Key TakeawaysAir pollution might increase people’s risk of developing non-cancerous brain tumorsSeveral types of air pollutants appear to increase risk of meningiomasThe risk rises with a person’s level of exposure.THURSDAY, July 10, 2025 (HealthDay News) — Folks who breathe in more air pollution have a higher risk of developing a common non-cancerous brain tumor, a new study says.Several different types of air pollutants, including particle pollution and nitrogen dioxide, appear to increase risk of meningiomas — tumors that form in the layers of tissue that cover the brain and spinal cord, researchers reported July 9 in the journal Neurology.“Various types of air pollution have been shown to have negative effects on health, and ultrafine particles are small enough to cross the blood-brain barrier and may directly affect brain tissue," lead researcher Ulla Hvidtfeldt, a senior scientist at the Danish Cancer Institute in Copenhagen, Denmark, said in a news release.“Our study suggests that long-term exposure to air pollution from traffic and other sources may play a role in the development of meningioma and adds to the growing body of evidence that air pollution can affect the brain — not just the heart and lungs,” she added.More than 170,000 people a year are diagnosed with meningioma in the United States, according to the Cleveland Clinic. Symptoms include headaches, dizziness, nausea, vision changes, hearing loss, seizures, memory problems, muscle weakness or paralysis, and behavioral or personality changes.Meningiomas can be treated with surgery, radiation therapy or chemotherapy, the Cleveland Clinic says. For the new study, researchers followed nearly 4 million adults in Denmark over a 21-year period. During that time, about 16,600 developed tumors of the brain or spinal cord, including more than 4,600 who developed meningioma.Using the people’s addresses, the research team estimated their long-term exposure to air pollution.Results show that people with the highest exposure to air pollution had triple the rate of meningioma compared to those with the least exposure – 0.2% of the population versus 0.06%.Further, the risk grew with mounting exposure to various air pollutants.For example, people had a 21% higher risk of meningioma for every four micrograms per cubic meter increase in exposure to fine particulate matter, or airborne particles 2.5 microns in diameter. By comparison, a human hair is 50 to 70 microns in diameter.Likewise, they had a:12% increased risk for every 8.3 Ug/m3 increase in nitrogen dioxide.10% higher risk for every increase of 5,747 particles/cm3 for ultrafine particles less than 0.1 micrometers in diameter.3% higher risk for every 0.4 Ug/m3 increase in airborne carbon.However, researchers did not find strong links between air pollutants and more aggressive brain tumors.“While research on the health effects of ultrafine particles is still in its early stages, these findings point to a possible link between traffic-related ultrafine particle exposure and the development of meningioma,” Hvidtfeldt said. Researchers noted that the study’s design cannot prove a direct cause-and-effect link between the air pollutants and meningioma, only an association.“More research is needed to confirm these results, but if cleaning up our air can help lower the risk of brain tumors, that could make a real difference for public health,” Hvidtfeldt added.More informationThe Cleveland Clinic has more on meningioma.SOURCE: American Academy of Neurology, news release, July 9, 2025 .What This Means For YouPeople should try to reduce their exposure to air pollution and take steps to reduce their contributions to unclean air..Sign up for our weekly HealthDay newsletter