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Background: Acute pollutant-related lung function changes among children varies across pollutants and lag periods. We examined whether short-term air pollutant fluctuations were related to daily lung function among a panel of children and whether these effects are modified by airway hyperresponsiveness, location and asthma severity.Methods: Students from randomly selected grade 4 classrooms at seven primary schools in Durban, participated, together with asthmatic children from grades 3-6 (n=423). The schools were from high pollutant exposed communities (south) and compared with schools from communities with lower levels of pollution (north), with similar socioeconomic profiles. Interviews, spirometry and methacholine challenge testing were conducted. Bihourly lung function measurements were performed over a 3-week period in four phases. During all schooldays, students blew into their personal digital monitors every 1.5-2 hours. Nitrogen dioxide (NO2), nitrogen oxide (NO), sulphur dioxide and particulate matter (<10 μm diameter) (PM10) were measured at each school. Generalised estimating equations assessed lag effects, using single-pollutant (single or distributed lags) models.Results: FEV1 declines ranged from 13 to 18 mL per unit increase in IQR for NO and 14-23 mL for NO2. Among the 5-day average models, a 20 mL and 30 mL greater drop in FEV1 per IQR for NO2 and NO, respectively, among those with airway hyperresponsiveness compared with those without. Effects were seen among those with normal airways.Conclusions: This first panel study in sub-Saharan Africa, showed significant declines in lung function, in response to NO and NO2 with effects modified by airway hyperresponsiveness or persistent asthma. [ABSTRACT FROM AUTHOR]

Abstract: Despite the toxicity and widespread use of manganese (Mn) and lead (Pb) as additives to motor fuels and for other purposes, information regarding human exposure in Africa is very limited. This study investigates the environmental exposures of Mn and Pb in Durban, South Africa, a region that has utilized both metals in gasoline. Airborne metals were sampled as PM2.5 and PM10 at three sites, and blood samples were obtained from a population-based sample of 408 school children attending seven schools. In PM2.5, Mn and Pb concentrations averaged 17±27ngm−3 and 77±91ngm−3, respectively; Mn concentrations in PM10 were higher (49±44ngm−3). In blood, Mn concentrations averaged 10.1±3.4μgL−1 and 8% of children exceeded 15μgL−1, the normal range. Mn concentrations fit a lognormal distribution. Heavier and Indian children had elevated levels. Pb in blood averaged 5.3±2.1μgdL−1, and 3.4% of children exceeded 10μgdL−1, the guideline level. Pb levels were best fit by a mixed (extreme value) distribution, and boys and children living in industrialized areas of Durban had elevated levels. Although airborne Mn and Pb concentrations were correlated, blood levels were not. A trend analysis shows dramatic decreases of Pb levels in air and children''s blood in South Africa, although a sizable fraction of children still exceeds guideline levels. The study''s findings suggest that while vehicle exhaust may contribute to exposures of both metals, other sources currently dominate Pb exposures. [Copyright &y& Elsevier]