Emissions (Air Toxics)
"...The petrol cars had higher emissions of benzene, ethene, propene, and 1-3 butadiene than their diesel counterparts...
...Most harmful gaseous emiss. lower for diesel..."
Source: Environmental and Health Impact From Modern Cars, May 2002 and August 2002 (DEER Conference); Ecotraffic
"...It is interesting to note that the levels of several of the most toxic compounds emanating from gasoline engines are higher (for example, benzene, 1-3 butadeine, formaldehyde) than from diesels...."
Source: THE DIESEL PARADOX: WHY DIESELIZATION WILL LEAD TO CLEANER AIR, James J. Eberhardt, U.S. Department of Energy
"...Benzene accounts for one to two percent of the exhaust hydrocarbons, expressed as a percentage of total organic gases (TOG), in diesel engines....For gasoline-powered highway vehicles, the benzene fraction of TOG...is generally higher than for diesel engines, about three to five percent...." (Page 2-73)
Source: EPA Final Regulatory Impact Analysis: Control of Emissions from Nonroad Diesel Engines, http://www.epa.gov/otaq/cleaner-nonroad/r03008.pdf
"...Dr Grosjean identified about 100 carbonyls in the Tuscarora Mountain and Caldecott Tunnels. Total carbonyl emission factors from diesel-powered trucks were found to be about 4 times those from gasoline powered cars when both were calculated on a distance-traveled basis. On a fuel-consumed basis, total carbonyl emission factors for diesel trucks were slightly less than for cars. Formaldehyde, acetaldehyde and acetone were the three major carbonyls present...."
Source: Airborne Carbonyls from Motor Vehicle Emissions in Two Highway Tunnels; Daniel Grosjean. (HEI Report)
"...At similar dilutions, Gasoline had more "stuff" than Diesel...
...the gasoline atmosphere has much higher volatile organics, including "air toxics"..."
"...Ambient levels of volatile organic MSATs [mobile source air toxics] in the SoCAB were mainly associated with gasoline vehicles...."
Source: Fujita and Zielinska, "Assessment of Exposures to Mobile Source Air Toxics". Air Toxics Workshop II, Houston, Texas June 12-13, 2007
"...Chemical mass balance (CMB) receptor model calculations attributed the sum of BTEX almost exclusively to gasoline engine exhaust for on-road samples and all but 5% to 10% of the BTEX at the three near-road sites..."
Source: Fujita et al. "Concentrations of air toxics in motor vehicle-dominated environments." Res Rep Health Eff Inst. 2011 Feb;(156):3-77, https://www.ncbi.nlm.nih.gov/pubmed/21608416
"...Although GDI engines emit lower levels of CO2, they emit more black carbon-the climate-warming particle commonly known as soot-and toxic volatile organic compounds, such as benzene and toluene...."