Air Pollution: A Historical Perspective On Recent Developments

Air pollution is a pressing issue that affects millions of people worldwide. It refers to the contamination of indoor or outdoor environments by pollutants that modify the natural characteristics of the atmosphere. While air pollution has been a concern for decades, it is not a recent development, and its history can be traced back to the 18th century. The sources of air pollution are diverse and context-specific, including residential energy use, vehicles, power generation, agriculture, waste incineration, and industrial facilities. The effects of air pollution are far-reaching, impacting human health, ecosystems, and the climate. With the growing awareness of its harmful effects, efforts have been made to address air pollution through interventions, initiatives, and policies. Despite improvements in some regions, air pollution remains a significant challenge, with millions still breathing unhealthy air and facing its adverse consequences.

The Clean Air Act

Air pollution is a pressing issue that affects millions of people worldwide. It is caused by a variety of sources, including residential energy use, vehicles, power generation, and industrial facilities. The Clean Air Act (CAA) is a comprehensive federal law enacted in the United States to address this issue by regulating air emissions from stationary and mobile sources.

One of the key components of the Clean Air Act is its focus on reducing emissions from major sources. Section 112 of the Act defines "major sources" as stationary sources or groups of stationary sources that emit or have the potential to emit hazardous air pollutants above specified thresholds. The EPA is responsible for establishing emission standards for these major sources, aiming for the maximum degree of reduction in hazardous air pollutant emissions.

Since the implementation of the Clean Air Act, significant progress has been made in reducing air pollution and mitigating its health impacts. The EPA has achieved dramatic reductions in emissions, with a 50% decline in key air pollutants since 1990. However, air pollution remains a persistent issue, and continued efforts are necessary to address the complex and diverse sources of pollution and their impacts on public health and the environment.

Air pollution and health

Air pollution is a major threat to global health and prosperity. It is a familiar environmental hazard, with the brown haze that settles over cities, the exhaust that billows across highways, and the plumes that rise from smokestacks. However, some air pollution is invisible and only detectable by its pungent smell. According to the World Health Organization (WHO), air pollution kills an estimated seven million people worldwide every year, and 9 out of 10 people breathe air containing high levels of pollutants.

Air pollution is the presence of one or more contaminants in the atmosphere, such as dust, fumes, gas, mist, odour, smoke, or vapour, in quantities and durations that can be harmful to human health. The main pathway of exposure is through the respiratory tract, which can lead to inflammation, oxidative stress, immunosuppression, and mutagenicity in cells throughout the body, impacting the lungs, heart, and brain, among other organs, and ultimately leading to disease. Pollutants of major public health concern include particulate matter, carbon monoxide, ozone, nitrogen dioxide, and sulfur dioxide. Outdoor and indoor air pollution cause respiratory and other diseases and are important sources of morbidity and mortality.

The sources of air pollution are multiple and context-specific. The major outdoor pollution sources include residential energy for cooking and heating, vehicles, power generation, agriculture/waste incineration, and industry. Household combustion devices, motor vehicles, industrial facilities, and forest fires are common sources of indoor air pollution.

Air pollution exposure is associated with oxidative stress and inflammation in human cells, which may lay the foundation for chronic diseases and cancer. Research has also shown that short-term exposure to higher levels of outdoor air pollution is associated with reduced lung function, asthma, and cardiac problems. The health burden of air pollution is not evenly shared, with some people being more at risk of illness and death than others. Factors that affect an individual's level of risk include exposure and susceptibility. In general, the higher the exposure, the greater the risk of harm. Susceptibility is influenced by genetics, comorbidities, nutrition, and sociodemographic factors. Individuals who are pregnant, children, older adults, and people living with chronic conditions, especially heart and lung disease, may be more susceptible to the health impacts of air pollution.

To tackle air pollution effectively, it is essential to understand its sources and implement interventions that will have the biggest impact. The Community Emissions Data System (CEDS) is a valuable resource for long-term global and national data on emissions, extending back to the 18th century and frequently updated with the latest estimates. The WHO provides technical support to its member states and develops normative guidance, tools, and authoritative advice on health issues related to air pollution and its sources. The organization also monitors and reports on global trends and changes in health outcomes associated with actions taken to address air pollution. Policies and investments that support sustainable land use, cleaner household energy and transport, energy-efficient housing, improved power generation, better industrial and municipal waste management, and the electrification of healthcare facilities can effectively reduce key sources of ambient air pollution.

Air pollution and climate change

Air pollution is a serious global issue that has severe impacts on both public health and the Earth's climate and ecosystems. According to the World Health Organization (WHO), air pollution is responsible for approximately seven million premature deaths worldwide each year. Furthermore, WHO data reveals that a staggering 99% of the global population breathes air that exceeds the recommended limits and contains high levels of pollutants, with low- and middle-income countries suffering the highest exposures.

Outdoor air pollution is caused by a range of sources, including residential energy use for cooking and heating, vehicles, power generation, agriculture/waste incineration, and industry. The combustion of fossil fuels, in particular, releases harmful pollutants and high levels of carbon dioxide (CO2) into the atmosphere, contributing to climate change. Climate change, in turn, can worsen air quality by increasing ground-level ozone, particulate matter, and pollen, as well as reducing visibility.

The effects of climate change on air quality vary by region. For example, in the United States, climate change is expected to worsen ground-level ozone and increase people's exposure to allergens. Regulatory initiatives, partnership programs, and individual actions can help mitigate these impacts by reducing air pollutants and greenhouse gas emissions. The US Environmental Protection Agency (EPA), for instance, has implemented standards for greenhouse gas emissions and fuel economy for vehicles and is developing regulations to ensure that transportation fuel contains a minimum volume of renewable fuel.

Additionally, certain air pollutants are powerful short-lived climate pollutants (SLCPs) that contribute to both climate change and ill health. Methane and black carbon, for example, have a greater global warming potential than CO2, despite having shorter lifetimes in the atmosphere. Black carbon, a component of fine particulate matter, is a significant contributor to global warming after CO2, as it absorbs sunlight and accelerates the melting of snow and ice.

Addressing air pollution and climate change requires a multi-faceted approach. Policies and investments that support sustainable land use, cleaner household energy and transport, energy-efficient housing, improved waste management, and regulatory interventions can effectively reduce key sources of ambient air pollution. Furthermore, initiatives to raise awareness about the risks of air pollution and promote healthy sectoral policies, such as those led by the WHO, are crucial for mitigating the health and environmental impacts of air pollution and climate change.

Sources of air pollution

Air pollution is a serious issue that has been affecting human health and the environment for centuries. While natural sources like wildfires, wind-blown dust, and volcanoes contribute to air pollution, human activities are the primary drivers. The sources of air pollution can be categorised into four main types: mobile sources, stationary sources, area sources, and natural sources.

Mobile Sources

Mobile sources, such as cars, trucks, buses, planes, and trains, are a significant contributor to air pollution. According to the Environmental Protection Agency (EPA), mobile sources account for more than half of all air pollution in the United States, with automobiles being the primary culprit. Older diesel engines, in particular, produce alarmingly high levels of fine particulate pollution. To address this, federal regulations have been implemented to improve vehicle and equipment efficiency and reduce pollution.

Stationary Sources

Stationary sources, like power plants, oil refineries, industrial facilities, and factories, emit large amounts of pollution from a single location. These sources release pollutants such as ozone, sulfur dioxide, nitrogen oxides, and particulate matter into the atmosphere. Power plants, especially coal-fired ones, have been a major concern, leading to the implementation of regulations like the Mercury Emissions Reduction Act to curb emissions.

Area Sources

Area sources encompass smaller pollution sources that collectively have a significant impact. This includes agricultural areas, cities, residential wood burning, and gas-powered yard and recreational equipment. Residential wood burning, often used for home heating, accounts for a substantial portion of fine particle emissions. Additionally, emissions from diesel engines used in agriculture, construction, and transportation contribute to air pollution.

Natural Sources

While natural sources like wildfires, wind-blown dust, and volcanic activity contribute to air pollution, they typically do not create ongoing pollution problems compared to human-generated sources. However, natural sources can still have significant impacts, especially when combined with human-generated pollution.

It is important to note that air pollution has severe health consequences, including respiratory diseases, cardiovascular disease, neurological disorders, and even certain types of cancer. By understanding the sources of air pollution, we can implement effective interventions and policies to improve air quality and protect public health.

Initiatives to tackle air pollution

Air pollution is a pressing issue, and it is encouraging to see that various initiatives are being implemented to tackle it. Here are some examples of initiatives and programmes aimed at reducing air pollution:

Clean Air Zones

The UK has been working to establish Clean Air Zones, aiming to reduce motorised transport and associated emissions. Newcastle, for instance, is developing a Clean Air Zone in collaboration with the Gateshead Council to improve air quality.

Reducing Transport Emissions

The UK government has committed to ending the sale of new diesel and petrol cars and vans from 2040. This initiative surpasses the efforts of most other European nations in addressing emissions from vehicles.

Agriculture Emissions Reduction

The UK government is also targeting agriculture, which accounts for 88% of ammonia emissions. They have launched a £3 million programme through the Catchment Sensitive Farming partnership to provide farmers with training, advice, and support in adopting low-emission farming techniques and minimising fertiliser pollution.

Local Initiatives

Local initiatives play a crucial role in improving air quality. Supporting or starting local garden initiatives can help enhance long-term air quality in neighbourhoods. Plants and trees consume CO2, helping to clean the air.

Cycling and Walking Revolution

Encouraging a shift towards cycling and walking instead of driving can significantly reduce CO2 emissions and other pollutants like nitrogen dioxide. Cities like London and Brussels are promoting active transportation and traffic-free routes to reduce pollution and improve air quality.

International Campaigns

The Clean Air Fund's Breathe Cities initiative is a global campaign utilising $30 million to reduce air pollution, cut carbon emissions, and improve public health in cities. It builds on existing efforts in cities like Brussels, Jakarta, London, and Paris.

Greening Urban Spaces

Bangkok, facing severe air pollution, launched the Green Bangkok 2030 project. This initiative aims to increase green spaces, with a goal of 10 square metres of green space per person and trees covering 30% of the city's area, ultimately encouraging a decrease in private transportation reliance.

Air Quality Monitoring

Warsaw, Poland, has established Breathe Warsaw in partnership with the Clean Air Fund and Bloomberg Philanthropies. With 165 air sensors, the city aims to develop an air quality database to better understand pollution sources and implement measures to improve air quality.

These initiatives demonstrate a global commitment to tackling air pollution and improving public health and the environment.

Frequently asked questions