City environmental health inspectors in Denver, CO have installed odor-detecting “electronic noses” to detect foul odors from industrial facilities – such as those in pet food manufacturing, marijuana production, asphalt shingle and coating materials manufacturing, petroleum refining, sewage treatment, and wood preservation. The city is expecting more resident complaints about foul odors, as gentrification of north Denver neighborhoods – historically home to factories – continues and the weather becomes warmer.
Rising odor complaints in 2016 led the Denver City Council to tighten the city’s nuisance law and lowered the threshold number of complaints triggering an inspection to five within a month from the previous 5 complaints within a 12 hour period.
According to the federal Agency for Toxic Substances and Disease Registry at the Centers for Disease Control and Prevention, foul smells can signal potential risks to human health. Studies have shown that some people can smell chemicals in the air before concentrations reach harmful levels.
The $50,000 pilot project uses e-nose sensors that measure concentrations of ammonia, hydrogen sulfide, and volatile organic chemicals. These are combined to calculate odor intensity, and wind speed and directional data are then used to try to pinpoint sources of the smells. City enforcers will then make site visits to the offender to inspect odor-control equipment and discuss potential solutions. Offenders are rarely ticketed.
“Odor is a nuisance,” said Gregg Thomas, environmental quality division director for the Denver Department of Public Health and the Environment.. “It doesn’t cause a physical health impact. But if you are exposed to odors all the time, there’s a mental health impact.”