Environment Canada, partnering with Health Canada, compared the impact of ultra-low (<10 ppm) sulphur gasoline on vehicle tailpipe emissions with conventional gasoline (<30 ppm sulphur).

This study complements the April 2013 U.S. EPA study on “The effects of gasoline sulfur levels on emissions from Tier 2 vehicles in the in-use fleet”. Two key issues addressed are the impacts of sulphur in gasoline at a cold temperature of -18°C and the impacts of the sulphur level on particle number counts and size distribution, in addition to total particulate matter.

The Emissions Research and Measurement Section tested two light-duty vehicles: a 2011 vehicle using port fuel injection (PFI) and a 2012 vehicle using gasoline direct injection (GDI). Tests were conducted at ambient temperatures of 22°C and -18°C, to represent both Canadian summer and winter conditions, across three drive cycles representing city, highway, and aggressive driving. Detailed analyses of the exhaust for carbon monoxide, nitrogen oxides, total hydrocarbons, greenhouse gases, volatile organic hydrocarbons, and total particulate matter emissions were conducted.

Ultra-low sulphur gasoline was not observed to negatively affect emissions, and particulate mass and particle number count decreased in the GDI vehicle using ultra-low fuel. This finding is of interest, since previously, GDI vehicles have shown increased particulate mass compared to PFI gasoline and diesel passenger vehicles. Fuel-efficient GDI vehicles are rapidly entering the Canadian marketplace.

On June 8, 2013, Environment Canada announced a Notice of Intent to develop regulations to further limit emissions of smog-forming air pollutants from new cars and light trucks and to reduce the sulphur content of gasoline. The data from this study will inform policy makers and may be used by Environment Canada for adjustments to the Sulphur in Gasoline Regulations in the Canadian Environmental Protection Act, 1999 and by Health Canada for human health risk modelling.

Contact: Debbie Rosenblatt, (613) 998-9590, Debbie.Rosenblatt@ec.gc.ca, Emissions Research and Measurement, Air Quality Research Division