Statistical analysis of PM2.5 observations from diplomatic facilities in China

- Demonstrates utility of continuous, public air quality data from U.S. diplomatic facilities.
- First analysis of diurnal PM2.5 variability of large polluted Chinese cities.
- Found marked diurnal PM2.5 variability across seasons and between cities.
- Beijing had the highest annual average but all cities had episodic poor air quality.

Systematic monitoring of air quality are lacking in many parts of the world, especially in cities where air quality is poor. Since 2008, the U.S. Embassy in Beijing has been collecting real-time air-quality data from a monitor on the Embassy's rooftop and sharing that data publicly through social media. Using this freely available data, as well as those from four other U.S. consulates in China that are also now collecting and sharing data publicly, we demonstrate that rooftop air-quality monitors installed at embassies and consulates can further our understanding of air quality and provide a rich, hourly-averaged, long-term data source for the academic community and decision-makers. For example, this is the first study to present an analysis of diurnal variability of PM2.5 in Chengdu, Guangzhou, Shanghai, and Shenyang. We analyzed the diurnal variability of PM2.5 over the entire period of measurement for those cities and Beijing, and found marked variation across seasons and between cities. This dataset allows comparison of the PM2.5 annual average concentrations in 2013, with Guangzhou reporting 56.3 μg/m3, Shanghai 61.6 μg/m3, Chengdu 96.1 μg/m3, Beijing 99.6 μg/m3, and Shenyang 76.3 μg/m3 (note the average in Shenyang is from August 2013-July 2014). This study demonstrates the potential uses of air quality data that is currently systematically being collected and made publicly accessible by U.S. embassies and consulates in polluted but under-studied locations.