Collaborative Research: Sizing Up the Smoke--Evaluating and Improving Our Ability to Predict Aged Wildfire Aerosol Size Distributions

本研究的重点是研究生物质燃烧排放的老化问题。生物质燃烧释放出的小颗粒会在大气中发生反应，改变它们的大小、数量和组成。这些老化过程将被建模，模型结果将与现场活动的实际数据进行测试。以下问题将被调查：(1)什么化学过程，当与生物质燃烧排放的分散和凝固相结合时，捕捉到在实验室和现场看到的气溶胶大小和数量浓度的演变？(2)实验室测量的二次有机气溶胶（SOA）形成速率和尺寸分布变化与气溶胶老化的现场测量结果是否一致？如果不是，我们能否确定原因（例如，在室内实验中缺乏连续稀释或壁损失）？(3)哪些特性对老化生物质燃烧气溶胶的大小和数量影响最大？例如，总质量排放通量、新鲜颗粒大小、燃料类型、改性燃烧效率、风速、火灾面积、垂直混合深度、阳光。(4)老化生物质燃烧气溶胶的大小和数量的变化是否可以通过一个简单的参数化来捕获，该参数化是上述最重要性质的函数？

This research is focused on studying the aging of emissions from biomass burning. Small particles emitted from biomass combustion can react in the atmosphere, changing their size, number, and composition. These aging processes will be modeled and the model results will be tested against actual data from field campaigns.The following questions will be investigated: (1) What are the chemical processes that, when combined with the dispersion and coagulation of biomass-burning emissions, capture the evolution of aerosol size and number concentrations seen in the laboratory and the field? (2) Are the secondary organic aerosol (SOA) formation rates and size-distribution changes measured in lab experiments consistent with the field measurements of aerosol aging? If they are not, can we determine why (e.g. lack of continuous dilution or wall losses in chamber experiments)? (3) What properties most strongly determine the aged biomass-burning aerosol size and number? E.g. total mass emission flux, fresh particle size, fuel type, modified combustion efficiency, wind speed, fire area, vertical mixing depth, sunlight. (4) Can the variability in aged biomass-burning aerosol size and number be captured by a simple parameterization that is a function of the most important of the above properties?