Regular rains improve air quality in city

Monitoring stations claim air quality has never been so clean in the city

The recent spells of rains, some heavy, such as the one the city experienced on Wednesday evening well into the night, created many problems on the ground in terms of flooding in several parts of the city and chaos on city roads, but they also washed the city’s air clean.

The air quality of the city which was earlier a blazing flash of red on the air quality index (AQI), has now become nothing more than a string of green boxes, indicating that the quality of air in the city has improved immensely.

Whether on the national air quality monitoring stations or the state air quality monitoring stations, the city’s air has never been better. This, experts say, is due to the bouts of rain that the city has been receiving.

On Wednesday evening, certain pockets of the city like Jubilee Hills, Rajendranagar and Falaknuma experienced the highest rainfall (till 7.30 pm), 109 mm, 104.3 mm, and 99.3 mm respectively.

As explained by environmental scientists from the Telangana State Pollution Control Board (TSPCB), whenever a raindrop falls through the atmosphere, it attracts tiny aerosol parti

cles to its surface before hitting the ground. The process by which droplets and aerosols attract is coagulation, a natural phenomenon that can act to clear the air of pollutants like sulphates, and organic particles, along with dust.

“The air-quality always improves during the monsoon season. During this time, the pollutants are attached to the raindrops,” Prasad Dasari, senior scientist with the state pollution board told Deccan Chronicle.

“There are two types of precipitation — dry and wet. While in dry precipitation, the pollutants stick to buildings, trees or other such things, during wet precipitation, the pollutants stick to the water droplets. Since they cover a larger area than buildings or trees, the quantum of pollutants is lower,” he adds.

During the summer month of May this year, particulate matter 10 microns (PM10) was measured to 74 ug/m3 at the university of Hyderabad. Similarly, at the Nehru zoological park, Pashamylaram, Bolarum, and ICRISAT, the levels were 91, 87, 86, and 76 respectively.

However, in August the pollution levels had dropped to 31, 31, 26 28, and, 22 respectively.