On February 10th a new study published in the Journal of Medicine found that daily exposure to ground-level ozone increases the risk of death. Ground ozone is a highly active gas, commonly found in urban and suburban environments, is the formation of pollutants in the sun reaction. The current World Health Organization air quality threshold range is 100 ?g/m3. Studies have shown that 80 per cent of the world’s urban population is exposed to air pollution levels above WHO standards.
Previous studies have found a link between ground-level ozone and mortality, but differences in research design and air quality make it difficult to reach consistent conclusions in different regions.
To address this problem, an international team of researchers analysed deaths and environmental indicators in 406 cities in 20 countries, spanning between 1985 and 2015.
Using data from the multi-city multi-country cooperative research network, they were able to estimate the additional deaths caused by ozone per day against a backdrop of an average daily ozone level above 70?g/m3, as well as particulate matter, temperature and relative humidity at each observation point.
A total of 45165,171 deaths were analyzed in 406 cities, and on average, when ozone concentrationincreases increased by 10 ?g/m3 during the day, the risk of death increased by 0.18%, indicating potential direct (causal) evidence.
This equates to 6,262 additional deaths per year in 406 cities (0.2 per cent of the total mortality rate), which could have been avoided if countries had implemented stricter air quality standards in accordance with WHO guidelines.
The researchers also stressed that this is an observational study, so the cause cannot be determined and points to some limitations. For example, there were no reports or assessments in parts of South America, Africa and the Middle East, and differences in monitoring and data collection between countries could affect the accuracy of assessments.