title: Investigating the influence of long-range transport on surface O3 in Nevada, USA, using observations from multiple measurement platforms.
abstract: The current United States (US) National Ambient Air Quality Standard (NAAQS) for O3 (75 ppb) is expected to be revised to between 60 and 70 ppb. As the NAAQS becomes more stringent, characterizing the extent of O3 and precursors transported into the US is increasingly important. Given the high elevation, complex terrain, and location in the Intermountain West, the State of Nevada is ideally situated to intercept air transported into the US. Until recently, measurements of O3 and associated pollutants were limited to areas in and around the cities of Las Vegas and Reno. In 2011, the Nevada Rural Ozone Initiative began and through this project 13 surface monitoring sites were established. Also in 2011, the NASA Ames Alpha Jet Atmospheric eXperiment (AJAX) began making routine aircraft measurements of O3 and other greenhouse gases in Nevada. The availability of aircraft and surface measurements in a relatively rural, remote setting in the Intermountain West presented a unique opportunity to investigate sources contributing to the O3 observed in Nevada. Our analyses indicate that stratosphere to troposphere transport, long-range transport of Asian pollution, and regional emissions from urban areas and wildfires influence surface observations. The complexity of sources identified here along with the fact that O3 frequently approaches the threshold being considered for a revised NAAQS indicate that interstate and international cooperation will be necessary to achieve compliance with a more stringent regulatory standard. Further, on a seasonal basis we found no significant difference between daily 1-h maximum O3 at surface sites, which ranged in elevation from 888 to 2307 m, and aircraft measurements of O3 <2500 m which suggests that similar processes influence daytime O3 across rural Nevada and indicates that column measurements from Railroad Valley, NV are useful in understanding these processes.
authors.affiliation: Department of Natural Resources and Environmental Science, University of Nevada-Reno, Reno, NV, USA. Electronic address: rebekkafine@gmail.com.
authors.forename: Rebekka
authors.initials: R
authors.lastname: Fine
authors.affiliation: Department of Natural Resources and Environmental Science, University of Nevada-Reno, Reno, NV, USA.
authors.forename: Matthieu B
authors.initials: MB
authors.lastname: Miller
authors.affiliation: Atmospheric Science Branch, NASA Ames Research Center, Moffett Field, CA 94035, USA.
authors.forename: Emma L
authors.initials: EL
authors.lastname: Yates
authors.affiliation: Atmospheric Science Branch, NASA Ames Research Center, Moffett Field, CA 94035, USA.
authors.forename: Laura T
authors.initials: LT
authors.lastname: Iraci
authors.affiliation: Department of Natural Resources and Environmental Science, University of Nevada-Reno, Reno, NV, USA. Electronic address: mgustin@cabnr.unr.edu.
authors.forename: Mae Sexauer
authors.initials: MS
authors.lastname: Gustin
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D000397:Air Pollution / Q000706:statistics & numerical data; D001272:Atmosphere / Q000737:chemistry; D004784:Environmental Monitoring; D008956:Models, Chemical; D009505:Nevada; D010126:Ozone / Q000032:analysis*
chemical_list: D000393:Air Pollutants; D010126:Ozone
keywords: Asian pollution; Back trajectory; Stratosphere to troposphere transport