Table 3 Associations between residential fossil fuel combustion and other factors and indoor air pollutant concentrations by city and in a pooled analysis.
Pollutant | Season | Factor | Percent change in pollutant concentrations and 95% confidence intervals | ||||
|---|---|---|---|---|---|---|---|
Edmonton | Halifax | Regina | Windsor | Pooled | |||
NO2 (µg/m3) | Summer | Presence of gas stoves (yes) | 31 (−2 to 75)† | 181 (89 to 319)**** | 125 (75 to 190)**** | 138 (87 to 204)**** | 114 (77 to 159)**** |
Presence of gas clothes dryers (yes) | 47 (10 to 97)* | ||||||
Outdoor NO2 concentration (per 10% increase) | 4 (3 to 4)**** | 5 (4 to 6)**** | 2 (0.6 to 3)** | 8 (7 to 8)**** | 7 (6 to 8)**** | ||
Home construction year | |||||||
─ after 1990 (reference) | |||||||
─ 1949 to 1990 | 6 (−17 to 35) | −18 (−42 to 15) | 38 (7 to 77)* | 13 (−6 to 35) | |||
─ before 1949 | 58 (16 to 116)** | 44 (−2 to 110)† | 32 (−4 to 82)† | 31 (5 to 64)* | |||
Windows opened (yes) | 31 (11 to 55)** | 30 (1 to 68)* | 53 (29 to 83)**** | 36 (2 to 81)* | |||
Indoor temperature (°C) | 7 (2 to 12)** | 8 (2 to 15)** | |||||
Indoor relative humidity (%) | 2 (−0.2 to 4)† | ||||||
Winter | Presence of gas stoves (yes) | 103 (60 to 157)**** | 354 (168 to 668)**** | 202 (64 to 458)** | 191 (122 to 279)**** | ||
Heating system fuel type | |||||||
─ electric (reference) | |||||||
─ gas homes built before 1949 | 65 (29 to 111)*** | 38 (−48 to 267) | 66 (−36 to 328) | 62 (−2 to 168)† | |||
─ gas homes built 1949 to 1990 | 14 (−9 to 42) | 15 (−43 to 133) | 30 (−19 to 109) | ||||
─ gas homes built after 1990a | 34 (−57 to 320) | −25 (−74 to 118) | 11 (−35 to 89) | ||||
─ oil | 85 (17 to 192)** | 58 (4 to 141)* | |||||
Presence of gas clothes dryers (yes) | 54 (3 to 129)* | ||||||
Candles used (yes) | 22 (8 to 37)** | 28 (8 to 51)** | 53 (22 to 93)*** | ||||
Outdoor NO2 concentration (per 10% increase) | 3 (2 to 3)**** | 2 (1 to 3)**** | 3 (0.7 to 5)* | 4 (1 to 6)** | |||
Close to construction sources (yes) | 75 (15 to 166)* | 40 (11 to 76)** | |||||
Indoor temperature (°C) | 4 (−0.1 to 9)† | 9 (1 to 17)* | |||||
Indoor relative humidity (%) | 4 (1 to 7)** | ||||||
Peak hourly CO (ppm) | Summer | Presence of gas stoves (yes) | 26 (7 to 49)** | ||||
Candles used (yes) | 12 (1 to 25)* | ||||||
Windows opened (yes) | −6 (−12 to 0)* | ||||||
Indoor temperature (°C) | 8 (7 to 10)**** | 3 (0 to 5)† | 3 (0.7 to 5)** | 5 (4 to 7)**** | |||
Indoor relative humidity (%) | 2 (1 to 3)**** | −1 (−2 to −0.1)* | |||||
Air exchange rate (h-1) | −17 (−24 to −9)**** | −5 (−10 to −0.1)* | |||||
Winter | Presence of gas stoves (yes) | 55 (12 to 114)** | 43 (2 to 102)* | ||||
Indoor temperature (°C) | 11 (6 to 16)**** | 6 (−0.6 to 13)† | 4 (0.9 to 7)** | ||||
Daily average CO (ppm) | Summer | Presence of attached garages (yes) | 19 (1 to 39)* | ||||
Indoor relative humidity (%) | 1 (0.5 to 2)*** | −0.7 (−1 to −0.1)* | |||||
Indoor temperature (°C) | 7 (6 to 8)**** | 2 (−0.1 to 4)* | 3 (2 to 5)**** | 5 (3 to 6)**** | |||
Air exchange rate (h-1) | −9 (−14 to −5)*** | −5 (−8 to −2)** | |||||
Winter | Presence of attached garages (yes) | 19 (−1 to 43)† | |||||
Indoor relative humidity (%) | 0.8 (−0.1 to 2)† | ||||||
Indoor temperature (°C) | 6 (3 to 10)*** | 3 (0.8 to 5)** | |||||
Formaldehyde (µg/m3) | Summer | Home construction year | |||||
─ after 1990 (reference) | |||||||
─ 1949 to 1990 | −20 (−38 to 3)† | −41 (−57 to −19)** | −24 (−41 to −3)* | −33 (−44 to −19)**** | |||
─ before 1949 | −51 (−65 to −31)*** | −47 (−63 to −23)** | −18 (−45 to 24) | −48 (−59 to −34)**** | |||
Major renovations within the last month (yes) | 55 (3 to 134)* | 65 (−0.9 to 174)† | 83 (24 to 170)** | ||||
Hair spray used (yes) | 11 (1 to 21)* | ||||||
Windows opened (yes) | −8 (−14 to −3)** | −15 (−23 to −6)** | −27 (−42 to −7)** | −28 (−47 to −2)* | |||
Air cleaner used (yes) | −47 (−63 to −22)** | ||||||
Presence of dehumidifiers (yes) | −30 (−47 to −7)* | −28 (−43 to −9)** | |||||
Air conditioning used (yes) | −10 (−20 to 1)† | 29 (4 to 60)* | |||||
Indoor relative humidity (%) | 2 (1 to 3)**** | 1 (0.4 to 2)** | |||||
Indoor temperature (°C) | 8 (6 to 10)**** | 12 (9 to 14)**** | 6 (1 to 10)* | ||||
Air exchange rate (h-1) | −44 (−48 to −40)**** | −41 (−44 to −37)**** | −51 (−59 to −42)**** | ||||
Winter | Home construction year | ||||||
─ after 1990 (reference) | |||||||
─ 1949 to 1990 | −13 (−30 to 9) | −47 (−63 to −24)** | −30 (−42 to −15)*** | −27 (−38 to −15)**** | |||
─ before 1949 | −38 (−52 to −20)*** | −55 (−69 to −35)*** | −54 (−65 to −40)**** | −46 (−55 to −34)**** | |||
Indoor relative humidity (%) | 3 (2 to 4)**** | 5 (4 to 6)**** | 4 (3 to 5)**** | 4 (2 to 5)**** | |||
Indoor temperature (°C) | 9 (7 to 12)**** | 10 (8 to 13)**** | 10 (6 to 14)**** | 8 (4 to 11)**** | |||
Air exchange rate (h-1) | −23 (−37 to −7)** | −35 (−53 to −10)* | −29 (−50 to 2)† | ||||
Acetaldehyde (µg/m3) | Summer | Home construction year | |||||
─ after 1990 (reference) | |||||||
─ 1949 to 1990 | −2 (−37 to 52) | −16 (−47 to 32) | −10 (−34 to 22) | ||||
─ before 1949 | −41 (−67 to 4)† | −37 (−63 to 5)† | −39 (−58 to −12)** | ||||
Perfume used (yes) | 23 (−3 to 57)† | ||||||
Air conditioning used (yes) | 73 (36 to 119)**** | ||||||
Windows opened (yes) | −36 (−50 to −17)*** | ||||||
Air cleaner used (yes) | −40 (−62 to −6)* | ||||||
Air exchange rate (h-1) | −12 (−22 to 0.4)† | −11 (−18 to −4)** | −13 (−19 to −6)*** | ||||
Winter | Home construction year | ||||||
─ after 1990 (reference) | |||||||
─ 1949 to 1990 | 14 (−18 to 57) | −59 (−78 to −23)** | −35 (−54 to −9)* | −23 (−38 to −4)* | |||
─ before 1949 | −27 (−50 to 6)† | −61 (−79 to −26)** | −47 (−68 to −14)* | −34 (−50 to −14)** | |||
Cooked with oil (yes) | 31 (0.7 to 70)* | ||||||
Indoor relative humidity (%) | 3 (0.9 to 5)** | 5 (3 to 7)**** | 4 (2 to 6)**** | ||||
Indoor temperature (°C) | 10 (3 to 17)** | 6 (0.9 to 10)* | |||||
Air exchange rate (h-1) | −22 (−41 to 3)† | −58 (−74 to −31)*** | |||||
