Advisory to mask up as SO₂, PM2.5 & PM10 worsen AQI

Guwahati: Sulfur dioxide (SO2) has emerged as a prominent air pollutant in Guwahati over the past two days — Sunday and Monday — alongside PM2.5 and PM10, raising concerns over respiratory health risks.

Additional chief environmental scientist of the Assam Pollution Control Board (APCB), Gautam Kumar Mishra said, “Sulfur dioxide usually remains well below the 24-hour limit of 80 micrograms per cubic metre, but its concentration was found higher in Panbazar area on Sunday and Monday. The reasons will come out after analysis.”




Mishra said sulfur dioxide levels in the city typically range between 10 and 20 micrograms per cubic metre against the 24-hour limit of 80 micrograms per cubic metre. “In Panbazar area also, it is usually found around 40 micrograms per cubic metre. However, the CPCB daily bulletin showing the sulfur dioxide as one of the prominent pollutants is a matter of examination,” he added. He said sulfur dioxide in Guwahati is generated from road dust and crackers bursting, and advised residents to wear face masks as a precaution.

Mishra said the AQI is calculated by monitoring pollutants including PM2.5, PM10, sulfur dioxide and carbon monoxide, and added that sulfur dioxide poses severe health risks similar to particulate pollution.

A city-based doctor, speaking on condition of anonymity, said, “Sulfur dioxide may cause immediate severe respiratory irritation and asthma attacks while micro pollutants like PM2.5 poses a higher long-term risk because it penetrates deep into lungs and enters the bloodstream.”

PM2.5 refers to particulate matter 2.5 microns or less in diameter, made up of a mix that can include smoke, soot, liquid or solid particles, mould, bacteria, pollen and animal dander. Because these particles can be inhaled deep into the lungs, they are linked to heart or lung disease, acute and chronic bronchitis, asthma attacks and other respiratory symptoms.

PM10 refers to particulate matter with a diameter of 10 micrometres or less. These particles can enter the lungs through the nose and throat and are associated with serious health impact.