Usb4000 vis nir miniature fiber optic spectrometer

PM_2.5 was collected by sampling air in the child's home at 1.5L/min for 7days. BC and ETS were quantified on the filter using a recently validated multi-wave length optical absorption technique developed for Teflon filters utilizing a modified Lawless method (Yan et al., 2011 ). The optical device used consisted of a balanced deuterium tungsten halogen light source (DH-2000-BAL), an integrating sphere (ISP-50-8-R), a lab-made filter holder, and an Ocean Optics USB4000-VIS-NIR miniature fiber-optic spectrometer. Children's home addresses were geocoded and linked to a previously described GIS database (Lovasi et al., 2009 (link)). The density of buildings burning residual oil and the truck route density in a 500-m Euclidean radius were examined as potential predictors due to a previously seen association between these two variables and domestic BC levels (Cornell et al., 2012 (link)). In order to examine neighborhood level exposures, annual averages of PM_2.5 and elemental carbon (EC), which is representative of the same carbonaceous fraction as BC and are considered comparable, were obtained from the NYC Community Air Survey for 2009 and assigned to each participant based on their United Hospital Fund (UHF) ID.

The optical device used for measuring BC and UV-PM levels consists of a balanced deuterium tungsten halogen light source (DH-2000-BAL), an integrating sphere (ISP-50-8-R), a lab-made filter holder, and an Ocean Optics USB4000-VIS-NIR miniature fiber-optic spectrometer (Yan et al. 2011 (link)). Teflon filters from different manufacturer’s lots (Pall Corporation) may have slight difference in background and absorbance tendency; for minimizing this effect, lab blanks from the same manufacturer’s lot number were used as white reference.