Personal Exposure To Black Carbon And Acute Respiratory Responses Among Children In A Large Northeastern US City

Abstract

Introduction: Interpretation of findings from epidemiologic studies on ambient black carbon (BC) and asthma exacerbations among children has been hampered by uncertainties in exposure assessment and in the precise nature of the airway responses. Evidence linking personal BC exposure on acute respiratory symptoms and biomarker responses in both asthmatic and non-asthmatic children are relatively sparse. We examined associations of personal BC concentration with respiratory symptoms among asthmatic and non-asthmatic children in a large northeastern US city. We hypothesized that personal BC would be associated with respiratory biomarker responses and that effects would be more pronounced among asthmatic than non-asthmatic children. Methods: Daily lung function (FEV1/FVC and FEF2575/FVC), exhaled nitric oxide (eNO), a biomarker of oxidative stress (8-isoprostane) samples, and previous 24-hour personal BC data were collected among 30 asthmatic and 24 non-asthmatic 9/10 years old children. Repeated measures were collected at six different occasions over 3 to 4 weeks. The short-term associations between personal BC and respiratory biomarkers and lung function were assessed using linear mixed-effect models. Results: We found that the association between short-term exposure to BC and lung function decrements was modified by asthma status. Percent decreases in FEV1/FVC associated with each interquartile range (1.5 µg/m3) increase in 24hr average personal BC was 1.55 [95%CI: 0.34, 2.75] among non asthmatic children. We did not observe significant associations between personal BC and lung function among asthmatic children. We did not observe effects of BC on eNO in either subgroup. 8-isoprostane samples are currently being analyzed and findings will be presented. Conclusions: Our findings suggest short-term exposure to BC may have adverse effects on lung-function in non-asthmatic children. Greater variability in respiratory function among asthmatics may have limited power.