A new modelling study has found that 86% of people living in cities worldwide (or 2. 5 billion people) are exposed to annual average levels of fine particulate matter exceeding the World Health Organisation (WHO) guideline from 2005.
This is even as another study has revealed that nearly 2 million cases of asthma in children can be linked to traffic-related nitrogen dioxide air pollution, with two in three occurring in cities.
Inhalation is known to increase the risk of premature death from conditions such as cardiovascular disease, respiratory disease, lung cancer, and lower respiratory infection.
The two studies which were published in The Lancet Planetary Health journal, highlight the urgent need for strategies to improve air pollution and reduce exposure to harmful emissions, particularly among children and the elderly.
In the first study, researchers looked at PM2.5 (fine particulate matter with a diameter of 2.5 micrometres or less) – the leading environmental risk factor for disease. The new studies also examined PM2.5 concentrations and associated mortality trends in over 13,000 cities globally between 2000-2019.
The studies also found that the average population-weighted PM2.5 concentration across all urban areas globally was 35 micrograms per cubic metre in 2019, with no change from 2000.
Read also: STUDY: Damaged coral reefs can provide seafood
This is equivalent to seven times the 2021 WHO guideline for annual average PM2.5 (five micrograms per cubic metre) [2].
The authors also estimated that 61 in every 100,000 deaths in urban areas was attributable to PM2.5 in 2019. They maintained that although global urban average PM2.5 concentrations were consistent over this period, there were large variations by region.
They explained that urban areas in South-East Asia (including India) saw the largest regional increases, with a 27% increase in average population-weighted PM2.5 concentration between 2000-2019.
“South-East Asian cities also saw the largest increase in PM2.5-attributable mortality rates over this period, increasing by 33% from 63 to 84 in 100,000 people “they added.
