Particulate matter pollution

The "Particulate matter pollution" fact sheet analyzes the national compliance with the objectives imposed on particles with a diameter of fewer than 10 μm in the air, in order to protect human health.


Inhalable particles are potentially hazardous substances when deposited in the respiratory tract, being one of the most serious air pollutants in terms of public health.

In cities, particulate matter have their origin predominantly in traffic emissions, in particular, diesel vehicles, but also in the emissions of some industries, civil construction or household heating. Occasionally, high levels may occur resulting from natural events such as the transport of long-distance particles from the arid regions of Africa or associated with forest fires.

Inhalation of particles lower than or equal to 10 microns in diameter may affect the lungs, with consequences that may lead to persistent coughing, increased mucus and short-term respiratory distress, or problems ranging from asthma and chronic bronchitis to heart disease that in the long run may imply a reduction of the average life expectancy.

The daily exposure of people to this pollutant, especially in cities, has led to the establishment of the daily limit value (VL) of PM10 (50 μg/m3, which should not be exceeded more than 35 days per calendar year) and the annual VL μg (40/m3), ensuring the protection of human health from its harmful effects.

The indicator of the number of exceedances to the daily limit value identifies the possible need to trigger the implementation of measures in zones/agglomerations where monitored levels are above the VL, in order to reach the defined target.

The calculation of the annual national average results from the aggregation of the worst case data for each zone/agglomeration, taking into account the use of all existing stations in the zone with a monitoring efficiency (percentage of data valid over the measurement period ) higher than 75%. If the evaluation strategy defined for the zone is the indicative measurement, stations with a measuring efficiency of more than 14% are considered.

The evolution of exposure of the population to this pollutant is obtained through the aggregation of annual average values, associated with the worst situation in each zone/agglomeration.

This fact sheet concerns mainland Portugal, the Autonomous Regions of Madeira and the Azores and will be updated annually.

Objectives and targets: 
  • Ensure compliance with the objectives set at EU level for ambient air quality, which aim to avoid, prevent or limit the harmful effects of different air pollutants on human health and the environment;
  • Evaluate ambient air quality throughout the national territory, with a special focus on urban centres;
  • Preserve the air quality in cases where it is good and improve it everywhere else;
  • Promote and improve public access to air quality information, including on the prediction of particulate matter concentrations and on the consequences to human health due to exposure;
  • With regard to targets, to avoid exceedance of the thresholds set forth in the legislation (Decree-Law no. 102/2010):
    • Limit value for the average daily concentration of 50 μg/m3 of inhalable particulates (PM10), not to be exceeded more than 35 times per calendar year;
    • Limit value for the average annual concentration of PM10 of 40 μg/m3.
Progress analysis:
Last update: 
Monday, 29 October, 2018