Air quality in Orange County has been steadily improving since the ‘60’s. Climate change could stifle that progress.

The county’s cleaner air today stems from legislative and regulatory changes across transportation and energy, researchers say. A clear view of the mountains is a telltale sign.

But researchers warn about the impact of climate change. 

Editor’s Note: This story series was produced by Chapman University journalism students working with the VOC Collegiate News Service.

The idea for the series was sparked by the fall oil spill off Orange County’s coast. But it also goes further — examining the seen and unseen pollution across the local environment — in drinking water sources, ocean waters, on land and in the air. We hope with this series to give residents balanced and informative stories that people can use to be empowered in the community. If you have questions, comments and story ideas please contact Sonya Quick, digital editor at Voice of OC and Chapman adjunct professor.

Climate change could lead to higher temperatures, which accelerates the formation of ground-level ozone. Climate change is also increasing the frequency, extent and severity of wildfires. Wildfires increase the presence of fine particulate matter, another harmful pollutant, according to the Environmental Protection Agency

Fine particulate matter and ozone can both cause respiratory problems, such as asthma attacks and shortness of breath. Fine particulate matter can also cause harm to the cardiovascular system, including heart attack and strokes, according to the Environmental Protection Agency

Understanding Air Quality

To understand Orange County air pollution, it’s important to establish that air quality is divided geographically by air basins, not county lines. Orange County is part of the South Coast Air Basin, along with parts of Los Angeles, San Bernardino and Riverside counties, according to the South Coast Air Quality Management District.

“Orange County air quality is pretty good, especially compared to Los Angeles, San Bernardino or Riverside counties,” said Michael Mac Kinnon, environmental scientist at UC Irvine. “But all of the actions that have been taken to improve it have been enacted in that whole area, not just in Orange County.” 

Air pollution is quantified by two main pollutants – ozone and particulate matter.

Ground-level Ozone

Mac Kinnon says ground-level ozone is essentially smog. If the average amount of smog during an eight-hour period is greater than 70 parts per billion, it is considered an exceedance day. 

Exceedance days happen when air pollution is higher than the level considered healthy by law. Therefore, the more exceedance days per year, the more unhealthy the air quality.

Research from the South Coast AQMD shows there have consistently been more ozone exceedance days per year than fine particulate matter exceedance days in the South Coast Air Basin, meaning that ozone is more of a problem than fine particulate matter in the South Coast Air Basin. 

“Ozone degrades materials like plastic and rubber,” said Marc Sospedra, air quality specialist. “It can also reduce the yield of crops because it affects the tissues of leaves that absorb sunlight.”

Ozone is relatively high in the South Coast Air Basin partially because of weather, Sospedra said. Ozone increases with sun and heat, and Orange County’s higher temperatures makes the area favorable for ozone formation.

“We have wind blowing inland from the ocean, and then we have tall mountains in the north and the east that trap pollutants, and then we have sun baking everything, so that’s kind of the perfect recipe for ozone formation.”

Marc Sospedra, air quality specialist

Because there’s no control over the weather and the presence of the mountains, the most efficient way to decrease ozone is to decrease vehicle emissions, Sospedra said.

However, decreasing vehicle emissions is difficult when the South Coast Air Basin has nearly 20 million people, with more than 12 million vehicles, Sospedra said.

Particulate Matter

Vehicle emissions contribute to an increase in particulate matter, solid particles and liquid droplets in the air, according to the Environmental Protection Agency. This category of air pollution is usually shortened to PM.

PM2.5 refers to particulate matter with a diameter 2.5 micrometers or less. PM10 refers to PM with a diameter 10 micrometers or less.

The smaller the particulate matter number, the more concern for health as it becomes because it’s easier for people to inhale smaller particles.

PM can change drastically on a day-to-day basis. For example, fireworks on July 4 drastically increase PM levels.

“There’s different pollutants that are all lumped together under the idea of air quality, each with their own effect, each with their own characteristics and sources,” Mac Kinnon said.

Sources of Air Pollution

Air pollution can come from a variety of sources. Sospedra said there are five main sources of air pollution:

  • Vehicle emissions
  • Power plants
  • Body shops and car repairs
  • Heavy-duty diesel equipment and trucks
  • Human activity

Sospedra said many of these sources have become cleaner over the years with increased regulation. 

For example, Sospedra said power plants that previously ran with oil or diesel have now switched to natural gas, and body shops have switched from dust spraying and some are now enclosed to recycle emissions. 

Legislation that Improved Air Quality

The legislation that continued to improve air quality began in the 1940s, when air pollution became a big problem in Los Angeles, according to the California Air Resources Board.

Scientists hadn’t before seen the unique smog, characterized by eye irritation, high oxidant levels and plant damage.

In 1947, the first body dedicated to controlling air pollution in the nation, the Los Angeles County Air Pollution Control District, was formed to figure out what was causing the smog.

By the early 1950s, it became clear that car emissions played a significant role, according to the state air board. California began to take statewide action, creating the Bureau of Air Sanitation, which established air quality standards and set controls on motor vehicle emissions.

In 1966, California established the first tailpipe emissions standards in the nation, according to the state air board. 

A year later, the California Air Resources Board was established, and the Federal Air Quality Act gave California the ability to set its own more stringent air quality rules.

The California Air Resources Board has been enforcing legislation since 1966 to improve the air quality throughout California. In the 1980s and 1990s, California cars and fuel became the cleanest in the world.

The Pandemic’s Influence on Air Quality

The pandemic caused fossil carbon dioxide emissions to decline by an estimated 2.4 billion tons in 2020 globally, according to researchers at the University of East Anglia and the University of Exeter

Traffic in March 2020 was 18.6% of that from March 2019, according to the Federal Highway Administration

However, March through May typically aren’t high pollutant months for Orange County because cooler temperatures and rain decreases the presence of ozone. This coupled with ozone-forming high temperatures in July to September 2020 resulted in the pandemic having less of an impact on improving air quality in Orange County, says Sospedra.

“The pandemic didn’t actually improve the air quality in Orange County as much as we thought it was going to,” Mac Kinnon said. “It really highlighted the role of other factors besides emissions, like meteorology, in overall air quality.”

Wildfire Influence on Air Quality

Southern California met the PM2.5 standard for the first time last year, according to South Coast AQMD, despite 2020 having the highest recorded number of acres burned in California, according to Cal Fire.

Wildfires drastically impact air quality, particularly increasing the PM levels. 

However, wildfires are considered exceptional events, meaning wildfire days don’t count when determining if the region has achieved air quality standards, Sospedra said.

“This is happening because of climate change,” Sospedra said. “Because we have an expanding population, people get to live closer to forest areas, so there’s a higher chance for homes to be burned because of wildfires.” 

What You Can Do

Sospedra says everyone can help improve air quality. He recommends residents:

  • Reduce vehicle emissions by
    • using mass transit,
    • switching to an electric vehicle,
    • or carpooling.
  • Switch from central heating to a heat pump that both heats and cools.
  • Install solar panels to reduce emissions from power plants.
  • Avoid using personal care products that include cyclopentasiloxane (a silicone commonly found in cosmetics) to reduce ozone.

Sospedra says the most important concept people should understand is that improving air quality doesn’t come free. 

“Achieving cleaner air takes effort,” Sospedra said. “It requires money and investment, but the benefits far outweigh the costs.”

Story written by Adrienne Mitchel. Edited by Savannah Sauer.

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