Collaborative Research: Aerosols, Nitrogen Oxides, and Ozone at the Mt. Bachelor Observatory

该项目支持俄勒冈州中部巴学士山天文台（MBO）继续进行大气测量。MBO是一个高海拔（海拔2.8公里）的天文台，在过去的15年里一直用于大气化学研究。该项目将建立在MBO过去观测的广泛知识基础上，以检查春季和夏季美国西部空气质量的关键控制因素。春季和夏季，自然和国际人为来源的O3和气溶胶占主导地位，而夏季，野火烟雾是区域空气污染的主要驱动因素。MBO将持续测量O3、CO、CO2、气溶胶质量、散射和吸收系数以及气象学。本研究将提出三个具体假设：(1)基线O3的日变化是由大尺度动力学和运输驱动的，包括厄尔尼诺-南方涛动、太平洋年代际涛动和气候变化。从MBO和TEMPO卫星的数据中可以观察到O3的变化，这对美国西部顺风空气质量很重要。(2)生物质燃烧羽流中的氮氧化物化学成分受初始排放和化学过程的控制。从气溶胶硝酸盐（有机和无机）中生成亚硝酸盐是一个重要的氮氧化物回收机制，也是羟基自由基的来源。(3)气溶胶的性质取决于化学成分和老化。棕色碳的光吸收可以与黑碳相当或超过黑碳的吸收，并且可以与特定的化学成分或发色团联系起来。有机气溶胶挥发性随老化和氧化而降低。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This project supports the continuation of atmospheric measurements at Mt. Bachelor Observatory (MBO) in Central Oregon. The MBO is a high elevation (2.8 km above sea level) observatory that has been utilized for atmospheric chemistry research for the past 15 years. This project will build on the extensive knowledge base of past observations from MBO to examine key controls on western U.S. air quality in the spring, when natural and international anthropogenic sources of O3 and aerosols dominate, and summer, when wildfire smoke is a major driver of regional air pollution. Continuous measurements will be made at MBO of O3, CO, CO2, aerosol mass, scattering and absorption coefficients and meteorology. Three specific hypotheses will be addressed in this research: (1) Daily variations in baseline O3 are driven by large scale dynamics and transport including the El Nino-Southern Oscillation, the Pacific Decadal Oscillation, and the changing climate. The variations in O3 that can be observed in data from both MBO and the TEMPO satellite and are important for downwind air quality in the western U.S. (2) Nitrogen oxide chemistry in biomass burning plumes is controlled by both initial emissions and chemical processing enroute. Production of nitrous acid from aerosol nitrates (organic and inorganic) is an important NOx recycling mechanism and a source of hydroxyl radical. (3) Aerosol properties depend on chemical composition and aging. Light absorption by brown carbon can be comparable or exceed absorption by black carbon and can be linked to specific chemical components or chromophores. Organic aerosol volatility decreases with aging and oxidation.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.