Estimating Ground-Level Ozone Concentrations in Eastern China Using Satellite-Based Precursors

Abstract

The monthly ground-level ozone (O3) concentrations in eastern China (EC) are estimated using the surface NO2 and CH2O concentrations derived from the ozone monitoring instrument (OMI) according to the geographically weighted regression (GWR) method. The accuracy assessment shows that the proposed GWR model performed well for estimating monthly O3 concentrations ( ${R} ^{2} =0.81$ , absolute error (AE) $= 7.38~\mu \text{g}/\text{m}^{3}$ for the fitted results, and ${R} ^{2}= 0.77$ , AE $= 8.20~\mu \text{g}/\text{m}^{3}$ ). The estimated yearly average O3 concentration is $56.20~\mu \text{g}/\text{m}^{3}$ , with a standard deviation of $3.68~\mu \text{g}/\text{m}^{3}$ in 2014 across EC. The O3 concentrations show great spatial variation, with hotspots extending from north-EC to the Yangtze River Delta and the Pearl River Delta. The monthly O3 concentrations are generally low during the cold season and high during the warm season, but local areas show different seasonal variations.