Forty million people in the United States suffer from allergies. And a new company is trying to make their hotel stays a little more allergy-friendly, one room at a time.

A Cheektowaga, N.Y., company called Pure Solutions has made improvements to 75 hotel rooms across the country to reduce allergy triggers.

Designated as "Pure Rooms," they have undergone a special six-step process of cleaning, sanitizing and nearly eliminating irritants such as mold, fungi, bacteria, dust and pollen that can cause problems for allergy sufferers and the additional 10 million people with asthma. Special air filters, purifiers and charcoal-filtered showerheads have been added to each room.

"We saw an opportunity to fill a need that was not being filled in that market but it is a need that was on their radar screen," said Tom Pickles, director of operations for Pure Allergy Friendly Rooms.

The company has created rooms for selected Hampton Inn, Resident Inn Marriott, Fairfield Inns, Four Points Sheraton and Conrad hotel chains, as well as the MGM Grand in Las Vegas.

Vanessa Campbell, acting general manager of the Holiday Inn Select Pittsburgh South in Bethel Park, Pa., said that when the owners bought the hotel several years ago, they intended to accommodate guests who wanted these kinds of rooms. The Pure Rooms rent for $10 more per night than the daily corporate rate of $119.

"Right now we don't get very much call for them," Campbell said.

However, the hotel has several guests who stay frequently and specifically ask for the Pure Rooms. "They will not stay in any other room," she said.

Hotels are slowly starting to heed the call to create rooms that help guests who have allergies, asthma and other respiratory ailments — a growing health problem, particularly in children, that has baffled doctors.

"Nobody knows why, but a lot of people think it has something to do with our being exposed to more chemicals, living in tighter buildings and maybe even being in more hygienic surroundings all the time," said Dr. Richard L. Green, an allergist in Pittsburgh for 30 years.

"A lot of people have trouble in hotel rooms because sometimes they're encountering feathers or more dust. Sometimes there's smoke exposure; some rooms are dingy, damp and musty."

Many hotels are going beyond designating a block of rooms as nonsmoking to address these problems.

In January, the Westin chain banned smoking in all of its hotels. Not only are the rooms nonsmoking, but so are the bars and restaurants.

Freshstay.com is an online directory of smoke-free hotels. Launched in January, it has assembled a list of 120 smoke-free properties so far.