Continuous exposure to traffic-related air pollution can raise the risk of developing childhood cancers, including childhood leukemia, according to a new study. The research confirmed the link between traffic-related air pollution and childhood cancer through a meta-analysis of studies accumulated over the past 30 years, pointing to the need for air pollution reduction policies to protect children and pregnant women.
The National Cancer Center said Thursday that a joint domestic and international research team, including Dr. Kim Byung-mi of the Cancer Prevention Division, published its findings on the link between traffic-related air pollution (TRAP) and childhood cancer incidence in the international journal Environmental Research.
The researchers reviewed 1,632 related studies published between 1990 and 2024, then selected 25 for a systematic literature review and meta-analysis. The analysis examined the association between traffic-related air pollutants such as fine particulate matter (PM2.5), nitrogen dioxide (NO₂), and benzene, and the incidence of childhood cancer.
The analysis found that for every 10 μg/m³ increase in fine particulate matter (PM2.5) concentration, the risk of childhood acute lymphoblastic leukemia (ALL) rose by 29%. The risk of retinoblastoma, an eye cancer that occurs in infants and young children, increased by 68%. In addition, for every 1 μg/m³ increase in benzene concentration, the overall risk of childhood leukemia rose by 12% and the risk of acute myeloid leukemia (AML) rose by 22%, the analysis found.
The comparison of exposure timing before and after birth also drew attention. The researchers found a tendency for exposure to traffic-related air pollutants during infancy after birth to be more closely associated with an increased risk of childhood leukemia than exposure during pregnancy.
Unlike adult cancers, childhood cancers are influenced more by genetic factors and exposure to environmental hazards than by lifestyle habits such as smoking, drinking, or diet. The researchers explained that when substances such as fine particulate matter and benzene enter the body, they may cause inflammatory responses and oxidative stress and damage DNA, potentially raising the risk of cancer.
The study was jointly conducted by the "Korea-U.S. Pediatric and Adolescent Cancer Consortium," which includes the National Cancer Center, Ewha Womans University, the University of Minnesota, and Boston College. The researchers assessed the study as significant in that it confirmed the link between traffic-related air pollution and increased childhood cancer risk through a meta-analysis synthesizing global research accumulated over more than 30 years.
"This is a result that systematically demonstrates that exposure to traffic-related air pollution can raise the risk of developing certain childhood cancers, including childhood leukemia," said Dr. Kim Byung-mi of the National Cancer Center's Cancer Prevention Division. "To protect the health of children, who are the future generation, air pollution reduction policies and follow-up research must continue."
