Source Apportionment of Ozone and Its Health Effects in North China Plain and Southeast U.S.

Abstract

Ground-level ozone (O3), as one of six common air pollutants set by National Ambient Air Quality Standards from the U.S. Environmental Protection Agency (EPA), is of great interest due to its health and economical effects. However, O3 contributions from different emission sources are not well understood due to its complicated nonlinear reactions. In this study, O3 source apportionment methods and the applications are firstly reviewed to provide a comprehensive understanding for O3 formations. Application of High-order Decoupled Direct Method (HDDM), brute force method (BFM), O3 source apportionment technology (OSAT) and source-oriented method in O3 simulations are discussed in detail. And applications of different O3 regime schemes are compared with each other. Improved three regime scheme (3R) has better performance in tracking O3 contributions from its precursors. Then, the Community Multi-scale Air Quality (CMAQ) model is applied to predict O3 concentrations in NCP with meteorological conditions generated by the Weather Research and Forecasting (WRF) model. Model performance from using anthropogenic emissions from the updated Emissions Database for Global Atmospheric Research (EDGAR+) and the Multi-resolution Emission Inventory for China (MEIC) are validated. The statistical analysis reveals a better performance from EDGAR+. The source-oriented simulation with 3R technique indicates that NOx emissions dominate in most regions while contributions from VOCs are higher in megacities than in other regions in NCP. Industry, on-road and energy emissions are major sources, which account for ~75% of total emission-related O3 formation. Emissions from local and surrounding regions are the main O3 contributors and emissions from central China and YRD have strong impacts in peak episodes. O3 simulation and source apportionment in SUS reveal that NOx emissions from on-road, energy dominate the emission-related O3 while VOCs emissions have less contribution except those from biogenic sectors. Health risk analysis indicates that more than 0.11 million premature mortalities are associated with O3 level in NCP due to respiratory (0.04-0.05 million) and cardiovascular (0.07-0.06 million) diseases. A total of 0.03 all-cause premature mortality is estimated for SUS with ~4.6 and ~7.9 thousand from respiratory and cardiovascular diseases, respectively.