Table 2 Environmental characteristics of the asthmatic adults
Environmental characteristicValue (%)
Smoking habits (n = 324)
    Never smokers49.7
    Ex-smokers30.2
    Current smokers20.1
Passive smoking (n = 290)
    Current smoking parents or spouse31.4
Educational level (n = 259)
    Primary32.4
    Secondary27.0
    University40.6
Occupational exposure (n = 260)
    Exposed to asthmogens19.6
Indoor exposure
    Current gas heating, (n = 323)34.4
    Current gas cooking, (n = 324)80.9
    Water damage in the last 12 months (n = 283)8.5
Outdoor air pollution (1st method: annual concentrations based on 1991–1995 nearby background and traffic monitoring stations data)Value (μg.m−3)
NO2 (n = 290)
    Mean (SD)40.2 (14.7)
    25th-75th percentiles (IQR)31–45 (14)
SO2 (n = 255)
    Mean (SD)21.3 (8.6)
    25th–75th percentiles (IQR)15–27 (12)
O3-8 h (n = 210)
    Mean (SD)60.5 (19.4)
    25th–75th percentiles (IQR)42–73 (31)
Value (days)
O3-days (n = 289)
    Mean (SD)37.8 (24.4)
    25th–75th percentiles (IQR)20–56 (36)
Outdoor air pollution (2nd method: model-based annual concentrations assessed for the 1998 year)Value (μg.m−3)
NO2 (n = 308)
    Mean (SD)35.9 (9.3)
    25th–75th percentiles (IQR)28.8–38.7 (9.9)
SO2 (n = 308)
    Mean (SD)9.9 (5.6)
    25th–75th percentiles (IQR)5.3–13.5 (8.2)
O3-summer (n = 308)
    Mean (SD)63.0 (10.4)
    25th–75th percentiles (IQR)56.9–67.8 (10.9)
  • IQR, interquartile range; SD, standard deviation.

  • NO2, nitrogen dioxide; O3, ozone; SO2, sulphur dioxide.