Assessment of the Marine Emissions Inventory for the Corpus Christi Urban Airshed

摘要

The two largest and yet uncertain sub-categories of air emissions from non-road sources include marine vessels and pleasure boats. Ocean going vessels (OGV) contribute a significant amount of emissions in the Corpus Christi urban airshed (CCUA). CCUA is classified as a near non-attainment area. To assess the effects of marine emissions of NO_x, VOC, CO, etc. on urban ozone levels, a comprehensive emissions inventory was developed. The methodology developed by ENVIRON was adopted for quantifying emissions from marine vessels. It was noted that marine emissions comprised approximately 3% of the total NO_x and 18% of the total VOC in the CCUA. The NONROAD model was used to develop the emissions inventory for pleasure crafts using local activities and population, temperature and other activities data collected from surveys along with local meteorological parameters. Spatial allocation of the estimated emissions was done by using a Geographical Information System (GIS). Comprehensive Air Model with extensions (CAMx) was used to evaluate the impact of these two subcategories of precursor emissions on the urban ozone level within Corpus Christi and surrounding areas. A high ozone episode of September 13-20, 1999 was used as the base case for the modeling analysis. The model was used to assess the impact of emissions from the marine sources on the urban ozone levels. It was observed that the maximum contribution from both marine vessels and pleasure crafts on the urban ozone was approximately 18 ppb.