Trends of Ambient O3 Concentrations associated with O3 Sensitivity to HCHO and NO2 in California: Synergy from Satellite and Ground Observations
Abstract
Ambient ozone (O3) is adversely associated with multiple health outcomes and thus regulated by air quality management agencies as one of criteria air pollutants. In California, there are many non-attainment areas that do not meet O3 air quality standards, which necessitates further research on O3. In this study, we first examined the trends of ambient maximum 8-hour average O3 concentrations in California during the O3 season (May-October) for the years 2005-2017. Across California, a majority of the ground O3 monitors showed the decline in annual average O3 concentrations. A generalized additive model was used to evaluate the influence of NO2 mitigation strategies on O3 trends. The model indicates that without NO2 mitigation strategies, the site-specific average O3 concentrations would have increased by 0.65 ppb per year on average (25th-75th percentiles= 0.29-0.97 ppb per year). Furthermore, we related these NO2-O3 relationships to O3 sensitivity indicated by the ratios of (HCHO:NO2) from satellite Ozone Monitoring Instrument (OMI). At the O3 ground monitoring locations, the (HCHO:NO2) ratios increased at the average rate of 0.23 (SE=0.03) per year during the study period, implying that ambient O3 was likely to become more sensitive to NO2 over time. This was supported by positive associations between ground O3 and NO2 that became stronger over time. Despite limited data availability, ground Volatile Organic Compounds (VOCs) data will be also examined as another critical precursor of O3 production. This study is the first attempt to connect the relationships between ground O3 and its precursor gases with satellite-based O3 sensitivity to O3 precursor gases.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMGH21B1214L
- Keywords:
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- 0230 Impacts of climate change: human health;
- GEOHEALTH;
- 0240 Public health;
- GEOHEALTH;
- 0245 Vector born diseases;
- GEOHEALTH;
- 0299 General or miscellaneous;
- GEOHEALTH