Research Article
The Influence of Climate Factors, Meteorological Conditions, and Boundary-Layer Structure on Severe Haze Pollution in the Beijing-Tianjin-Hebei Region during January 2013
Figure 2
Variation of hourly average (sawtooth lines) and daily average (step lines) concentrations of PM2.5 in different sites and regional average AOD in January 2013 over the BTH region. Dashed lines show the Grade II National Ambient Air Quality Standard.
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