Sesquiterpene Emissions and Their Impact on Aerosol Formation in the United States

该项目将建立一个美国主要天然灌木和树木的季节性倍半萜排放率数据库。 实验将在科罗拉多博尔德的一个苗圃进行，并辅以到其他选定地点的实地考察。 将使用可现场部署的气相色谱/质谱仪监测各种物质的排放率，还将探讨质子转移反应质谱仪的使用。 用于生成SQT标准品的毛细管扩散系统将用于实验程序的校准和表征。 为了减少小尺度吨排放率的不确定性，将采取几种办法：对重要生物量属的物种进行大量重复测量;将比较同一物种但不同种群的树木和灌木;将通过全年测量调查排放率的季节变化;以及可能影响SQT排放率的参数，如温度、光照、机械应力、干旱、虫害和臭氧暴露将被检查。 数据将纳入“自然界气体和气溶胶排放模型”，以评估SQT排放对大气浓度和生物气溶胶形成的影响。 SQT排放率和排放算法将提供给科学界用于空气质量建模。研究生和本科生将参与实地研究和建模工作。 研究结果将被纳入讲座和其他演讲，一个教育网站将介绍这项研究，用于课堂教学。 计划在当地开展几项外联工作，包括海报展示、传单和在当地林业理事会会议上发表讲话。

This project will establish a database of seasonal sesquiterpene (SQT) emission rates from the dominant natural United States shrubs and trees. Experiments will be conducted at a tree nursery in Boulder, Colorado, supplemented by field trips to other selected sites. Speciated emission rates will be monitored with a field-deployable gas chromatography (GC)/mass spectrometry (MS) instrument, and the use of a proton transfer reaction mass spectrometer (PTRMS) will also be explored. A capillary diffusion system for generation of SQT standards will be used for calibration and characterization of the experimental procedures. In order to reduce uncertainties in SQT emission rates, several approaches will be taken: a high number of replicate measurements will be performed on species of important biomass genera; trees and shrubs from the same species but from different populations will be compared; seasonal changes in emission rates will be investigated with year-round measurements; and parameters that may affect SQT emission rates, such as temperature, light, mechanical stress, drought, pests, and ozone exposure will be examined. Data will be incorporated into the Model of the Emissions of Gases and Aerosol from Nature (MEGAN) for an assessment of SQT emissions on atmospheric concentrations and biogenic aerosol formation. SQT emission rates, and emission algorithms will be made available to the scientific community for use in air quality modeling.Graduate and undergraduate students will participate in the field studies and modeling efforts. The results will be incorporated into lectures and other presentations, and an educational website will present this research for use in classroom teaching. Several local outreach efforts are planned, including a poster presentation, flyers, and a talk at a local forestry council meeting.