A study of the dispersion of vinyl chloride from a renewable energy facility located in Ontario, Canada

This study compared the results of modelling vinyl chloride emissions from a renewable energy generation plant, located in the City of Kawartha Lakes, Ontario, Canada, using American Meteorological Society/Environmental Protection Agency Regulatory Model (AERMOD) and California Puff (CALPUFF). The plant utilizes landfill gas emissions from the existing Lindsay/Ops landfill to fuel an on-site generator, and thus generate electricity. The modelling was performed for July 20, 2013 and November 17, 2013, from 00h00 local standard time (LST) to 23h00 LST for both days. The results showed that modelling contaminant dispersion using CALPUFF resulted in significantly higher concentrations than when modelling with AERMOD. This may be due to the several limitations of AERMOD, including its assumptions of straight line trajectory, steady-state and a uniform atmosphere, its inaccuracy when determining long-range transport, and its inability to retain the memory of the previous hours' emissions. The CALPUFF modelling results also showed that the contaminant concentration may, in some instances, be higher farther away from the source than closer to it. The results also show that the concentration of vinyl chloride on July 20, 2013, as modelled by CALPUFF, exceeds the applicable regulatory limit. Thus, it is recommended to use CALPUFF instead of AERMOD to assess the dispersion of emissions from a facility more conservatively. Using CALPUFF will also ensure that the dispersion is assessed further away from the emissions sources as well as nearer to them. The appropriate selection of dispersion models is especially important when the results of one of the models may deem the facility's emissions non-compliant with the applicable regulatory limits.