Indoor Air Pollution and Sick Building Syndrome. Monitoring Aerosol Protein as a Measure of Bioaerosols

Excess aerosol protein concentration is suggested to be a diagnostic marker for biological causes of impaired air quality of a building. A simple inexpensive instrument has been developed to measure aerosol protein concentration. Aerosol particles are collected by allowing injected steam to condense upon them, thus resulting in their growth, followed by cooling and impaction. The liquid stream, bearing dissolved and suspended aerosol constituents, is put through a silica preconcentration column that is eluted subsequently with dilute H 3 PO 4 . The eluite stream is reacted with acidic Coomassie blue G; the color of the protein-dye adduct is detected by optical absorbance at ∼600 nm. Optimization efforts have been carried out to choose the best stationary phase for protein preconcentration and reagent composition. In liquid-phase experiments, bovine serum albumin (BSA) displays a limit of detection (LOD) of 16 ng. In aerosol experiments, there is some increased noise and the LOD deteriorates by ∼2×. The system collects aerosol particles with 99.5+% efficiency. The LOD for a 300 L (30 min at 10 L/min) air sample is thus equivalent to a concentration of ∼100 ng/m 3 BSA. The system is mounted on a single two-tier standard laboratory cart and has the potential to be an effective transportable monitoring device for airborne biological contamination. Detectable protein concentrations were found in an apartment dwelling setting during cooking activities and in a hotel known to have a fungal contamination problem.