New Delhi, July 10 (Reporter) A recent large-scale Danish study has revealed that ultrafine particles in air pollution can cross the blood-brain barrier and may increase the risk of developing tumors of the central nervous system (CNS), particularly meningiomas --the most common type of primary brain tumor. The findings published in journal Neurology add to growing evidence that air pollution’s harmful effects extend beyond respiratory and cardiovascular health, potentially affecting the brain as well. Given the high pollution burden in Indian metropolitan areas such as in Delhi, Mumbai, and Kolkata, the study’s implications are particularly relevant for Indian urban populations. Cities frequently exceed World Health Organization (WHO) guidelines for PM2.5 and NO₂, with vehicular emissions, construction activities, and industrial sources contributing significantly to overall pollution levels. The study, which followed nearly four million Danish adults over a period of 21 years, found that individuals with the highest exposure to UFPs and other pollutants—including nitrogen dioxide (NO₂), fine particulate matter (PM2.5), and elemental carbon—had a markedly higher risk of developing meningiomas compared to those with the lowest exposure levels. “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,” said Dr. Ulla Hvidtfeldt, lead author and researcher at the Danish Cancer Institute in Copenhagen. The study utilised national registries and residential histories to estimate personal exposure to air pollution, and applied advanced modelling techniques to account for both local traffic emissions and broader environmental sources. While no strong associations were identified between pollution and more aggressive brain tumours such as gliomas, the study’s findings underscore the broader public health implications of chronic exposure to air pollution. Notably, the study acknowledged certain limitations, including the inability to account for indoor air quality or occupational exposure, both of which could influence an individual's cumulative exposure to pollutants. Experts argue that while more research is required to confirm causal links, these findings offer yet another compelling reason to implement stringent air quality controls. “If cleaning up our air can help lower the risk of brain tumours, that could make a real difference for public health,” said Dr. Hvidtfeldt...////...