Evaluating Emissions Inventory Improvements Using Observations and the CMAQ Model: Impacts on Air Quality Attainment Strategies

The Environmental Protection Agency (EPA) monitors and regulates surface ozone, which has a primary attainment standard of 70 ppb over an 8-hour average. In this analysis, we investigate the representation of emissions sectors, such as large commercial marine vessels, within the Community Multiscale Air Quality (CMAQ) model, an EPA approved regulatory air quality model used by state agencies and research institutions to develop ozone attainment strategies.  We compare model output for June, July, and August 2011 with surface ozone data from the EPA Air Quality Sites (AQS) in order to examine various model scenarios and improve the representation of emissions within CMAQ. Satellite data from the Ozone Monitoring Instrument (OMI) for summer 2011 are used to further investigate how well CMAQ is able to capture the non-linear production of surface ozone. Additionally, we test how improvements to the model framework influence the effectiveness of a future attainment strategy for June, July and August 2018.