Table 3.

Percentage of days each year meeting current US and Chinese air quality standards and WHO guidelines.

China	2008	2009	2010	2011	2012	2013	2014	2015	Mean
Beijing	18%	15%	17%	23%	25%	17%	22%	29%	21%
Shanghai					37%	32%	36%	37%	35%
Chengdu					6%	8%	8%	13%	9%
Guangzhou				14%	32%	29%	33%	53%	37%
Shenyang						27%	16%	22%	21%
WHO	2008	2009	2010	2011	2012	2013	2014	2015	Mean
Beijing	9%	10%	10%	16%	15%	10%	13%	20%	13%
Shanghai					21%	17%	17%	18%	18%
Chengdu					2%	2%	1%	4%	3%
Guangzhou				6%	20%	16%	20%	35%	22%
Shenyang						13%	5%	10%	9%
US	2008	2009	2010	2011	2012	2013	2014	2015	Mean
Beijing	2%	0%	1%	1%	2%	1%	3%	7%	2%
Shanghai					7%	4%	2%	2%	4%
Chengdu					2%	0%	0%	1%	0%
Guangzhou				0%	6%	0%	5%	2%	3%
Shenyang						0%	0%	1%	0%