Table 1 Distributions of environmental variables and number of deaths, Montreal, June–August 1990–2003

	Number of deaths	Number of days of measurements	Mean (SD)	Minimum	25th percentile	75th percentile	Maximum
Total daily deaths	48 272	1288	31.5 (7.1)	15	33	42	97
Deaths at home	6888		5.3 (2.6)	0	4	7	38
Deaths in hospital	33 523		26.6 (5.3)	8	22	29	54
Deaths in long-term care facilities	7861		6.1 (2.8)	0	4	8	20
Total, ⩾65 years	37 689	1288	29.3 (6.3)	11	25	33	73
Cause of death
Respiratory	3675	1288	2.9 (1.8)	0	1	4	10
Cardiovascular	16 433	1288	12.8 (4.0)	1	10	15	45
Daily mean ambient temperature (°C)*	–	1288	20.4 (3.2)	9.6	18.2	22.6	29.3
Daily maximum ambient temperature (°C)*	–	1288	24.9 (3.7)	12.2	22. 8	27.2	35.6
Daily mean O₃ (μg/m³)	–	1288	42.3 (20.1)	3.5	28.5	51.4	133.6
Dwelling value (at six-character postal codes of former residence, $C) computed from the tax property assessment)†			56 946 (51 462)	465	28 492	67 400	903 050
Surface temperature at residence of decedents (°C)
From satellite image taken on 11 July 1990‡			26.4 (2.3)	12	26	28	32
From satellite image taken on 11 August 2001‡			30.2 (1.8)	20	29	31	39

*Ambient temperatures from observations at Pierre Elliott Trudeau International Airport.
†n = 14 861 postal codes of residences.
‡Only one surface map was used for decedents and the surface temperature attributed to a postal code of place of death thus remains the same during control and hazard periods; n = 4790 postal codes at the places of death.