Pollution Levels: A Global Drop?

Air pollution is a pressing issue that affects the lives of millions of people worldwide. While there have been efforts to reduce pollution levels, the problem persists, with varying degrees of success. According to reports, air pollution still affects nearly half of Americans, despite improvements in air quality over the past decades. Similarly, a study published in 2025 revealed that toxic wildfire pollution has infiltrated the homes of over a billion people annually in the last two decades, underlining the urgent need for effective measures to combat this global issue. The high cost of air purifiers, which can run into hundreds of dollars annually, poses a challenge, especially in low-income countries. The negative health impacts of air pollution are well-documented, with premature deaths, respiratory problems, and cardiovascular issues being linked to poor air quality. As the world grapples with the consequences of pollution, it is essential to address these concerns through policy interventions, technological advancements, and a collective commitment to protecting the environment and public health.

Wildfires and indoor pollution

Wildfires are becoming more frequent and more intense, with the climate crisis driving up the risk by increasing heatwaves and droughts. The tiny particles produced by wildfires can travel thousands of miles and are known to be more toxic than urban air pollution, due to higher concentrations of chemicals that cause inflammation. Wildfire pollution has been linked to early deaths, worsened heart and breathing diseases, and premature births.

A recent study published in the journal Science Advances found that more than 1 billion people a year had at least one day when indoor particle levels were above World Health Organization (WHO) limits, with wildfires responsible for at least half of the pollution. This is due to smoke from wildfires infiltrating homes, even when doors and windows are closed. The greatest exposure was in South America and Central Africa, followed by the west coast of North America, northwest Australia, and north and southeast Asia.

Indoor pollution can be mitigated using air purifiers, but these can be costly, and the financial burden is often borne by regions and countries that can least afford it. The cost of buying, maintaining, and running air purifiers can be hundreds of dollars a year per household. In low-income countries such as Niger and Chad, the annual costs of air purifiers are greater than the average yearly income. This exposes those who cannot afford the cost of air purifiers to higher health risks, providing evidence of climate injustice.

There are other measures that can be taken to reduce exposure to indoor wildfire pollution, such as wearing face masks, relocating vulnerable people away from the fires, and making buildings more airtight. Local officials may advise people to stay indoors during a smoke event, but it is important to be aware that some smoke from outdoors can enter homes and make the indoor air unhealthy to breathe. Mechanical ventilation devices such as bathroom or kitchen fans that vent outdoors, or heating, ventilation, and air conditioning (HVAC) systems with a fresh air intake can help to reduce smoke infiltration.

Air quality and health

Air pollution is the presence of contaminants in the atmosphere, such as dust, fumes, gases, mist, odour, smoke or vapour, in quantities 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, ultimately leading to disease.

The World Health Organization (WHO) has established that 99% of the world's population lives in places where air quality does not meet its guidelines. The combined effects of ambient and household air pollution are associated with 6.7 million premature deaths annually. Ambient air pollution alone caused 4.2 million premature deaths worldwide in 2019, with 89% of those deaths occurring in low- and middle-income countries. WHO's Global Air Quality Guidelines (AQG) provide guidance on thresholds and limits for key air pollutants that pose health risks. These guidelines are developed through a transparent, evidence-based process and offer interim targets to promote a gradual shift towards lower pollutant concentrations and their associated health benefits.

Air pollution exposure is associated with oxidative stress and inflammation in human cells, which can lead to chronic diseases and cancer. Fine particulate matter, such as PM2.5, is of particular concern as it can penetrate deep into the lungs, enter the bloodstream, and cause systemic damage to tissues and cells. Short-term exposure to high levels of particulate matter can lead to reduced lung function, respiratory infections, and aggravated asthma, while long-term exposure increases the risk of non-communicable diseases, including stroke, heart disease, chronic obstructive pulmonary disease, and cancer. Children, the elderly, and pregnant women are more susceptible to air pollution-related diseases, with maternal exposure linked to adverse birth outcomes such as low birth weight and pre-term births.

Agricultural practices, such as burning crop remnants, can contribute to poor air quality and respiratory health issues in children. Air pollution has also been linked to an increased risk of neurological disorders, including Parkinson's disease, Alzheimer's disease, and other dementias. Wildfire pollution, driven by the climate crisis, is a pressing global issue, with tiny particles from wildfires known to be more toxic than urban air pollution due to higher concentrations of inflammatory chemicals. Wildfire smoke has been associated with early deaths, worsened heart and breathing diseases, and premature births, affecting over 1 billion people annually.

Improving air quality is crucial for public health. Measures to reduce exposure to air pollution include wearing face masks, improving indoor air quality with air purifiers, and implementing policies for cleaner transport, energy-efficient homes, and better waste management.

Clean Air Act

The Clean Air Act (CAA) is the primary federal air quality law in the United States, which was initially enacted in 1963 and has been amended many times since. It is one of the country's first and most influential modern environmental laws. The Act is administered by the Environmental Protection Agency (EPA) in coordination with state, local, and tribal governments.

The Clean Air Act is the law that defines the EPA's responsibilities for protecting and improving the nation's air quality and the stratospheric ozone layer. The Act calls for state and local governments to work in partnership with the EPA to solve multiple air pollution problems through programs based on the latest science and technology information.

The CAA ozone program, for example, is a technology transition program intended to phase out the use of chemicals that harm the ozone layer. The 1990 CAA Amendments also created a new title to address the issue of acid rain, particularly nitrogen oxides and sulfur dioxide emissions from electric power plants.

Section 112 of the Clean Air Act addresses emissions of hazardous air pollutants. The 1990 Amendments revised this section 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 per year or more of a hazardous air pollutant.

The Clean Air Act has substantially reduced air pollution and improved US air quality. Since 1990, there has been approximately a 50% decline in emissions of key air pollutants, preventing hundreds of thousands of cases of serious health effects each year.

US pollution and health disparities

Air pollution is a pressing global issue, with 99% of the world's population living in places where the WHO air quality guidelines levels were not met in 2019. The combined effects of ambient air pollution and household air pollution are associated with 6.7 million premature deaths annually.

In the United States, racial and ethnic minorities, lower-income groups, and people of colour are disproportionately affected by air pollution and face higher health risks. Studies have found that people of colour are exposed to greater than average concentrations of harmful pollutants, which can cause lung and heart problems, especially for those with chronic diseases, younger people, older people, and other vulnerable populations. This disparity exists across states, urban and rural areas, and income levels, indicating that race plays a significant role in exposure to air pollution.

Several factors contribute to these disparities. Firstly, pollution sources tend to be located near disadvantaged communities, increasing exposure to harmful pollutants. Secondly, low-income groups and racial and ethnic minorities often have limited access to healthcare, healthy food options, and quality education, which can make them more susceptible to the health impacts of air pollution. Additionally, existing health conditions and behaviours may predispose certain groups to greater risk. For example, the elderly, African Americans, and people living near central cities have been identified as being at higher risk from air pollutants.

The EPA's goal is to provide an environment where all people are equally protected from environmental and health hazards and have equal access to the decision-making process to maintain a healthy living, learning, and working environment. Addressing these disparities requires effective regulations and policies that promote environmental justice and reduce key sources of outdoor air pollution, such as supporting cleaner transport, energy-efficient homes, and better municipal waste management.

Trump's environmental policies

During his first term, former US President Donald Trump was heavily criticized for his environmental policies, which were seen as detrimental to the planet and public health.

Trump's administration took numerous actions to roll back environmental rules and regulations, particularly those enacted under the Obama administration. For example, in February 2017, Trump overturned President Obama's Stream Protection Rule, which aimed to protect waterways from coal mining waste. The Trump administration also proposed a rollback of the Clean Water Act, which would reduce water pollution in areas under federal jurisdiction.

Trump's loyalty to the fossil fuel industry was evident in his policies. He offered exemptions from tariffs to the industry and blocked renewable energy sources. His administration weakened rules limiting methane emissions from oil and gas production and reduced regulations on coal ash disposal and storage, leading to increased water pollution. They also targeted regulations on airborne emissions of mercury and other toxic substances from power plants.

The Trump administration's efforts to decrease pollution regulation were widespread. They refused to strengthen National Ambient Air Quality Standards (NAAQS) for fine particulate matter and ozone, which are crucial for reducing air pollution. In June 2020, the EPA finalized a rule that ended the rights of states, tribes, and the public to object to federal permits for projects that could pollute waterways. This was seen as a way to speed up oil pipelines, undermining state and tribal efforts to protect drinking water sources.

In addition, Trump withdrew the US from the Paris climate accord on his first day in office, froze funding for clean energy projects, and declared a "national energy emergency" to increase domestic fossil fuel production.

Overall, Trump's environmental policies were characterized by a rollback of regulations, support for the fossil fuel industry, and a disregard for the planet's well-being and public health consequences.

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