Dust cloud spreads 500m, takes 15 minutes to settle

NOIDA: As the twin towers of concrete and metal crumbled - one floor at a time - a deluge of dust engulfed all in its way.
For about an hour after the detonation on Sunday afternoon, a haze lingered over residential buildings in the vicinity of the now non-existent twin towers in Sector 93A. The demolition's ground zero, Emerald Court and ATS Greens Village adjacent to it, were covered with a thick layer of dust. The two societies, most vulnerable to the implosion's effects, had been evacuated earlier in the day.
The others in the vicinity - Parsvnath Prestige (800 metres), Eldeco Utopia (1.9km) and Purvanchal Silver City (3km) - bore some of the impact of the dust cloud.
Its residents said the first few minutes were uneasy, with the distinct smell of explosives in the air. To block out the dust from entering their flats, they had locked themselves inside for an hour. Most of it was back to normal in two hours or so, they said.
According to officials, the dust cloud expanded up to 500 metres around the towers, including the sector road in front of them. But the particles started settling within 15 minutes, and it took an hour or so for the air to return to some semblance of normal.
As was expected, the level of pollutants spiked nearly 20 times of the count recorded earlier on Sunday. Real-time data from the air monitoring station in Sector 91 showed a spike in PM10, which touched 1,042 (g/m³) at 2.50pm, 20 minutes after the controlled explosion. PM10 was between 75 and 82 (g/m³) just hours before.
The AQI, however, remained in the 55-60 range before and after the demolition. At 78.9 (g/m³), PM10 too had been brought under control by 6pm.
Officials said this was due to the quick response of the authorities. "With the efforts of all the stakeholders, Noida Authority brought back AQI and PM 10 levels to the pre-demolition range within 30 minutes. The data from the Sector 91 monitoring station, which is closest to the demolition site, confirms this," said Ritu Maheshwari, the CEO of Noida Authority.
Around 400 workers, 100 water sprinklers and tankers, 22-anti-smoke guns, six road washing machines and four earthmovers were dispatched within minutes to clean the sector.
Pollution board officials also said the wind direction on Sunday afternoon was towards the east, which drifted the dust towards Parsvnath Prestige and Greater Noida. Mahesh Palawat of private forecaster Skymet Weather said this likely spared Delhi from dust pollution.
"The dust cloud swiftly spread around four sides of the demolition site, but the wind took most of it to the east. Emerald Court, ATS, Subhash Chandra Marg in front of the twin towers, a park next to it and the Jaypee flyover were affected the most. On the east, the dust cloud hit Eldeco Utopia, Parsvnath Prestige and Purvanchal Silver City. On the other two sides - the Noida expressway and Gejha road were also covered with dust," said an official of the Noida Authority.
Residents of Parsvnath said they went up to their balconies and terraces to watch the demolition, but rushed back inside when the dust cloud headed in their direction and enveloped their society.