Oxidation Processes in Forest Canopies and Biosphere-Atmosphere Exchange of Nitrogen Oxides

University Of California-Berkeley, Berkeley CA

Investigators

Abstract

This project aims at an improved understanding of atmospheric oxidation processes, using the Sacramento urban plume and its interactions with the forest ecosystems of the mid-elevation Sierra Nevada Mountains as a case study, and an improved understanding of the mechanisms of atmosphere-biosphere exchange of nitrogen occurring in those forests. Specific tasks include: 1) development and subsequent field deployment and evaluation of a new instrument for detection of HONO (nitrous acid); 2) two four-month field campaigns including measurements of concentrations of NO (nitric oxide), NO2 (nitrogen dioxide), HONO, NO3 (nitrate radical), N2O5 (dinitrogen pentoxide), the sum of PNs (acyl peroxynitrates), the sum of ANs (alkyl nitrates), HNO3 (nitric acid), and NOy (total reactive nitrogen), some at more than one height in the forest canopy, along with fluxes of most of these species, and 3) development of new models and analyses to interpret the measurements obtained in the field studies, with the aim of understanding the role of atmospheric nitrogen oxides in regulating the rates of oxidative photochemistry, chemistry in the forest canopy, and the mechanisms of atmosphere-biosphere exchange of nitrogen. The ultimate goal of the project is to better understand the influence of nitrogen oxide emissions on air pollution, climate, and ecosystem processes. Other broader impacts include 1) training of women and minority graduate students; 2) participation of undergraduates in research; and 3) continued encouragement of graduate student volunteer work in K-8 schools. The project is highly collaborative and will bring Berkeley graduate students into contact with students from several other institutions during the field studies. The results and methodology will be included in an introductory chemistry class and new materials will be prepared for use in the physical chemistry laboratory.