Assessing transfer distances and separation areas of odorous compounds from probability analysis with numerical dispersion modeling.

Abstract Odor pollution caused by volatile compounds from waste-treatment facilities is a typical nuisance, and assessing its potential impacts is crucial. Challenges in odor-dispersion simulation and impact assessment are attributed to the occasional and fluctuant emissions of odorous compounds and varying meteorological conditions for dispersion. This study established an approach to assessing the transfer distances and determining the separation areas of odor pollution by combining probability analysis and numerical dispersion simulation. With a waste transfer station as a case, we analyzed odorous compounds from 96 samples and performed 2190 simulation rounds with different meteorological parameters throughout an entire year by using a specialized model (ModOdor). Ethanol, dimethyl disulfide, and dimethyl sulfide were identified as typical odorous compounds in terms of source intensity and detection frequency. The concentration distribution, probability of transfer distances in terms of month and year, and separation area determination from cumulative probability were investigated. Under most studied conditions, the compound concentrations rapidly decreased after being released. From the year-round perspective, an ethanol concentration exceeding 1 μg/m3 was in approximately 80% probability limited in the area with a radius of 200 m. With a cutoff of 95% probability, the closest transfer distances towards all orientations can circle the odor separation area. The compound concentrations in the separation area had a probability higher than 5% throughout the year to exceed the assigned reference concentrations. The approach and demonstration can solve the mutability problem of odor pollution from a probability perspective and thus potentially improve odor pollution control in waste management.