Published in the Financial Times, November 1, 2016.
Sir, The Financial Times reports that New Delhi pollution has moved “off the charts” (“New Delhi air pollution rockets after Diwali fireworks”, November 1), and correctly refers to it as “killer smog”. The FT is one of the few newspapers to point out that the record high AQI (air quality index) level of 999 may underestimate the problem: AQI gauges present only three digits — the real level could be much higher. But even 999 is incredible: AQI levels of 0-50 are considered to be “good”; 51-100 to be “acceptable”; 101-150 to be problematic for some people; 151-200 to be problematic for everyone; 201-300 to be “serious” for everyone; and 301-500 a real emergency.Bottom of Form
Not so long ago 500 was the top of scale. When Beijing’s AQI reached 755 in January 2013, it topped even the “crazy bad” reading of above 500 two years previously. Today’s AQI in Los Angeles, once considered a very smoggy city, is 48. And Beijing is 30, no longer crazy bad. Truly aggressive action can defeat killer smog.
Los Angeles, CA, US