CO Modeling in Alaska

Abstract

According to the Clean Air Act of 1970, maximum allowable ambient carbon monoxide (CO) levels are 9 ppm for eight hours and 35 ppm for one hour. The frequent violation of these standards in Fairbanks and Anchorage, Alaska, has prompted these communities to encourage strategies intended to reduce CO concentrations. To help gauge the relative merits of various strategies, computer models are commonly used to predict both CO emissions and the resultant concentration of CO in the atmosphere. This study has focused on the use of CALINE4 as a line source dispersion model in Alaska. A large amount of applicable meteorological, air quality, and traffic data for Fairbanks has been assimilated as part of this study. This model may be used to approximate peak values and trends over time for CO levels in Fairbanks, but a lack of more detailed data precludes the formulation of quantitative global statements about the predictability of peaks and detailed spatial trends. More detailed emissions and meteorological data are needed. However, the separation of horizontal dispersion from vertical dispersion bodes well for the future application of CALINE4 in Alaska.