The relationship of air pollution to the prevalence of allergic diseases in Taichung and Chu-Shan in 2002

This study was conducted in order to determine the relationship between air pollution and the varying prevalence of allergic diseases in the city of Taichung and the rural town of Chu-Shan. We used questionnaires to screen children aged from 7 to 15 years in Taichung and Chu-Shan and compared the results from these 2 areas with the factors related to air pollution. The study included 11,580 children in Taichung and 2621 children in Chu-Shan. In Taichung, the prevalence of asthma was 7.0%, of allergic rhinitis 27.6% and of atopic dermatitis 3.4%. In Chu-Shan, the prevalence of asthma was 5.6%, of allergic rhinitis 21.8% and of atopic dermatitis 3.3%. We also collected data on the concentration of air pollutants in the 2 areas over a 1 -year period from January to December 2001 and compared the average annual concentrations of various pollutants. Compared with Chu-Shan, Taichung had higher air concentrations of nitric oxide (NO; 11.47 ± 4.75 vs 5.07 ± 2.81 ppb), carbon monoxide (CO; 0.78 ± 0.19 vs 0.59 ± 0.12 ppm), nitrogen dioxide (NO2; 24.99 ± 6.8 vs 21.45 ± 7.87 ppb) and sulfur dioxide (SO2; 2.58 ± 1.0 vs 2.44 ± 0.88 ppb). Student's t test results showed that CO and NO were related significantly to the prevalence of allergic disease (p<0.005). The prevalence of both asthma and allergic rhinitis is higher in Taichung than in Chu-Shan, a finding that could be related to higher levels of some air pollutants in the urban location.