This is part one of a two-part article about handling marijuana odors.

It’s a tale as old as time … or at least for as long as people have lit up this particular bud. Marijuana smoke comes with a certain pungent smell.

Measures have passed by voters in four states, plus Washington, D.C., allowing recreational use of marijuana. An additional 19 states allow marijuana to be used for medicinal purposes.

Along with the freedom of living uninhibited and toking up comes the responsibility — or prerogative of local businesses, at least — to ensure an odor-free area for customers or nearby patrons. In order to combat the pot smell problem, businesses have looked to the marketplace for odor control solutions — and several manufacturers have risen to the challenge.

Brian Coffey, the national sales manager of Fresh Wave IAQ, Long Grove, Ill.,  — which does business in the states that have legalized marijuana — has seen the marketplace grow.

“Mostly, it is in hospitality,” says Coffey. “In Colorado, we’ve had a couple of customers come to us [because] they are seeing a lot of out-of-state visitors coming in, trying out the products in their hotel rooms and the [smoke] penetrates the walls.”

In addition to hotels, marijuana sellers are looking for ways to deodorize their stores, says Todd Sauser, director of marketing, Nilodor Inc., Bolivar, Ohio.

Colorado voters approved recreational marijuana use in November 2012, and marijuana-selling stores opened in January 2014. In Washington, voters also approved an initiative to legalize recreational marijuana in November 2012. Oregon voters approved a ballot measure in 2014 to allow for nonmedical cultivation and use of marijuana.

Washington, D.C., also approved legalizing marijuana but restricted recreational use to private residences, greenhouses and garages.

Earlier this year, Alaskan voters also approved legalizing marijuana, but for the moment those 21 and over are only allowed to possess 1 ounce or less of marijuana and can only grow it on their private property. It currently is still illegal to use, buy or sell marijuana in public places in Alaska, but beginning in 2016, businesses will be allowed to sell the plant.