Nine areas in California met the 1997 national health-based air quality standard for smog (or ground-level ozone) this year, announced the U.S. Environmental Protection Agency on Aug. 31.
The areas that fulfilled the requirements within their regulatory deadlines include Amador, Butte, Calaveras, Mariposa, Tuolumne and portions of Sutter, Kern and Nevada counties.
The EPA determined that these areas met the requirements based on the air quality data from local and state monitors.
El Dorado County Air Pollution Control Officer Dave Johnston said that El Dorado County did not make the list because out of the five monitoring sites in the El Dorado County area, four reported ozone levels higher than regulations.
“We have monitoring sites that received a lot of air pollution,” he said. “There was air blown to these areas from Sacramento that contributed to this.”
Johnston then explained that there are two monitoring areas in Tahoe that rarely record levels over the limit. However, the site in Placerville was over the limit five times last year and the one in Cool went over the limit 25 times.
The health-based limit for the federal eight-hour ozone standard is 0.08 parts per million of ozone measured over eight hours.
Various regions are given different nonattainment designations ranging from marginal, moderate, serious, severe or extreme if the eight-hour ozone design value concentration exceeds the national ambient air quality standard.
The Sacramento region (which includes all of Sacramento and Yolo counties and parts of El Dorado, Placer, Solano and Sutter counties) is designated as a “serious” nonattainment area.
With a “serious” nonattainment classification, the Sacramento region was given an attainment deadline of June 15, 2013. However, the region determined that this deadline was not enough time to reach the federal standards, so the district requested that the EPA reclassify the region with a “severe” status, thus granting the area a June 15, 2019 attainment deadline.
Members of different Sacramento region air pollution control districts plan to reach this deadline by preparing a comprehensive eight-hour ozone attainment and reasonable further progress plan and periodic progress reports.
The EPA and other organizations place such a strong emphasis on ground-level ozone reduction because this irritant has been shown to place adverse effects on human health.
Exposure to this substance can cause a decrease in lung function, an increase in cardiovascular problems such as heart attacks and strokes, the creation and exacerbation of asthma and premature death.
Even though the federal standards for ozone levels were not met this year, Johnston noted that El Dorado County has been decreasing in ozone levels since 1990, and there is hope that this pattern will continue through time.
“Based on the trend of past years, we forecast that the ozone levels in El Dorado County will meet federal standards by 2018,” he said.
To learn more about national standards and ground-level ozone, visit epa.gov/airquality/ozonepolution.