Air pollution: a climate change both consequence and causeEnergy 2 February 2020
Air pollution is a global threat leading to large impacts on human health and ecosystems. Emissions and concentrations have increased in many areas worldwide. When it comes to Europe, air quality remains poor in many areas, despite reductions in emissions and ambient concentrations.
Air pollution is currently the most important environmental risk to human health, and it is perceived as the second biggest environmental concern for Europeans, after climate change. As a result, there is growing political, media and public interest in air quality issues and increased public support for action. Growing public engagement around air pollution challenges, including ongoing citizen science initiatives engaged in supporting air quality monitoring (EEA, 2019) and initiatives targeting public awareness and behavioural changes, have led to increasing support and demand for measures to improve air quality.
The European Commission supports the Member States in taking appropriate action and has implemented various initiatives to increase its cooperation with them. The European Commission has also launched infringement procedures against several Member States in breach of air quality standards, while both national and local governments face a rise in the number of lawsuits filed by non-governmental organisations (NGOs) and citizen groups.
Effective action to reduce air pollution and its impacts requires a good understanding of its causes, how pollutants are transported and transformed in the atmosphere, how the chemical composition of the atmosphere changes over time and how pollutants affect humans, ecosystems, the climate and subsequently society and the economy.
To curb air pollution, collaboration and coordinated action at international, national and local levels must be maintained, in coordination with other environmental, climate and sectorial policies. Holistic solutions involving technological developments, structural changes and behavioural changes are also needed, together with an integrated multidisciplinary approach. Efforts to achieve most of the Sustainable Development Goals (SDGs) are linked directly or indirectly to mitigating air emissions and changes in atmospheric composition.
Although air pollution affects the whole population, certain groups are more vulnerable to its effects on health, such as children, elderly people, pregnant women and those with pre-existing health problems. People living on low incomes are, in large parts of Europe, more likely to live next to busy roads or industrial areas and so face higher exposure to air pollution.
Energy poverty, which is more prevalent in southern and central eastern Europe, is a key driver of the combustion of low-quality solid fuels, such as coal and wood, in low efficiency ovens for domestic heating. This leads to high exposure of the low-income population to particulate matter (PM) and polycyclic aromatic hydrocarbons (PAHs), both indoors and outdoors. Furthermore, the most deprived people in society often have poorer health and less access to high-quality medical care, increasing their vulnerability to air pollution.
Air pollution continues to have significant impacts on the health of the European population, particularly in urban areas. Europe’s most serious pollutants, in terms of harm to human health, are PM, NO2 and ground-level O3. Some population groups are more affected by air pollution than others, because they are more exposed or vulnerable to environmental hazards. Lower socio-economic groups tend to be more exposed to air pollution, while older people, children and those with pre-existing health conditions are more vulnerable. Air pollution also has considerable economic impacts, cutting lives short, increasing medical costs and reducing productivity through working days lost across the economy.
Estimates of the health impacts attributable to exposure to air pollution indicate that PM2.5 concentrations in 2016 were responsible for about 412 000 premature deaths originating from long-term exposure in Europe (over 41 countries;), of which around 374 000 were in the EU-28. The estimated impacts of exposure to NO2 and O3 concentrations on the population in these 41 European countries in 2016 were around 71 000 and 15 100 premature deaths per year, respectively, and in the EU‐28 around 68 000 and 14 000 premature deaths per year, respectively.
Air pollution and climate change are intertwined. Several air pollutants are also climate forcers, which have a potential impact on climate and global warming in the short term. Tropospheric O3 and black carbon (BC), a constituent of PM, are examples of air pollutants that are short-lived climate forcers and that contribute directly to global warming. Other PM components, such as organic carbon, ammonium (NH +), sulphate (SO 2–) and nitrate (NO –), have a 443-cooling effect. In addition, methane (CH4), a powerful greenhouse gas, is also a contributor to the formation of ground level O3. Changes in weather patterns due to climate change may alter the transport, dispersion, deposition and formation of air pollutants in the atmosphere, and higher temperatures will lead to increased O3 formation.
As greenhouse gases and air pollutants share the same emission sources, benefits can arise from limiting emissions of one or the other. Policies aimed at reducing air pollutants might help to keep the global mean temperature increase below two degrees. Moreover, climate policies aimed at reducing CH4 emissions and indirectly also those aimed at reducing CO2 emissions usually can reduce the damage to human health and the environment. Implementing integrated policies would also mitigate negative impacts of climate policies on air quality. Examples are the negative impacts on air quality arising from subsidising diesel cars (which, generally, for a typical vehicle, have lower carbon dioxide (CO2) emissions per kilometer but higher PM and NOX emissions per kilometer than the equivalent petrol vehicle), and the potential increase in PM emissions and emissions of other carcinogenic air pollutants, which an increase in wood burning for residential heating may cause.
Continued reductions in air pollution and greenhouse gas (GHG) emissions are essential, as they pose serious threats to both people’s health and the environment across the world. Air quality and climate policies can provide mutual benefits: climate change mitigation actions can help reduce air pollution, and clean air measures can help reduce GHG emissions leading to reductions in global warming. There can also be trade-offs, if reducing a particular pollutant emission leads to additional atmospheric warming rather than cooling.
Furthermore, air pollution and climate change influence each other through complex interactions in the atmosphere. Increasing levels of GHGs alter the energy balance between the atmosphere and the Earth’s surface which, in turn, can lead to temperature changes that change the chemical composition of the atmosphere. Direct emissions of air pollutants (i.e. black carbon), or those formed from emissions such as sulfate and ozone, can also influence this energy balance. Thus, climate change and air pollution management have consequences for each other.