Decoupling environmental drivers of bioaerosol emissions during food waste degradation

Food waste, a significant source of bacterial and fungal bioaerosols, poses environmental and health risks throughout its management cycle. Bioaerosol emissions from initial food waste decomposition are characterized using field-level sampling in this study. Proteobacteria (primarily derived from ambient air) and Ascomycota (primarily derived from food waste) were identified as the dominant phyla in food waste bioaerosols, and they exhibited clear seasonal variations and source-specific differences. In this study, the effects of environmental conditions such as temperature, relative humidity (RH), ultraviolet (UV) intensity, and wind speed on bioaerosol emissions during initial food waste decomposition were decoupled and quantified using a custom-designed laboratory-scale simulation system. The results showed that increases in temperature and RH significantly promoted bacterial aerosol emissions, with peak concentrations observed at 35°C (216.87 ± 5.62 CFU/m³) and 90% RH (185.51 ± 12.49 CFU/m³). In contrast, the fungal aerosol concentrations exhibited a unimodal response to these factors, reaching maximum levels at 25°C (208.92 ± 6.87 CFU/m³) and 60% RH (306.98 ± 6.87 CFU/m³) prior to declining. UV irradiation at 365 nm (UVA) exerted a particularly strong inhibitory effect on bioaerosol release, with fungi showing greater sensitivity than bacteria. Wind speed played a dual role by enhancing mechanical aerosolization while diluting airborne concentrations. SHapley Additive exPlanations (SHAP) analysis provided interpretable quantification of the driver importance and confirmed that temperature was dominant factors with nonlinear effects. These findings improve the current understandings of bioaerosol generation mechanisms during food waste degradation and offer a scientific basis for targeted emission mitigation strategies.