Beijing’s Bad Air Would Be Step Up for Smoggy Delhi

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http://www.nytimes.com/2014/01/26/world/asia/beijings-air-would-be-step-up-for-smoggy-delhi.html

Beijing’s Bad Air Would Be Step Up for Smoggy Delhi
By GARDINER HARRIS | JAN. 25, 2014

NEW DELHI — In mid-January, air pollution in Beijing was so bad that the government issued urgent health warnings and closed four major highways, prompting the panicked buying of air filters and donning of face masks. But in New Delhi, where pea-soup smog created what was by some measurements even more dangerous air, there were few signs of alarm in the country’s boisterous news media, or on its effervescent Twittersphere.

Despite Beijing’s widespread reputation of having some of the most polluted air of any major city in the world, an examination of daily pollution figures collected from both cities suggests that New Delhi’s air is more laden with dangerous small particles of pollution, more often, than Beijing’s. Lately, a very bad air day in Beijing is about an average one in New Delhi.

The United States Embassy in Beijing sent out warnings in mid-January, when a measure of harmful fine particulate matter known as PM2.5 went above 500, in the upper reaches of the measurement scale, for the first time this year. This refers to particulate matter less than 2.5 micrometers in diameter, which is believed to pose the greatest health risk because it penetrates deeply into lungs.

But for the first three weeks of this year, New Delhi’s average daily peak reading of fine particulate matter from Punjabi Bagh, a monitor whose readings are often below those of other city and independent monitors, was 473, more than twice as high as the average of 227 in Beijing. By the time pollution breached 500 in Beijing for the first time on the night of Jan. 15, Delhi had already had eight such days. Indeed, only once in three weeks did New Delhi’s daily peak value of fine particles fall below 300, a level more than 12 times the exposure limit recommended by the World Health Organization.