CCP 01-11-1999 - Laserfiche WebLink

Home Browse Search

\~hJ Generally, worst case CO concentrations occur during the fall or winter months. In the fall and winter, vehicles emit more CO because of lower operating temperatures. Also during the fall and winter, meteorological conditions (low wind speeds, temperature inversions) resulting in higher concentrations are more likely to occur. For these reasons, EP A recommends that monitoring conducted during the summer months be adjusted to account for worst case meteorology likely to occur during the winter. This adjustment is based on average seasonal atmospheric mixing height and wind speed. Using EPA procedures and data, a seasonal adjustment factor of 1.2 corrects the summer CO monitoring to worst case winter conditions. Thus, the worst case background CO concentrations expected in the vicinity of the project are 1.8 PPM one-hour average and 1.4 PPM eight-hour average. 5.2.2 Environmental Impacts No-Build Alternative The no-build alternative will generate no additional traffic in the area and will therefore have no impact on air quality, Proposed Proiect - Mixed.Use Development The residential units associated with the proposed project could generate particulate (wood smoke) emissions and odors if they are equipped with fireplaces, The business park uses may generate emissions from heating equipment or industrial processes. Emissions from these potential sources are dependant on the fuel used, type of equipment and type of industrial process. If facilities are proposed that require air emissions permits, permits will be obtained prior to construction. The impacts of the proposed project on air quality have been evaluated by modeling future traffic flow and vehicle emissions at intersections in the vicinity of the project to estimate CO concentrations with project generated traffic. The air quality modeling methodology consists of the following steps: . Traffic analysis - the results of the traffic impact analysis are used to determine traffic volumes and intersection operational parameters including lane geometry, signal and phase length. . Emissions estimates - The EPA MOBILE5a mobile source emissions model is used to estimate CO emission rates for vehicles traveling at various speeds, . Dispersion model- The CAL3QHC line source dispersion model is used to model the dispersion of pollutants from the roadway sources to the selected receptor locations. . Background CO - As documented in the previous section, background CO concentrations are added to the results of the modeling of local sources to estimate the total future CO concentrations. WISP ARK Rice Creek Corporale Park DraftEIS December 10. 1998 Page 78 - .- I I I I I I I .. I I I I I I .. I I