Table 2.
Individual and environmental predictors of total CO2 emissions from motorised travel, car CO2 allocated between drivers and passengers (N = 3474).
| Variable | Level | Median | Regression coefficients (βs) and 95% CI for standardised log-transformed carbon |
|||
|---|---|---|---|---|---|---|
| Min-adjusteda |
Multivariable 1 |
Multivariable 2 |
Multivariable 3 |
|||
| R2 = 0.22 | R2 = 0.29 | R2 = 0.38 | ||||
| Sex | Female | 15.7 | 0⁎⁎⁎ | 0⁎⁎⁎ | 0⁎ | 0⁎⁎⁎ |
| Male | 23.7 | 0.17 (0.09, 0.26) | 0.15 (0.06, 0.23) | 0.09 (0.01, 0.17) | 0.12 (0.05, 0.19) | |
| Age | 18–34 years | 14.8 | 0⁎⁎⁎ | 0⁎ | 0⁎⁎ | 0⁎⁎ |
| 35–49 years | 26.6 | 0.38 (0.26, 0.50) | 0.10 (−0.01, 0.22) | 0.08 (−0.03, 0.20) | 0.09 (−0.01, 0.19) | |
| 50–64 years | 22.8 | 0.29 (0.18, 0.41) | 0.17 (0.05, 0.29) | 0.21 (0.08, 0.33) | 0.20 (0.09, 0.31) | |
| >65 years | 13.6 | −0.11 (−0.23, 0.01) | 0.09 (−0.07, 0.25) | 0.12 (−0.04, 0.28) | 0.14 (−0.01, 0.30) | |
| Ethnicity | White | 18.8 | 0 | 0 | 0 | 0 |
| Non-white | 16.9 | −0.16 (−0.42, 0.09) | 0.02 (−0.23, 0.27) | 0.06 (−0.18, 0.29) | 0.10 (−0.12, 0.31) | |
| Any child under 16 | No | 17.2 | 0⁎ | 0 | 0 | 0 |
| Yes | 24.6 | 0.14 (0.02, 0.26) | 0.07 (−0.04, 0.19) | 0.09 (−0.02, 0.19) | 0.03 (−0.07, 0.13) | |
| Education | Degree | 24.9 | 0⁎⁎⁎ | 0⁎⁎⁎ | 0⁎⁎⁎ | 0⁎ |
| A-level | 18.6 | −0.34 (−0.47, −0.20) | −0.11 (−0.24, 0.01) | −0.10 (−0.22, 0.02) | −0.08 (−0.20, 0.03) | |
| GCSE | 17.7 | −0.35 (−0.47, −0.23) | −0.19 (−0.30, −0.07) | −0.19 (−0.30, −0.08) | −0.10 (−0.20, 0.00) | |
| No formal | 12.2 | −0.56 (−0.68, −0.44) | −0.27 (−0.39, −0.16) | −0.25 (−0.36, −0.13) | −0.17 (−0.28, −0.05) | |
| Annual household income | >£40,000 | 31.3 | 0⁎⁎⁎ | 0⁎⁎⁎ | 0⁎⁎⁎ | 0⁎ |
| £20–40,000 | 21.7 | −0.22 (−0.33, −0.11) | −0.10 (−0.21, 0.01) | −0.03 (−0.13, 0.06) | −0.02 (−0.11, 0.08) | |
| <£20,000 | 10.7 | −0.71 (−0.83, −0.59) | −0.31 (−0.43, −0.19) | −0.23 (−0.34, −0.12) | −0.15 (−0.25, −0.05) | |
| Housing tenure | Owned | 22.2 | 0⁎⁎⁎ | 0⁎⁎⁎ | 0⁎⁎⁎ | 0 |
| Privately rented | 9.8 | −0.55 (−0.70, −0.41) | −0.35 (−0.50, −0.21) | −0.19 (−0.33, −0.05) | −0.07 (−0.20, 0.06) | |
| Council rented | 5.6 | −0.91 (−1.07, −0.76) | −0.53 (−0.69, −0.37) | −0.43 (−0.59, −0.27) | −0.11 (−0.26, 0.04) | |
| Other | 14.3 | −0.06 (−0.29, 0.17) | 0.06 (−0.14, 0.26) | 0.07 (−0.12, 0.27) | 0.17 (−0.01, 0.34) | |
| Employment status | Full-time | 31.3 | 0⁎⁎⁎ | 0⁎⁎⁎ | 0⁎⁎⁎ | 0⁎⁎⁎ |
| Part-time | 20.4 | −0.26 (−0.36, −0.15) | −0.21 (−0.31, −0.11) | −0.13 (−0.23, −0.03) | −0.14 (−0.23, −0.04) | |
| Student | 4.3 | −0.90 (−1.12, −0.68) | −0.73 (−0.95, −0.51) | −0.68 (−0.89, −0.47) | −0.52 (−0.72, −0.32) | |
| Retired | 13.8 | −0.52 (−0.65, −0.39) | −0.40 (−0.53, −0.28) | −0.15 (−0.31, 0.00) | −0.16 (−0.32, −0.01) | |
| Home duties | 13.5 | −0.54 (−0.74, −0.33) | −0.41 (−0.60, −0.23) | −0.25 (−0.46, −0.05) | −0.19 (−0.38, −0.01) | |
| Other | 5.8 | −1.01 (−1.19, −0.83) | −0.66 (−0.84, −0.47) | −0.44 (−0.64, −0.24) | −0.32 (−0.52, −0.13) | |
| Site | Southampton | 12.1 | 0⁎⁎⁎ | 0 | 0 | |
| Cardiff | 19.5 | 0.26 (0.16, 0.36) | 0.04 (−0.09, 0.16) | 0.04 (−0.07, 0.16) | ||
| Kenilworth | 23.8 | 0.43 (0.32, 0.54) | 0.11 (−0.02, 0.24) | 0.12 (0.00, 0.24) | ||
| Urban/rural status | Urban | 18.1 | 0⁎⁎⁎ | 0⁎ | 0⁎ | |
| Rural | 32.3 | 0.47 (0.32, 0.61) | 0.21 (0.04, 0.39) | 0.18 (0.02, 0.34) | ||
| Population density | Change per 10 people per hectare | – | −0.05 (−0.06, −0.03)⁎⁎⁎ | −0.01 (−0.02, 0.01) | 0.00 (−0.02, 0.01) | |
| Home-work distance | 0–2 km or did not commute | 11.2 | −0.18 (−0.31, −0.04) | −0.05 (−0.19, 0.09) | −0.05 (−0.18, 0.08) | |
| 2–5 km | 13.8 | 0⁎⁎⁎ | 0⁎⁎⁎ | 0⁎⁎⁎ | ||
| 5–10 km | 25.7 | 0.40 (0.24, 0.56) | 0.25 (0.09, 0.41) | 0.20 (0.06, 0.33) | ||
| 10–20 km | 36.1 | 0.77 (0.59, 0.94) | 0.56 (0.41, 0.70) | 0.46 (0.32, 0.60) | ||
| ⩾20 km or variable | 68.3 | 0.92 (0.76, 1.08) | 0.77 (0.63, 0.91) | 0.67 (0.54, 0.81) | ||
| Home-retail distance | Change per kilometer | − | 0.08 (0.06, 0.09)⁎⁎⁎ | 0.00 (−0.03, 0.03) | −0.01 (−0.04, 0.01) | |
| Cars per adult in household | No cars | 3.0 | −0.97 (−1.10, −0.84) | −0.75 (−0.88, −0.61) | ||
| <1 Car per adult | 14.9 | 0⁎⁎⁎ | 0⁎⁎⁎ | |||
| ⩾1 Cars per adult | 28.6 | 0.52 (0.44, 0.59) | 0.32 (0.25, 0.39) | |||
| Any adult bike | No | 15.7 | 0 | 0⁎⁎ | ||
| Yes | 21.7 | 0.01 (−0.08, 0.11) | −0.12 (−0.20, −0.04) | |||
⁎
p < 0.05.
⁎⁎
p < 0.01.
⁎⁎⁎
p < 0.001.
a
Minimally-adjusted analyses adjust for age and sex only, multivariable analyses adjust for all variables in column. The dependent variable is kilograms of CO2 per week transformed as log([CO2/mean(CO2)] + 0.01), meaning the unit of analysis is standard deviations of log-transformed CO2 and dimensionless.