Air Pollution: Why Is It So Bad Today?

Air pollution is a pressing issue that poses significant risks to human health and the planet. According to the World Health Organization (WHO), air pollution is responsible for millions of deaths worldwide each year, with 99% of people breathing air that exceeds the recommended pollutant levels. While air quality has improved in some regions due to regulatory efforts, climate change and other factors continue to contribute to worsening air pollution in many parts of the world. This introduction aims to provide an overview of the topic of air pollution, highlighting its impacts and the ongoing challenges faced in addressing this global issue.

Climate change

One of the key ways climate change exacerbates air pollution is by increasing the frequency and severity of extreme weather events, such as wildfires, droughts, and storms. Wildfire smoke can spread dangerous particulate matter over vast distances, polluting the air and posing significant health risks. For example, in 2023, a blanket of smoke from wildfires in Canada drove levels of ozone and particle pollution in central and eastern US states to alarming levels. Similarly, droughts and dust storms can increase particulate matter in the air, causing air quality issues that affect both outdoor and indoor environments.

The impacts of climate change on air quality vary by region, and certain areas are more vulnerable than others. For instance, the 2025 "State of the Air" report by the American Lung Association revealed that nearly half of Americans live in areas with poor air quality, with over 156 million people residing in counties that received failing grades for ozone or particle pollution. Western cities in the US, in particular, have been struggling with worsening ozone pollution, demonstrating how climate change is undermining the progress that would have otherwise been made.

To address these pressing issues, interventions are needed at multiple levels. The Clean Air Act, implemented by the US Environmental Protection Agency, has played a crucial role in driving pollution reduction for over 50 years. However, climate change presents new challenges that necessitate additional measures. These can include regulatory initiatives, partnership programs, and individual actions to reduce air pollutants and greenhouse gas emissions. By tackling air pollution and mitigating climate change simultaneously, we can improve air quality, enhance public health, and mitigate the global impacts of a warming planet.

Fossil fuels

When fossil fuels are burned, they release large amounts of carbon dioxide, a greenhouse gas. Greenhouse gases trap heat in the atmosphere, causing global warming and climate change. The average global temperature has already increased by 1°C, and global temperatures passed the critical 1.5°C milestone in 2024. This warming risks further sea level rise, extreme weather, biodiversity loss, species extinction, food scarcity, and worsening health and poverty for millions worldwide. Fossil fuels are also used to create products such as plastics and chemicals, which have negative environmental impacts.

The three main types of fossil fuels are coal, oil, and natural gas. Coal is the dirtiest, responsible for over 0.3°C of the 1°C increase in global temperatures. It is the most carbon-intensive fossil fuel and has devastating effects when mined, with entire swaths of terrain, including forests and mountaintops, destroyed to access coal. Oil releases a huge amount of carbon when burned, accounting for approximately a third of the world's total carbon emissions. Oil spills have also devastated ocean ecosystems in recent years. Natural gas is often promoted as a cleaner alternative but is still a fossil fuel, contributing to a fifth of the world's carbon emissions.

The combustion of fossil fuels has been linked to approximately 8.7 million premature deaths annually, with a new study putting the global death toll at more than twice that of previous estimates. Exposure to fine particulate matter (PM 2.5) from burning fossil fuels was responsible for about 8.7 million deaths globally in 2018, mainly in China and India. PM 2.5 particles are tiny, about one-thirtieth the width of a human hair, and they linger in the air, easily inhaled and able to penetrate deep into the lungs, entering the bloodstream and damaging multiple organs. Fossil fuel pollution contributes to respiratory issues, cardiovascular disease, and cancer.

While fossil fuel companies continue to be huge polluters, there is a growing trend towards clean energy. The cost of solar energy has dropped by 90% in the last decade, and wind energy costs have fallen by 70%. Many countries are setting ambitious clean energy targets, and existing policies are already making a positive impact. For example, the Inflation Reduction Act of 2022 could prevent up to 180,000 premature deaths in the US and lower asthma and lung disease rates over the next decade by reducing air pollution.

Wildfires

Climate change is a key factor in the increasing intensity and frequency of wildfires. As global temperatures rise, hotter and drier conditions create an ideal environment for fires to ignite and spread rapidly. This trend is expected to continue, with the number of wildfires projected to increase by 15% by 2030 and 30% by 2050, according to a UNEP-backed report. The mutual exacerbation between wildfires and climate change is a growing concern, as fires not only contribute to air pollution but also accelerate the warming of the planet.

The impact of wildfires on air quality can be felt far beyond the immediate vicinity of the blaze. Air movement patterns, influenced by large-scale pressure systems, can carry smoke and pollutants over long distances, affecting areas hundreds of kilometres from the source of the fire. This was evident in the case of wildfires in Canada, where the smoke travelled down to the East Coast of the United States, shrouding cities like New York and Washington, D.C. in a haze of smoke and causing record-breaking levels of air pollution.

The health risks associated with wildfire smoke are significant. The fine particles produced by wildfires are small enough to reach deep into the lungs and even enter the bloodstream, leading to respiratory issues such as shortness of breath, reduced lung function, and an increased risk of asthma attacks. Additionally, these particles can have cardiovascular effects, including heart attacks and strokes, and have been linked to premature death. The vulnerable populations at the highest risk include older adults, children, pregnant women, and individuals with pre-existing respiratory or heart conditions.

To address the issue of wildfire-induced air pollution, a multifaceted approach is necessary. While individuals can minimise outdoor activities during periods of high air pollution, particularly for those in vulnerable groups, the primary focus should be on mitigating climate change and reducing greenhouse gas emissions. This includes reducing fossil fuel combustion and diverting more resources towards planning for and preventing wildfires, rather than solely responding to them. By tackling the root causes of climate change, we can hope to slow down the increasing frequency and intensity of wildfires and improve air quality for the well-being of people and the planet.

Regulatory changes

Strengthening and Enforcing Existing Regulations: The Clean Air Act, established in 1970 in the United States, has played a significant role in reducing emissions and improving air quality. However, it is crucial to periodically review and strengthen these regulations based on scientific advancements and emerging challenges, such as climate change. This includes setting more stringent limits on soot and particle pollution, as well as reducing exemptions for emissions-intensive industries like coal-fired power plants.

Protecting and Supporting Environmental Agencies: Environmental agencies like the Environmental Protection Agency (EPA) in the United States play a vital role in monitoring air quality, conducting research, and implementing regulations. It is essential to ensure these agencies receive adequate funding and support. Threats to their staffing and funding, as seen in proposed cuts by the Trump administration, endanger their ability to protect public health and the environment effectively.

Addressing Environmental Racism and Vulnerable Communities: Cumulative impact mapping has revealed that certain communities, particularly those with high levels of poverty and unemployment, bear a disproportionate burden of pollution. Regulatory changes should focus on land use and public health reforms to ensure that vulnerable areas are not further overburdened. This includes affirming the right to clean air for outdoor laborers, such as migrant and seasonal farmworkers, and empowering them to advocate for their rights.

International Cooperation and Knowledge Sharing: Air pollution is a global issue, and regulatory changes can benefit from international cooperation. Sharing best practices, scientific advancements, and successful emission reduction strategies across countries can accelerate progress in tackling air pollution. The World Health Organization (WHO), for example, provides important guideline limits for pollutants that can inform regulatory decisions.

Adopting Stringent Standards for Common Pollutants: Regulatory changes should focus on adopting stringent standards for common air pollutants, including fine particles, ground-level ozone, carbon monoxide, nitrogen dioxide, sulfur dioxide, and lead. This involves setting emission standards for vehicles, non-road engines, and industrial equipment, as well as providing guidance for state and local implementation plans. These standards have proven effective in improving air quality and protecting public health.

Health impacts

Air pollution is a mix of hazardous substances from both human-made and natural sources. It is the presence of one or more contaminants in the atmosphere, such as dust, fumes, gas, mist, odour, smoke, or vapour, in quantities that can be harmful to human health. The main pathway of exposure is through the respiratory tract, but pollutants can also enter the bloodstream and circulate throughout the body, leading to systemic inflammation and carcinogenicity.

The health impacts of air pollution vary depending on the type of pollutant, the length and level of exposure, and individual health risks. Fine particulate matter (PM2.5) is one of the most common and critical pollutants, causing a wide range of negative health impacts. These tiny particles can penetrate deep into the lungs, enter the bloodstream, and travel to organs, causing systemic damage to tissues and cells. Ozone (O3), nitrogen dioxide (NO2), and sulphur dioxide (SO2) are also major pollutants that can cause and worsen asthma, bronchial symptoms, lung inflammation, and reduced lung function. Carbon monoxide (CO) is another harmful pollutant that can lead to serious health issues.

The vulnerable populations most susceptible to air pollution-related health issues include children, the elderly, and pregnant women. Genetics, comorbidities, nutrition, and sociodemographic factors also play a role in an individual's susceptibility. Maternal exposure to air pollution has been linked to adverse birth outcomes, such as low birth weight, pre-term birth, and small gestational age births. Air pollution has also been associated with an increased risk of diabetes, neurological development issues in children, obesity, Alzheimer's disease, dementia, and various types of cancer.

Air pollution is a significant environmental health hazard, contributing to millions of premature deaths each year globally. It is the second leading risk factor for early death, after high blood pressure. It is estimated that air pollution currently shortens the average person's lifespan by one year and eight months. In 2021, the World Health Organization (WHO) published updated air quality guidelines, highlighting the damaging effects of air pollution on human health. Regulatory frameworks and interventions are crucial in mitigating the health impacts of air pollution and reducing the number of deaths attributed to it.

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