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Outdoor air pollution

Outdoor air pollution

The term “air pollution” refers to harmful particles suspended in the air, or gases in the atmosphere, that can be breathed in. It is a mixture including particles, ozone, nitrogen oxides, volatile organic compounds and carbon monoxide. The mixture is different depending on location, season and sources of pollution in the area.

  • What is it?

     Air pollution comes from:

    • Human activity: including the burning of fuels in cars, trucks and aeroplanes, industrial activity, power plants and household heating and cooking systems
    • Natural processes: such as volcanic eruptions, dust storms in deserts
  • Harmful Effects

    Air pollution has a negative impact on human health and exposure to it can affect 100% of the population, from unborn babies to the very elderly. The lungs are the first point of entry for air pollution into the body and are therefore the first affected organ. Damage to the lungs is thought to be caused by oxidative stress and inflammation. Pollution also has a serious effect on the heart and circulatory system and increases the risk of heart attacks.   

    Air pollution affects people in different ways. Factors such as current health conditions, age, lung capacity, lifestyle and time spent in polluted air can all influence how pollutants affect overall health.

    There are many different pollutants in the air. The interactions between these pollutants and the different levels of pollution can produce a range of health effects, both in short term (within hours and days) and long term (after a number of years).

    There is not one single pollutant that is responsible for all the adverse effects. The consequences are due to the whole mixture.

    Different types of particulate matter are measured by their size. For example, PM10 refers to particulate matter that is up to 10 micrometers in size.

    Levels of air pollution are often measured by the mass per volume of air. The measurement commonly used is the number of micrograms of pollution per cubic meter. The symbol for this is: μg/m3

    Short-term problems

    Air pollution is known to trigger heart attacks in people with cardiovascular diseases and to exacerbate symptoms for people who already suffer with lung conditions, such as asthma and chronic obstructive pulmonary disease (COPD).

    Studies have shown an increase in wheezing, cough and attacks of breathlessness with a reduction in lung function and need for medication when pollution levels are increased.

    Research has shown an increase in doctors’ consultations, emergency hospital visits and hospital admissions for asthma and heart conditions, such as heart attacks, on days with higher pollution levels. Health registries also report more cases of death from these problems on days with higher pollution levels. 

    Long-term problems

    Lifetime exposure to air pollution can have a range of effects in adults and children, leading to long-term problems, such as asthma, chronic bronchitis and heart diseases. Pollution has been shown to decrease life expectancy due to earlier death from cardiovascular and respiratory diseases and lung cancer. 

    Children are generally more active, engage in more outdoor activities than adults, and breathe more rapidly, even with the same level of activity. As a consequence, they inhale more pollution. Their immune system is also not fully developed and their lungs are still growing. Air pollution has been shown to impair growth of the lungs in children, which will have an impact for the rest of their life. 

    Long-term effects in children and adults: 


    • Cough
    • Acute bronchitis
    • Lower lung volumes
    • Asthma 


    • Chronic cough
    • Phlegm
    • Wheeze
    • Accelerated loss of lung function
    • Lung cancer

     This graph shows how the symptoms follow the rates of near-road traffic-related pollutants such as ultrafine particles, diesel soot, carbon monoxide and other primary pollutants. These associations exist even when other risk factors are removed.

  • Burden

    A large proportion of Europe’s population lives in areas with unhealthy outdoor air quality and is therefore unable to avoid exposure and harmful effects of pollution. For some pollutants in certain areas the situation is either not improving or getting worse.

    A number of studies have shown that reducing air pollution could decrease the cost of these illnesses and increase life expectancy.

    Research has shown that:

    • Deaths from illness increased by 0.6% per 10 μg.m3 increase in daily PM 10 concentration
    • Emergencies and hospital admissions for asthma increased by 1% per 10 μg.m3 increase in daily PM 10 concentration
    • 8% increase in lung cancer cases per 10 μg.m3 increase in long-term exposure to PM
    • 3.7% increase in lung cancer cases per 10 μg.m3 increase in long-term exposure to NOx
  • Current and Future Needs

    • Living close to a busy road increases a child’s risk of developing asthma and urban planning needs to consider proximity of road traffic to housing and schools
    • Current evidence shows urgent action is needed to tackle air pollution in Europe
    • The EU should implement WHO recommended air quality guidelines for outdoor air – through an ambitious revision of limit values for ambient air pollution
    • All European countries should support the WHO Parma Declaration on Environment and Health reinforce efforts to reduce source pollution from all sectors – industrial, transport and energy
    • EU Member States must make air quality an integral part of their transport, industrial and energy policies and ensure that the correct level of governance – national, regional or local is equipped to tackle the sources of pollution
    • Member States also need to improve cooperation on trans-boundary pollution