Evaluation of Innovative Ozone Mitigation Strategies
San Joaquin Valleywide Air Pollution Study Agency
Project Background:The most recent ozone State Implementation Plans (SIPs) for San Joaquin Valley Air Pollution Control District (SJVAPCD), Bay Area Air Quality Management District (BAAQMD), and Sacramento Metropolitan Air Quality Management District included four common strategies that required further study: Alternative Energy, Energy Efficiency, Urban Heat Island Mitigation, and Episodic Controls. As part of the Central California Ozone Study, San Joaquin Valleywide Air Pollution Study Agency (SJVAPSA) commissioned Providence to evaluate the four strategies for their potential to reduce ozone in the three air districts.
Project Description: The study was divided into two parts. Part One was to document and evaluate examples of the four strategies that have been employed by air quality agencies across the country. For Part Two, Providence evaluated the feasibility and value of Waste-to-Energy (WTE) systems in the Sacramento Federal Ozone Nonattainment Area, Indirect Source Review (ISR) in the BAAQMD, and Urban Heat Island Mitigation (UHIM) in all three districts.
- For WTE, we investigated potential ozone precursor emission reductions from municipal green waste and dairy waste. We employed traditional engineering methods to review each measure’s emission reductions, financial costs, and environmental impacts.
- The ISR evaluation was based on the ISR rule adopted by SJVAPCD in 2005, and used construction permitting data for the San Francisco Bay Area. We also employed the California Emissions Estimator Model (CalEEMod) to estimate baseline emissions and reductions.
- For the evaluation of UHIM, we used the Mitigation Impact Screening Tool (MIST) developed by US EPA to simulate the atmospheric effects of citywide pavement and roofing albedo changes for San Francisco, Sacramento, and Fresno. We also calculated the cost-benefit of these urban-scale changes using cost data for various construction materials.
Key Findings: In Part One, Providence found that many agencies nationwide have implemented these strategies, but virtually none have included them for credit in SIPs. We also found that California agencies and utilities lead the nation in implementation. Additionally, we found that Energy Efficiency measures and some Alternative Energy measures have limited ozone benefits in central California, as benefits accrue only at the point of electrical generation, and central California is a net importer of electricity. In Part Two, Providence concluded that UHIM and ISR could be valuable as parts of an attainment strategy, depending on the details of implementation. Specifically, Providence found the following:
- Increasing the albedo of roofs under the UHIM strategy is the most promising innovative measure we studied. The ambient cooling effects and ozone reductions from cooler roofs come with a significant initial cost, but in-building energy savings provide lifetime financial savings.
- WTE appears to offer a significant financial payback, but initial costs are very high and NOx increases would need to be mitigated. The small amount of VOC reduction produced by this measure would not justify the high capital cost and the increase in NOx.
ISR could produce significant benefits (1.4 to 3.4 tons per day of NOx reductions)in the San Francisco Bay Area, and at relatively low cost. BAAQMD staffing increases could be significant, however.