Assessment of urban air quality in China using air pollution indices (APIs)

This study gathered and processed the available air quality daily reports in 86 cities throughout China in 2001–2011. Urban air quality was assessed in terms of the evolution of the key pollutants, the pollution level, and the PM10 (particulate matter with an aerodynamic diameter <10 μm) concentrations. The authors conclude that PM10 is the most important pollutant in Chinese cities, especially after the national sulfur dioxide (SO2) controls during the 11th Five Year Plan (FYP; 2006–2010). A notable advance was the reduction of extremely heavily polluted days with air pollution index (API) above 150 from 7% in 2001 to 1% in 2011 in the all-city average. In addition, the average API-derived PM10 concentrations continually decreased during the past 11 yr. Additionally, the pollution pattern of “more severe from south to north” in China became less obvious due to the decline of PM10 concentrations in the northern cities and the more obvious regional characteristics of air pollution. Nevertheless, more pollu...