Figure 1
From: PM2.5 in Beijing – temporal pattern and its association with influenza
PM 2.5 concentrations (μg/m 3 ) from 2008 to 2013 in Beijing. Top-24-hour averages of PM2.5 measurements superimposed with standards by the WHO (25 μg/m3 for the 24-hour average, black line), the USEPA (35 μg/m3 for the 24-hour average, redline), and the Chinese State Environmental Protection Administration (SEPA, 75 μg/m3, implemented from 2012, green line; the 75 μg/m3 standard, or Class II standard, was developed specific for residential, commercial, industrial, and heavy-traffic areas) (ref, Cao et al. Chinese and US air quality standard evolution paper). Middle - Monthly variations in average, 97.5 and 2.5 percentiles of PM2.5 from 2008 to 2013 in Beijing. Bottom – Annual averages of PM2.5 concentrations from 2008 to 2013, superimposed with the standards by the WHO (10 μg/m3 for the annual average, black line), the US EPA (15 μg/m3 for the annual average, redline, the EPA standard was reduced to 12 μg/m3 after 2013), and the SEPA (35 μg/m3, implemented from 2012).