Hi Dan Lou,
Excellent job! In my opinion, the north of China (like Beijing and Shenyang), burn coal in winter. That makes the difference in season. For Shanghai, mainly problem may be the bad traffic. It caused pollution in rush hour.
Your last graphics Total Hours of PM2 .5 >= 200 ?g/m3 in a Year looks interesting.
If we count every polluted hour, it looks 2015 is no clearly improved than 2014 and 2013.
I suggest you can make this point more clearly or visualize it.
When those polluted hour (PM2 .5 >= 200) will happened in every day through a month or a whole year?
If you havent watched this video, I recommend this for you. It's well-known speech in last year.
She tries to search and explain many complex and complicated reasons behind air pollution in China.
Chai Jing, Under the dome (????????).
Video Links:
http://www.donews.com/net/201503/2882208.shtm
http://edu.sina.com.cn/kids/2015-03-03/094887930.shtml
