Gurugram: Air quality fluctuates with seasonal changes; pollution expected to surge in next two weeksUpdated: Sep 28, 2020, 00:00 IST
After recording ‘moderate’ air quality for two weeks in succession — from September 9 to September 22 — air pollution readings in the city have shown a wide variation in the past five days, with experts warning that the city’s air quality is likely to deteriorate in the next few weeks due to the incoming pollutants from stubble burning in the neighbouring states.
From 184 on the Central Pollution Control Board’s (CPCB) daily air quality index (AQI) bulletin on Saturday (the highest concentration of pollutants recorded all month), the city on Sunday recorded 82 on the AQI, indicating ‘satisfactory’ air (among the lowest recorded in September).
Experts and officials attributed these wide variations to the changing meteorological conditions. “When air quality varies so widely from day to day, it means we are in a transitory period, in terms of weather and meteorology. For example, on September 23 and 24, wind speeds in Gurugram were very high and the winds were accompanied by light showers. This helped to bring air quality back into the satisfactory AQI range. But on September 26, when wind speed was low and atmospheric moisture was high, the reading shot back up because particulate matter was being ‘held’ in the atmosphere,” said Sachin Panwar, a city-based air quality scientist.
The next two weeks, however, are likely to witness a steep deterioration in the air quality, with transboundary pollutants from across the Indian border, as well as from Punjab, expected to accumulate in the northern Indian plains. “The next couple of weeks will give us an idea of how the winter will progress. Incoming pollutants due to crop stubble burning are expected to reach NCR within the next week itself,” said Kuldeep Singh, regional officer, Haryana State Pollution Control Board (HSPCB).
Changes in atmospheric temperature, Singh, will also play an important role in determining the nature and extent of pollution in the coming days. “The daily maximum temperature has been around 35 degrees throughout September, and it dropped sharply to about 33 degrees Celsius over the weekend. But this was immediately followed by high wind speeds, which improved the air quality on Sunday,” he said.
According to the Early Air Quality Warning System for Delhi-NCR, operated by the Indian Institute of Tropical Meteorology, “The air quality over Delhi-NCR is likely to improve marginally but remain in the moderate category on 27.09.2020 and 28.09.2020. The air quality is likely to remain in moderate category on 29.09.2020.” The forecast also states, “The predominant surface wind is likely to be coming from northwest direction in Delhi with wind speed up to 20 kmph, mainly clear sky and strong surface winds (20-30 kmph) during the day on 29.09.2020.”
Experts said that while these high speed winds may have a positive impact on air quality in Gurugram in the short term, they will eventually bring in pollutants from crop burning within the next two weeks. “Once the temperature drops and winter commences, there will be little wind left to disperse these pollutants, and we can expect the AQI in Gurugram to touch about 250, in the poor category,” said Panwar.
September 21: 112
September 22: 139
September 23: 82
September 24: 97
September 25: 114
September 26: 184
September 27: 89