New Delhi, Sept 2 (UNI) In a first-of-its-kind study examining health risks from airborne pathogens over metropolitan cities like Delhi, a team of Indian researchers has uncovered alarming evidence: pathogenic bacteria responsible for respiratory, gastrointestinal, oral, and skin infections are twice as prevalent in densely populated urban areas due to elevated concentrations of fine particulate matter (PM2.5).
The research highlights that the Indo-Gangetic Plain (IGP) — one of the world’s most densely inhabited and polluted regions — faces a unique confluence of meteorological and environmental factors during winter. Western disturbances cause a sharp drop in temperature and a rise in relative humidity, leading to stagnant air and a low boundary layer height. These conditions trap pollutants close to the ground, resulting in heightened microbial concentrations.
Delhi, situated within the IGP, stands out as a rapidly expanding urban hub with one of the highest pollution levels globally. The study confirms earlier findings of significant spikes in airborne microbes during winter but goes further to reveal the critical role of PM2.5 particles as carriers that facilitate the deep lung penetration of pathogenic bacteria.
Dr. Sanat Kumar Das, who led the investigation, noted that seasonal transitions—particularly hazy days or winter rains—create “high-risk windows” where airborne infections can spread more rapidly. The combined effect of pollution, humidity, and weather patterns allows microbes to persist longer in the atmosphere, increasing health risks for millions.
Published in the international journal Atmospheric Environment: X, the study serves a crucial alert for urban health policymakers. It underscores the need for integrating microbial air quality monitoring into public health strategies and urban planning, especially in megacities like Delhi, where millions inhale contaminated air daily, said the researchers.
Understanding the interplay between pollution, climate, population density, and airborne bacterial communities can better equip authorities to forecast disease outbreaks and design cities that safeguard residents from invisible microbial threats, they added.
