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Ambient near-surface ozone pollution threatens public health. Over the past decades, the world has seen complex ozone changes across the globe, with important implications for public health. Previous studies have estimated premature mortality attributable to ozone exposure in more recent years, yet a historical assessment of the health impacts of ozone is largely lacking. Contrary to controlling many other air pollutants endangering public health, reducing ozone pollution is complicated by its nonlinear chemistry and complex relationship with precursor emissions. A historical evaluation is crucial to understanding the long-term changes in surface ozone concentration, driving factors, and health implications. This study uses chemical transport model simulations, ground measurements, and pollution-health response models to estimate the ozone changes over the past few decades, their health impacts, and the effectiveness of precursor emission control. Our results will help improve the ozone mitigation strategies on the global scale. [ABSTRACT FROM AUTHOR]

Emission datasets of nitrogen oxides (NOx) at high horizontal resolutions (e.g., 0.05°×0.05°) are crucial for understanding human influences at fine scales, air quality studies, and pollution control. Yet high-resolution emission data are often lacking or contain large uncertainties especially for the developing regions. Taking advantage of long-term satellite measurements of nitrogen dioxide (NO2), here we develop a computationally efficient method to inverting NOx emissions in major urban areas at the 0.05°×0.05° resolution. The inversion accounts for the nonlinear effects of horizontal transport, chemical loss, and deposition. We construct a 2-dimensional Peking University High-resolution Lifetime-Emission-Transport (PHLET) model, its adjoint model (PHLET-A), and a Satellite Conversion Metrix approach to relate emissions, simulated NO2, and satellite NO2 data. The inversion method is applied to summer months of 2012–2016 in the Yangtze River Delta area (YRD, 118°E-123°E, 29°N-34°N), a major polluted region of China, using the POMINO NO2 vertical column density product retrieved from the Ozone Monitoring Instrument. A systematic analysis of inversion errors is performed, including using an Observing System Simulation Experiment-like test. Across the YRD area, the inverted summer average emission ranges from 0 to 12.0 kg km-2 h-1, and the lifetime (due to chemical loss and deposition) from 1.4 to 3.6 h. Our inverted emission dataset reveals fine-scale spatial information tied to nighttime light, population density, road network, and maritime shipping. Many of the inverted fine-scale emission features are not well represented or not included in the widely used Multi-scale Emissions Inventory of China. Our inversion method can be applied to other regions and other satellite sensors such as the TROPOspheric Monitoring Instrument. [ABSTRACT FROM AUTHOR]