Contribution of Oil and Natural Gas Emissions on Summertime Air Quality over the Continental US from an Air Quality Modeling Perspective

Abstract:

The rapid development of the oil and natural gas production across the United States in recent decade has been associated with significant amounts of methane and other volatile organic compounds (VOCs) released to the atmosphere. It is challenging for the existing emission inventories to adequately represent the rapidly evolving oil and natural gas production sector emissions. Hence, their contribution on air quality, especially summertime ozone and particulate matter pollution is not well characterized.

We present methane and air quality simulations for summer of 2013 over the continental US by using a coupled meteorology-chemistry model WRF-Chem on 12km resolution grid over the CONUS domain. In the model we used VOCs and nitrogen oxides (NO_x) emission estimates constrained by the in-situ measurements for a number of the shale basins obtained by NOAA’s multiple fields campaigns. Also, a bottom-up emission dataset for the oil/gas sector, based on EPA’s National Emission Inventory 2011 version 2 release was used in this modeling study.

Here, we discuss the differences in the NO_x and VOC emissions for the oil/gas sector in the top-down and bottom-up emission estimates. We modeled the contribution of the oil/gas sector emissions in the US to ozone, several oxidants, PM_2.5 mass and composition. For the model evaluations, detailed observations of meteorology, gaseous and aerosol species within several oil/gas producing basins obtained during NOAA sponsored aircraft SENEX-2013 field study were utilized. In addition, continuous ozone and PM2.5 measurements from hundreds of surface stations within the US EPA AQS data archive were used to evaluate the model simulations during summer of 2013.