Relief after mild rain, 75% dip in CO level

Gurgaon: The level of carbon monoxide (CO) in the city air dipped by nearly 75% as compared to that in the early days of this month.
The drastic fall in the CO level was attributed to humidity triggered by light rain during the days in question.
Starting from December 30, the CO level kept rising, till it touched the mark of 68.91µg/m³ on January 4. The CO level remained between 68.91µg/m³ and 22.36µg/m³ in the past 15 days.However, the CO level saw a sudden dip (of nearly 75%) on Monday with the average level recorded at 15.39µg/m³.
The CO level in the city in the past 15 days surpassed that in the national capital. Average concentration of CO is usually measured at three stations in Delhi — Punjabi Bagh, Shadipur and Dilshad Garden — and it remains below 4µg/m³ (prescribed value of CO).
Also, the concentration of PM2.5 also came down from 445.06µg/m³ on Saturday to 234.56µg/m³ on Monday.
The AQI (Air Quality Index), meanwhile, was recorded below 200 on Monday, which is considered ‘unhealthy’, that is, members of sensitive groups may experience more serious health effects, while it was recorded above 350 in the past 10 days.
Both experts and the Haryana State Pollution Control Board (HSPCB) said the fall in the CO level was caused by light rain around the city.
“Meteorological conditions such as increase of rainfall, humidity, wind speed and change in the direction of wind have a negative correlation with the level of particulate matter in the atmosphere. It is quite possible that particulate matter in the atmosphere got dispersed after light showers in the northern region might have led to sudden decrease in the CO level,” an official of HSPCB said.