A week ago, we showed you that Beijing was still failing to meet its promise of clean air for the Olympic Games.
I said that we would carry on testing for particulates (PM10) every day in the run-up to the Games. We've done so.
Here's what we've found over the last week...
We also took photos every day from the same spot in central Beijing. Click here to see a gallery.
It's important to say this - our measurements are just a snapshot. We've measured for a single period in the middle of Beijing in the middle of the day. The hand-held device that we're using has a margin of error of about 20%.
But our readings show that Beijing has continued to exceed the World Health Organisation's most generous PM10 standards (remember - Beijing promised that the air during the Olympics would meet WHO standards). On two days out of the last seven, we detected particulate levels far above the WHO's guidelines.
But Beijing insists it still has time to get it right (it would also say that its own readings show PM10 levels which are much lower than ours.) On July 20th, this city's imposing a series of emergency clean air measures - more than a million cars will be taken off the streets, and all construction work will have to stop. That gives 19 days for the dust and the particles to settle before the Games begin.
We'll carry on testing to see what difference these emergency measures make.