Researchers find link between ozone, heart disease

Jan Flatley-Feldman/Staff

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UC Berkeley researchers have discovered a link between the regional prevalence of the common air pollutant ozone and an increased risk of premature death from heart disease, the No. 1 cause of death in the United States.

The team used a state-of-the-art statistical model to aggregate mortality rates from different regions in California from 1982 to 2000 and levels of ozone and particulate matter gathered from government monitors situated across California. They found that in sunny areas such as Los Angeles, where there is a high concentration of ozone, more deaths resulted from cardiovascular issues.

The study is the first to show that exposure to ozone — a powerful greenhouse gas that protects the Earth from ultraviolet rays but acts as harmful chemical smog in the lower atmosphere — can lead to death from cardiovascular disease instead of just respiratory disease.

According to Michael Jerrett, chair of the School of Public Health’s environmental health sciences department and a participant in the study, ozone and a few other pollutants penetrate deep into the lungs, where they exchange oxygen and cause “oxidative stress.” The lungs then mount a defense against the foreign substances that, in combination with the stress, begins an inflammatory process that can spread to the cardiovascular system. This causes both a shrinkage and thickening of the coronary artery, blocking blood flow to the heart and potentially causing a heart attack.

“Another reason to like the Bay Area is the fogginess protects us from this pollution,” Jerrett said.

He estimates that according to the statistical model, anywhere from 100,000 to half a million deaths can be attributed to air pollution, although there is “no guarantee” that global organizations will take the data into consideration to further regulate ozone levels, despite the potential benefits.

“One of the problems is that some of the effects we’re dealing with may happen 30, 50, a hundred years out, and people have a tendency to discount the future,” Jerrett said.

Another obstacle in increasing regulation of ozone — which also could help mitigate climate change — comes from what Seth Shonkoff, an environmental health researcher at UC Berkeley who wasn’t affiliated with the study, calls an “environment against the economy” narrative.

“A lot of political pressure comes from this false idea that doing things better for the environment are worse for the economy,” he said, adding that emission-reduction technologies are regarded as too costly for businesses to legitimately consider.

However, he noted that “morbidity and mortality” driven by air pollution creates a significant drain on the economy, because tax dollars have to pay for the hospitalizations.

According to the researchers, about 119 million people live in areas that do not meet ozone regulation standards in the United States, but many are unaware of this fact and its implications.

“It’s not just doing the science but communicating the science to the community in ways that make people feel empowered to do something about it,” Shonkoff said.

Virgie Hoban is the lead research and ideas reporter. Contact her at [email protected] and follow her on Twitter @VirgieHoban.