Improvement of the Theoretical Model for Evaluating Evaporative Emissions in Parking and Refueling Events of Gasoline Fleets Based on Thermodynamics.

Evaporative emissions from gasoline vehicles are known as an emission source of volatile organic compounds that are the precursors of tropospheric ozone and secondary organic aerosols. We formulated new estimation models based on thermodynamics for two main evaporation processes, namely diurnal breathing loss (DBL) and refueling loss (RFL) from gasoline vehicles. The models enable us to evaluate real-world evaporative emissions using the fuel composition and environmental temperature as input parameters. The proposed models well replicated the experimental results of the canister breakthrough emission from DBL (DBLb) and RFL obtained in previous experimental studies. The evaporative DBLb and RFL emissions in Japan in 2015 were then estimated using the new models. The evaporative emission from DBLb was approximately 8800 t/y, and that from RFL was 73,300 t/y. In addition, we estimated the variation in fuel evaporative emissions due to the market penetration of zero-emission vehicles. Even if the sale of gasoline vehicles is banned from 2035, the evaporative emissions of DBLb and RFL from gasoline vehicles will only be halved after 2040. The two models proposed for estimating the DBLb and RFL in this study are expected to be applied in the evaluation of the emission inventories of volatile organic compounds in future work.