Tuesday, August 05, 2008

Beijing Still Hazy !!

Reuters reported today, "Beijing still hazy with three days to go".

This is after a series of control measures in place, like shutting down half of the 3+ million cars and more 200 most polluting industries in the city.

The hazy reports are based on the pictorial evidence and the air pollution index (API) published by the Beijing pollution bureau. This API is based on two main pollutants - particulates and ozone, besides the sulfur dioxide and nitrogen oxides, which are also integral part of the particulates and ozone formation.

Here is a report saying "Cars are not enough". An article on April 16th, 2007, "Improving Air Quality for 2008 Beijing Olympics" states that the problem with Beijing air lies, not entirely with the vehicular emissions, since the ozone (dependent on NOx and VOC emissions) is one of the key elements for haze formation. These articles argue that, "the VOCs from small factories, emissions from heavy vehicles (trucks) are worst during the night, since trucks are banned from the city during the day. Studies have shown that Beijing's pollution levels are highest in the early morning, due to early morning ozone formation dependent on NOx and VOC emissions during the night. This would not be the case if most of the pollution came from passenger cars, which operate mainly during the day. But it is good evidence that the chief sources of pollution are the VOC-producing factories and trucks operating at night."

Here is a report by Science Daily on July 17th, 2008, which argues that it's more to do with the meteorology than shutting down industries in the city. The percentage contributions are unknown, but the industries with their large chimneys contribute more to outside Beijing than inside, and similarly, the industries in the vicinity of the Beijing (such as Tainjin, Shijiazhuang, and Taiyuan, all of which fall with in 100 km) are more important and probably contributing to the pollution levels of Beijing. At the end, it is a borderline case between meteorology and shutting down industries within Beijing.

See my blog on July 31st, with news articles reporting the (then) latest on interventions in place for clear skies for the 2008 Olympic games.

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