EPA proposes approval of new ozone plans for the two of the worst Air Quality Zones in US: California’s San Joaquin Valley and South Coast
|US EPA Region 9 8-hour ozone trends, 1979-2000. Source: EPA. Click to enlarge.|
The US Environmental Protection Agency (EPA) is proposing to approve the 8-hour ozone air quality plans—which include their attainment demonstrations, enforceable commitments and reductions from new technologies—for California’s San Joaquin Valley (SJV) and South Coast (SC) areas, two of the worst air quality areas left in the country. These State Implementation Plans (SIPs) are the roadmaps to meeting the 1997 8-hour ozone National Ambient Air Quality Standards (NAAQS) of 0.08 parts per million (ppm) by 2024.
In 1997, EPA first established the 8-hour ozone standard, which replaced the older 1-hour ozone standard (0.12 ppm). The 8-hour standard is more protective of human health because it addresses the impacts of exposure over longer periods of time. In 2008, the 8-hour standard was lowered to 0.075 ppm. The more stringent ozone NAAQS recently shelved by President Obama would have further reduced the 8-hour standard to within the range of 0.060-0.070 parts per million (ppm). (Earlier post.)
The two areas suffer from some of the worst air quality in the country due to a number of factors, such as meteorology, geography, climate and weather. The Clean Air Act (CAA) allows areas such as these (designated and classified as “extreme” nonattainment under the CAA) to rely on the development and implementation of new and improved technologies given the relatively long time between SIP development and attaining clean air. EPA said that the air districts are making steady progress toward meeting the 0.08 ppm standard.
There have been vast improvements in air quality in California over the previous decades. The worst sites in California have demonstrated a 52% improvement in ozone from 1976 to 2010, a 29% improvement in fine particulate matter (PM2.5) from 2001 to 2010, an 84% improvement in carbon monoxide from 1970 to 2009, and a 92% improvement in sulfur dioxide from 1970 to 2009.
These new SIPs demonstrate that, by 2024, pollution will be reduced to the level needed to attain the 1997 8-hour ozone standard of 0.08 ppm.
For the SJV to attain 0.08 ppm by 2024, NOx will have to be reduced by 75% and VOCs by 25% from 2002 levels.
For the SC to attain 0.08 ppm by 2024, NOx will have to be reduced by 90% and VOCs by 52% from 2002 levels.
In their 8-hour ozone plans, roughly 12% of the needed NOx reductions in SJV and 26% of the needed NOx reductions in SC reductions are attributed to new and improved technologies. The SC also attributes 9% of the needed VOCs reductions to new and improved technologies.
In both areas, statewide measures such as the in-use truck and off-road diesel rules, and smog-check improvements will further reduce air pollution. In the San Joaquin Valley, district rules will reduce pollution from open burning, boilers, composting, and livestock operations. In the South Coast, the marine vessel rules and district rules targeting pollution from solvents, lubricants and boilers will reduce ozone pollution.
Ground-level ozone is formed when nitrogen oxides (NOx) and volatile organic compounds (VOCs) react in the atmosphere in the presence of sunlight. Motor vehicle exhaust, industrial emissions, and chemical solvents are the major sources of these ozone precursors. Ozone pollution is a concern especially when the weather conditions needed to form it—lots of sun and hot temperatures—occur. Ozone pollution can irritate airways, worsen asthma symptoms and increase hospitalizations for respiratory cases. Children and the elderly are most impacted by ozone pollution.
EPA is providing a 30-day public comment period on its 8-hour ozone proposed actions.