Source : INDIA TODAY NEWS
Delhi witnessed a dramatic atmospheric reset on Sunday, May 31, as the city-wide Air Quality Index (AQI) plummeted from a stifling average of around 156 during the peak heatwave down to a clean 85 following heavy pre-monsoon showers.
Following a period of fierce winds that choked the city with dust, heavy pre-monsoon showers finally broke the back of a punishing heatwave.
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This sudden atmospheric reset drastically lowered oppressive night temperatures and purged toxic pollutants from the air.
HOW DID RAIN CLEAN DELHI AIR QUALITY?
The significant improvement in the Air Quality Index of Delhi, which dropped to a satisfactory 85, was driven entirely by the rainfall.
These heavy showers triggered a natural cleansing mechanism known as atmospheric scavenging.
In this scientific process, falling raindrops collide with suspended pollutants, effectively trapping microscopic dust and pulling it down to the ground.
This natural wash cycle scrubbed the skies clean, giving the capital its most breathable day since October 8.
Data from the Central Pollution Control Board confirms this steep decline in pollution levels.
DO DUST STORMS REDUCE AIR POLLUTION?
A common misconception is that high winds blow away existing pollution.
In reality, dust storms are a net negative for air quality. When gusty winds sweep in from arid regions like the Thar Desert, they transport massive amounts of loose sand and soil.
This significantly increases the levels of PM10, which is coarse particulate matter measuring 10 micrometres or less in diameter.
Before the rain began, these winds actually worsened the pollution and reduced visibility by importing external dust.
The real saviour was the subsequent rain.
WHY DID DELHI NIGHT TEMPERATURES DROP?
Convective storms, which are powerful weather systems driven by rising warm air, provide immense thermal relief.
Thick cloud cover acted as a shield against scorching solar radiation. Furthermore, evaporative cooling from the rainfall combined with gusty winds to slash night temperatures.
Official weather observations from the India Meteorological Department at 8:30 IST confirmed a significant thermal plunge.
At the Safdarjung base station, the minimum temperature dropped to 23.3 degrees Celsius, which is 3.6 degrees below normal.
The Palam station plummeted even further to a refreshing 21.0 degrees Celsius.
For a city more accustomed to grey horizons, this fleeting atmospheric truce is a beautiful reminder of nature’s power to completely rewrite the sky.
– Ends
SOURCE :- TIMES OF INDIA
