Whether we know it or not, we use heat engines for a great many things and heat engines are fueled mostly through the act of combustion. Fossil fuels, including coal, natural gas, and petroleum oil, are the main source of energy for combustion; one that the U.S. is highly dependent on (approximately 84% of total energy generated) (1). Fossil fuels are hydrocarbons comprised mostly of carbon, hydrogen, sulfur, nitrogen, oxygen, and other mineral matter (this turns to ash when burnt). Combustion is the rapid oxidation of these fossil fuels to generate heat needed within the heat engine. The issue with combustion is that not everything is completely used up, some products are released into the atmosphere such as carbon dioxide, carbon monoxide, sulfur dioxide, nitrogen oxides, and particulate matter (2).
Carbon dioxide is the major product released since carbon alone accounts for 60-90% of most fossil fuels’ composition. The release of carbon dioxide has been increasing steadily through the decades all across the world (2). Though not a pollutant that is harmful to our health directly, carbon dioxide is proven to be a greenhouse gas and contributes to the climate change currently in effect (3).
Carbon monoxide comes from vehicle exhaust and contributes to 55% of all CO emissions of the United States. Non-road engines (boats and heavy equipment like construction vehicles) account for 22% of all CO emissions nationwide. Carbon monoxide emission also come from industrial plants, woodstoves, gas stoves, and unvented gas/kerosene space heaters (2). At high levels of exposure carbon monoxide can be poisonous and may contribute to:
- visual impairment;
- reduced work capacity;
- reduced manual dexterity;
- poor learning ability;
- difficulty in performing complex tasks
As such, it’s expected to have carbon monoxide detector within buildings to prevent a buildup of CO in the ambient air (3).
Sulfur dioxide, though easily dissolvable in water, occurs in all raw materials (crude oil, coal, common metal ores, etc.). It dissolves in water vapor to form an acid that interacts with other gases in air to form sulfates that are harmful to people and the environment (2). Sulfur dioxide is also a pollutant that can directly cause health issues. Depending on the amount of exposure one may experience temporary breathing impairment (short-term) or respiratory illness and aggravation of existing cardiovascular diseases (long-term). SO2 also contributes to acid rain which introduces acid to the soil, lakes, and streams as well as corrodes human-made structures (buildings and monuments) (3).
Nitrogen oxides (NOx) are a group of incredibly reactive gases that a both colorless and odorless. These products form when fossil fuels are burned at high temperatures (find in the combustion process of motor vehicles, electric utilities, and industrial/commercial/residential sources). The most common pollutant from this group is nitrogen dioxide and is a main component of smog found generally around big cities(2). NOx react within air and forms a ground-level ozone containing particulates that affects health in a variety of ways. It can change lung function in people with respiratory illnesses within three hours as well as increase the possibility of children developing a respiratory illness. With long-term exposure a person gains increased susceptibility to respiratory infection and it may also cause irreversibly changes in lung structure (obstructing breathing). NOx also contribute to environmental impacts such as acid rain. They can also change plant species composition/diversity in wetland systems if in increased concentrations as well as cause eutrophication (a condition that stimulates excessive algae growth) in bodies of water that depletes the oxygen and increases toxins (4).
Pisupati, Sarma. “Introduction to Fossil Fuels and Products of Combustion.” EGEE 102: Energy Conservation and Environmental Protection, The Pennsylvania State University, 2018, www.e-education.psu.edu/egee102/node/2207.
Pisupati, Sarma. “Fossil Fuel Elements.” EGEE 102: Energy Conservation and Environmental Protection, The Pennsylvania State University, 2018, www.e-education.psu.edu/egee102/node/1950.
Pisupati, Sarma. “Health and Environmental Effects of Primary Pollutants.” EGEE 102: Energy Conservation and Environmental Protection, The Pennsylvania State University, 2018, www.e-education.psu.edu/egee102/node/1952.
Pisupati, Sarma. “Health and Environmental Effects of Primary Pollutants, Page 2.” EGEE 102: Energy Conservation and Environmental Protection, The Pennsylvania State University, 2018, www.e-education.psu.edu/egee102/node/1979.