Road transportation emissions and energy consumption in cold climate cities

Many cities worldwide face cold climates and sub-zero temperatures for significant parts of the year. Due to environmental concerns, vehicle technologies are shifting from internal combustion engines to alternative fuels, hybrid powertrains, and battery electric vehicles. However, the impact of cold ambient temperature on emissions and energy consumption of various technologies is not fully understood. We systematically analyzed peer-reviewed journal publications for any assessment of the impact of cold climate on vehicles' emissions and energy consumption. We found that a cold environment adversely impacts the energy and emissions of almost all vehicle technologies due to the poor performance of after-treatment systems and batteries in low temperatures. While the research findings and available data on the impact of cold climate depend on vehicle technology and test cycle, some general trends are observed. Battery electric vehicle ranges are reduced to less than 60% of their normal range when the ambient temperature is 15 circle C. The change in conventional fuel vehicle emissions is more drastic, as literature showed an increase of particulate matter by five times and nitrogen oxides by 2.5 times for selected technologies. Our analysis showed a significant knowledge gap in data and understanding of the impact of cold climate on vehicle emissions and energy consumption. Such knowledge is essential in developing policies and regulations for decarbonizing urban transportation in cold climate cities.