An air pollutant is any substance in air that could, in high enough concentrations, harm humans, animals, vegetation or material. Once emitted, pollutants interact with each other and the environment, depending on temperature, humidity and other environmental conditions

The main pollutants include ozone (O₃), nitrogen dioxide (NO₂), particulate matter (PM) and sulphur dioxide (SO₂).

Near the ground, O₃ is made by chemical reactions between the sun’s rays and gases emitted by cars and power plants. More than 40% of emissions of NO₂ come from road transport that burn fossil fuels. Man-made PM mainly results from industrial processes, construction work, emissions from diesel and petrol engines and friction from tires on road surfaces. Almost 40% of primary PM2.5 emissions come from transport. Most SO₂ comes from industries that burn fossil fuels.

Other air pollutants, like volatile organic compounds (VOCs) and carbon monoxide (CO) emissions are partly generated by road traffic.

The main sources of air pollution are road transport; agriculture activities; energy production and distribution; businesses, public buildings and households.

For more information:

• European Lung Foundation – Outdoor Air Pollution and the Lungs
• European Environmental Agency – Air Pollution
• European Respiratory Society – Air Pollution and Health: Fact and Myths

In 2021, exposure to fine particulate matter and nitrogen dioxide levels above the World Health Organization recommendations cause an estimated 253,000 and 52,000 premature deaths, respectively. Over 1,200 deaths in people under 18 years of age are estimated to be caused by air pollution every year in EEA member and collaborating countries.

All EU countries reported levels of ozone and nitrogen dioxide above the health-based guideline levels set by the World Health Organization. These pollutants are linked to asthma, heart disease and stroke. Overall, 97% of the EU’s urban population was exposed to levels of fine particulate matter above the latest guidelines set by WHO in 2021.

For more information:

• World Health Organization – Ambient air pollution
• European Environmental Agency – Europe’s air quality status 2023
• World Health Organization – Ambient air pollution data portal

Pathogens might transform quickly and pass from animals to humans. Several diseases have originated in animals, e.g. AIDS, SARS, avian influenza, swine flu, Ebola, and now the new coronavirus. Human overexploitation of nature is one of the key factors behind the spread of new diseases. Changes in land use that bring wildlife, livestock, and humans into closer contact with each other facilitate the spread of diseases, including new types of bacteria and viruses.

The chances of pathogens passing from wild and domestic animals to humans may be increased by the destruction and modification of natural ecosystems, the illegal or uncontrolled trade of wild species and the unhygienic conditions under which wild and domestic species are mixed and marketed. Conserving and maintaining nature and the benefits it provides is essential for preserving our health and well-being.

For more information:

• The Lancet Planetary Health – Interconnecting global threats: climate change, biodiversity loss, and infectious diseases
• WWF International – The Loss of Nature and Rise of Pandemics: Protecting Human and Planetary Health

Long-term exposure to air pollution causes chronic diseases, which damage the immune system. Preliminary data show that most of the fatalities from COVID-19 had at least one health condition, and co-morbidity can lead to higher death rates.

Historically, air pollution was a factor in the deaths registered during pandemics. It is proven with other diseases, e.g. flu, SARS, that air pollution damages the immune system. In case of COVID-19, this is likely but given the disease is new, this needs to be proven. It is thus imperative to enforce existing air pollution regulations for public health reasons.

For more information:

• EPHA – Air pollution and damages to immunity
• EPHA – Air pollution caused conditions: the risk of co-morbidities
• Harvard University – Exposure to air pollution and COVID-19 mortality in the United States
• European Parliament, Air pollution and COVID-19
• Environmental Pollution – Can atmospheric pollution be considered a co-factor in extremely high level of SARS-CoV-2 lethality in Northern Italy?

Air pollution and cardiovascular diseases

Air pollution increases risk of coronary heart disease (CHD), stroke, heart failure, cardiac arrhythmias, thrombosis and atherosclerosis. Cardiovascular disease, like CHD and stroke, accounts for 80% of all premature deaths from air pollution in Europe. Air pollution from PM2.5 alone increases the risk of premature death from stroke by 19% and from CHD by 13%. Cardiovascular diseases are also a major cause of disability. While harmful to everyone, avoiding exposure to air pollutants is especially important for susceptible individuals with chronic cardiovascular or pulmonary disease, children, and the elderly.

For more information:

• European Heart Network paper – Air pollution and cardiovascular diseases

Air pollution and paediatric asthma

Asthma is the most common chronic disease in children. Many studies suggest that exposure to air pollution may increase the risk of developing this respiratory disease during childhood. 33% of new childhood asthma cases in Europe are attributable to air pollution. Up to 11% of new childhood asthma cases could be prevented each year if European countries complied with the WHO PM2.5 air quality guidelines.

For more information:

• Institute for Global Health – 33% of New Childhood Asthma Cases in Europe Attributable to Air Pollution

Air pollution and diabetes

Diabetes is one of the fastest growing diseases, affecting more than 420 million people worldwide and about 60 million Europeans. Research links air pollution to an increased risk of diabetes, even at low levels of pollution currently considered safe. In diabetes, fine particulate matters reduce insulin production and trigger inflammation, preventing the body from converting blood glucose into energy that the body needs to maintain health. Overall, it is estimated that air pollution contributed to 3.2 million new diabetes cases globally in 2016, which represents about 14 percent of all new diabetes cases globally that year.

For more information:

• Washington University School of Medicine in St.Louis – Air pollution contributes significantly to diabetes globally
• The Lancet Planetary Health – Estimates, trends, and drivers of the global burden of type 2 diabetes attributable to PM2·5 air pollution.

Air pollution and dementia

Air pollution has been a focus of several studies on cognitive impairment and dementia risk. Fine particulate matter (PM2.5) can pass into the brain via the bloodstream. Contrary to the link between air pollution and heart or lung health for which there is a lot of evidence, the effect on the brain and cognitive health is less clear. Exposure of animals to traffic pollution suggests that air pollution could be associated with cognitive impairment. In people, those who are exposed to high levels of pollutants perform poorer on cognitive tests over time.

For more information:

• Alzheimer’s Society – Air pollution and dementia

WHO sets recommended limits for health-harmful concentrations of key air pollutants based on the latest scientific evidence. The WHO Air Quality Guidelines cover annual and daily concentrations of fine particulates, nitrogen dioxide, sulfur dioxide, carbon monoxide and ozone.

However, each country sets up its own air quality standards to protect the public health of its citizens. The European Union has established objectives for a number of pollutants present in the air but are still much higher than the WHO Air Quality Guidelines. The Medics4CleanAir campaign demands the EU air quality standards to be aligned with the latest WHO guidelines.

For more information:

• World Health Organization – Air quality guidelines
• European Commission – EU Air Quality Standards

Europe needs to phase out the sale of diesel and petrol vehicles by 2028 if it wants to meet its commitments to the Paris climate agreement. State parties have resolved to limit the rise in global average temperatures to 1.5°C. In order to have a high (66%) chance of achieving this, the EU will need to end all sales of conventional fossil fuel-powered vehicles by 2028 and phase out all petrol and diesel cars by 2045. By vehicles, we mean cars, vans, lorries, motorcycles and buses.

For more information:

• German Aerospace Center (DLR) – Development of the car fleet in EU 28 +2 to achieve the Paris Agreement target to limit global warming to 1.5°C