Annual mean concentration of NO2, PM10, and PM2.5 in metropolitan cities Italy 2022

The WHO air quality guidelines for nitrogen dioxide (NO2) and particulate matter (PM10 and PM2.5) were not followed in any of the 14 metropolitan Italian cities investigated by a recent study on air pollution. The most polluted cities were Milan and Turin, where NO2 and PM2.5 concentrations were as high as over three and four times the recommended WHO values, respectively.

What are the sources of air pollution?

Rome, Milan, Naples, and Turin are the largest cities in Italy. In such densely populated urban areas, fossil fuels combustion by road traffic, energy distribution, and industries are the main sources of NO2. A relevant share of PM10 is emitted by domestic heating systems, agriculture, and road vehicles, while PM2.5 is mainly of secondary origin. They are the result of chemical reactions in the atmosphere involving fossil fuels and biomass burning, nitrate and sulfate compounds, and biogenic particles.

Air pollution and health

The WHO air quality guidelines give recommendations regarding the annual mean concentrations of air pollutants that should not be exceeded to protect public health. The effects of short- and long-term exposure to elevated concentrations of NO2, PM10, and PM2.5 range from dizziness, headache, and irritation of the nose and throat to chronic pulmonary and cardiovascular diseases. PM2.5 can penetrate deeply into the respiratory system because of its small size (its diameter is smaller than 2.5 micrometers) and is responsible for around 50,000 premature deaths in Italy every year.