Beijing Air Pollution

[Note : I am getting more concerned that the source data just does not accurately represent the air experience.� This was commented on widely on 18 June 2009 when the air looked real bad but was reported as 158 “slightly polluted”.� Other independent measurements put this day in the “hazardous” category.� I wonder if there is any point continuing.

One of my (acceptable) personal hobbies is monitoring Beijing’s air pollution statistics. My graph based on Beijing’s published statistics is shown below. You can make your own mind up about whether the numbers are improving.� While I had my doubts about improvements, it seems to me that the Beijing Olympics were possibly the biggest factor in improvements since mid-2007.� Of course, the shutting down of a few heavy industries and moving them to other parts of the country may be only exporting the problem elsewhere.� Now its just a battle to keep improving emissions against the seemingly unstoppable number of cars appearing on Chinese roads.

The index is a unique index used by the Chinese authorities and apart from making it difficult to compare with indices used in other countries, the maximum recorded index value is 500, meaning anything more than 500 is recorded as 500.� Note that there was in early 2008 some discussion over the possible “adjustment” of numbers in order to meet targets. It has been suggested that replacing monitoring stations near the centre of Beijing with ones out past the 4th ring road has distorted the results in a downward direction. There is also pretty convincing statistical evidence that some figures just below 100 were astutely adjusted downwards to get below this key target level. Read the following link and decide for yourself :

http://iopscience.iop.org/1748-9326/3/3/034009/fulltext?ejredirect=migration

Beijing Average Monthly Air Pollution Index

Month 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012
Jan 113 116 93 89 90 128 102 83 83 74 51 86
Feb 119 110 101 108 76 98 110 73 89 77 101 73
Mar 158 155 105 125 91 132 96 109 92 108 83 82
Apr 131 168 104 116 137 177 94 103 83 83 108 115
May 154 94 94 87 93 120 106 142 83 89 80 96
Jun 118 106 89 95 97 92 86 117 91 78 85 86 73
Jul 86 84 86 94 77 86 71 94 77 74 87 73 61
Aug 89 80 96 86 86 88 74 82 56 76 70 77 70
Sep 95 92 91 86 94 98 95 89 57 85 70 73 61
Oct 86 118 98 98 139 102 107 80 75 82 82 91
Nov 128 102 105 119 89 149 115 103 80 97 103 91
Dec 110 102 135 94 126 82 120 138 98 103 95 73

Beijing air pollution stats

The green line plots the daily values while the red line is a smoothed trendline. The Firefox extension called “Image Zoom” is not bad for manipulating the zoom or you can just click on the image to see it in its own window.

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