Meteorological factors, ambient air pollution, and daily hospital admissions for depressive disorder in Harbin: A time-series study

Table 1 Descriptive statistics of variables (sample size = 2922 d)

Variable (unit)	mean ± SD	Percentile
		Min	P25	Median	P75	Max
Admissions for depressive disorder (n)	28.7 ± 21.2	0	9	28	42	130
AT (℃)	5.4 ± 15.1	-29.2	-8.4	7.8	19.0	30.6
AP (mmHg)	749.3 ± 7.0	727.9	743.7	748.9	754.8	768.0
WS (m/s)	2.9 ± 1.2	0.4	2.0	2.6	3.5	9.8
RH (%)	66.2 ± 15.6	14.9	56.1	67.9	77.8	100.0
PM2.5 (μg/m3)	47.2 ± 54.6	0.0	16.0	29.0	58.0	906.0
PM10 (μg/m3)	71.3 ± 59.3	0.0	35.0	53.0	87.0	644.0
SO2 (μg/m3)	22.0 ± 23.6	3.0	9.0	13.0	26.0	222.0
CO (mg/m3)	0.9 ± 0.4	0.3	0.6	0.8	1.0	4.3
NO2 (μg/m3)	36.7 ± 17.8	8.0	24.0	33.0	44.0	145.0
O3_8h (μg/m3)	75.8 ± 34.1	0.0	50.0	71.0	96.0	253.0

AT: Air temperature; AP: Atmospheric pressure; WS: Wind speed; RH: Relative humidity; PM_2.5: Fine particles; PM₁₀: Inhalable particles; SO₂: Sulfur dioxide; CO: Carbon monoxide; NO₂: Nitrogen dioxide; O₃_8h: Maximum 8-h average concentration of ozone.

Table 2 Spearman correlation coefficients between environmental factors

	AP	WS	RH	PM2.5	PM10	SO2	CO	NO2	O3_8h
AT	-0.75c	0.07c	0.18c	-0.61c	-0.46c	-0.78c	-0.49c	-0.42c	0.60c
AP		-0.27c	-0.17c	0.50c	0.40c	0.62c	0.41c	0.44c	-0.48c
WS			-0.35c	-0.16c	-0.13c	-0.11c	-0.26c	-0.41c	0.17c
RH				-0.17c	-0.25c	-0.19c	-0.02	-0.06c	-0.21c
PM2.5					0.92c	0.77c	0.78c	0.76c	-0.19c
PM10						0.69c	0.71c	0.75c	-0.09c
SO2							0.67c	0.64c	-0.35c
CO								0.76c	-0.21c
NO2									-0.24c

^cP < 0.001.

AT: Air temperature; AP: Atmospheric pressure; WS: Wind speed; RH: Relative humidity; PM_2.5: Fine particles; PM₁₀: Inhalable particles; SO₂: Sulfur dioxide; CO: Carbon monoxide; NO₂: Nitrogen dioxide; O₃_8h: Maximum 8-h average concentration of ozone.