In the complete combustion of hydrocarbons the products are carbon
dioxide, water and unaffected nitrogen. However with the incomplete
combustion of hydrocarbons in automobiles the products include
unburned hydrocarbons, nitrogen oxides, carbon monoxide, carbon
dioxide and water. These types of auto emissions are responsible for
carbon monoxide poisoning and affect global environmental trends.
What do the acronyms mean?
NOx = Nitrogen oxide emissions
The major source of Nitrogen Oxide emissions are high-temperature combustion
processes, such as in automobiles and power plants. Diesel engines typically emit higher
levels of NOx than gasoline engines. Long term exposure to NOx may lead to increased
susceptibility to respiratory infection. Nitrogen Oxides also contribute to the formation of
acid rain, and other environmental effects damaging wetland and terrestrial vegetation.
Air quality also affects the health of rivers, streams, forests, wetlands, and other forms of
natural capital that are rich with a diversity of species.
CO = Carbon monoxide
Is fuel that actually began to burn, but the fire went out before the burn was
complete.
Carbon monoxide is a colorless, odorless, tasteless, toxic gas that has the molecular
formula CO. The molecule consists of a carbon atom that is triply bonded to an oxygen
atom. In Automobiles Carbon Monoxide is produced by the incomplete combustion of
fossil fuels. Ecological effects: At concentrations commonly found in the ambient air,
CO does not appear to have adverse effects on plants, wildlife or materials. However, CO
is oxidized to form carbon dioxide (CO2) a contributor to global warming.
CO2 = Carbon Dioxide Emissions
Carbon dioxide is a chemical compound composed of one carbon and two oxygen
atoms. It is often referred to by its formula CO2. In the United States, most carbon
dioxide (98 percent) is emitted as the result of the combustion of fossil fuels;
consequently, carbon dioxide emissions and energy use are highly correlated.
Carbon Dioxide Emissions Predicted To Reduce Density Of Earth's
Outermost Atmosphere By 2017
Science Daily — Carbon dioxide emissions from the burning of fossil fuels will
produce a 3 percent reduction in the density of Earth's outermost atmosphere by
2017, according to a team of scientists from the National Center for Atmospheric
Research (NCAR) and Pennsylvania State University (PSU). See full report
http://www.sciencedaily.com/releases/2006/12/061211221048.htm
HC = Hydrocarbons
A hydrocarbon is a chemical compound that consists only of the elements carbon (C)
and hydrogen (H). Hydrocarbons contain a backbone consisting of carbon atoms, called a
carbon skeleton with hydrogen atoms attached to that backbone. Hydrocarbons, which
are combustible, are the main components of fossil fuels, which include petroleum, coal,
and natural gas. The most abundant hydrocarbon is methane. HC PPM = the amount of
unburned fuel. That’s Fuel that went into the engine, and right out the exhaust.
According to the U.S. Environmental Protection Agency (EPA) ground level
ozone is the most challenging urban air quality problem in the United States.
Nearly 100 US cities have ground ozone levels that exceed EPA’s National
Ambient Air Quality Standards.
PM = particulate matter
Particulate matter is the term for solid or liquid particles found in the air. Some particles
are large or dark enough to be seen as soot or smoke, but fine particulate matter is tiny
and is generally not visible to the naked eye. Mobile source particulate emissions consist
mainly of these very tiny particles, also known as PM2.5, because they are less than 2.5
microns in diameter.
Fine particulate matter is a health concern because very fine particles can reach the
deepest regions of the lungs. Health effects include asthma, difficult or painful breathing,
and chronic bronchitis, especially in children and the elderly. Fine particulate matter
associated with diesel exhaust is also thought to cause lung cancer and is therefore listed
as a mobile source air toxic. Fine particulate matter can travel long distances on air
currents and is also a major cause of haze, which reduces visibility, affecting cities and
scenic areas throughout the United States.
