Project No: 16304519

Title: Mechanistic Studies of Formation of Nitroxy Organosulfates derived from monoterpenes in the atmosphere

Principal Investigator: Prof. Jianzhen YU

Co-Investigator: Prof. Xinming WANG


Nitroxy Organosulfate (NOS) compounds derived from monoterpenes (NOSMT) are molecules produced in the atmosphere incorporating signatures from both anthropogenic pollutants (e.g., SO2, NOx) and organic compound emissions from the nature in the oxidative atmospheric environments. NOSMT are consistently detected in atmospheric environments ranging from remote, rural, forest, suburban to urban environments. Its chemical linkages to both anthroposphere and biosphere make NOSMT potential markers to monitor anthroposphere-biosphere interactions. Despite the ubiquitous presence, their formation mechanisms are unclear due to a lack of available standards for NOSMT compounds and key immediate precursors. An examination of existing laboratory study evidence leads us to propose three immediate precursors to NOSMT, namely diol, epoxide, and hydroxyl nitrate. Our recent advance in synthesizing a series of organosulfates and NOS compounds derived from MT has partially lifted this bottleneck. In this work, we propose to conduct smog chamber experiments to individually test the potential immediate organic precursors in the presence of NO2 and SO2 or acid sulfate seed aerosols. The goal is to test the hypothesized pathways and to obtain NOSMT formation yields. Field samples will also be collected from contrast atmospheric environments in regard to the relevant precursors (MT, SO2, NOx) and key influential physical parameters (relative humidity, temperature). We will also build an aerosol C & N analyzer by integrating an aerosol C analyzer and a NOx analyzer for the determination of total organic nitrogen in chamber samples and field filter samples. The mechanistic understanding of NOSMT formation and quantitative yield data obtained from this project will provide fundamental knowledge in improving modeling the interactions between anthroposphere and biosphere.