Table 5.

Cumulative relative risk (RR) and 95% confidence intervals (95% CI) for high levels of air pollution on HFMD over a lag of 14 days

Groups	PM2.5	SO2	NO2	O3-8 h
All age	0.71 (0.46–1.09)	2.32 (1.42–3.79)	2.01 (1.22–3.31)	1.02 (0.69–1.53)
Sex
Male	0.79 (0.47–1.31)	2.38 (1.33–4.25)	2.23 (1.24–4.01)	1.06 (0.66–1.70)
Female	0.62 (0.36–1.10)	2.20 (1.15–4.18)	1.82 (0.83–1.40)	1.02 (0.60–1.71)
Age, years
0–4	0.73 (0.47–1.15)	2.39 (1.44–3.96)	2.02 (1.21–3.39)	0.88 (0.58–1.33)
5–14	0.59 (0.26–1.32)	1.86 (0.71–4.89)	2.21 (0.85–5.76)	2.31 (1.09–4.89)

Note. Statistically significant (P < 0.05) were labelled in bold font. The reference values were the 1st percentiles of each air pollutant. The effects of high levels of air pollution were estimated by calculating the risk of HFMD at the 99th percentiles of each air pollutants relative to the reference.