Air pollution, as it turns out, is incredibly difficult to avoid no matter where you are on the planet. A new study from Monash University in Australia found that nearly 99 percent of the world’s population are exposed to unhealthy levels of dangerous air pollutants called ambient fine particulate matter (PM 2.5).
The study was published March 6 in the journal Lancet Planetary Health. The team of researchers used computer models to assess annual and daily PM2.5 concentrations around the world from 2000 to 2019.
The models used data from ground stations that monitor air quality, weather, and simulations of how chemicals travel through the air. They found that in 2019, only 0.001 percent of the global population was exposed to levels of PM 2.5 pollution that World Health Organization (WHO) deems safe. The WHO says concentrations higher than 5 micrograms of PM 2.5 per cubic meter is considered hazardous.
The study described that while daily levels of air pollutants have decreased in North America and Europe in the two decades studied, levels increased in Australia, New Zealand, Southern Asia, Latin America, and the Caribbean. Over 70 percent of the days monitored in these regions had air pollution that was above WHO recommended levels. The highest concentrations were generally found in southern Asia, eastern Asia, and northern Africa.
According to study co-author and global public health and epidemiologist Yuming Guo, there are seasonal patterns that take place amid unsafe PM2.5 concentrations. Northeast China and northern India saw higher levels during December, January, and February and eastern regions of North America had higher PM2.5 during summer months.
“We also recorded relatively high PM2.5 air pollution in August and September in South America and from June to September in sub-Saharan Africa,” Guo said in a statement.
Guo told The Washington Post on March 6 that the study does have some limitations—some countries didn’t have as much ground data, which could affect how the models perform in those regions.
This study, possibly the first of its kind, aligns with data released by the WHO in April 2022 that also found that dangerous levels of air pollution affects 99 percent of the population.
“Particulate matter, especially PM2.5, is capable of penetrating deep into the lungs and entering the bloodstream, causing cardiovascular, cerebrovascular (stroke) and respiratory impacts. There is emerging evidence that particulate matter impacts other organs and causes other diseases as well,” the WHO wrote in a statement last year.
Other studies have shown that even low levels of air pollution can increase excess mortality, traffic pollution could be connected to low birthweight, and is linked to an increased risk of depression and bipolar disorder.
“[This study] provides a deep understanding of the current state of outdoor air pollution and its impacts on human health,” Guo said in a release. “With this information, policymakers, public health officials, and researchers can better assess the short-term and long-term health effects of air pollution and develop air pollution mitigation strategies.”