Is rural air more toxic than urban air?

It's easy to see air pollution when the smog settles over the city.

However, even in rural areas - where the air appears to be cleaner - researchers have found unhealthy particles floating in the atmosphere there.

In the end, the beautiful countryside air may not be as fresh as we once thought.

According to a report in Science Alert, it is believed that fine particles less than 2.5 micrometers in diameter - referred to as PM 2.5 - cause the greatest harm to human health, as these pollutants are as small as Enough to infiltrate deeply into our lungs, damaging the cells and tissues in the lungs.

So, the World Health Organization has set a safety line for ambient levels of particulate matter, however, this line overlooks the nuances of intrinsically toxic chemicals.

The health risks of agricultural activities (pixels) cannot be ignored.

agricultural activities

Recent research suggests that the mass of the fine particles we breathe may be less important to human health than their “chemical composition”;

This is because some of the lighter particles are more likely to produce types of reactive oxygen, which can have toxic effects on human health.

When researchers in the United States compared 3 urban areas to one rural area in the Midwest, they found similar levels of redox potential at all four sites.

This was true even though the rural site had a relatively lower mass than PM2.5.

While agricultural activities contributed only 12% of the PM2.5 mass at the rural site, they represented more than 60% of the cellular redox potential in the area.

On the other hand, the oxidizing capacity of most urban sites was less than 54%.

In a paper published in the Journal of Hazardous Materials, the authors write, “Overall, our study indicates that the sources that contribute most to PM 2.5 mass are not necessarily as important in terms of its health effects.

Instead, the researchers argue, our health measures of air pollution should be based more on the potential toxicity of fine particles than on their actual mass.

Air pollution measures should be based on potential toxicity and not on the mass of actual particles (pixels).

study samples

The study is based on weekly samples of PM2.5 taken during the summer and fall of 2018 and winter and spring of 2019 from urban sites in Chicago, Indianapolis and St. Louis, as well as a rural site in Illinois, United States.

By analyzing the composition, mass, and oxidizing potential of these samples, the team found a weak correlation between the mass of the particles and their toxicity.

In rural areas, lighter chemicals were more likely to produce unhealthy by-products.

The researchers found that the floating effects of iron and organic carbon, for example, were closely related to the year-round cellular redox potential.

While other industrial chemicals, such as lead, aluminium, copper and manganese, tended to increase during the winter and fall seasons.

The strong seasonal component of these findings indicates that many of the toxic chemicals inhaled in rural Illinois are due to agricultural activities, such as the use of fertilizers and herbicides.

Phosphate fertilizers sprayed on crops, for example, contain pollutants from heavy metals, such as lead and chromium, that can easily infiltrate the air and lungs.

Copper fungicides are also sprayed in a similar manner.

Although the village in question is located 12 kilometers from a coal-fired power plant, coal combustion and biomass burning account for more than 80% of the PM 2.5 mass in this rural area of ​​Illinois.

The mass of the fine particles we breathe may be less important to human health than their chemical composition (Getty Images)

Coal is no more dangerous than agricultural sources

If the study authors simply measured PM 2.5, then coal would appear to be the most dangerous factor to human health. But this may not be true. Instead, agricultural sources - which are lighter by mass - appeared to have twice the toxicity by mass. burnt vitality.

The authors concluded that "despite its minor contribution to the 'PM2.5' mass, the health risks of agricultural activities cannot be ignored."

Nor can we ignore the lighter forms of microparticles.

For example, another study conducted in Beijing in 2019 found that vehicle emissions contributed only 10% of PM2.5 mass in the region.

However, it accounted for more than half of all toxic substances measured in the air.

Hence, the way we measure air pollution is clearly flawed and does not capture the full extent of the damage.

Therefore, measuring the oxidizing potential of individual chemicals is more complex than simply weighing the mass of all the surrounding pollutants.

The authors of the current study hope that their new methodology will make testing toxic air easier for future environmental regulators and policy makers.