Air pollution in Beijing

I just heard from a friend that on CCTV 9, the English language channel on the Central Chinese Television network, that the trial run to remove a million cars from the roads has worked marvelously. The quote came through to me that:

BizChina (CCTV 9) states that "air quality has improved dramatically over the past three days" apparently, the particulate count dropped from 116 (ppm?) on Thursday to 90 yesterday

Well, I thought that this statement needed a little context, so I have created a graph from the month of August, up until yesterday to see what a dramatic effect the removal of so many cars from Beijing's roads has really had. The data is taken from sepa.gov.cn where you can freely look at the countries pollution levels. I've created a graph from Beijing's recent data to see what the announcement really means.

The cars were removed from the roads in the last four days of the graph. The sudden drop from 115 to around 90 (similar, as far as I can tell, to the other changes throughout the month) is the result of the cars, or so we're told. I'm sure there's more to it than that, but this sounds like statistics being used without any context behind them.

For more context on the pollution index, take a look at this, though China's own pollution index is not exactly the same as this one, they seem very similar.

Apologies for the hastily created graphics, I'm in the midsts of calculations as I type.