Air Quality

Air quality issues, such as smog and acid rain are issues that primarily affect the lowest part of the atmosphere within the zone of air we breath. Greenhouse gases affect long-term changes in the climate altering the chemical composition of the atmosphere impacting on global climate conditions.

Ground level ozone and fine particulate matter are two key components of smog and have negative impacts on human health and the environment. Ground level ozone and fine particulate matter have been linked to negative health impacts ranging from minor respiratory problems to cardiovascular disease and premature death.

Ground level ozone is formed by chemical reactions involving primarily nitrogen oxides (NOx) and volatile organic compounds (VOC) in the presence of sunlight. Human activities such as the burning of fossil fuels in the transportation, industry and electrical generation sector contribute to the formation of ground level ozone. Production and use of paints, cosmetics and the evaporation of liquid fuels such as gasoline and diesel add VOC’s to the air. Ozone concentrations are also affected by the formation and transport of pollutants from other areas and are dependent on meteorological conditions.

Fine particulate emissions (PM2.5) are emitted directly as a pollutant or are formed as a secondary pollutant. Emissions from the industrial sector, wood burning for home heating and transportation form the major fine particulate emissions. As reported in the Canadian Environmental Sustainability Report – 2007 ozone concentrations were highest in southern Ontario, southern Quebec and Alberta. The highest fine particulate concentrations were measured in southern Ontario and in southern Quebec. Factors affecting the elevated ozone and fine particulate matter levels in southern Ontario and Quebec can be explained by the high level of human activities in these areas as well as migration of these pollutants from emissions sources in the United States. In addition, particulate matter is the main cause of haze within urban centers.

Propane as a transportation fuel can assist in reducing urban smog and fine particulate matter. According to the Alternative Fuels Vehicle Institute, as compared to conventional gasoline, the use of propane in vehicles reduces particulate matter (PM10) by 40%, nitrogen oxides by 50% and total hydrocarbon (THC) emissions by 87%.

Many of the substances emitted from a gasoline fuelled automobile tailpipe are considered to be harmful to human health in the immediate environment they are used. According to the California Air Resources Board the following substances are among the most toxic substances emitted by vehicle exhausts: 1,3-butadiene; formaldehyde; benzene; acetaldehyde and polycyclic organic matter (POM) associated with particulates. Particulate matter from diesel engines is considered to be the most carcinogenic followed by 1,3-butadiene and benzene. The health effects of diesel exhaust particulate matter are well documented by the California Air Resources Board. Studies performed by the World LP Gas Association show that propane as a vehicle fuel is significantly cleaner than gasoline or diesel fuel in the release of air toxics.

Toxic chemicals in the air All data in milligrams of chemicals/mile
	1,3-Butadiene	Formaldehyde	Benzene	Acetaldehyde
Conventional Gasoline	0.57	2.00	7.67	0.61
Diesel	0.58	1.65	4.72	0.56
Propane	0.11	1.68	0.63	0.43