Table 3. National-average percentage increase with 95% CI in daily hospital admissions for pneumonia associated with a 10 μg/m³ increase in PM_2.5 and PM₁₀ concentrations using different lag days in 184 Chinese cities, 2014–2017.

Lag day	Percentage increase (95% CI)	P value
Unadjusted analyses
PM2.5
Lag 0	0.14 (0.04–0.24)	0.007
Lag 1	0.11 (0.01–0.21)	0.027
Lag 2	0.15 (0.06–0.25)	0.002
Lag 0–2	0.23 (0.08–0.37)	0.002
PM10
Lag 0	0.11 (0.04–0.18)	0.001
Lag 1	0.06 (−0.01–0.13)	0.093
Lag 2	0.10 (0.02–0.17)	0.008
Lag 0–2	0.15 (0.04–0.25)	0.005
Adjusted analyses*
PM2.5
Lag 0	0.23 (0.14–0.33)	<0.001
Lag 1	0.15 (0.05–0.25)	0.004
Lag 2	0.11 (0.01–0.21)	0.039
Lag 0–2	0.31 (0.15–0.46)	<0.001
PM10
Lag 0	0.18 (0.12–0.25)	<0.001
Lag 1	0.08 (0.02–0.15)	0.015
Lag 2	0.04 (−0.02–0.11)	0.218
Lag 0–2	0.19 (0.11–0.30)	<0.001

*Adjusted for temperature, relative humidity, calendar time, day of the week, and public holiday.

Abbreviations: PM_2.5, particulate matter ≤2.5 μm in aerodynamic diameter; PM₁₀, particulate matter ≤10 μm in aerodynamic diameter