Table 2. Regression coefficients from multivariate models examining associations between multiple factors and hourly pollutant concentrations from September 8, 2014 to January 5, 2015.
All covariates were included simultaneously in the model for each pollutant of interest
| Near-road DRIVE Study Site (NR DRIVE) | Black Carbon | Carbon Monoxide | Nitrogen Oxides | IMSI | ||||
|---|---|---|---|---|---|---|---|---|
| Est. | 95% CI | Est. | 95% CI | Est. | 95% CI | Est. | 95% CI | |
| Late Evening (9 PM-0 AM) | 0.23* | (0.04,0.42) | 6.08 | (−27.25,39.41) | 5.00* | (0.35,9.65) | 0.13* | (0.01,0.26) |
| Midnight & Early Morning (1–5 AM) | 0.24* | (0.03,0.44) | −8.52 | (−44.92,27.88) | 3.18 | (−1.82,8.18) | 0.10 | (−0.03,0.24) |
| Morning Rush Hour (6–9 AM) | 0.39* | (0.13,0.64) | −11.98 | (−55.88,31.92) | 5.65 | (−0.34,11.64) | 0.13 | (−0.04,0.29) |
| Mid Day (10 AM-3 PM) | 0.14 | (−0.04,0.32) | −27.31 | (−58.23,3.61) | 1.28 | (−3.00,5.57) | −0.01 | (−0.13,0.10) |
| Temperature (C) | 0.01* | (0.00,0.02) | 2.35* | (0.74,3.97) | −0.06 | (−0.28,0.16) | 0.00 | (−0.01,0.01) |
| Relative Humidity | 0.00 | (0.00,0.01) | −0.37 | (−1.31,0.58) | 0.06 | (−0.07,0.20) | 0.00 | (0.00,0.00) |
| Wind Speed (mph) | −0.20* | (−0.26,−0.14) | −40.75* | (−50.09,−31.40) | −6.88* | (−8.19,−5.56) | −0.21* | (−0.25,−0.18) |
| Northerly Wind (from Upwards) | −0.27* | (−0.47,−0.08) | −36.78* | (−70.63,−2.92) | −10.04* | (−14.88,−5.20) | −0.21* | (−0.33,−0.10) |
| Easterly Wind (from the highway) | −0.73* | (−0.95,−0.51) | −59.43* | (−97.25,−21.61) | −29.25* | (−34.65,−23.85) | −0.47* | (−0.60,−0.34) |
| Southerly Wind (from downwards) | −0.30 | (−0.76,0.17) | −7.17 | (−83.98,69.64) | −23.95* | (−35.24,−12.65) | −0.28* | (−0.55,0.00) |
| Weekend | −0.61* | (−0.97,−0.26) | −11.84 | (−74.45,50.77) | −14.03* | (−21.95,−6.10) | −0.28 | (−0.56,0.00) |
| Traffic Counts (per 1,000) | 0.06* | (0.04,0.07) | 8.60* | (6.56,10.64) | 1.58* | (1.30,1.86) | 0.04* | (0.03,0.05) |
| Mixing Heights (per 100 meters) | −0.03* | (−0.05,−0.01) | −3.41 | (−7.12,0.30) | −0.99* | (−1.53,−0.45) | −0.01 | (−0.03,0.00) |
| EPA Near-road Georgia Institute of Technology Monitoring Site (NR GIT) | Black Carbon | Carbon Monoxide | Nitrogen Oxides | IMSI | ||||
|---|---|---|---|---|---|---|---|---|
| Est. | 95% CI | Est. | 95% CI | Est. | 95% CI | Est. | 95% CI | |
| Late Evening (9 PM-0 AM) | 0.54* | (0.29,0.79) | 47.63* | (6.97,88.29) | 11.39* | (6.59,16.19) | 0.35* | (0.15,0.56) |
| Midnight & Early Morning (1–5 AM) | 0.52* | (0.24,0.79) | −22.45 | (−66.23,21.34) | 10.85* | (5.58,16.13) | 0.25* | (0.03, 0.48) |
| Morning Rush Hour (6–9 AM) | 0.70* | (0.37,1.03) | −1.59 | (−54.11,50.94) | 14.18* | (7.94,20.41) | 0.32* | (0.05, 0.59) |
| Mid Day (10 AM-3 PM) | 0.49* | (0.25,0.72) | 25.87 | (−11.83,63.57) | 7.94* | (3.50,12.37) | 0.24* | (0.05, 0.43) |
| Temperature (C) | −0.02* | (−0.04,−0.00) | −4.00* | (−6.13,−1.86) | −0.89* | (−1.11,−0.66) | −0.03* | (−0.04, −0.01) |
| Relative Humidity | 0.00 | (−0.01,0.01) | −0.33 | (−1.59,0.93) | 0.00 | (−0.14,0.13) | −0.01 | (−0.01, 0.00) |
| Wind Speed (mph) | −0.19* | (−0.27,−0.12) | −45.35* | (−57.35,−33.34) | −5.33* | (−6.70,−3.96) | −0.20* | (−0.26, −0.14) |
| Northerly Wind (from Upwards) | −0.74* | (−1.28,−0.20) | −90.25* | (−134.28,−46.23) | −12.45* | (−17.54,−7.36) | −0.77* | (−1.20, −0.34) |
| Easterly Wind (from the highway) | −1.25* | (−1.79,−0.70) | −191.16* | (−240.46,−141.87) | −25.53* | (−31.20,−19.85) | −1.23* | (−1.66, −0.79) |
| Southerly Wind (from downwards) | - | - | −222.11* | (−324.75,−119.47) | −29.55* | (−41.41,−17.70) | - | - |
| Weekend | −0.81* | (−1.40,−0.22) | −9.13 | (−92.74,74.49) | −15.40* | (−24.01,−6.80) | −0.46* | (−0.89, −0.04) |
| Traffic Counts (per 1,000) | 0.75* | (0.60, 0.90) | 216.00 | (191.11, 240.89) | 27.60* | (24.68, 30.52) | 0.64* | (0.51, 0.77) |
| Mixing Heights (per 100 meters) | −0.09 | (−0.42, 0.24) | −63.9* | (−111.45, −16.35) | −6.36* | (−11.89, −0.83) | −0.17 | (−0.44, 0.10) |
| Urban Background Site (UB) | Black Carbon | Carbon Monoxide | Nitrogen Oxides | IMSI | ||||
|---|---|---|---|---|---|---|---|---|
| Est. | 95% CI | Est. | 95% CI | Est. | 95% CI | Est. | 95% CI | |
| Late Evening (9pm–12am) | 1.00* | (0.03, 0.22) | 20.7 | (−3.1, 44.5) | 3.20 | (−1.1, 7.5) | 0.12* | (0.01, 0.23) |
| Early Morning (1–5am) | 0.65 | (−0.04, 0.16) | −11.7 | (−37.2, 13.7) | −0.04 | (−4.7, 4.7) | 0.00 | (−0.12, 0.12) |
| Morning Rush Hour (6–9am) | 0.10 | (−0.03, 0.22) | −2.9 | (−33.8, 28.1) | 0.24 | (−5.5, 6.0) | 0.03 | (−0.12, 0.19) |
| Mid Day (10am-3pm) | 0.00 | (−0.08, 0.09) | −7.0 | (−28.9, 15.0) | −0.49 | (−4.5, 3.5) | −0.02 | (−0.12, 0.08) |
| Temperature | −0.01* | (−0.01, −0.00) | −6.3* | (−7.6, −5.9) | −0.99* | (−1.2, −0.8) | −0.03* | (−0.03, −0.02) |
| Relative Humidity | 0.01* | (0.00, 0.01) | 1.8* | (1.2, 2.5) | 0.23* | (0.1, 0.4) | 0.01* | (0.01, 0.01) |
| Wind Speed | −0.29* | (−0.33, −0.25) | −69.6* | (−79.7, −59.5) | −13.2* | (−15.0, −11.4) | −0.16* | (−0.40, −0.30) |
| Northerly Wind | 0.06 | (−0.00, 0.13) | 41.3* | (24.4, 58.2) | 8.59* | (5.6, 11.6) | 0.17* | (0.09, 0.25) |
| Easterly Wind | 0.01 | (−0.08, 0.10) | 9.4 | (−13.3, 32.1) | 5.67* | (1.6, 9.8) | 0.05 | (−0.06, 0.15) |
| Southerly Wind | −0.05 | (−0.12, 0.03) | −20.4* | (−39.9, −1.0) | −0.87 | (−4.3, 2.6) | −0.07 | (−0.16, 0.02) |
| Weekend | −0.15 | (−0.40, 0.06) | 1.1 | (−56.2, 58.3) | −6.11 | (−15.5, 3.3) | −0.12 | (−0.40, 0.15) |
| Traffic Counts (per 1,000) | 0.02* | (0.01, 0.02) | 3.8* | (2.4, 5.2) | 0.59* | (3.2, 8.6) | 0.02* | (0.01, 0.02) |
| Mixing Heights (per 100 meters) | −0.01 | (−0.01, 0.01) | 2.8 | (−0.04, 5.6) | 0.22 | (−0.3, 0.7) | 0.01 | (−0.00, 0.02) |
Est. Estimate of Coefficient; 95% CI- 95% Confidence Interval; Unit for Black Carbon: μg/m3; Unit for Carbon Monoxide, Nitrogen Oxides;
*
p-Value<0.05