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Traffic-related air pollution linked to cancer in children

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September is Childhood Cancer Awareness Month. Sadly, childhood cancer is on the rise. In fact, cancer is the second leading cause of death (after accidents) for children under 15 years of age, according to the American Cancer Society. One major cause appears to be traffic-related air pollution. Researchers in Denmark this summer reported that even low-level exposure to air pollution over time is strongly associated with lung cancer in adults. Now there is new evidence that air pollution – specifically, traffic-related air pollution – is associated with cancer in children.

What is traffic-related air pollution?

Traffic-related air pollution refers to airborne pollutants generated by cars and trucks. While tailpipe emissions are the largest contributor to traffic-related air pollution, other sources include dust from brakes, tires and the road surface itself. Particulate matter (black carbon, fine and ultrafine particles, etc.), gases such as nitrogen oxides and carbon monoxide, and volatile organic compounds (VOCs) are the most common traffic pollutants.

The California Air Resources Board says diesel particulate matter can damage DNA and cause cancer. Volatile organic compounds (VOCs) can also cause cancer, the air quality agency reports. Common carcinogenic VOCs found in traffic-related air pollution include formaldehyde, acetaldehyde, benzene and others. VOCs also play a role in forming ozone pollution.

Most people live too close to freeways

Studies conducted by the Southern California Particle Center indicate that particle pollution levels remain elevated up to about 300 meters from a busy roadway. The problem is that in urban areas such as San Francisco, Los Angeles, New York and elsewhere, as many as four out of five residents live within 300 meters of a busy roadway. Schools also are often within 300 meters of a major roadway. Only a handful of states have passed regulations restricting the building of new schools close to busy roadways, and these regulations only apply to new school construction.

Study quantifies increased risk of cancer for children

Recent research conducted at the University of California, Los Angeles confirmed the link between traffic-related air pollution and childhood cancer. The study, presented to the American Association for Cancer Research, linked exposure to air pollution during pregnancy to three specific childhood cancers, including leukemia, cancer of the eyes and germ-cell tumors.

The researchers studied 3,590 children who developed cancer. They focused on air pollution exposure beginning with conception, because they realized that "certain childhood cancer cases originate in utero." They examined exposures to traffic emissions from cars, diesel trucks, distance from roadways and even factored in weather conditions through the first year of life. They found that each incremental increase (in interquartile range) in exposure was associated with a 4% increased risk for developing leukemia, up to 19% increased risk for eye cancer and 17% increased risk for germ-cell tumors.

Moving to a new home that is farther from the freeway or transferring children to a different school isn’t an option for most, or even many, people. So here are steps you can take to help reduce your level of exposure to traffic-related air pollution:

What you can do

The Centers for Disease Control and Prevention promotes a program called "Safe Routes to School," which encourages two basic approaches to lessen children's exposure to traffic pollution: Decrease the concentration of pollutants they breathe, and reduce the duration of their exposure. 

1. Ask your school district local school principal to help develop a program that will encourage drivers of cars and buses to shut off their cars near the school instead of idling.

2. Select lower-traffic routes to and from school for your child. Levels of traffic pollution can be much lower just one block from a busy road, according to the California Air Resources Board.

3. Schools in areas affected by elevated traffic pollution should consider high-performance air filtration for classrooms.

4. At home, close windows and doors during peak traffic hours. Also, consider a high-performance air filtration system to remove particulates and other pollutants from the indoor air.

Air Quality Life is brought to you by IQAir, a global air quality information and technology leader since 1963. With actionable insights based on the latest air quality research and information, we seek to advance awareness about the impact of air pollution on health.

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