Temporo-spatial Variations and Sector-Specific Analysis in the Emission Control of VOC and NOx, Two Important Precursors of Ozone Pollution, in China.

China faces escalating ozone pollution challenges, with O3 becoming the primary pollutant in summer since 2013 and exhibiting deteriorating compliance rates (Grade I attainment plummeted from 6.9 to 0.3% during 2015-2023). Critical hotspots include the Beijing-Tianjin-Hebei region (exceeding standards by 20 µg/m3), driven by inadequate coordinated control of VOC and NOx. Analysis of the ABaCAS-EI v2.0 dataset (2005-2021) reveals divergent precursor trends: VOC emissions shifted from residential to industrial dominance, with industrial solvents (PRSO) surging 389% during 2005-2013 and comprising 61% of national totals by 2021. Spatially, eastern provinces (e.g., Guangdong) showed transport-industrial emission profiles (TRON: 28%; PRSO: 32%), while northern regions achieved significant NOx reductions through industrial restructuring, with Hebei's emissions falling 46% from peak levels. Conversely, NOx emissions peaked earlier (2011), but transportation's share grew to 42% by 2021 (TRON: 31%). Regional disparities persist-coastal areas leveraged advanced controls, whereas western provinces struggled with expanding pollution bases. These findings underscore the imperative for spatially-explicit strategies addressing sector-region heterogeneities to mitigate ozone's health/ecological impacts.