A comprehensive approach to study stack emissions from a research building in a small urban setting

Gaseous emissions from research facilities within an urban environment have not been fully studied. The present study investigates the impacts of stack emissions from a research building in Hong Kong on nearby urban areas. Fifteen chemicals emitted from the laboratories of the building were selected for a year-long air monitoring. Among the 15 chemicals, the levels of NO₂, acetonitrile, and total volatile organic compounds (TVOC) exceeded the predetermined exposure levels. A tracer gas study was performed to identify the dilution factor of the environment and to validate two turbulence models, namely, Renormalized Group (RNG) and Realizable (RLZ) k-ε models. Statistical tests, including geometric mean bias (MG) and factor of two (FAC2), demonstrated that the RNG (MG: 0.88–1.5; FAC2: 0.67–1.14) was better than the RLZ k-ε model (MG: 0.26-0.68; FAC2: 1.47–3.80) for the prediction of pollutant dispersion and concentration distribution but still could not achieve statically sound results. Despite the RNG k-ε model is a popular and economical choice in numerical simulations, careful interpretation of data would be required, and it should also be used and read in conjunction with air monitoring and tracer gas assessment data as a comprehensive approach when assessing the impact of stack emissions in an urban setting.