Parts of Davis have been dealing with recurring compost-like odors in recent weeks, with residents complaining about headaches and smells that linger after being outside. The odor is reportedly strongest on foggy mornings and on days when yard-waste trucks operate, and local regulators and county officials say they are tracking and investigating the complaints.
Air District Asks Residents to Report Smells
The Yolo-Solano Air Quality Management District says it has logged multiple odor complaints and looks into each one. The agency is urging residents to jot down the time, date, location and suspected source whenever they catch a whiff. Complaints can be filed by calling (530) 757-3650 or by using the Yolo-Solano Air Quality Management District website.
Where Officials Think the Smell Is Coming From
Local officials say the odor appears to be coming from composting operations at the Yolo County Central Landfill just north of the city. The spike in complaints, according to county and air-district staff, lines up with wet, foggy winter weather and an especially busy leaf-collection season, as reported by CBS Sacramento.
County Response and Odor Controls
Yolo County says it has spent roughly $200,000 this year on odor-reducing aerators and diffusers. Officials say those systems knock down smells for about 300 days a year, but they can be overwhelmed when certain seasons and weather patterns line up the wrong way. The county says it is working with its contracted composting facility operator to put short-term and long-term odor-reduction strategies in place, according to The Sacramento Bee.
How the Composting Operation Is Run
Northern Recycling operates the composting facility at the Yolo County Central Landfill and processes green waste on-site, per the company’s information. Yolo County has previously described the facility’s Covered Aerated Static Pile system as a way to cut emissions and avoid turning the material, which officials say helps reduce odor releases, according to a Yolo County press release.
Recent Incidents Have Heightened Scrutiny
The recent surge in odor complaints follows a deadly industrial accident at the landfill on Dec. 10, 2025, when a dump-truck load fell onto the cab of another vehicle. That incident is under investigation by the Yolo County Sheriff’s Office and Cal-OSHA, as reported by The Sacramento Bee. Residents also point to a separate December incident in which a U-Haul trailer leaked coconut oil onto County Roads 32A and 105, forcing temporary road and rail closures, a mess documented in coconut oil chaos.
What Residents Should Do
Officials say that if you encounter strong or persistent odors, you should note the time, date and location, along with any suspected source, then file a complaint with the Yolo-Solano Air Quality Management District through its Yolo-Solano Air Quality Management District online form. Investigators say detailed reports help them track patterns and pinpoint sources. County officials add that they will continue testing odor-control equipment and coordinating with the facility operator as they explore additional monitoring and mitigation steps.
