New Delhi: Pollution caused rains to turn increasingly acidic in many parts of the country, particularly in the last decade, the Lok Sabha was informed today. Union of Minister of State for Science and Technology and Earth Sciences YS Chowdary replied in affirmative when asked whether a research by the India Meteorological Department and the Indian Institute of Tropical Meteorology (IITM) has found that pollution is causing rain to turn acidic. Mr Chowdary cited the study, conducted during 1981-2012, which underlined a decreasing trend in potential of hydrogen (pH), a scale that tells how acidic or alkaline a substance is. More acidic solutions have lower pH.
Study during 1981-2012 has shown the decreasing trend in pH at all the ten global atmosphere watch (GAW) stations in India. This trend is more significant in the last decade. Decadal mean pH among ten stations for 1981-1990, 1991-2000 and 2001-2012 ranged between 7.31 to 5.76, 7.45 to 4.92 and 6.16 to 4.77, respectively, he said in a written reply.
The minister replied in affirmative when asked whether acid rain was a result of rain water in the atmosphere mixing with polluting gases such as oxides of sulphur and nitrogen emitted from power plants, automobiles and some industrial units.
“Temporal variation at all the GAW stations showed an increasing trend for sulphate and nitrate which are major acidifying components oxidised from their precursor gases sulfur dioxide and nitrogen dioxide, respectively; and decreasing trend of calcium which is major alkaline component,” the minister added.
In a written reply to a separate question posed to the Department of Space, Minister of State Jitendra Singh said the IITM was working in tandem with the National Oceanographic and Atmospheric Administration (USA) for development of high resolution seasonal and long-term climate forecasts through Monsoon Mission and Centre for Climate Change Research (CCCR) Programmes.