Everyone knows it is bad, but on the way back from a trip to Rangsit at the weekend, the view of the Bangkok skyline was scary. The airspace of the surrounding horizon is clear, but the airspace above the city looks a thick dirty grey, the only building above this being Baiyoke. Cleaning my aircon machine filters shows the effect of this, and I'm on the 30th floor!
I will thus be moving out to the suburbs within a month.
Even this pic below, which is called "beautiful Bangkok", shows the grey haze, at close distance.