Assessment of the Contribution of Traffic Emissions to the Mobile Vehicle Measured PM2.5 Concentration by Means of WRF-CMAQ Simulations

INE/AUTC 12.0

Numerical investigations on the contribution of point source emissions to the PM2.5 concentrations in Fairbanks, Alaska

AbstractSimulations with and without consideration of emissions from point sources were performed with the Weather Research and Forecasting model with online chemistry (WRF/Chem) to examine the contribution of point source emissions to the PM2.5 concentrations at breathing level in Fairbanks, Alaska during winter. On days and at locations where PM2.5 concentrations exceed the National Ambient Air Quality Standard of 35μg m −3, emissions from point sources account for 4% of the 24h–average PM2.5 concentration on average. The locations of highest concentrations were the same in both simulations. Point source emissions induced only five additional exceedance days in the nonattainment area. The magnitude of the PM2.5 concentrations depended on meteorological conditions (temperature, wind speed, mixing height) and emissions. The radius of impact of point source emissions on the PM2.5 concentration at breathing level of about 10–12km downwind results as a combination of low emission heights, low wind speeds and the presence of inversions

Emissions of organic compounds from produced water ponds II: Evaluation of flux chamber measurements with inverse-modeling techniques

<p>In this study, the authors apply two different dispersion models to evaluate flux chamber measurements of emissions of 58 organic compounds, including C2–C11 hydrocarbons and methanol, ethanol, and isopropanol from oil- and gas-produced water ponds in the Uintah Basin. Field measurement campaigns using the flux chamber technique were performed at a limited number of produced water ponds in the basin throughout 2013–2016. Inverse-modeling results showed significantly higher emissions than were measured by the flux chamber. Discrepancies between the two methods vary across hydrocarbon compounds and are largest in alcohols due to their physical chemistries. This finding, in combination with findings in a related study using the WATER9 wastewater emission model, suggests that the flux chamber technique may underestimate organic compound emissions, especially alcohols, due to its limited coverage of the pond area and alteration of environmental conditions, especially wind speed. Comparisons of inverse-model estimations with flux chamber measurements varied significantly with the complexity of pond facilities and geometries. Both model results and flux chamber measurements suggest significant contributions from produced water ponds to total organic compound emission from oil and gas productions in the basin.</p> <p><i>Implications</i>: This research is a component of an extensive study that showed significant amount of hydrocarbon emissions from produced water ponds in the Uintah Basin, Utah. Such findings have important meanings to air quality management agencies in developing control strategies for air pollution in oil and gas fields, especially for the Uintah Basin in which ozone pollutions frequently occurred in winter seasons.</p