The first evidence that exceeding the World Health Organization (WHO) ozone limit is associated with substantial increases in hospital admissions for heart attack, heart failure and stroke is published today in European Heart Journal, a journal of the European Society of Cardiology (ESC). Even ozone levels below the WHO maximum were linked with worsened health.

“During this three-year study, ozone was responsible for an increasing proportion of admissions for cardiovascular disease as time progressed,” said study author Professor Shaowei Wu of Xi’an Jiaotong University, China. “It is believed that climate change, by creating atmospheric conditions favouring ozone formation, will continue to raise concentrations in many parts of the world. Our results indicate that older people are particularly vulnerable to the adverse cardiovascular effects of ozone, meaning that worsening ozone pollution with climate change and the rapid ageing of the global population may produce even greater risks of cardiovascular disease in the future.”

Ozone is a gas and the main air pollutant in photochemical smog. Ozone pollution is different to the ozone layer, which absorbs most of the sun’s ultraviolet radiation. Ozone pollution is formed when other pollutants react in the presence of sunlight. These other pollutants are volatile organic compounds and nitrogen oxides which are emitted by motor vehicles, power plants, industrial boilers, refineries, chemical plants, and biomass and fossil fuel burning facilities. Previous studies have suggested that ozone pollution harms the heart and blood vessels, but there is limited and inconclusive evidence about its influence on the risk of cardiovascular disease.

This study examined the association between ambient ozone pollution and hospital admissions for cardiovascular disease. Data on daily hospital admissions for cardiovascular disease during 2015 to 2017 in 70 cities in China were collected from the two main national health insurance systems. During the study period, the two databases covered approximately 258 million people across the 70 cities, equivalent to more than 18% of China’s population. The types of cardiovascular disease included coronary heart disease, stroke and heart failure, plus subtypes such as angina, acute myocardial infarction, acute coronary syndrome, ischaemic stroke and haemorrhagic stroke.

Read the full article about ozone pollution and cardiovascular disease at Environmental News Network.