Looking at recent news of off-the-scale air pollution levels in China, in some cases more than 36-times the exposure level recommended by the World Health Organization (WHO), one can see that China has a serious issue with its environment. I've personally experience PM2.5* levels in excess of 400 μg/m3 in China and can appreciate firsthand why such pollution is a major health concern, in fact being linked to 1.2 million premature deaths in 2010 according to the Global Burden of Disease Study 2010 published in the journal Lancet.
Further, this pollution is finding its way into neighboring countries, chiefly Japan. The city of Osaka, for example, issued its first PM2.5 warning last Thursday. China's dirty ways are fast becoming more than just its own problem.