Reso13 PC 13-09 2859 Initial Study Mitigated Negative Declaration Kensington

Browse Search

feet from the nearest traffic lane. Based on the screening analysis,the maximum lifetime cancer risk for adult exposure would be 9.4 in one million for lst floor residents and 6.1 in one million for 2na floor residents nearest El Camino Real,which is below the 10 in one million significance threshold. To evaluate potential non-cancer health effects due to PM2.5,the BAAQMD has a significance threshold of an annual average PM2.5 concentration greater than 03 µg/m3. The exposure to PMz.S would be 022 µg/m3 for lst floor residents and 0.15 µg/m3 2na floor residents nearest El Camino Real, which is below the 03 µg/m3 significance threshold. The development of an assisted senior living facility on the project site would not expose future residents to significant levels of TACs or PM2.5 resulting from traffic volumes on El Camino Real. (Less Than Significant Impact) 4.3.3.3 Construction Impacts Community Risk Impacts Existing residences are located immediately adjacent to the project site, so a health risk assessment was completed to evaluate construction emissions of diesel particulate matter. A dispersion model was used to predict the off-site concentrations resulting from project construction. Construction period emissions were computed using the OFFROAD2007 model. This analysis assumed the following construction schedule: 1. Beginning in 2013, demolition of the existing buildings,hardscape, etc.would occur for 20 days (portion requiring use of diesel heavy-duty equipment may be substantially shorter); 2. Site grading would occur over a total period of 18 working days and involve the removal of 1,000 cubic yards of material; 3. Trenching would last about 15 work days; 4. Exterior building construction would occur for 50 work days; 5. Interior building construction that requires only a propane lift would occur over a period of 80 work days; 6. Fine or finishing grading would require 20 work days in 2014; and 7. Paving would occur over a period of 4 work days in 2014. The U.S. EPA ISCST3 dispersion model was used to predict concentrations of diesel particulate matter(DPM) at existing residences near the project site. Increased cancer risks were calculated using the modeled annual concentrations and BAAQMD recommended risk assessment methods for both a child exposure(3rd trimester through two years of age) and for an adult exposure. Since the modeling was conducted assuming emissions occurred 365 days per year,the exposure doses were the default California Office of Environmental Health Hazards Assessment(OEHHA) exposure period of 350 day/year was used. Kensington Assisted Living Facility Project 22 Initial Study Redwood City Apri12013