Table 1

Distribution of daily concentrations of gaseous air pollutants* in Toronto

Centiles
Gaseous pollutionMeanStandard deviationMinimum25th50th75thMaximum
*CO=carbon monoxide; SO2=sulphur dioxide; NO2=nitrogen dioxide; O3=ozone. †Daily average level. ‡Daily maximum one hour level.
CO (ppm)†1.180.5000.901.101.406.10
SO2 (ppb)†5.365.9001.004.008.0057.00
NO2 (ppb)†25.249.043.0019.0024.0030.0082.00
O3 (ppb)‡30.3917.87018.0026.0038.00141.00