In recent years, a decrease in air pollution has been observed in developed countries. There are some positive changes in Russia as well. For example, in 2019, the number of air samples near highways in which the maximum permissible concentrations of harmful substances were exceeded was 2.29 times less than in 2012. The air is becoming cleaner in some industrial cities.
However, some studies have shown that airborne pollutants can have health effects even at concentrations that are considered acceptable. The authors of the new scientific work assessed their danger to life.
Scientists analyzed data from eight studies conducted in six European countries, which covered about 325 thousand people. The participants were followed for almost 20 years.
The analysis confirmed that the higher the concentration of fine particles with a diameter of less than 2.5 microns (PM2.5) and nitrogen dioxide in the air, the greater the risk of death:
- An increase in PM2.5 particle concentration of 5 micrograms per cubic meter (µg / m3) was associated with a 13% increase in the risk of death;
- nitrogen dioxide at a concentration of 10 μg / m3 – at 8.6%.
Moreover, the association of these substances with the risk of death was significant even at very low concentrations that are acceptable by the WHO and developed countries. Without exceeding the standards, an increase in PM2.5 concentration of 5 µg / m3 was associated with an increase in the risk of death by almost 30%. The probability of death in people who inhaled nitrogen dioxide in acceptable doses increased by 10% for every 10 µg / m3 increase in nitrogen dioxide concentration.
The authors wrote in the conclusions of the work: “Our study contributes to the evidence base for the association of ambient air pollution with mortality rates even at levels below current standards in Europe, North America and WHO.” They indicated that this is important data for the revision of existing standards.