Aerosol Characteristics in a Subway Environment

This paper presents an attempt to characterize biological and nonbiological aerosols in a subway environment. This opportunity to study a subway station atmosphere was approached as a collaboration of different organizations within the Department of Defense (DoD) and a suite of instruments was assembled for real-time monitoring, sample collection, and subsequent sample analysis. Based on ultraviolet (UV) fluorescence, aerosols of a biological nature were found to comprise a small fraction of the total aerosols (typically <1%). The total number concentration of aerosols exhibits a diurnal cycle that depends on the station usage. Several bacterial species were identified using polymerase chain reaction (PCR) analysis. The most common element in the aerosols is iron. Sodium chloride is also prevalent in the aerosol mass.