PM2.5 stands for particulate matter with a diameter of 2.5 µm or less. These particles are emitted mainly from the combustion of solid fuels for domestic heating, industrial activities and road transport. As with PM10, they can also come from natural sources and can be formed in the atmosphere. Agricultural emissions of ammonia make a significant contribution to the formation of fine particulate matter in the atmosphere.
The highest PM2.5 concentrations were seen in northern Italy and some eastern European countries (Figures 5 and 7). As for PM10, the use of solid fuels is the main reason for the situation in central and eastern Europe, together with an older vehicle fleet. In northern Italy, the high concentrations are due to the combination of a high density of anthropogenic emissions and meteorological and geographical conditions that favour the accumulation of air pollutants in the atmosphere and the formation of secondary particles.
Figure 5. Concentrations of PM2.5 in 2021 and 2022 in relation to the EU annual limit value and the WHO annual guideline level
Figure 6: Percentage of reporting monitoring stations registering PM2.5 concentrations above the EU annual limit value and the WHO guideline levels in 2021 and 2022
Concentrations of PM2.5 above the EU annual limit value were registered at 2% of monitoring stations (Figure 6), 72% of which were urban and 23% suburban.
Furthermore, Italy and Poland reported exceedances of the PM2.5 annual limit value based on assessment models for 5 and 46 air quality zones, respectively.
In 2021, all EU Member States continued to meet the exposure concentration obligation of 20 µg/m3, based on a 3-year average (2019-2021) measured at urban background stations, that was to be attained as of 2015 under the Ambient Air Quality Directive. Furthermore, only Romania did not meet the national exposure reduction target set for 2020. This indicator assesses the long-term exposure of the general population in urban areas.
Figure 7: PM2.5 concentrations in 2021 by country in relation to the EU annual limit value and the WHO annual guideline level
Note: The figure shows, per country, the concentrations of each reported station, the minimum and maximum concentrations, the median and the percentiles 25 (“Lower Hinge”) and 75 (“Upper Hinge”) of all the measurements.
An increase in PM levels could be expected in 2022 from the expected increase in the use of wood and coal as fuel, as a result of the energy crisis and higher gas prices seen in that period. Nevertheless, the data presented here are 2022 annual averages, and the beginning of the winter 2022-2023 was milder than usual in Europe.