The impacts of reactive terpene emissions from plants on air quality in Las Vegas, Nevada

Biogenic volatile organic compounds (BVOCs) emitted from vegetation can significantly impact tropospheric air quality by interacting with anthropogenic pollutants to produce ozone and particulate matter (PM). Monoterpenes and isoprene have been the focus of most BVOC studies, but recent research indicates that a class of very reactive BVOCs (VR-BVOCs) is emitted at especially high rates. Sesquiterpenes have been implicated as significant VR-BVOCs due to their rapid reactivities. Very little is known about VR-BVOC emissions and the concomitant effects on air quality because their chemistry is complicated and measurements are difficult. The present study examined emissions of sesquiterpenes, monoterpenes, and isoprene from dominant vegetation in the Las Vegas metropolitan area. BVOC emission measurements were obtained using a novel collection system and these data were then synthesized with a GIS framework to develop an emissions inventory for the Las Vegas metropolitan area. A series of atmospheric chemistry box model simulations utilizing the BVOC emissions inventory data were run to assess impacts of BVOCs on air quality for industrial, suburban, and rural areas.; Monoterpene emissions were an order of magnitude higher than sesquiterpene emissions for almost every plant species measured. As a result of their low emissions, sesquiterpenes did not exert a significant influence over ozone and PM pollution in the troposphere, but other BVOCs did. Total BVOCs had the greatest effect on ozone concentrations in a rural area, and in the mid-afternoon, ozone growth rates were almost 50 times greater with BVOCs present than without. Total monoterpenes had the strongest effect on PM pollution in a rural area as well, and contributed roughly 30% of the total organic carbon measured at this site. Studying the magnitude of BVOC emissions provides a more thorough understanding of the factors contributing to ozone and PM pollution. This information is of increasing importance as the Las Vegas area continues to expand at a rapid pace and local planners search for ways to mitigate air quality problems.