Table 2
Correlation among the exposure variables (24 hour averages)
Variable
Black carbon
PM
2.5
Ozone
CO
SO
2
NO
2
Black carbon
1
PM
2.5
0.37
1
Ozone
− 0.03
0.62
1
CO
0.83
0.61
0.21
1
SO
2
− 0.22
0.10
0.13
− 0.18
1
NO
2
0.54
0.29
0.02
0.55
− 0.28
1