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The information on this page was reviewed and approved by
Maurie Markman, MD, President, Medicine & Science at CTCA.

This page was updated on September 21, 2021.

Pollution and cancer risk

Pollution in the environment, including in the air you breathe and the water you drink, is a major public health concern. For decades, authorities have worked to study and reduce the negative effects of pollution on health, including its relationship to cancer. Air pollution is closely associated with lung cancer, and other kinds of pollution may have an effect on cancer risk as well.

What is pollution?

Pollution occurs when harmful substances—known as pollutants—make their way into the air and water. Pollution is largely a human-made problem, resulting from sources such as manufacturing, energy production, farming, flying, driving, shipping and more. Wildfires are another source of air pollution, as are home fireplaces.

Government environmental agencies are tasked with controlling and reducing pollution. Regulations aim to limit the amount of pollution that industries emit, and advancements in technology have helped reduce emissions from other sources, such as cars.

Still, the level and type of pollution vary depending on where you live, and people in communities with high exposure to pollution face serious health effects, including increased risk for certain cancers. For example, residents near high-volume roads or highways may face more exposure to air pollution because of the number of cars and trucks.

Your body is essentially a filter for everything that goes into it. Look to your air and water sources for potential sources of pollution.

Does pollution cause cancer?

Evidence suggests that air pollution from particulate matter—small, airborne particles—may lead to lung cancer, with hundreds of thousands of lung cancer deaths worldwide attributed to air pollution. It’s the second leading cause of lung cancer after smoking, according to a 2020 American Cancer Society review in CA: A Cancer Journal for Clinicians.

The 2020 review also noted some evidence to suggest that air pollution may increase the risk of bladder, breast, kidney, colon and rectal cancers. However, studies regarding these cancers are less conclusive, and research is ongoing. Scientists are also studying whether air pollution may contribute to the risk of childhood leukemia.

It’s unknown exactly how air pollution leads to cancer, but researchers have focused on a few possibilities:

  • One potential pathway is from physical damage to cells caused by particulate matter when it enters the lungs. This may produce inflammation and oxidative stress and lead to cell mutations down the line.
  • Another possible pathway is from specific carcinogens (cancer-causing substances) found in air pollution that may be absorbed into the body when inhaled. These substances include benzene, formaldehyde, polycyclic aromatic hydrocarbons (PAHs) and dioxins, among others.

Water is another key source of pollution. Water contaminated with high levels of arsenic is a cause of bladder cancer, and it’s also been associated with skin and lung cancers. Drinking water from private wells was found to be a source of arsenic, according to a study in the Journal of the National Cancer Institute. Nitrates, also found in higher levels in private wells, have been associated with colon, kidney and stomach cancers when combined with higher meat intake.

Scientists continue to research the effects of contaminated water on cancer risk, including whether pesticides (which may also be in the air), disinfectant by-products, per- and polyfluoroalkyl substances (PFAS), and other water pollutants may be to blame.

How to reduce your risk of cancer from pollution

There are some steps to help reduce the risk of cancer from air pollution, including:

  • Use an indoor air filtration system and change filters regularly
  • Avoid driving or walking in high-traffic areas
  • Avoid spending too much time near sources of diesel exhaust, such as trucks or buses

If you drink water from a private well, the Centers for Disease Control and Prevention recommends that you have it checked once every year for contaminants.

Other steps, such as walking or biking rather than driving to work, are most helpful when they’re community-based initiatives—if many people do their part, they may collectively help lower pollution in their area.