Ambient air pollution and respiratory mortality in Xi’an, China: a time-series analysis

Respiratory Research

Table 1 Descriptive statistics of daily mortality counts, air pollutant concentrations, and meteorological parameters

	Mean ± SD	Min	P25	P50	P75	Max
Respiratory diseases	9 ± 3.95	1	6	9	11	23
Male	5.63 ± 2.84	1	3	5	7	17
Female	3.59 ± 1.98	1	2	3	5	11
≤ 64 years	1.90 ± 1.07	1	1	2	2	8
≥ 65 years	3.22 ± 1.81	1	2	3	4	10
Air pollutant concentration (μg/m³)^a
PM_2.5	66.63 ± 50.13	11	36	53	77.25	527
SO₂	26.38 ± 21.55	2	12	19	35	145
O₃	39.62 ± 24.45	5	20	33	56	117
Meteorological parameters
Temperature (°C)	13.48 ± 9.60	−8	5	14	22	34
Humidity (%)	65.43 ± 15.8	21	55	65	78	99

^a 24-hour averages for PM _2.5 , and SO ₂ ; the maximal 8-h average for O ₃
SD: standard deviation; Px (xth percentiles)

ISSN: 1465-993X