Climate Change: Air Pollution's Sinister Twin?

Air pollution and climate change are closely linked. While climate change is known to worsen air quality, certain air pollutants can also affect climate change. For example, hot sunny days associated with a warming climate can increase ground-level ozone in some areas. Ground-level ozone is a greenhouse gas that contributes to climate change by trapping heat in the atmosphere. In addition, climate change increases the production of allergenic air pollutants, including mold and pollen. Air pollution is the leading environmental cause of illness and premature death, with fine particulate matter or aerosols (PM2.5) responsible for 6.4 million deaths every year. As air pollution and climate change are two sides of the same coin, they should be tackled together with a focus on protecting people's health.

Ground-level ozone increases

Ground-level ozone is a harmful air pollutant and the main ingredient in smog. It is not emitted directly into the air but is created by chemical reactions between oxides of nitrogen (NOx) and volatile organic compounds (VOCs) emitted by cars, power plants, industrial boilers, refineries, chemical plants, and other sources. These chemical reactions occur in the presence of sunlight. As a result, ozone concentrations typically reach a daily maximum a few hours after midday, and ozone is more likely to reach unhealthy levels on hot, sunny days.

Ozone is a gas composed of three atoms of oxygen. While stratospheric ozone is beneficial as it protects living things from ultraviolet radiation from the sun, ground-level ozone is harmful. It can trigger a variety of health problems, particularly for children, the elderly, and people of all ages who have lung diseases such as asthma. It is also a strong greenhouse gas that contributes to climate change by trapping heat in the atmosphere.

Tropospheric or ground-level ozone is a short-lived climate pollutant, remaining in the atmosphere for only a few hours to a few weeks. It is highly reactive and significantly reduces crop productivity and the uptake of atmospheric carbon by vegetation. It also affects the climate beyond increased warming, impacting evaporation rates, cloud formation, precipitation levels, and atmospheric circulation.

The fluctuation of ozone levels from year to year depends on how warm and dry the summer is, and intense heatwaves can lead to peak ozone values. The probability of heatwaves is expected to increase due to climate change, leading to higher peak concentrations of ground-level ozone. Increased solar radiation and summertime temperatures will also accelerate the chemical process of ozone formation.

Since 1995, free tropospheric ozone has increased by between 2-12% per decade, depending on the region of the world. The largest increases have been found over developing regions, including East Asia, the Persian Gulf, India, northern South America, the Gulf of Guinea, and Malaysia/Indonesia. The increase in Europe between 2005 and 2019 was slight, and the highest peaks declined during this period. However, projections suggest that by the end of the century, ozone concentrations could increase by up to 8 µg/m3.

Wildfires and air quality

Climate change and air pollution are closely linked, with climate change worsening air quality and certain air pollutants contributing to climate change. One of the ways climate change impacts air quality is by increasing the frequency and severity of wildfires. Wildfires emit smoke, which is a mixture of air pollutants, including particulate matter, and is the principal public health threat from wildfires. The smoke from wildfires can degrade air quality and harm human health, particularly for those with respiratory or cardiovascular diseases, children, older adults, pregnant women, and people of lower socioeconomic status.

In 2020, wildfires burned over 10 million acres of land in the United States, the highest amount ever recorded. The smoke and haze from these wildfires spread across North America, affecting air quality in both the United States and Canada. Wildfires can be started naturally, such as by lightning or volcanoes, or through accidental or unauthorized human actions. The EPA and the U.S. Forest Service have developed resources to help people protect their health from wildfire smoke, including the AirNow Fire and Smoke Map, which provides information on fire locations, smoke plumes, and real-time air quality.

The impact of wildfire smoke on air quality is significant, as particulate matter can act as a climate forcer, contributing to the warming of the Earth's atmosphere. Black carbon, a product of combustion, is a particular concern as it is a short-lived climate pollutant (SLCP) with a strong warming potential. Addressing SLCP emissions can lead to dual benefits: improved local air quality and health outcomes, as well as the global benefit of mitigating climate change.

The effects of climate change on air quality can vary by region, and regulatory initiatives, partnership programs, and individual actions can help reduce air pollutants that harm human health and contribute to climate change. However, it is important to note that the impact of climate change on air quality is not limited to outdoor environments. Increases in outdoor air pollutants can also lead to higher indoor exposures, as these pollutants can enter buildings through doors, windows, and ventilation systems. Therefore, it is crucial to address the impact of wildfires and other sources of air pollution on both outdoor and indoor air quality to protect public health and mitigate climate change.

Damp indoor conditions and mould

The presence of mould and dampness in indoor environments can have a significant impact on respiratory health. Mould spores, which are microscopic, can easily be inhaled, leading to allergic reactions and respiratory issues. Additionally, damp conditions can provide a favourable environment for the growth of bacteria, which can further contribute to indoor air pollution.

Climate change plays a role in the increase of damp indoor conditions and mould. As temperatures rise due to climate change, there is an increased risk of water damage from extreme weather events such as flooding and storms. This, in turn, creates the ideal conditions for mould growth.

Furthermore, climate change-related precipitation and storms can directly contribute to increased indoor moisture levels, providing the necessary environment for mould to thrive. The impact of damp and mould on respiratory health is particularly concerning, as climate change is also expected to worsen outdoor air quality, increasing exposure to allergens and pollutants. This combination of factors can exacerbate respiratory conditions and create a challenging environment for those with asthma or allergies.

To mitigate the health risks associated with damp indoor conditions and mould, it is crucial to address the root cause of the moisture issue. This may involve repairing any water damage, improving ventilation, and taking steps to reduce indoor humidity levels. Additionally, regular cleaning and maintenance can help prevent the growth of mould and the accumulation of indoor pollutants.

Particulate matter and climate

Air pollution and climate change are two sides of the same coin. While they are typically addressed separately, they should be tackled jointly, with a focus on protecting people's health.

Particulate matter, or PM2.5, is a major contributor to air pollution. These fine particles are emitted through human activities such as burning fossil fuels and using diesel-fueled vehicles. They pollute the air and affect the Earth's radiation budget, exerting a cooling influence on the planet. However, coarser dust particles have been found to have a warming effect, compensating for the cooling effect of fine dust.

The warming effect of particulate matter is particularly relevant in the context of climate change. As the planet warms, the intensity and duration of wildfires increase, injecting smoke into the atmosphere. Warmer temperatures also lead to more severe and prolonged droughts, which contribute to increased airborne dust. Both smoke and dust are atmospheric pollutants that negatively impact air quality and human health.

The health impacts of particulate matter exposure are significant. Short-term and long-term exposure to fine particles can lead to premature death, non-fatal cardiovascular events, respiratory issues, and adverse effects on pregnant women, newborns, and people with certain health conditions. According to the World Health Organization, more than 99% of the world's population breathes air that exceeds its health-based air quality guidelines. This is particularly prevalent in developing countries, where billions of people are exposed to harmful levels of particulate matter.

Addressing particulate matter emissions is crucial for mitigating climate change and improving air quality and public health. NASA's Multi-Angle Imager for Aerosols (MAIA) mission is a collaborative effort with space agencies and health organizations to study the connections between particulate matter air pollution and human health using space-based data. By understanding the sources and health effects of particulate pollution, decision-makers can implement effective measures to reduce particle emissions and improve air quality.

Air pollution and health

Air pollution is the world's leading environmental cause of illness and premature death. Fine air pollution particles or aerosols, also known as fine particulate matter (PM), are responsible for millions of deaths every year. These deaths are caused by diseases such as ischaemic heart disease, stroke, lung cancer, chronic obstructive pulmonary disease, pneumonia, type 2 diabetes, and neonatal disorders.

The health impact of air pollution exposure depends on the duration and concentration of exposure, as well as the health status of the affected populations. Some individuals are more sensitive to the health impacts of air pollution than others due to factors such as age, pre-existing health conditions, and particular behaviours. Children, the elderly, and people living in areas with high levels of air pollution are especially susceptible. In addition, people in low socioeconomic neighbourhoods and communities may be more vulnerable to air pollution due to various factors, including proximity to industrial sources of pollution, underlying health problems, poor nutrition, and stress.

Ozone air pollution, also known as ground-level ozone, is a powerful lung irritant. When inhaled, ozone reacts with the delicate lining of the small airways, causing inflammation and other damage that can impact multiple body systems. Ozone exposure can also shorten lives. Ozone has a serious effect on the respiratory system, and when ozone levels are high, many people experience breathing problems such as chest tightness, coughing, and shortness of breath, often within hours of exposure. Even healthy young adults may experience respiratory symptoms and decreased lung function.

Particle pollution, also known as particulate matter or soot, is a mixture of tiny bits of solids and liquids in the air. These particles come from various sources, including factories, power plants, and diesel- and gasoline-powered vehicles. These sources emit fine particles or generate other pollutants, such as nitrogen oxides (NOx) and sulfur oxides (SOx), which can then form into fine particles in the atmosphere. Other sources of particle pollution include wildfires, burning wood in stoves or fireplaces, and burning biomass for electricity.

Climate change can also worsen air quality and increase exposure to allergens and pollutants. Warmer temperatures can increase ground-level ozone, and climate-driven changes in weather conditions can increase particulate matter, such as windblown dust from droughts or smoke from wildfires. Regulatory initiatives, partnership programs, and individual actions can help reduce air pollutants and greenhouse gases that contribute to climate change.

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