Objectives: To evaluate the relationship between exposure to gaseous air pollutants (ozone [O3], carbon monoxide [CO], nitrogen dioxide [NO2], and sulfur dioxide [SO2]) socioeconomic status and the prevalence of symptoms of asthma, rhinitis and atopic eczema in adolescents.

Subjects and Methods: A sample of 16 209 adolescents from São Paulo West (SPW), São Paulo South (SPS), Santo André (SA), Curitiba (CR), and Porto Alegre (PoA) were enrolled. Data on air pollutants and socioeconomic status were compared to prevalence of symptoms with the Spearman correlation coefficient.

Results: Socioeconomic status was quite similar in all cities. The levels of O3 in SPW, SPS, and SA, and of CO in SA were higher than the acceptable ones. In relation to O3 and CO exposures, adolescents from SPW and SA had a significant risk of current wheezing, whereas living in SPW was associated with a high risk of rhinoconjunctivitis, eczema, and flexural eczema and living in CR to rhinitis. Exposure to NO2 was associated with a high risk of current wheezing in SPW and SA, and of severe asthma in SPW and PoA. Exposure to SO2 was associated with a high risk of current wheezing in SPW and SA, severe asthma in SPW and PoA, and nighttime cough, eczema, flexural eczema and severe eczema in SPW. Living in SPW, CR, or PoA was associated with a high risk of rhinitis, rhinoconjunctivitis, and severe rhinitis.

Conclusions: Although we did not detect a characteristic pattern for all symptoms evaluated or a specific air pollutant, our data suggest a relationship between higher exposure to photochemical pollutants and high prevalence or risk of symptoms of asthma, rhinitis, and atopic eczema.

Key words: Air pollution. Asthma. Atopic eczema. Rhinitis. Gaseous pollutants. Ozone. Carbon monoxide. Nitrogen dioxide. Sulfur dioxide.