| Title: | Two Decades of Changes in Summertime Ozone Production in California's South Coast Air Basin |
| Author(s): | Perdigones BC; Lee S; Cohen RC; Park JH; Min KE; |
| Address: | "School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology, Gwangju 61005, Korea. Department of Chemistry, University of California, Berkeley, California 94720, United States. Department of Earth and Planetary Science, University of California, Berkeley, California 94720, United States. Climate and Air Quality Research Department, National Institute of Environmental Research, Incheon 22689, Korea" |
| ISSN/ISBN: | 1520-5851 (Electronic) 0013-936X (Linking) |
| Abstract: | "Tropospheric ozone (O(3)) continues to be a threat to human health and agricultural productivity. While O(3) control is challenging, tracking underlying formation mechanisms provides insights for regulatory directions. Here, we describe a comprehensive analysis of the effects of changing emissions on O(3) formation mechanisms with observational evidence. We present a new approach that provides a quantitative metric for the ozone production rate (OPR) and its sensitivity to precursor levels by interpreting two decades of in situ observations of the six criteria air pollutants(2001-2018). Applying to the South Coast Air Basin (SoCAB), California, we show that by 2016-2018, the basin was at the transition region between nitrogen oxide (NO(x))-limited and volatile organic compound (VOC)-limited chemical regimes. Assuming future weather conditions are similar to 2016-2018, we predict that NO(x)-focused reduction is required to reduce the number of summer days the SoCAB is in violation of the National Ambient Air Quality Standard (70 ppbv) for O(3). Roughly, approximately 40% ( approximately 60%) NO(x) reductions are required to reduce the OPR by approximately 1.8 ppb/h ( approximately 3.3 ppb/h). This change would reduce the number of violation days from 28 to 20% (10%) in a year, mostly in summertime. Concurrent VOC reductions which reduce the production rate of HO(x) radicals would also be beneficial" |
| Keywords: | *Air Pollutants/analysis *Air Pollution/analysis California Environmental Monitoring Humans *Ozone/analysis *Volatile Organic Compounds air quality ozone production rate ozone production sensitivity prediction regulation tropospheric ozone; |
| Notes: | "MedlinePerdigones, Begie C Lee, Soojin Cohen, Ronald C Park, Jeong-Hoo Min, Kyung-Eun eng Research Support, Non-U.S. Gov't 2022/07/21 Environ Sci Technol. 2022 Aug 2; 56(15):10586-10595. doi: 10.1021/acs.est.2c01026. Epub 2022 Jul 19" |
