Table 1.

Summary statistics of daily emergency hospital admissions, air pollution concentrations, and weather conditions in Hong Kong, 2000–2005.

No. of days	Percentile
	Variable	Mean ± SD	Minimum	25th	50th	75th	Maximum
Daily emergency hospital admissions
Total respiratory diseases		2,192		236.7 ± 55.4		89	198	230	269	518
COPD		2,192		81.1 ± 20.3		22	68	80	95	165
Asthma		2,192		19.6 ± 8.0		1	14	19	25	61
Respiratory diseases in TW residents		2,192		50.0 ± 12.4		18	41	49	57	104
Pollution concentration (μg/m3)
PM10		1,998		56.1 ± 27.8		13.5	34.9	49.2	72.5	231.5
PM2.5		1,997		39.4 ± 20.7		8.9	23.8	34.8	50.1	179.8
PMc		1,997		16.6 ± 9.2		0.8	10.0	14.5	20.9	82.9
NO2		1,995		64.4 ± 22.4		13.0	48.4	61.6	77.4	193.9
SO2		1,998		22.9 ± 17.1		1.0	11.3	18.3	28.7	143.3
O3		1,995		31.1 ± 24.3		1.0	13.2	24.2	42.8	171.7
Meteorology measures
Temperature (°C)		2,192		23.5 ± 5.0		8.2	19.6	24.9	27.8	31.8
Relative humidity (%)		2,192		78.2 ± 9.7		32	73	79	85	97
Minimum is the lowest value, and maximum is the highest value in the full range.