A14E-04:
Development of a Statistical Model to Identify Spatial and Meteorological Drivers of Elevated O3 in Rural Nevada and Its Application to Other Rural, Mountainous Regions

Monday, 15 December 2014: 4:45 PM
Rebekka Fine1, Matthieu B Miller1 and Mae Sexauer Gustin2, (1)University of Nevada Reno, Natural Resources and Environmental Science, Reno, NV, United States, (2)University of Nevada-Reno, Reno, NV, United States
Abstract:
Baseline ozone (O3) has been defined as the mixing ratio of O3 measured at sites not influenced by recent, local emissions. Measurements of O3 at relatively remote monitoring sites, particularly in the western US, are useful for quantifying baseline O3 and subsequently the magnitude of O3 not controllable by local regulations. As the National Ambient Air Quality Standard (NAAQS) for O3 becomes more stringent, there is an increased need to quantify baseline O3 particularly in the western US where regional and global sources can significantly enhance O3 measured at surface sites yielding baseline mixing ratios approaching or exceeding the NAAQS threshold. With the pending reduction in O3 NAAQS, there is a growing need to develop tools to quantify baseline O3 that are readily comprehensible to a wide range of stakeholders. Past work has indicated that meteorological conditions as well as site specific spatial characteristics (e.g. elevation, basin size, gradient) were significantly correlated with O3 intercepted at rural monitoring sites. Here, we used 2 years of data measured at sites throughout rural Nevada to develop a readily comprehensible Categorical And Regression Tree (CART) model to identify spatial and meteorological characteristics that lead to elevated baseline O3. A third year of data from rural Nevada sites was used to test the model and its applicability to the state of Nevada. Data from other sites in the intermountain west were used to test the representativeness of the model for sites throughout the region.