November 1

Winter cocktail of dust and pollution is here

[1 NOVEMBER, 2001]

NEW DELHI: The haze is back. Still air hanging heavy with dust blocked the sun in many parts of the Capital on Wednesday. Besides diminished visibility, it held out the threat of exacerbating respiratory problems.

Delhi meteorological office director S C Gupta said haze was a natural, seasonal phenomenon. "The winds are calm and so cannot blow out the dust. They remain trapped in a layer at about 400 metres above the earth, blocking sunlight. Sunlight gets reflected back, thereby scattering light, which reduces visibility to as low as 1,000 metres, especially in the mornings," Gupta says.

With winds unable to disperse dust, the level of suspended particulate matter in the atmosphere has also risen. Central Pollution Control Board chairman Dilip Biswas says: "With so much of construction activity and several flyovers coming up, a considerable amount of dust is being generated. The wind flow is inadequate to carry it away."

SPM levels in the Capital have been consistently higher than the national standard of 100 microgram per cubic metre. According to the CPCB, on October 18 the SPM count at ITO was as high as 270. On October 30, SPM count at anothercongested intersection, Lajpat Nagar, was a whopping 448 microgram per cubic metre.

The good news is that concentration of sulphur dioxide and nitrogen dioxide, the most common ingredients of vehicular pollution, has remained on the safer side.

But the haze is dangerous for those suffering from respiratory diseases. Dr V K Arora of Lala Ram Swaroop TB Clinic says the haze affects patients of asthma and chronic bronchitis. "Patients complain of increased coughing with expectoration. This is a time when the risk of viral infection also rises." Dr Arora, however, says the worst is yet to come. "The number of patients at our OPD clinics rise around December when smog begins to form. The combination of pollutants, humidity and low temperatures is deadly for asthma and bronchitis patients," he says. Dr Arora advises that those with respiratory complaints should stay indoors. "Avoid autorickshaws and roll up the windows of your car," he says.

Delhi Pollution Control Committee chief Naini Jayaseelan, however, says there’s no reason for alarm. "It is true that in the last one week levels of SPM have shot up. However, as long as the levels of sulphur dioxide and nitrogen dioxide remain low, we have no cause to worry."