Endotoxin and Particle Concentrations in Subsidized Households with Asthmatic Children in Philadelphia: A Pilot Study

Abstract

This study seeks to identify the home and behavior characteristics that may affect indoor exposures to endotoxin and particles in subsidized housing of asthmatic children in Philadelphia, PA. Sixty seven endotoxin samples were collected from children’s usual sleeping surfaces, and 97 airborne indoor particle measurements were made. The geometric mean (GM) endotoxin concentration was 1933 EUm−2; the total particle count (≥0.3 µm) was 9.72 × 107 (ptm−3). Between-home variability of endotoxin measurements (geometric standard deviation, GSD, 6.3) was greater than that of particle counts (GSD 2.2-3.2). Endotoxin concentrations were negatively associated with the presence of upholstered furniture and stuffed toys, evidence of mold and increased ventilation in the home. The smoking status of the household was a significant determinant of concentrations of particles smaller than 2.0 µm. None of these determinants explained more than 11% of exposure variability. Endotoxin and particle concentrations were not correlated. Direct measurement of contaminants of interest remains the best option for indoor air quality investigations in the households surveyed.