Remarks on Ambient Air Pollution and Health Outcomes

Abstract

Background. For some health problems, the impact of air pollution may be evident to the patients in a specific age range, but it is not necessary extended for other age ranges. Non-simultaneous exposure to two or more air pollutants may have different relationships with health outcomes than does simultaneous exposure. Subjects and methods. Case-crossover technique including a time-stratified approach to define controls was used to analyze data on emergency department (ED) visits for ischemic heart disease (IHD), epistaxis, and upper respiratory infection (URI). A conditional logistic regression model was used to estimate odds ratios (OR) and their 95% confidence intervals (95% CI) corresponding to an increase in an interquartile range (IQR) of air pollutant concentrations, after controlling for temperature and humidity. Results. The results for IHD (for all patients OR = 1.12; 95% CI: 1.02 – 1.23, IQR = 2.9 ppb for SO 2 ) show that for older patients (age 60+ years), the association between sulphur dioxide (SO 2 ) exposure and IHD is weak. For ED visits for epistaxis, both ozone (O 3 ) and SO 2 lagged differently in the common model indicated significant statistical associations, but not for common lags. A similar effect was observed for ED visits for URI in the case of ozone and nitrogen dioxide (NO 2 ). Conclusions. The study findings, based on analyzed examples, suggest that: (i) IHD cases in older age are less related to air pollution; and (ii) air pollutants may affect some health conditions by a specific sequence of exposure occurrences.