Agerholm, Harriet. "China Orders Local Officials to Stop Issuing Smog Alerts, Sparking Fears of Government Air Pollution Cover-Up." Independent, January 18, 2017. http://www.independent.co.uk/news/world/asia/china-smog-alert-order-government-air-pollution-cover-up-levels-beijing-fossil-fuels-environment-a7532631.html.
I trust this source because it was written by Harriet Agerholm, a reporter/writer for the Independent, the Times of India, and the Guardian.
"Beijing Air Pollution: Real-time Air Quality Index (AQI)." Air Quality Index. Accessed February 5 2017. http://aqicn.org/city/beijing/.
I trust this source because it's a worldwide real-time air quality index, and its information is sourced from each country's Environmental Protection Agency.
EurekAlert! "Lifting the Fog on China's Unwieldy Air Pollution Problem." January 25, 2017. Accessed February 1, 2017. https://www.eurekalert.org/pub_releases/2017-01/acs-ltf012517.php.
I trust this source because it's the "Global Source for Science News", operated by AAAS, thE science society.
NewsRx. "Future PM2.5 Air Pollution over China." December 6, 2016. http://link.galegroup.com/apps/doc/A472582556/GIC?u=nysl_me_horman&xid=8978955b.
I trust this source because it was from NewsRx, which "monitors all emerging research and discoveries". It was founded in 1984, and has been approved and claimed trustworthy by the NewYork Times, Smithsonian, the Wall Street Journal, U.S. News, and more.
Tan, Huileng. "China's Air Pollution Woes Need a Greater Clean-Up Push, Environmental Groups Say." CNBC, January 19, 2017. Accessed February 3, 2017. http://www.cnbc.com/2017/01/19/chinas-air-pollution-woes-need-a-greater-clean-up-push-environmental-groups-say.html.
I trust this source because it was written by Huileng Tan, a writer at CNBC who covers a broad range of topics in Asia. I also trust this source because CNBC is a world leader in business news.