Weight of Evidence Analysis for Attributing Monitored Sulfur Dioxide Exceedances to Emission Source Zones

摘要

The National Ambient Air Quality Standard (NAAQS) for sulfur dioxide (SO_2) was revised in 2010 with the primary standards at annual and 24-hour averaging times replaced with a 1-hour standard. Analyses are needed to assess the drivers for observed violations with the short term objective to propose nonattainment area boundaries and the long term objective to support control strategy development. In many areas, exceedances of the 1-hour standard are likely driven by one or a few sources proximate to the monitoring station. Dispersion modeling of specific hours can be confounded by inaccurate emissions estimates when derived from an emissions inventory developed for longer averaging times. Furthermore, the predictive power of dispersion modeling for specific hours is subject to error from the inability to specify all parameters that influence transport dynamics.