Characteristics of size-segregated aerosols emitted from an aerobic moving bed biofilm reactor at a full-scale wastewater treatment plant

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Aerosol emissions from wastewater treatment plants (WWTPs) have been associated with health reverberation but studies about characteristics of size-segregated aerosol particulate matter (PM) are scarce. In this study, the measurement of particulate number size distribution in the range of < 10 µm, and the collection of PM10–2.5, PM2.5–1.0 and PM1.0, were conducted from an aerobic moving bed biofilm reactor (MBBR) at a full-scale WWTP. MBBR aerosols showed a unimodal number size distribution, with the majority of particles (>94%) in the ultrafine size range (<100 nm). For toxic metal(loid)s or potential pathogens, significant differences were found within MBBR aerosols (PM10–2.5, PM2.5–1.0, and PM1.0), and also between MBBR aerosols and wastewater. Both wastewater and ambient air had important source contributions for MBBR aerosols. The compositions of toxic metal(loid)s in PM1.0, and the populations of potential bacterial or fungal pathogens in PM10–2.5 and PM2.5–1.0, were dominated by that from wastewater. Compared to PM10–2.5 and PM2.5–1.0, PM1.0 had the highest aerosolization potential for the toxic metal(loid)s of As, Cd, Co, Cr, Li, Mn, Ni, U, and Zn, and the genera of Acinetobacter, Pseudomonas and Fusarium. Due to the size-segregated specialty, targeted measures should be employed to reduce the health risks. CapsuleThe compositions of toxic metal(loid)s in PM1.0, and the populations of potential pathogens in PM10–2.5 and PM2.5–1.0, were dominated by that from wastewater.