Research Article
Attached Smoking Room Is a Source of PM2.5 in Adjacent Nonsmoking Areas
Figure 4
Boxplots of average excess PM2.5 exposure concentrations in (a) 24-hour and (b) annual averaging time in mahjong club. The WHO AQG for 24-hour and annual averaging time are 15 and 5 μg/m3, also shown in the figure.
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| (b) |