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PM2.5 Working Group Meeting #2. South Coast Air Quality Management District July 11, 2006. Update on CEIDARS List. Contacted CARB Redundant categories represent different years, i.e., before & after regulations in effect Includes implementation of ULSD requirements
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PM2.5 Working Group Meeting #2 South Coast Air Quality Management District July 11, 2006
Update on CEIDARS List • Contacted CARB • Redundant categories represent different years, i.e., before & after regulations in effect • Includes implementation of ULSD requirements • Developing a list without redundancy • CARB Considering revising list at county level
Update on CEIDARS List (Cont.) • Staff Recommendations: • Staff will prepare a general list based on AQMP inventory categories with a few more detailed categories • Other PM2.5 data can be used, e.g., project or site-specific data • Staff will update list as information becomes available
Preliminary Results of PM2.5 LST Analysis • Initial recommendation for PM2.5 construction LST assumed little contribution from construction combustion sources • Working group member modeling results presented at 6/8/06 meeting appeared to show large contribution from combustion sources • Staff modeled PM2.5 emissions using LST construction scenarios
Preliminary Results of PM2.5 LST Analysis (Cont.) • Modeling showed: • Construction equipment combustion emissions contribute ~75% - 100% • Contribution of fugitive sources dependant on construction phase • Demolition & site preparation have highest fugitive dust contributions • Construction & asphalt paving phases have highest construction combustion contributions
Preliminary Results of PM2.5 LST Analysis (Cont.) • Staff recommendations • Revise PM2.5 construction LST from 2.5 µg/m3 to 10.4 µg/m3 • No changes to any other staff recommendations • Exceedance of either PM10 or PM2.5 construction LST is a significant localized air quality impact
Mitigation Options to Reduce PM2.5 Emissions • Mitigation to reduce fugitive PM2.5 same as for fugitive PM10: • Watering 2 – 3 times per day (control efficiency [CE] = 50% – 68%) • Chemical dust suppressants (CE = 65%) • Enclose & water exposed piles (CE = 74%) • Apply mitigation CEs only to fugitive dust portion of PM2.5 estimate
Mitigation Options to Reduce PM2.5 Emissions (Cont.) a Percent reduction based on PM10 • Keep engines properly tuned, PM CE of 5%
Mitigation Options to Reduce PM2.5 Emissions (Cont.) • Operation on-road mitigation consistent with CARB-verified technologies • Level 1 > 25 % reduction in particulates • Level 2 > 50 % reduction in particulates • Level 3 > 85 % reduction in particulates (Note: % reduction based on PM10) • List of CARB-verified technologies at: • www.arb.ca.gov/verdev/verifiedtechnologies/cvt.htm
Schedule • Comments on revised proposal due 7/26/06 • Presentation to Mobile Source Committee 7/28/06 • Public Workshop August 9, 2006 • Recommendations to Governing Board Meeting on September 8, 2006