Concentration characteristics and emission estimates ofmajor HCFCs and HFCs at three typical fluorochemical plants in China based on a Gaussian diffusion model

Estimating the emissions of hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs) is of great significance for assessing global ozone depletion and climate change, where the emissions from fluorochemical plants play an important role. However, no research has been conducted on the HCFC and HFC emissions from fluorochemical plants based on observation data and diffusion model. This study observed the concentration of two HCFCs and six HFCs around three typical fluorochemical plants in China. It used the Gaussian plume diffusion model to explore their emissions. The results showed that the concentration difference between the downwind and upwind sites (from now on referred to as down-up difference) of each substance is ranked. Only in plant A, the substance with the largest down-up difference is HCFC. The total HFC down-up differences of the three plants were higher than that of HCFCs, and the total emissions of six HFCs accounted for 46% of three plant’s emission, suggesting that the HFC production of the three typical fluorochemical plants in China had reached a large scale with the phase-out of ODSs (ozone-depleting substances). The total emissions of HCFCs and HFCs from the three plants are 56.62 Mt (million ton) CO₂-equiv yr⁻¹. The emissions from the three plants are approximately 20–76% of the bottom-up national emissions estimated using IPCC 2019 emission factors. On the contrary, the emissions of the three plants are 2–6 times higher than the national emissions (contained 20 fluorochemical plants) based on the IPCC 2006 emission factor. This revealed that using the default emission factors for fluorochemical production recommended by IPCC 2006 to estimate the emissions of HCFCs and HFCs from fluorochemical plants in China may lead to underestimation.