The World Health Organization (WHO) estimates that air pollution leads to 7 million premature deaths every year.
Out of the six common air pollutants, particulate matter measuring 2.5 microns or smaller in diameter, or PM2.5, is accepted as the most harmful to human health. This is due to its prevalence in the atmosphere and the broad range of adverse health effects associated with its exposure, such as heart disease, stroke, lung cancer and chronic respiratory diseases.
With that context in mind, this visualization from Visual Capitalist's Selin Oğuz and Miranda Smith uses IQAir’s World Air Quality Report to map out the 2022 average PM2.5 concentrations in select major cities around the globe, expressed in micrograms per cubic meter (μg/m³).
Did you know that in 2019, only 1% of the global population lived in places where WHO global air quality guidelines were met?
Designed to protect public health from the harmful effects of air pollution, the guidelines cover a range of air pollutants, including particulate matter, ozone, nitrogen dioxide, sulfur dioxide, and carbon monoxide.
The healthy limits for PM2.5 are set at an annual average of 0-5 μg/m³.
*Percentages are calculated as a proportion of the 131 countries that had sufficient air quality data and were included in IQAir’s World Air Quality Report in 2022.
According to IQAir’s World Air Quality Report, only 13 countries or territories met the recommended concentration of PM2.5 in 2022. Among them were Australia, Finland, Puerto Rico, Iceland, Bermuda, and Guam.
Above this guideline, many countries fell within the four interim targets, while nearly 14% recorded air pollution levels that exceeded all target levels.
While it can be a little difficult to grasp what the above concentrations represent, thinking of them in terms of their effect on mortality can shed some light on their significance.
According to the WHO, non-accidental mortality rates multiply by 1.08 per 10 µg/m³ increase in PM2.5 concentration, but only up to 35 μg/m³. Above that, mortality growth rates may not be linear, resulting in many more deaths.
Here is an example to highlight what that means.
Beyond Interim Target 1 (above 35 μg/m³), deaths would potentially grow much faster. As of 2022, around 14% of countries report levels above this threshold, including Chad, India, Pakistan, Qatar, and Nigeria.
While many cities in North America and Europe have seen steady and relatively lower PM2.5 concentrations during the last few years, many cities (especially those in Asia) have been making strides in lowering their air pollution levels.
Nonetheless, many of them still record PM2.5 concentrations that are more than six times the WHO guideline.
Most parts of the world did not meet the annual WHO recommendation for clean and healthy air in 2022.
However, the cost of inaction toward cleaner air is very high. In addition to the millions of premature deaths each year, the global cost of health damages associated with air pollution currently sits at $8.1 trillion.
Unfortunately, things that are integral to our quality of life, such as industrial activities, transportation, energy production, and agricultural practices, are also the leading causes of air pollution around the world.
As such, a multi-faceted approach to lowering pollution is essential to protect lives, especially to benefit those already more vulnerable to poor air quality, such as kids and the elderly.