Pollution Alert: Are We Doomed To Breathe Worse Air?

Climate change is causing more dangerous air pollution, with extreme heat, drought, and wildfires increasing air pollution levels. The American Lung Association's 2024 report found that 131 million people in the US are exposed to unhealthy levels of air pollution, with nearly 4 in 10 people living in areas that received a failing grade for at least one measure of air pollution. While there has been a general improvement in air quality over the last 25 years, climate change is making it harder to protect this progress. This is reflected in the 2025 report, which finds that the geographic distribution of air pollution is shifting back East, with 156 million Americans breathing in too much soot or ozone.

Climate change

Air pollution is caused by solid and liquid particles, known as aerosols, and certain gases that are suspended in the air. These particles and gases can come from car and truck exhaust, factories, dust, pollen, mold spores, volcanoes, and wildfires. NASA uses satellites to monitor air pollution, tracking the movement of aerosols and their impact on the Earth's energy budget.

In addition, climate change can lead to more frequent and intense extreme weather events, including wildfires, droughts, and storms, which further contribute to air pollution. Wildfire smoke, windblown dust from droughts, and storm damage can all negatively impact air quality.

Addressing air pollution is crucial for mitigating climate change. Reducing air pollution can lower emissions of carbon dioxide (CO2) and short-lived climate pollutants (SLCPs) such as methane and black carbon, which have a significant global warming potential. By tackling these challenges together, we can improve air quality, slow down climate warming, protect ecosystems, and enhance public health.

While there has been some progress in reducing air pollution, more action is needed. Regulatory initiatives, partnership programs, and individual efforts can help decrease air pollutants and greenhouse gas emissions. Additionally, integrating air quality standards into climate targets and advocating for bold policies and investments in clean air measures are essential steps toward addressing climate change and improving air quality.

Wildfires

While there has been a decrease in bad air quality days in the eastern United States due to new regulations on ozone-forming pollutants, the global situation is more concerning. The increase in wildfires worldwide has been a significant contributor to high pollution days.

The relationship between wildfires, air pollution, and climate change forms a vicious cycle. Human activities, such as burning fossil fuels, transportation, and industrial processes, release greenhouse gases and black carbon emissions, contributing to climate change. These emissions trap heat in the atmosphere, leading to rising global temperatures and more erratic weather patterns, including intensified heatwaves and altered weather patterns. As a result, drought conditions become more severe, making forests and vegetation more susceptible to fires. Wildfires then release additional carbon and particulate matter into the atmosphere, further degrading air quality.

NASA employs various tools and satellites, such as MODIS and CALIPSO, to track and monitor wildfires and their impact on air pollution. MODIS detects fires by identifying unusual hotspots, while CALIPSO provides information on the vertical distribution of aerosols in the atmosphere. By utilizing these technologies, scientists can better understand the extent and severity of wildfires' contribution to air pollution and take steps to mitigate their impact.

To summarize, wildfires are a significant contributor to high pollution days, and their increasing frequency is closely linked to climate change. The release of pollutants from wildfires has severe consequences for human health and the environment, and the resulting air quality deterioration forms a cycle that further exacerbates the impacts of climate change. NASA's efforts to monitor and understand wildfires through satellite observations are crucial for developing effective strategies to combat this escalating global crisis.

Human behaviour

One of the primary sources of air pollution is emissions from transportation. Vehicle exhaust releases harmful pollutants, such as nitrogen dioxide (NO2), into the atmosphere, affecting air quality. In addition, industrial emissions and manufacturing processes release pollutants, including particulate matter and volatile organic compounds, which can remain suspended in the air for extended periods.

Furthermore, human activities that cause climate change indirectly impact air quality. For instance, the increased frequency and intensity of wildfires, attributed to human-induced climate change, release massive amounts of smoke and particulate matter into the atmosphere, affecting air quality over vast regions. Similarly, heatwaves and droughts, intensified by climate change, can worsen air pollution by creating conditions that impede the dispersion of pollutants.

The impact of air pollution on human behaviour itself cannot be overlooked. Studies suggest a correlation between air pollution and unethical behaviour. For example, increased levels of NO2 have been associated with a higher inclination towards perceiving and engaging in fatal unethical behaviours, such as murder, terrorism, and suicide. Physical discomfort caused by air pollution, including eye and throat irritation, may also lead to increased aggression and unethical behaviour.

Addressing the human behaviours that contribute to air pollution is crucial to mitigating its adverse effects. This involves adopting cleaner technologies, transitioning to renewable energy sources, improving energy efficiency, and implementing stricter emission control measures. By modifying our behaviours and adopting sustainable practices, we can reduce the frequency and severity of high pollution days and safeguard the health and well-being of millions of people.

Meteorological factors

Wind and Air Movement: Wind patterns and air movement significantly impact the dispersion of pollutants. Calm or stagnant air allows pollutants to concentrate in a specific area, leading to higher pollution levels. On the other hand, strong, turbulent winds can quickly disperse pollutants, resulting in lower concentrations. The direction and speed of wind also determine the transport of pollutants from one region to another. For example, the northwest wind in Beijing gradually weakens as it moves away, leading to higher pollution concentrations in the southern part of the city.

Temperature and Solar Radiation: Temperature and sunlight (solar radiation) influence the formation of photochemical smog from other pollutants. Higher temperatures and increased solar radiation can lead to favourable conditions for smog formation. Additionally, temperature variations create convection currents, which move pollutants from the ground to higher altitudes.

Water Vapour and Humidity: Water vapour in the atmosphere, often measured as relative humidity, plays a crucial role in atmospheric chemical reactions. High humidity can help reduce ozone pollution by slowing down its production and aiding in its destruction. However, water molecules can also interact with particles and gases in the air, impacting visibility and air quality. The amount of water vapour is influenced by geographic location, proximity to water bodies, wind direction, and air temperature.

Atmospheric Pressure: High-pressure systems can lead to stagnant air, allowing pollutants to concentrate in a particular region. This stagnation contributes to increased pollution levels.

Seasonal Variations: Meteorological conditions, including wind speed, precipitation, relative humidity, and atmospheric pressure, exhibit seasonal variations that influence air pollution levels. For example, certain pollutants like O3 show a stronger correlation with meteorological conditions during autumn and winter in China.

Overall, these meteorological factors interact with pollution sources to determine the distribution and concentration of pollutants in the atmosphere, ultimately affecting air quality. Understanding these factors is crucial for developing strategies to mitigate the impacts of air pollution on human health and the environment.

Clean Air Act

The Clean Air Act (CAA) is the primary federal air quality law in the United States. It is a comprehensive law that regulates air emissions from stationary and mobile sources. The Act was initially enacted in 1963 and has been amended several times since, making it one of the country's first and most influential modern environmental laws. The Clean Air Act defines the Environmental Protection Agency's (EPA) responsibilities for protecting and improving the nation's air quality and the stratospheric ozone layer.

The Clean Air Act has been instrumental in reducing air pollution and improving air quality in the United States. Since 1990, there has been an approximate 50% decline in emissions of key air pollutants. The Act has achieved this through various programs and regulations that target specific pollution problems. For example, the National Ambient Air Quality Standards (NAAQS) program sets standards for concentrations of certain pollutants in outdoor air, including ground-level ozone, carbon monoxide, particulate matter, and nitrogen dioxide. The National Emissions Standards for Hazardous Air Pollutants program sets standards for emissions of particular hazardous pollutants from specific sources.

The Clean Air Act also addresses emissions of hazardous air pollutants. Section 112 of the Act was amended in 1990 to require the issuance of technology-based standards for "major sources" and certain "area sources". Major sources are defined as stationary sources that emit or have the potential to emit 10 tons or more of a hazardous air pollutant per year. The EPA is required to establish emission standards that ensure the maximum degree of reduction in emissions for these major sources, known as "maximum achievable control technology" or "MACT" standards.

The Clean Air Act has been challenged in court numerous times by both environmental groups seeking stricter enforcement and by states and utilities seeking greater flexibility in regulation. Despite these challenges, the Act has substantially reduced air pollution and improved air quality in the United States. However, climate change continues to pose challenges to maintaining and improving air quality, and the Act recognizes the need to tackle emerging pollution threats.

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