Air Carcinogens: What Pollutants Cause Cancer?

Air pollution is a major contributor to the global disease burden, with emissions from industry, power generation, transportation, and domestic burning being the main sources. Outdoor air pollution and particulate matter (PM) in outdoor air pollution have been classified as Group 1 human carcinogens, alongside asbestos, plutonium, silica dust, ultraviolet radiation, and tobacco smoke. Particle pollution, a mix of tiny solid and liquid particles in the air, can be emitted directly from sources such as wood stoves, forest fires, and vehicles, or formed indirectly from other types of pollution. Hazardous air pollutants, which can be gases or compounds and metals, are known or suspected carcinogens that cause serious health issues such as cancer and birth defects.

Particle pollution

The particles in the air can vary in size, from ultra-fine particles that are less than or equal to 100 nanometres in diameter, to fine particles that are about 100 nanometres to 2.5 micrometres in diameter, and finally to larger particles that are up to 10 micrometres in diameter. While breathing in larger particles can be harmful and cause irritation to the eyes, nose, and throat, smaller particles are more dangerous. This is because our bodies have natural defences that help us to cough or sneeze out the larger particles. However, the smaller particles can get past these defences and become trapped deep in the lungs, and can even enter the bloodstream, causing damage to our health.

In 2013, the World Health Organization (WHO) International Agency for Research on Cancer reviewed all the available science and concluded that particulate matter causes lung cancer. This conclusion was supported by extensive evidence from indirect models that showed how outdoor air pollution contributes to abnormal cell proliferation and cancer. The IARC, in the same year, classified both outdoor air pollution and PM in outdoor air pollution as Group 1 human carcinogens for lung cancer. This evaluation was based on studies with quantitative data on long-term estimates of outdoor air pollution exposure, including the large-scale American Cancer Society (ACS) Cancer Prevention Study-II (CPS-II) and the European Study of Cohorts for Air Pollution Effects (ESCAPE).

The Clean Air Act in the United States has helped to reduce particle pollution by lowering emissions from power plants and retiring dirty diesel engines. However, some members of Congress are trying to block the EPA's work to limit dangerous air pollution by adding riders to crucial bills. This is a concern as particle pollution has been linked to lung cancer and increases the risk of early death, heart disease, and asthma attacks. It can also interfere with the growth and function of the lungs.

Hazardous air pollutants

Outdoor air pollution is a significant contributor to the burden of diseases worldwide. Most people reside in areas where air pollution levels are high due to emissions from industries, power generation, transportation, and domestic burning. These emissions often contain hazardous air pollutants, including specific carcinogens and other agents that increase cancer risk.

The Clean Air Act in the United States has helped reduce emissions from power plants and dirty diesel engines, lowering particle pollution. However, there is still work to be done to meet the World Health Organization's (WHO) health-based air quality guidelines. In 2013, the WHO's International Agency for Research on Cancer classified outdoor air pollution and PM in outdoor air pollution as Group 1 human carcinogens for lung cancer.

Particle pollution, or particulate matter, is a mix of tiny solid and liquid particles in the air. These particles can be emitted directly from sources such as wood stoves, forest fires, and vehicles. They can also form from other types of pollution, such as power plants. While larger particles can irritate the eyes, nose, and throat, smaller particles are more dangerous as they can enter deep into the lungs.

Some specific examples of hazardous air pollutants include hydrogen chloride, benzene, toluene, asbestos, cadmium, mercury, and chromium. These pollutants can settle into waterways, streams, rivers, and lakes, leading to ingestion through water or consumption of fish. Additionally, children may be exposed to hazardous pollutants in the dirt that they play in and potentially put in their mouths.

Outdoor air pollution

Particulate matter, a mix of tiny solid and liquid particles like acids, organic chemicals, metals, and dust, poses a significant risk to human health. In 2013, the World Health Organization (WHO) and the International Agency for Research on Cancer (IARC) concluded that this particulate matter in outdoor air pollution causes lung cancer. This conclusion was based on studies of humans and experimental animals, as well as mechanistic evidence. The IARC classified outdoor air pollution and particulate matter within it as Group 1 human carcinogens for lung cancer.

The sources of particulate matter are diverse and include vehicle exhaust, coal-fired power plants, industrial sources, wood stoves, forest fires, and power plants. These sources emit pollutants that can build up in the lungs and damage cells, potentially leading to cancer. While the Clean Air Act in the United States has helped reduce particle pollution, certain areas still have high levels of carcinogens in the air.

The health risks associated with outdoor air pollution are not limited to lung cancer. It can also increase the risk of heart disease, asthma attacks, and interfere with lung growth and function. Additionally, outdoor air pollution has been linked to an increased incidence of childhood cancers and other types of cancers in adults. Implementing measures to reduce cancer risk from outdoor air pollution is challenging due to the numerous combustion sources and the presence of various carcinogens and risk-increasing agents.

To protect oneself from particle pollution, individuals can check the air quality index forecast and limit their activities when pollution levels are high. Additionally, avoiding exercising near heavily trafficked highways and reducing contributions to local pollution sources, such as not burning wood or trash and minimizing vehicle idling, can help lower exposure to harmful pollutants. While smoking has a more significant impact on lung cancer risk, outdoor air pollution is still a significant concern, and reducing exposure to it is crucial for public health.

Air toxics

Major sources of outdoor air toxics include emissions from coal-fired power plants, industries, refineries, and vehicles. Certain industries also produce specific toxins, such as ethylene oxide leaks from medical equipment sterilization facilities. Indoor air can also contain hazardous pollutants, including tobacco smoke, asbestos from building materials, and chemicals from cleaning supplies and air fresheners.

The Clean Air Act has helped reduce emissions from power plants and retire dirty diesel engines, lowering particle pollution levels in the United States. However, some members of Congress are attempting to block further EPA efforts to limit dangerous air pollution.

Particle pollution, a mix of tiny solid and liquid particles in the air, is a significant component of air toxics. These particles, emitted from sources like wood stoves, forest fires, and vehicles, can be harmful when inhaled, with smaller particles posing greater risks. The World Health Organization (WHO) and its International Agency for Research on Cancer (IARC) have classified outdoor air pollution and particulate matter as Group 1 human carcinogens, alongside asbestos, plutonium, silica dust, and tobacco smoke.

Research and epidemiological evidence have established a link between outdoor air pollution and lung cancer incidence and mortality worldwide. Studies have also examined the association with other types of cancers in adults and children, underscoring the need for multi-level interventions to protect public health.

Lung cancer

Outdoor air pollution is a major contributor to the burden of disease worldwide. Most people are exposed to air pollution that exceeds the World Health Organization's (WHO) health-based air quality guidelines. This pollution is caused by emissions from industry, power generation, transportation, and domestic burning. Outdoor air pollution is a mixture of tiny dust-like particles and substances in the air, which can be artificial or natural. Examples of artificial sources include vehicle exhaust, coal-fired power plants, and other industrial sources, while natural sources include wind-blown dust, radon, and ozone.

Particle pollution, or particulate matter (PM), is a mix of tiny solid and liquid particles in the air. These particles can be made up of acids, organic chemicals, metals, soil, and dust particles. They are emitted directly from sources like wood stoves, forest fires, vehicles, and power plants. Particulate matter with an aerodynamic diameter of less than 2.5 microns (PM2.5) in outdoor air pollution has been classified as carcinogenic to humans and a cause of lung cancer. PM2.5 is often evaluated in epidemiology studies, and its presence has been observed in multiple locations with different pollution mixtures, suggesting an effect of PM2.5 itself on lung cancer.

In 2013, the World Health Organization (WHO) International Agency for Research on Cancer (IARC) reviewed all the available science and concluded that particulate matter causes lung cancer. This conclusion was supported by mechanistic evidence and studies of humans and experimental animals. The number of lung cancer deaths attributable to PM air pollution is estimated to be in the hundreds of thousands annually worldwide.

While smoking is a much bigger contributor to lung cancer cases than air pollution, it is important to recognize that air pollution also plays a significant role. Exposure to air pollution increases the risk of lung cancer, and the risk from air pollution is not limited to outdoor settings, as indoor air pollution, such as second-hand tobacco smoke, can also cause lung cancer.

To reduce the risk of lung cancer and other lung diseases, it is crucial to address air pollution. This includes implementing measures to reduce emissions from major sources, such as industry and transportation, as well as individual actions to minimize our contribution to air pollution.

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