Unveiling the Chemistry of Urban Rain: An Acid-Alkaline Balance

A study by the IMD and IITM, Pune, reveals how air pollution affects rainfall acidity in Indian cities. Findings indicate urban emissions can make rain more acidic, while desert dust can counteract these effects, leading to alkaline rain. Urbanization significantly impacts rainwater chemistry.

An in-depth analysis conducted by the India Meteorological Department (IMD) and the Indian Institute of Tropical Meteorology (IITM) in Pune has unveiled significant insights into how air pollution is altering the acidity levels of rainfall across various Indian cities. The study spanned data recorded at Global Atmosphere Watch (GAW) stations from 1987 to 2021, focusing on the pH levels of rain in ten cities.

The research highlights the role of urban emissions in causing more acidic rain in cities like Vishakhapatnam, Allahabad, and Mohanbari, while revealing that desert dust influences could be making the rain in Jodhpur, Pune, and Srinagar more alkaline. Urbanization and industrialization have a marked impact on the chemical makeup of rainwater, as the research finds.

Interestingly, while acidic rain is not an immediate threat in the region, the study discloses that over time, rainfall has generally become more acidic in most cities analyzed. The source of acidity in specific areas links to local industries and natural emissions. The findings underline the critical relationship between atmospheric conditions, local emissions, and rain chemistry.

(With inputs from agencies.)