Table 2

Spearman correlations between different traffic characteristics, outdoor PM10 and indoor NO

Car trafficTruck trafficDistance of school from motorwayDistance of home from motorwayOutdoor PM10 same day*Outdoor PM10 lag 1Outdoor PM10 lag 2Outdoor PM10 lag 3§Indoor NO
Total traffic0.95 (n=9)0.76 (n=9)0.15 (n=9)0.14 (n=812)−0.22 (n=13)0.02 (n=13)0.31 (n=13)0.26 (n=13)0.36 (n=13)
Car traffic0.68 (n=9)−0.02 (n=9)0.18 (n=812)−0.38 (n=13)−0.17 (n=13)−0.10 (n=13)0.03 (n=13)0.44 (n=13)
Truck traffic−0.08 (n=9)0.02 (n=812)−0.27 (n=13)−0.02 (n=13)0.21 (n=13)0.20 (n=13)−0.27 (n=13)
Distance of school from motorway0.12 (n=812)−0.08 (n=13)0.03 (n=13)0.34 (n=13)0.12 (n=13)−0.01 (n=13)
Distance of home from motorway−0.06 (n=812)−0.06 (n=812)−0.00 (n=812)−0.02 (n=812)0.26 (n=812)
Outdoor PM10 same day*0.55 (n=13)0.18 (n=13)−0.09 (n=13)0.29 (n=13)
Outdoor 1 PM10 lag 10.73 (n=13)0.29 (n=13)0.10 (n=13)
Outdoor 1 PM10 lag 20.65 (n=13)0.07 (n=13)
Outdoor 1 PM10 lag 3§−0.02 (n=13)
  • * On day of exhaled NO measurements.

  • 1 day before exhaled NO measurements.

  • 2 days before exhaled NO measurements.

  • § 3 days before exhaled NO measurements.

  • P<0.05.

  • PM10, particulate matter with a 50% cut-off aerodynamic diameter of 10 μm.