2005-05-24_PWETC_AgendaPacket - Laserfiche WebLink

Home

Background CO Levels Background CO concentrations were monitored by Interpoll Laboratories for two weeks (December 21, i996 through January 13, 1997) at 2983 Centre Pointe Road. Forpurposes of the analysis, these background concentrations were adjusted for region-wide increases in traffic volumes (using traffic growth factors based on traffic forecast modeling) and vehicle emissions (to adjust for anticipated decreases in carbon monoxide emissions from motor vehicles due to emission controls). Because monitoring was performed in the winter, no temperature adjustment is needed. The results are summarized in Table 10. Table 10 Calculation of CO Background Concentrations 2020 Factor I-Hour 8-Hour Average Average Maximum 1997 Monitored Concentration (ppm) 2.2 1.6 Background Traffic Volume Adjustment Factor 1.58 1.58 Emission Adjustment Factor 0.79 0.79 Worst-Case Background Concentration (ppm) 2.8 2.0 Carbon Monoxide Modeling Results The CO concentration analyses were based on forecast peak hour traffic volumes and optimized signal timing. The analyses were performed for year 2020. The sidewalk averaging technique was used at all analyzed intersections to predict the average CO concentration along each sidewalk adjacent to the intersection. The listed result shows the maximum of the eight sidewalks adjacent to the intersection. Table 11 presents the worst case CO concentrations at the modeled intersection. The wind direction column in each table indicates the wind direction that resulted in the worst case conditions for that analysis location. The I-hour and 8-hour average modeling results are well below the state thresholds for all conditions modeled. Twin Lakes AUAR Traffic. Air and Noise Analysis -26- SRF Consulting Group, Inc. May 3, 2001