Air pollution in Delhi

Air pollution in biggest cities four times above safe levels

Image credit: Dreamstime

An investigation by OpenAQ has found that the average level of air pollution in the world’s largest cities is nearly four times higher than the maximum levels recommended by the WHO.

According to estimates, 90 per cent of the world experiences harmful levels of air pollution; the problem is particularly acute in cities in the Global South and disproportionately affects poorer communities in these cities.

OpenAQ’s investigation found that the average annual level of PM2.5 air pollution was 39μg/m3, almost four times higher than the World Health Organisation guidelines (10μg/m3). PM2.5 is fine particulate matter from sources such as car exhausts; it is the type of air pollution that has the most severe impact on human health. It its linked to numerous health conditions ranging from respiratory to psychiatric, and exacerbates Covid-19 fatalities. Air pollution in the US alone is estimated to account for 100,000 deaths a year.

Overall, 33 of the world’s largest cities are exceeding WHO guidance for PM2.5 levels.

The worst affected cities were all in Asia: Lahore in Pakistan, Delhi in India, Dhaka in Bangladesh, Ahmedabad in India, and Xi’an in China had the highest levels measured. The findings illustrate the association between global inequality and air pollution; for instance, PM2.5 levels in Delhi are 102μg/m3 compared with 7.7μg/m3 in New York City, 10.15μg/m3 in Los Angeles, and 11.5μg/m3 in London.

The investigation was carried out by NGO OpenAQ. The organisation has this week announced the launch of a new open-source data platform, which will enable citizens to collect air quality data using low-cost sensors, which can be installed by individuals and communities as well as by governments. According to another study from OpenAQ, 51 per cent of the world’s population has no access to official government data on air quality.

The platform brings together data from the Environmental Defense Fund’s Air Quality Data Commons, Purple Air, HabitatMap, and Carnegie Mellon University, and already has more than 750,000,000 data points from 99 countries.

“We want to encourage new, affordable solutions to monitor air quality, and bring that data to OpenAQ to increase funding and action for those communities who are most affected by air pollution,” said Jeremy Taub, executive director of OpenAQ. “It will fill important data gaps allowing communities to develop solutions to air pollution.”

Professor Albert Presto of Carnegie Mellon University added: “Sensors bring air pollution data to the neighbourhood level, but people need to be able to access the data from trusted sources using reliable tools. OpenAQ is one source that will allow us to further disseminate this valuable data.”

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