Ozone air pollution has now been directly tied to the risk of developing cardiovascular disease, which expands the list of health effects known to be caused by ozone exposure, and also lowers the threshold at which ozone is known to be dangerous (by a fair amount).
To explain, it’s been known for quite some time that exposure to ozone is associated with reduced lung function — and everything that goes along with that — but the new work now shows that high blood pressure (and the risk of experiencing a heart attack and/or a stroke) are associated with it as well.
“We know that ozone can damage the respiratory system, reduce lung function and cause asthma attacks,” commented study author Junfeng Zhang, from Duke and Duke Kunshan University. “Here, we wanted to learn whether ozone affects other aspects of human health, specifically the cardiovascular system.”
As a bit of further background here — the ozone that we commonly think of as air pollution forms in urban areas (and elsewhere) when nitrogen oxides and other organic compounds released through fossil fuel combustion and agriculture are exposed to sunlight. In other words, the air pollution coming from car and truck exhaust, and from coal-fired power plants, interacts with sunlight and breaks down into ozone in some instances/circumstances.
The press release provides more: “Zhang and colleagues studied 89 healthy adults living in Changsha City, China, for one year. They monitored indoor and outdoor ozone levels, along with other pollutants. At four intervals, the study team took participant blood and urine samples and used a breathing test called spirometry to examine a set of factors that could contribute to cardiovascular and respiratory disease.
“The team examined inflammation and oxidative stress, arterial stiffness, blood pressure, clotting factors and lung function in participants. They noted blood platelet activation (a risk factor for clotting) and an increase in blood pressure, suggesting a possible mechanism by which ozone may affect cardiovascular health. These effects were found with ozone exposure lower than that which affects respiratory health, and lower than current Environmental Protection Agency (EPA) air quality standards.”
To say that again: the effects of ozone on cardiovascular health as observed in the study occur at exposure levels lower than the levels considered to be “safe” by the US EPA.
“This study shows that standards for safe ozone exposure should take into account its effect on cardiovascular disease risk,” continued Zhang. “In 2015, 108 million Americans — one third of the population — lived in counties with ozone levels that exceeded standards set by the EPA. In contrast, only 31 million Americans live in counties where other pollutants exceed EPA standards.”
This situation is only going to get worse in the coming years, as ozone formation from air pollution increases as temperatures rise.
A paper on the new study was published in the July 17, 2017 edition of the journal JAMA Internal Medicine.