WAKE COUNTY | Solid Waste Management Division

Does the landfill smell more often this time of year?

For most of the year, the prevailing winds in our area blow toward the northeast, carrying any odors that may have escaped the landfill away from most nearby neighborhoods. But that trend flips from mid-August to mid-November, when winds are more likely to blow southwest toward Forest Springs and 12 Oaks.

Those were the findings of a 2014 study that looked at seven years of local climate data, and that trend continues to hold according to measurements from the landfill's two on-site weather stations. (You can see one of our weather stations in the photo to the right.)

The study also found that high windspeeds are our friend, and data from odor reports back that trend up too. When winds blow above 7 mph, they mix with enough fresh air to dilute any odors picked up at the landfill. Low windspeeds from 4-7 mph are the most likely to carry noticeable odors to our neighbors. Winds under 4 mph allow odors to accumulate and, if low windspeeds persist, can allow those smells to slowly spread out from the landfill.

Of course, this seasonal shift is no excuse for odor issues. Wake County is committed to investing in the latest technology and implementing the best operational practices to minimize the frequency and duration of odor issues around the landfill. We just have to work a little harder this time of year when Mother Nature works against us.

And, as always, let us know if you smell something! We rely on your odor reports to identify problems at the landfill and track our odor-fighting efforts.

Update to the Holly Springs Town Council

On Sept. 6, Wake County presented an update on our efforts to reduce odors and increase communications around the South Wake Landfill. Working with the Town, we've made substantial progress over the past two years, but the work to control odor never ends.

Watch the Video

Does it smell more around sunup and sundown?

On days with clear skies and low winds, you may notice more odors around the landfill around dawn and dusk due to a temperature inversion.

Ordinarily, the temperature of air gets cooler and cooler the higher up you go. That's why some places in the Blue Ridge Mountains average temperatures 20 degrees lower than Wake County.

During an inversion, a layer of air forms where the temperature is warmer than the air below it. That warm layer acts like a lid, trapping cooler air near the ground and preventing circulation. Odors are also trapped when an inversion occurs around the landfill, which holds those smells closer to the ground where we're more likely to notice them.

Inversions usually happen when sunrise or sunset causes temperatures to change and there's not enough wind to circulate the air. After dawn, a warm layer can form as the sun begins to heat things up and, after dusk, an inversion may happen as the atmosphere cools and the ground radiates a layer of heat.

Fortunately, inversions usually pass in a matter of hours. The quickest fix is for high winds to stir up the air, mixing the warm with the cold and breaking up the lid. If wind speeds remain low, the sun will eventually heat the air below the inversion layer to become hot enough to escape upward and carry odors away.

Regardless of whether you suspect a temperature inversion to be at play, please submit an odor report to let us know if you smell odor around the landfill.

Image credit: Science Learning Hub – Pokapū Akoranga Pūtaiao, University of Waikato, www.sciencelearn.org.nz

Positive Trends Continue in Odor Reporting Data

As we reported in the last newsletter, we turned a corner in August 2020 based on the number of odors reported by our neighbors. We’re continuing to work hard and make major investments to reduce odor around the South Wake Landfill, and we're happy to report that the positive trend continued through August 2022.

Of course, that also means that we depend on your odor reports to tell us how we're doing! If you smell the landfill, please take the time to let us know. We use these data to measure which odor-fighting tactics are working and, if we see a sudden spike in reports, it alerts us to look for problems.

We've made some encouraging progress at the landfill, and there are many more improvements to come.

South Wake Landfill Traffic Report

It takes a lot of garbage routes to serve Wake County's 1.1 million residents, and all those trucks end up at the South Wake Landfill. From February through July, we saw an average of 4,174 truck trips per month and 164 per day when the landfill was open for business.

This Wednesday

South Wake Landfill Citizens Committee

We're meeting Wednesday, Sept. 28, from 6:30-8 p.m. The meeting will be held as a hybrid, so you can join us online or we'd love to see you in person!

Get Involved

Ever wondered what happens to your trash when it leaves the curb?

Find out with a FREE tour of the South Wake Landfill! You’ll learn everything Wake County does to fight odors, protect the environment and support public health while processing the garbage from more than 1.1 million residents.

After two and a half years, our public tours are finally back! Spots are limited, so sign up today. Got a group of 10 or more interested in taking the tour? Let us know and we’ll schedule a private tour on our bus.

Rather tour from the comfort of your couch? Check out our virtual tour, which includes access to behind-the-scenes areas and drone footage.

Take a Tour

Learn more about the South Wake Landfill →

We strive to keep residents well informed on activities taking place at the landfill and welcome all feedback. If have questions or concerns, please contact John Hamlin.

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Wake County Solid Waste Management

Telephone: 919-856-6424

Address: Wake County, Solid Waste Management Division, P.O. Box 550, Raleigh, NC 27602

Director: John W. Roberson, PE

Website: wakegov.com/landfill