Under the California Clean Air Act (CCAA) of 1988, air districts in areas that have not met the health-based state air quality standards must prepare clean air plans to attain them, and update the plans every 3 years. A public hearing is scheduled on December 20 for the proposed 2000 Clean Air Plan (CAP), which is being prepared by the Bay Area Air Quality Management District (Air District). At an Air District workshop in October the draft CAP and Proposed Addendum to the 1991 Clean Air Plan Environmental Impact Report (prepared for the 2000 CAP) were presented for public consideration and comment.
The 2000 CAP is an ozone attainment plan aimed at reducing emissions of reactive organic gases (ROG) and oxides of nitrogen (Nox), which react together in sunlight to form ground-level ozone. Trends in ozone levels have shown a steady improvement since the passage of the CCAA, although wide fluctuations in the weather from day to day and year to year have obscured the trend at times. In 1998, the national 1-hour ozone standard of 12 parts per hundred million (pphm) was exceeded on 8 days and the state standard of 9 pphm was exceeded on 29 days; during 1999, the national standard was exceeded on 3 days and the state standard on 20 days. As of September 21, 2000, the national standard had been exceeded on 3 days and the state standard on 11 days in the Bay Area.
Records from monitoring stations also show that peak ozone levels on the days when the standards were exceeded are diminishing each year. This means that the exposure of the Bay Area's population to unhealthful amounts of ozone has been reduced by 68 percent since 1988.
To comply with the requirements of the CCAA, the CAP includes an inventory of the sources of air pollution in the Bay Area, ozone trends reflecting the reduction in ozone levels at monitoring sites, and a description of the control measures that have been implemented. Also included are control measures in the 1997 CAP that will be carried over, those that will be deleted, proposed new measures, the control strategy with a proposed implementation schedule, and a discussion of future planning beyond 2003 when the next update is scheduled. Information on the CAP's effect on particulate matter (PM) is also included. This is because the health effects of PM are serious and control measures that reduce emissions of the precursors of ozone also reduce PM emissions.
The emissions inventory is intended to be a planning tool rather than an accurate measure of pollutants emitted. Some sources of pollution can be measured directly, but most must be estimated by a variety of methods that have varying degrees of accuracy. For example, a comparison of emissions from a given source in the 2000 inventory may not agree with the data for the same source in the inventory in the 1997 CAP, because improved techniques for estimating emissions are showing that earlier inventories may have underestimated some emissions.
For the year 2000, the emissions inventory estimates that 550 tons of ROG, 561 tons of NOx, and 174 tons of PM per day are being emitted. Of the stationary sources of air pollution that are regulated by the Air District, industrial and commercial sources are responsible for 5 percent of the ROG emissions, 1 percent of the NOx, and 9 percent of the PM. Petroleum products and solvent evaporation contributes 25 percent of the ROG. Combustion from stationary sources adds 1 percent of the ROG, 17 percent of the NOx, and 25 percent of the PM. (These numbers may change in the final CAP.)
Mobile source combustion emissions and consumer products are not under the regulatory jurisdiction of the Air District but contribute to ozone and PM emissions. On-road vehicles are responsible for 45 percent of the ROG, 46 percent of the NOx, and 0.5 percent of the PM. Off-road vehicles, entrained road dust, aircraft, consumer products, and other sources add 24 percent of the ROG, 36 percent of the NOx, and 61 percent of the PM.
Fifteen stationary source control measures in the 1997 CAP have been implemented. Fifteen measures from the 1997 CAP are recommended for deletion, including some that have been proved not to be feasible or cost-effective, or would result in insignificant emissions reductions. All 19 transportation control measures are partially implemented and will be retained. Two mobile source measures were expanded: the Vehicle Buy-Back Program and the Smoking Vehicle Program. The Air District has also approved a Carl Moyer program to replace diesel engines in marine vessels and locomotives with low emission engines and an expanded lawn mower buy-back program to promote the use of electric lawnmowers.
The 2000 CAP must contain all feasible control measures that can be implemented expeditiously. Besides the measures carried forward from the 1997 CAP, the Air District has identified four new measures in the 2000 CAP. These measures would reduce emissions from automobile refinishing coatings, wood products coatings, concrete coating operations, and residential water heaters.
A comprehensive revision of the CAP is expected to be made in 2003. By then, the findings of the Central California Ozone Study will be available to provide data to improve ozone modeling capabilities and to improve the identification of emissions reductions necessary to meet clean air standards.
The Air District will be studying the following areas to determine whether control measures may be developed that would produce significant emissions reductions and would be feasible:
Any of these areas that prove to be promising may be considered for future CAPs.
Besides the CAP to attain the state ozone standards, the Air District must also prepare plans to attain national air quality standards. The US Environmental Protection Agency (EPA) has approved new national standards for ozone, PM, and regional haze. The state Air Resources Board has determined from monitoring data that the Bay Area has not attained the new national 8-hour ozone standard. The Air District, therefore, expects to prepare an attainment plan for this standard in 2003.
However, a lawsuit before the US Supreme Court contesting the validity of the new standards complicates the matter. The schedule and requirements of the ozone plan have not been set, and the determination of the nonattainment areas for the new PM standard has been delayed pending the outcome of the lawsuit. The EPA is expected to review the PM standard in 2002.
Adelia Sabiston
For more information:
The draft Clean Air Plan is available online at http://www.baaqmd.gov/planning/cap/aqp.htm
For the Spare the Air Tonight advisory and to receive a free
copy of the Woodburning Handbook, call the Air District at
1-800-HELP-AIR.