Almost nowhere on Earth is safe in terms of air quality: study

When it comes to air quality, almost no one on Earth is safe, according to a new study.

Scientists have found that we constantly breathe in tiny particles that are harmful to our health, almost everywhere on the planet, and only 0.001 percent of the global population is exposed to the level of particles considered safe by the World Health Organization (WHO).

According to the researchers, this is the first study of its kind to examine air quality on a global scale. Poor air quality can lead to a higher disease burden in populations, as air pollution can contribute to the risk of strokes and respiratory diseases.

Most previous research on air quality has focused exclusively on city or national levels or only on global trends. The study, published this month in the journal peer-reviewed journal Lancet Planetary Healthlooked at daily average concentrations of particulate matter from 2000-2019.

The researchers found that in the two decades leading up to 2019, daily levels of certain fibers in Europe and North America declined. However, levels have increased in South Asia, Australia, New Zealand, Latin America and the Caribbean over the same period. .

And despite a decrease in levels in some regions, more than 70 percent of days in the study period had particulate matter concentrations higher than the WHO safety threshold. Only 0.18 percent of the global land area had annual exposure to fine particles below the WHO limit.

“In this study, we used an innovative machine learning approach to integrate multiple meteorological and geological information to estimate daily global surface-level (particle) concentrations,” Yuming Guo, professor at Monash University in Australia. said in the press release.

He explained that they studied the concentrations, focusing on areas where particulate levels exceeded the safe limit set by the WHO. They used a combination of satellite observations and ground monitoring.

The study specifically looked at fine particles 2.5 micrometers or smaller in diameter, which the WHO considers “the most dangerous pollutant” because its small size means it can “penetrate the lung barrier and enter the blood system, causing cardiovascular and respiratory diseases. and cancer.”

Air quality is not stable. Due to weather patterns and human activities, air quality in any region varies, and some regions may have more days with high particle concentrations than others.

One way to measure air quality is to look at the annual average concentration of air pollutants in a region.

The WHO has set a safe limit for the annual average concentration of fine particles of 15 micrograms of pollutant per cubic meter, which means that any region with an annual average concentration above this figure is considered to have unsafe air quality.

But there is also safety on days when the concentration of pollutants in the air is high. The WHO states that in order to remain in safe settings, a person should not have more than 3-4 days per year when they are exposed to more than 15 µg of pollutant per cubic meter in 24 hours.

Exposure to these levels of air pollutants twenty-four hours a day for more than four days per year is not safe for the human body, even if the person lives in a region with low average annual air pollution.

The study found that some regions saw significantly more days with hazardous concentration levels than others. In East and South Asia, more than 90 percent of days during the study period had daily particulate matter concentrations above the WHO threshold.

Air quality in Australia and New Zealand worsened in 2019, with a clear increase in concentrations above the WHO threshold, which researchers theorized could be linked to an increase in dust and bushfires that year.

Overall, Australia, New Zealand and South America had the lowest annual concentrations of particulate matter, the study found.

China had the highest estimated levels of particulate matter concentration in 2000, 2010 and 2019.

While Canada was one of the countries with consistently lower concentration levels and days exposed, we still saw 21.9 days with concentrations above safe levels in 2019, compared to 55 days in 2010 and 82.7 days in 2000. In 2019, our annual average particles were: about 16.6 micrograms of the pollutant per cubic meter, which puts us just above the WHO threshold.

Agreed Global Air Quality Report 2019Published in 2020, Canada’s air is relatively clean compared to other countries, ranking 90th out of 98 countries in terms of poor air quality.

The researchers noted that the study cannot predict personal exposure risks because population-weighted exposure estimates assume an even distribution of population across a country’s geography, which simply does not apply to the vast majority of regions.

But it is hoped that this study will promote greater understanding of where air quality needs to be addressed around the world.

“It provides an in-depth understanding of the current state of outdoor air pollution and its impact on human health,” Guo said. “With this information, policymakers, public health officials and researchers can better assess the short- and long-term effects of air pollution and develop strategies to reduce air pollution.”