Re: May I ask.....
It's probably still there, but the fraction of the atmosphere that is over China is relatively small so once it has diffused over the rest of the planet it doesn't show up as a big orange-red false colour splotch.
An atmospheric chemist (which I'm not) may chip in shortly to tell you that NO2 gets washed out as acid rain fairly rapidly whereas CO2 doesn't. Maybe. Or maybe they won't. Let's leave this assertion here, so that someone who knows better feels obliged to chip in.
Biting the hand that feeds IT
