Background
Study location | CO level, ppm (range) | Type of vehicle | Source |
---|---|---|---|
Paris, France | 3.8 | Taxi | [14] |
Guangzhou, China | 28.7 (10.5-46.1) | Taxi (A/C) | [15] |
Athens, Greece | 21.4 (14.6-40.0) | Private car | [16] |
London, UK | 1.3 (0–2.5) | Private car | [17] |
Beirut, Lebanon | 20.0 (0–120.5) | Private car | [13] |
Hanoi, Vietnam | 18.5 | Private car | [18] |
Beirut, Lebanon | 30.8 (20.4-43.2) | Private car | [19] |
Jakarta, Indonesia | 22.0 | Private car | [20] |
Tel Aviv, Israel | 11.6 (5.9-27.2) | Private car | [21] |
Methods
Study design and ethical approval
Study participants
Study visit
Exposure monitoring
Outcome measures
Results
Participant characteristics
Participants of first test | Participants of second test | |||||
---|---|---|---|---|---|---|
Men (n = 13) | Women (n = 10) | Total (n = 23) | Men (n = 10) | Women (n = 10) | Total (n = 20) | |
Age (Year) | 42.2 ± 12.6 | 39.0 ± 12.9 | 40.8 ± 12.6 | 38.5 ± 13.3 | 40.4 ± 10.8 | 39.5 ± 11.8 |
BMI (kg m-2) | 24.4 ± 3.6 | 22.5 ± 2.4 | 23.6 ± 3.2 | 24.1 ± 3.7 | 22.7 ± 2.9 | 23.4 ± 3.4 |
Systolic blood pressure (mmHg) | 123.2 ± 13.6 | 118.7 ± 9.0 | 121.3 ± 11.8 | 125.3 ± 13.4 | 121.3 ± 13.3 | 123.3 ± 13.2 |
Diastolic blood pressure (mmHg) | 76.8 ± 11.0 | 73.9 ± 7.6 | 75.6 ± 9.6 | 75.6 ± 9.8 | 70.8 ± 8.2 | 73.2 ± 9.2 |
Red blood cell (109 cells/L) | 4.7 ± 0.4 | 4.3 ± 0.2 | 4.5 ± 0.3 | 5.0 ± 0.3 | 4.5 ± 0.2 | 4.8 ± 0.4 |
White blood cell (109 cells/L) | 6.2 ± 1.1 | 6.5 ± 1.6 | 6.4 ± 1.3 | 6.1 ± 1.0 | 6.5 ± 1.8 | 6.3 ± 1.4 |
Platelets (109 cells/L) | 242.6 ± 48.9 | 272.4 ± 47.4 | 255.6 ± 49.5 | 250.0 ± 60.1 | 282.2 ± 55.5 | 266.1 ± 58.7 |
High sensitive C-reactive protein (mg/L) | 1.7 ± 3.4 | 0.6 ± 0.4 | 1.2 ± 2.6 | 0.7 ± 0.4 | 1.0 ± 0.8 | 0.9 ± 0.7 |
Total cholesterol (mg/dL) | 178.5 ± 33.4 | 193.2 ± 38.7 | 184.9 ± 35.7 | 191.6 ± 33.4 | 203.9 ± 47.1 | 197.8 ± 40.3 |
High density lipoprotein cholesterol (mg/dL) | 51.8 ± 10.3 | 59.8 ± 11.7 | 55.3 ± 11.4 | 58.1 ± 10.4 | 59.0 ± 8.6 | 58.6 ± 9.3 |
CO exposure in the vehicle
Targeted concentration of CO (ppm) | Measured CO concentration, ppm (Mean ± S.D) |
P value | |
---|---|---|---|
First test | 0 | 0.0 ± 0.1 | <0.001 |
30 | 33.2 ± 1.9 | ||
70 | 72.4 ± 1.4 | ||
Second test | 0 | 0.2 ± 0.3 | <0.001 |
30 | 30.2 ± 3.5 | ||
50 | 48.8 ± 3.7 |
Comparison of COHb levels after CO exposure
COHb levels in the first test (n = 23) | COHb levels in second test (n = 20) | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
33.2 ppm in comparison with 0 ppm | 72.4 ppm in comparison with 0 ppm | 30.2 ppm in comparison with 0 ppm | 48.8 ppm in comparison with 0 ppm | |||||||||
0 ppm | 33.2 ppm | Delta | 0 ppm | 72.4 ppm | Delta | 0 ppm | 30.2 ppm | Delta | 0 ppm | 48.8 ppm | Delta | |
COHb (%) | 1.2 0.9-1.5 | 1.6 1.4-2.1 | 0.4*
0.1-0.9 | 1.2 0.9-1.5 | 2.4 2.2-2.7 | 1.2*
1.1-1.5 | 1.2 1.0-1.4 | 1.6 1.4-1.7 | 0.4*
0.2-0.6 | 1.2 1.0-1.4 | 2.3 2.0-2.4 | 1.0*
0.9-1.2 |
Blood pressure changes after CO exposure
Blood pressure after the first test (n = 23) | Blood pressure after the second test (n = 20) | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
33.2 ppm in comparison with 0 ppm | 72.4 ppm in comparison with 0 ppm | 30.2 ppm in comparison with 0 ppm | 48.8 ppm in comparison with 0 ppm | |||||||||
0 ppm | 33.2 ppm | Delta | 0 ppm | 72.4 ppm | Delta | 0 ppm | 30.2 ppm | Delta | 0 ppm | 48.8 ppm | Delta | |
Systolic pressure (mmHg) | 137.0 127.5-144.5 | 133.0 124.5-145.0 | −2.0 −8.5-7.5 | 137.0 127.5-144.5 | 132.0 124–139.5 | −5.0 −12.5-2.5 | 121.5 116.5-128.8 | 116.5 114.75-139.5 | −5.0 −9.0-3.5 | 121.5 116.5-128.8 | 120.5 113.8-133.0 | −3.0 −12.5-3.5 |
Diastolic pressure (mmHg) | 86.0 78.0-90.0 | 80.0 74.5-85.0 | −2.0 −8.5-2.0 | 86.0 78.0-90.0 | 81.0 71.5-86.5 | −6.0*
−8.0- –1.0 | 74.5 64.5-85.0 | 70.0 63.8-79.3 | −3.0 −5.5-1.5 | 74.5 64.5-85.0 | 71.0 60.8-77.3 | −5.0*
−7.0- –2.5 |
Medical interview findings
Change in COHb levels of participants in the first and second tests
Targeted concentration of CO (ppm) | First test, % (n) | Second test, % (n) | Total, % (n) |
P value |
---|---|---|---|---|
0 | 1.3 (14) 1.0-1.5 | 1.1 (14) 1.0-1.4 | 1.2 (28) 1.0-1.4 | <0.001 |
30 | 1.8 (14) 1.4-2.2 | 1.5 (14) 1.4-1.6 | 1.7 (28) 1.4-1.9 | |
50 | - | 2.2 (14) 2.0-2.4 | 2.2 (14) 2.0-2.4 | |
70 | 2.5 (14) 2.3-2.8 | - | 2.5 (14) 2.3-2.8 |