Air and Noise

The air differs from most of the other natural resources because it is not scarce. Therefore, it does not need to be rationed. The vulnerability of the air lies primarily in its high risk of deterioration.

In general, air quality is the result of the interaction of a complex set of factors, such as danger of pollutants, volume of emissions, topography of the region and even weather conditions associated with it.

Industrial and energy production and transport are the largest emitters of air pollutants. These sectors release into the atmosphere some of the most hazardous compounds for human health, ecosystems and materials, such as sulphur dioxide, nitrogen dioxide, suspended particles, lead, benzene or carbon monoxide, among others.

Epidemiological studies have shown an important relationship between exposure to air pollutants and morbidity and mortality associated with respiratory (asthma, bronchitis, pulmonary emphysema and lung cancer) and cardiovascular (myocardial infarction, stroke) diseases, even when concentrations of pollutants in the atmosphere remain below the legally established maximum values.

The impacts of air pollution on the environment are equally burdensome: it directly influences global warming, is the source of acid rain, which accounts for the contamination of water and soils, and is an important factor for the degradation of ecosystems.

Public policies for air quality management aim to reduce emissions of air pollutants by ensuring that socio-economic development takes place in a sustainable and environmentally neutral manner.

Fact sheets

  • Air Quality Index (AQI)
    The “Air Quality Index” is an indicator that expresses the state of the ambient air quality at the national level and allows, through classification according to a colour scale, according to its results, to guide the citizen in order to adapt behaviours and actions towards the protection of human health, especially the most sensitive groups of the population.
  • Tropospheric Ozone Pollution Episodes
    The "Tropospheric Ozone Pollution Episodes" fact sheet contains information on situations in which ozone information thresholds are exceeded, which occurrence triggers an alert system for dissemination to the population and to the competent authorities.
  • Particulate matter pollution
    The "Particulate matter pollution" fact sheet analyses the concentration of particles in the air with a diameter of 10 μm or less, in order to protect human health.
  • Nitrogen Dioxide Air Pollution
    The "Nitrogen Dioxide Air Pollution" fact sheet analyses the progress towards the objectives imposed for this pollutant across the country, in order to safeguard the protection of human health.
  • Emissions of tropospheric ozone precursors
    The "Emissions of tropospheric ozone precursors" fact sheet shows the emissions of nitrogen oxides and non-methane volatile organic compounds, molecules that are at the origin of tropospheric ozone formation.
  • Emissions of acidifying and eutrophying substances
    The "Emissions of acidifying and eutrophying substances" fact sheet shows the emissions of sulphur dioxide (SO2), nitrogen oxides (NOx), and ammonia (NH3), substances which contribute to acidification of the environment.
  • Environmental noise
    The "Environmental noise" fact sheet assembles the information collected in the Strategic Noise Maps in mainland Portugal and the evolution of the population overexposed to noise levels above 55 dB(A) during night-time.