AgdaPkt 2017-04-03 Joint SA PFA - Laserfiche WebLink

Browse Search

Jonathan Hayes - Greystar Updated March 15, 2017 - Page 7 Emission factors for DPM (PM2.5 exhaust from diesel vehicles) were developed for the year 2020 using the calculated mix of cars and trucks on El Camino Real. Default EMFAC2014 vehicle model year distributions for San Mateo County were used in calculating emissions for 2020. Emissions were based on an average speed of 30 mph, 5 miles below the posted speed limit, for all hours of the day. Average hourly traffic distributions for San Mateo County roadways were developed using the EMFAC model,7 which were then applied to the site-specific ADT volumes to obtain estimated hourly traffic volumes and emissions for El Camino Real. Year 2020 emissions were conservatively assumed to be representative of future conditions over the time period that cancer risks are evaluated (30 years), since, as discussed above, overall vehicle emissions, and in particular diesel truck emissions will decrease in the future. Emissions of total organic gases (TOG) were also calculated for 2020 using the EMFAC2014 model. These TOG emissions were then used in the modeling the organic TACs. TOG emissions from exhaust and for running evaporative loses from gasoline vehicles were calculated using EMFAC2014 default model values for San Mateo County along with the traffic volumes and vehicle mixes for El Camino Real. The emission rates used in the analysis are shown in Attachment 2. Dispersion modeling of DPM and organic TAC emissions was conducted using the CAL3QHCR model, which is recommended by the BAAQMD for this type of analysis.8 East and west bound traffic on El Camino Real within about 1,000 feet of the project site were evaluated with the model. A five-year data set of hourly meteorological data (2001 - 2005) from the San Carlos Airport obtained from BAAQMD was used in the modeling. The airport is about 2.3 miles northwest of the project site. Other inputs to the model included road geometry, hourly traffic volumes, and emission factors. The modeling included on-site receptors placed throughout the new residential area with a 6 meter spacing (20 feet). Receptor heights of 1.5 meters (5 feet) and 6.0 meters (20 feet) were used, representative of the first and second floor levels where residences would be located. Figure 2 shows the roadway segments modeled and residential receptor locations used in the modeling. Attachment 1 includes a description of how community risk impacts, including cancer risk are computed. The maximum increased cancer risk was computed as 2.8 in one million. This was modeled at a second floor receptor in the residential area closest to El Camino Real, and is shown on Figure 2. Cancer risks at other locations would be lower than the maximum risk. The maximum increased cancer risk is well below the BAAQMD’s threshold of 10 in one million excess cancer cases per million. The modeling results and health risk calculations for the receptor with the maximum cancer risk from El Camino Real traffic are also provided in Attachment 2. Distance Cancer Risk (per million) Annual PM2.5 (µg/m3) Hazard Index El Camino Real at ~25 feet 2.8 0.297 <0.01 7 The Burden output from EMFAC2007, CARB’s previous version of the EMFAC model, was used for this since the current web-based version of EMFAC2011 does not include Burden type output with hour by hour traffic volume information. 8 BAAQMD, 2012. Recommended Methods for Screening and Modeling Local Risks and Hazards. May 2012. 8.A. - Page 90