Table 4

Ascorbic and uric acid concentrations in nasal lavage fluid by exposure and group

ExposureAscorbic acid concentration (μmol/l)Uric acid concentration (μmol/l)
nPrePostMean difference(95% CI)p valuenPrePostMean difference(95% CI)p value
Asthma
Air90.290.520.24(−0.05 to 0.52)0.14128.198.510.32(−1.07 to 1.72)0.66
Sulphur dioxide 200ppb80.360.460.1(−0.16 to 0.36)0.46117.828.680.87(−1.28 to 3.02)0.45
Sulphuric acid 200 μg/m390.260.450.20(−0.06 to 0.45)0.17127.809.231.43(−0.69 to 3.54)0.21
Sulphuric acid 2000 μg/m3100.250.380.13(−0.37 to 0.32)0.90128.209.901.70(0.13 to 3.28)0.06
Ammonium bisulphate 200 μg/m390.350.440.09(−0.27 to 0.44)0.64128.469.511.05(−1.07 to 3.18)0.35
Ammonium bisulphate 2000 μg/m390.230.340.11(−0.09 to 0.30)0.32118.0910.322.23(0.11 to 4.34)0.07
Normal
Air120.520.610.10(−0.24 to 0.44)0.58127.719.701.99(0.51 to 3.47)0.02
Sulphur dioxide 200ppb120.480.810.33(−0.06 to 0.60)0.14128.289.441.16(−1.12 to 3.44)0.34
Sulphuric acid 200 μg/m3110.650.56-0.09(−0.46 to 0.28)0.65117.9010.522.62(1.57 to 3.66)0.001
Sulphuric acid 2000 μg/m3100.990.92-0.07(−0.54 to 0.40)0.78128.6210.882.26(0.79 to 3.73)0.02
Ammonium bisulphate 200 μg/m3120.550.660.11(−0.16 to 0.43)0.40128.8811.162.27(0.59 to 3.96)0.02
Ammonium bisulphate 2000 μg/m3110.541.080.54(0.02 to 1.03)0.06117.9810.812.82(0.89 to 4.76)0.02