Acute respiratory health effects of air pollution on asthmatic adolescents residing in a community in close proximity to-mine dump in South Africa : panel study

Abstract

Air pollution arising from mine dumps has been a major public health concern to communities located in close proximity to these facilities in South Africa. The study investigated the association between acute changes in lung function and ambient air pollutants on asthmatic children in Noordgesig, Gauteng, South Africa. A panel study design with repeated measures was used to carry out the investigation which involved 15 asthmatic children. Each participating child completed an asthma daily symptom diary and performed forced expiratory flows in one second (FEV1) for 21 consecutive days. The 24 h ambient air pollution concentrations were monitored over this period. Linear mixed effect models adjusted for temperature, relative humidity, the day of the week, first order autocorrelation and 10 μg.m-3 increase of the mean of pollutant concentrations were used to determine the association between morning FEV1 and air pollutants. The association between air pollutants, respiratory symptoms and medication use were evaluated with logistic mixed effect models. The mean 24-hour concentration of NOx for current day was 0.762% (95% CI: -1.296 – -0.227), and for O3, the respective current and previous days were 0.780% (95% CI: -1.461 – -0.099) and 0.716% (95% CI: -1.386 – -0.045), all of these were significantly associated with the morning FEV1 decline. Single pollutant models showed significant positive associations between chest tightness, cough and NO2, O3, NOx, and SO2 pollutants. Medication use such as corticosteroids and short-acting β2 agonist were associated with NOx (OR = 1.07; 95% CI: 1.00 – 1.28) and O3 (OR = 1.57 95% CI: 1.03 – 2.72) respectively. Interestingly, a protective significant effect, was observed between SO2 and cough (OR = 0.45; 95% CI: 0.21 – 0.97). The findings of this study provide evidence that an acute change of gaseous air pollutants in communities situated near mine dumps exacerbates lung function in vulnerable children.