PARAMETERS MEASURED - SO₂, CO, PM10, TRS, and VOCs

SULFUR DIOXIDE — Sulfur Dioxide (SO₂) is measured to protect against exposure to the entire group of sulfur oxides (SO_x). SO₂ is the component of greatest concern and is used as the indicator for the larger group of gaseous sulfur oxides (SO_x). Other gaseous SO_x (such as SO₃) are found in the atmosphere at concentrations much lower than SO₂. The largest source of SO₂ in the atmosphere is the burning of fossil fuels by power plants and other industrial facilities. Smaller sources of SO₂ emissions include: industrial processes such as extracting metal from ore; natural sources such as volcanoes; and locomotives, ships and other vehicles and heavy equipment that burn fuel with a high sulfur content. SO₂ can affect both health and the environment. Short-term exposures to SO₂ can harm the human respiratory system and make breathing difficult. People with asthma, particularly children, are sensitive to these effects of SO₂. At high concentrations, gaseous SO_x can harm trees and plants by damaging foliage and decreasing growth.

CARBON MONOXIDE — Carbon Monoxide (CO) is a colorless, odorless gas that can be harmful when inhaled in large amounts. CO is released when something is burned. The greatest sources of CO to outdoor air are cars, trucks and other vehicles or machinery that burn fossil fuels. A variety of items in your home such as unvented kerosene and gas space heaters, leaking chimneys and furnaces, and gas stoves also release CO and can affect air quality indoors. Breathing air with a high concentration of CO reduces the amount of oxygen that can be transported in the blood stream to critical organs like the heart and brain. At very high levels, which are possible indoors or in other enclosed environments, CO can cause dizziness, confusion, unconsciousness and death. Very high levels of CO are not likely to occur outdoors.

PARTICULATE MATTER — Particulate Matter (PM) is a term for a mixture of solid particles and liquid droplets found in the air. Some particles, such as dust, dirt, soot, or smoke, are large or dark enough to be seen with the naked eye. Others are so small they can only be detected using an electron microscope. The measured PM in the PAMS is PM10 which is inhalable particles with diameters that are generally 10 micrometers and smaller. Some PM are emitted directly from a source, such as construction sites, unpaved roads, fields, smokestacks or fires. Most particles form in the atmosphere as a result of complex reactions of chemicals such as sulfur dioxide and nitrogen oxides, which are pollutants emitted from power plants, industries and automobiles.

TOTAL REDUCED SULFUR — Total Reduced Sulfur (TRS) refers to a gaseous mixture of compounds containing one or more sulfur atoms in their reduced state. TRS can be created by industrial sources, such as oil refineries, pulp and paper mills, steel mills and sewage treatment facilities. It can also be generated naturally, being released from swamps, bogs and marshy areas. Though not considered by the U.S. EPA to be a criteria pollutant and TRS compounds in small concentrations are not normally considered a health hazard, TRS is a source of odors producing a rotten egg or cooked cabbage-like smell which is offensive to many people.

VOLATILE ORGANIC COMPOUNDS — Volatile Organic Compounds (VOCs) are emitted as gases from certain solids or liquids. VOCs include a variety of chemicals, some of which may have short- and long-term adverse health effects. Concentrations of many VOCs are consistently higher indoors (up to ten times higher) than outdoors. VOCs are emitted by a wide array of products numbering in the thousands. Organic chemicals are widely used as ingredients in household products. Paints, varnishes and wax all contain organic solvents, as do many cleaning, disinfecting, cosmetic, degreasing and hobby products. Fuels are made up of organic chemicals. All these products can release organic compounds while you are using them, and, to some degree, when they are stored.

For more information, please visit https://www.airnow.gov/aqi/.