The first evidence that exceeding the World Health Organization (WHO) ozone limit is associated with a significant increase in hospitalizations for heart attack, heart failure and stroke was published today in the European Heart Journal, a journal of the European Society of Cardiology (ESC). . Even ozone levels below the WHO maximum have been linked to worsening health.
“During this three-year study, ozone was responsible for an increasing proportion of cardiovascular disease admissions over time,” said study author Professor Shaowei Wu of Xi’an Jiaotong University, China. “Climate change is believed to further increase concentrations in many parts of the world by creating atmospheric conditions favorable to ozone formation. Our results show that older people are particularly vulnerable to the adverse cardiovascular effects of ozone, meaning that increasing ozone pollution from climate change and the rapidly aging world population could put them at even greater risk of cardiovascular disease in the future. “
Ozone is a gas and the main air pollutant in photochemical smog. Ozone pollution is distinct from the ozone layer, which absorbs most of the sun’s ultraviolet radiation. Ozone pollution occurs when other pollutants react in the presence of sunlight. These other pollutants are volatile organic compounds and nitrogen oxides emitted by automobiles, power plants, industrial boilers, refineries, chemical plants, and plants that burn biomass and fossil fuels. Previous studies have shown that ozone exposure damages the heart and blood vessels, but there is limited and inconclusive evidence on its impact on cardiovascular disease risk.
This study examined the association between ozone pollution and hospitalizations for cardiovascular disease. Data on daily hospitalizations for cardiovascular diseases in 70 cities in China in 2015-2017 were collected by the two major national health insurance systems. During the survey period, the two databases covered approximately 258 million people in the 70 cities, accounting for more than 18% of China’s population. Types of cardiovascular disease included coronary artery disease, stroke, and heart failure, and subtypes such as angina, acute myocardial infarction, acute coronary syndrome, ischemic stroke, and hemorrhagic stroke.
The 8-hour daily maximum concentrations of ozone, particulate matter (PM2.5), respirable particulate matter (PM10), sulfur dioxide, nitrogen dioxide, and carbon monoxide were obtained for each city from the National Real-Time Publication Platform. of urban air quality in China.
During the study period, there were 6,444,441 cardiovascular disease hospitalizations in the 70 cities, and the eight-hour average daily maximum ozone concentration was 79.2 μg/m3. Exposure to atmospheric ozone, independent of other air pollutants, was associated with increased hospitalizations in all cardiovascular diseases studied, with the exception of hemorrhagic stroke. For example, every 10 μg/m3 increase in mean 2-day-8-hour peak ozone concentration was associated with a 0.40% increase in hospital admissions for stroke and 0.75% for heart attack.