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When are Odors a Violation of Missouri Law?
The city of Sugar Creek and the Missouri Department of Natural Resources (MDNR) often receive complaints from residents about odors. These odors may or may not be a health risk or a violation of Missouri State Law. If you are concerned about an odor, you may call the city of Sugar Creek or MDNR Air Quality Program and report the odor. The city has previously published information about how and where to report odor complaints. Complaints will be investigated by the city or MDNR and appropriate action will be taken according to state air quality regulations. The Sugar Creek fire department has recently received combustible monitoring equipment from the U.S. EPA and will use it when conditions warrant.
The ability to detect the odor of a specific chemical varies from person to person and depends on other conditions such as how often a person is exposed to the odor. People who are often exposed to a certain odor may become insensitive or extra sensitive to it. If you become insensitive to an odor, you may be surprised that other people can smell the odor when you cannot. If you become extra sensitive, you may smell the odor when others do not notice it. There are also differences in chemicals. Some chemicals have very low "odor thresholds" and can be detected at very low levels.
The "odor threshold" is the lowest concentration of a chemical in air that is detectable by smell. The odor threshold is only an estimate because odor thresholds are determined under controlled laboratory conditions using people trained in odor recognition.
The Hazardous Substances Database lists odor thresholds for many different chemicals. [Internet address: http://toxnet.nlm.nih.gov/] For example the odor thresholds for benzene, toluene, ethylbenzene, and xylene (common components of petroleum products) are listed as 4.9 milligrams per cubic meter (about 1.5 parts per million), 8 milligrams per cubic meter (about 2 parts per million), 8.7 to 870 milligrams per cubic meter (about 2 to 200 parts per million), and 4.5 milligrams per cubic meter (about 1 part per million), respectively.
Parts per million (ppm) is a way to measure very small concentrations. One part per million means that there is one molecule of chemical per one million molecules of air. One way to think of 1 part per million is to imagine one drop of sweetener in 178 cups (11 gallons) of coffee.
When the city of Sugar Creek or the Missouri Department of Natural Resources (MDNR) receives an odor complaint, an inspector from the city or MDNR responds to the complaint. MDNR inspectors may issue a violation of air quality notice if they discover odor at a level that violates state law and they can identify the source of the odor. When a business or individual receives a violation notice the matter is referred to the enforcement section of the MDNR Air Pollution Control Program. The enforcement section takes appropriate action to return the violator to compliance. The violator may or may not be fined depending on the circumstances.
Missouri law restricts the emission of odors in the Kansas City Metropolitan Area. In order to determine if the law has been violated, inspectors use a machine called a Scentometer to test for excessive odors. This machine dilutes the concentration of the odor by a certain amount. One volume of odorous air is diluted with seven volumes of odor-free air. If the inspector can still smell the odor in the diluted air, in two separate trials the odor is considered excessive. The two trials must be at least fifteen minutes apart within a one-hour period.
Correction to the May article on Understanding Measurements:
The last paragraph of the article stated that: For benzene, dividing the value of micrograms per liter (ug/L) by 3.25 will change the value to parts per billion. The correct units are micrograms per cubic meter NOT micrograms per liter.
Terrie Boguski
TOSC Program Coordinator
913-780-3328
