Several people stepping out of their houses eary in the morning were pleasantly surprised to see `dense vapour’ in the air. Initially perceived as fog, it did not take much time for them to realise that it was smog.
Pollution levels have escalated considerably over the past few days in the city, changing the air quality from `good’ to `moderate’ in four of the 10 locations being monitored by the Institute of Tropical Meteorology’s (IITM) System of Air Quality Forecasting and Research (SAFAR).
Currently, Shivajinagar, Lohegaon and Katraj have the worst air quality, causing nightmarish smog. PM 2.5 and PM 10 levels in these three locations have been consistently increasing since October 13 this year. PM 10 levels here have crossed the maximum permissible limit of 100 micrograms per cubic meter during all days from October 13 to 16.
SAFAR scientists said the rise in the level of pollution can be seen only since October, as city’s air quality during the previous months (monsoon season) was `good’.The highest rise in pollution levels have been noticed in Katraj, followed by Shivajinagar and then Lohegaon.
PM 10 levels rose the highest in Shivajinagar and Katraj on October 14, while highest PM 10 levels in Lohegaon were recorded on October 13.
The two locations where PM 2.5 levels have gone above the maximum permissible li mit of 60 micrograms per cubic meter since October 13 are Shivajinagar and Katraj.The highest rise was recorded in Shivajinagar on October 14 and 15, the data showed.
A SAFAR scientist said cooler temperatures in the morning affect the lowermost layer of the atmosphere. “Calm winds during this season trap pollutants near the earth’s surface, hindering their dispersal into the atmosphere. The pollution and dust mix with the water vapour in the air to form smog,“ the scientist said.
Particulate Matter (PM) includes both solid particles and liquid droplets found in the air. Many manmade and natural sources emit PM directly or emit other pollutants that react in the atmosphere to form PM. These solid and liquid particles come in a wide range of sizes.Particles up to 2.5 micrometers in diameter are called PM 2.5. PM 10 refers to particulate matter having a size less than or equal to 10 micrometer.
Experts said PM 2.5 can increase the susceptibility to respiratory infections and can aggravate existing respiratory diseases, such as asthma and chronic bronchitis.
Source : TOI