Residents of Chennai seeking a breath of fresh air during their morning walks are facing a hidden health hazard. Over the past three days, the Air Quality Index (AQI) in several interior neighborhoods of the city has plunged into the 'poor' category, posing risks especially during the early hours.
Nighttime Pollution Spike: The Alarming Numbers
The deterioration is most severe between midnight and 7 am. On Monday, Kodungaiyur recorded AQI levels ranging from a high of 239 to 204 during this critical window. Similarly, Arumbakkam saw AQI values between 223 and 204 from midnight to 5 am. In Perungudi, the air quality remained in the 'poor' bracket, with readings between 210 and 201 in the early morning.
While conditions improved slightly to 'moderate' after sunrise, this level can still trigger breathing difficulties for individuals with pre-existing lung, asthma, or heart conditions. The primary culprit identified across monitoring stations is PM2.5 – the dangerous fine particulate matter emitted from vehicles, dump yards, industries, and dust.
Why is Chennai's Air Suffocating at Night?
Meteorologists point to a combination of adverse weather conditions trapping pollutants close to the ground. Weak winds, hovering around just 5 kmph, combined with high humidity have led to the formation of mist.
"Mist forms when moist air cools, causing water vapour to condense into tiny droplets. Pollutants settle on these suspended droplets," explain experts. This toxic mix lingers until sunrise, when rising temperatures and stronger winds usually help in dispersal.
Mahesh Palawat, Chief Meteorologist at Skymet Weather, emphasized the localized nature of the problem. "The pollution is mostly due to localised sources... When winds fail to strengthen, pollutants can continue to linger in the air even after sunrise. Only strong, steady winds or widespread rainfall can effectively wash them away," he stated.
Forecast and Hope for Relief
The immediate forecast offers little respite. The India Meteorological Department (IMD) has predicted mist or haze during the early morning hours for Tuesday. The city can expect a partly cloudy sky with maximum temperatures of 30-31°C and minimums of 21-22°C.
However, there is a glimmer of hope by month's end. Experts anticipate an improvement in pollution levels with the return of rain activity. Weather blogger Pradeep John indicated a possibility of light rainfall around December 27. He also cautioned, "However, over the next couple of days, night temperatures may drop below 20°C, which could prevent pollutants from dispersing effectively."
For now, Chennai's citizens, especially those with respiratory vulnerabilities, are advised to exercise caution during their early morning outdoor routines and stay updated on real-time air quality reports.
