. During atmospheric transport, organic aerosol particles are chemically transformed due to reactions with trace oxidizing species such as the hydroxyl radical (OH), resulting in chemical aging and ultimately cleansing of the atmosphere. The chemical aging of BBA particles by reactive trace gas species is not well understood, and so far investigations have been limited mostly to room temperature and dry conditions, although most of the atmosphere exhibits oxidizing conditions at lower temperatures and wider variations in relative humidity. Ambient environmental parameters, which induce altered viscosity or even phase changes, are responsible for altered chemical reactivity in BBA, and may in turn be responsible for altering the kinetics of many of these chemical transformations. A series of laboratory based investigations, using proxy and surrogate compounds under controlled conditions, are to be carried out in order to further describe the chemical transformations taking place during the formation, dispersal and aging of natural, biomass burning aerosols

生物质燃烧气溶胶（BBA）在全球大气中无处不在。BBA源强度被认为与燃烧化石燃料的气溶胶具有相似的量级。生物质燃烧羽流可以在局部到全球范围内影响大气，BBAs可以对能见度产生重大影响，并由于辐射的直接散射和吸收而对辐射强迫产生重大影响。通过改变云的性质，BBA还对辐射平衡产生间接影响。有机气溶胶占亚微米级颗粒的主要质量分数，对人类健康有影响。在大气传输过程中，有机气溶胶颗粒由于与羟基自由基（OH）等痕量氧化物质反应而发生化学转化，导致化学老化并最终净化大气。 活性痕量气体物种对BBA颗粒的化学老化还没有很好的了解，到目前为止，研究主要限于室温和干燥条件，尽管大多数大气在较低温度下表现出氧化条件，相对湿度变化较大。 周围的环境参数，诱导改变粘度甚至相变，是负责改变化学反应性BBA，并可能反过来负责改变动力学的许多这些化学转化。 为了进一步描述天然生物质燃烧气溶胶的形成、扩散和老化过程中发生的化学变化，将在受控条件下使用代用品和替代化合物进行一系列基于实验室的研究