Quantifying the sources of ozone, fine particulate matter, and regional haze in the Southeastern United States

摘要

A detailed sensitivity analysis was conducted to quantify the contributions of various emission sources to ozone (O_3), fine particulate matter (PM_(2.5)), and regional haze in the Southeastern United States. O_3 and particulate matter (PM) levels were estimated using the Community Multiscale Air Quality (CMAQJ modeling system and light extinction values were calculated from modeled PM concentrations. First, the base case was established using the emission projections for the year 2009. Then, in each model run, SO_2, primary carbon (PC), NH_3, NO_x or VOC emissions from a particular source category in a certain geographic area were reduced by 30% and the responses were determined by calculating the difference between the results of the reduced emission case and the base case.rnThe sensitivity of summertime O_3 to VOC emissions is small in the Southeast and ground-level NO_x controls are generally more beneficial than elevated NO_x controls (per unit mass of emissions reduced). SO_2 emission reduction is the most beneficial control strategy in reducing summertime PM2.5 levels and improving visibility in the Southeast and electric generating utilities are the single largest source of SO_2. Controlling PC emissions can be very effective locally, especially in winter. Reducing NH3 emissions is an effective strategy to reduce wintertime ammonium nitrate (NO_3NH_4) levels and improve visibility; NO_x emissions reductions are not as effective. The results presented here will help the development of specific emission control strategies for future attainment of the National Ambient Air Quality Standards in the region.