Dear Dr... have checked the sky in Beijing? Even worse. 6 yrs ago, my lg and I were in BJ, he asked me some question regarding the atomosphere... I said, I do not know maybe its fog... he said, no, no,no,... it is poluted air.
But, 1984 when I was in BJ doing my MA study.... I used to feel the sky there is lot higher and blue than that of SHA.. not any more....