Steinemann likens our dryer vents to little tailpipes spewing the fragrance chemicals into the outside air.
Except that the government regulates tailpipes.
This is somewhat worrisome, given that about 73 percent of U.S. homes have clothes dryers. That they're vented outside doesn't mean there's no exposure.
It puts a new spin on those evenings I spend on my front porch in a rocker, sometimes noticing a sweet smell, and it isn't always the nearby spicebush. The dryer vent is around the corner.
The dryer study - more on that later - is the latest in a series of research projects Steinemann has completed on fragranced products.
"I got interested in this whole topic because of people getting sick," she said. "Not just mildly sick. Severely sick."
It began with e-mails and phone calls from people who said they had asthma attacks or other respiratory difficulty after breathing scented products. Some said they had seizures.
So, a curious Steinemann waded in.
One poll that focused on scented laundry products found that 10.9 percent of people randomly surveyed reported irritations from the vented air. It motivated her to investigate further.
Because companies aren't required to list the fragrance ingredients in their products - although recently some have voluntarily done so on company websites - Steinemann started looking at what was in the scents.
Previous research has documented more than 2,600 chemicals in fragrance concoctions.
In 2010, Steinemann tested 25 scented products - including cleaners, personal-care products, laundry products, and air fresheners - and found a total of 133 volatile chemicals. More than a third of the products emitted at least one chemical classified as a probable carcinogen by the U.S. Environmental Protection Agency.
A coalition of industry groups recently reiterated that fragrances are responsibly produced, rigorously tested, and safe.
More than that, fragrances are desirable.
One of the studies the industry touts has found that fragrances "have significant measurable effects on mood states." They can reduce irritation, stress, depression, and apathy. They can enhance happiness, sensuality, relaxation, and stimulation.
Drug companies have been trying to achieve these effects for decades. So all we had to do was sniff cleaning products?
I do understand the seduction. I've always kind of liked those smells.
But others are saying fragrance is becoming the new secondhand smoke. Given allergies, sensitivities, and other complaints - including differences of opinion about what smells good - some workplaces are instituting fragrance-free regulations.
Back to Steinemann, who in her latest study, published online last month in the journal Air Quality, Atmosphere and Health, looked at dryer vents.
She had heard from people who said they couldn't take their clothes to laundromats because of fragrance residue in "contaminated" washers and dryers. They wound up having to toss their clothes.
The most recent study was small, just two washers and dryers in two Seattle homes. They cleaned the machines with vinegar and ran subsequent cycles with just water.
Then they loaded up prerinsed organic cotton towels and started the test. The scented detergent and dryer sheets they used were major popular brands, although Steinemann didn't name them because she didn't want to give the impression that one detergent might be better or worse than another.
Analysis of the gases coming out of the dryer vents showed more than 25 volatile organic compounds, including seven hazardous air pollutants. Two of the chemicals, acetaldehyde and benzene, are classified by the EPA as carcinogens.
Steinemann is well aware of the study's limited scope. And she hasn't determined whether the chemicals are coming from the detergent or the dryer sheets.
Or even, potentially, residue from the machines, the prerinses notwithstanding. After all, the fragrances are made to persist. Ever stuff a package of dryer sheets into your grocery bag - it's reusable, right? - along with fruits and vegetables, and later the apple smells like "clean linen"?
"My point is: What does a typical dryer emit, using best-selling products?" Steinemann said. "The main message I want to get across is that these chemicals are coming out of dryer vents, and they're coming when we're using fragranced products."
She recommends that people use fragrance-free products, which I'm seeing more of on grocery-store shelves, so demand must be there.
But she cautions that fragrance-free products, even "green" ones, are not necessarily free of other toxins.
It shows how hard it is to come clean.
Contact staff writer Sandy Bauers at 215-854-5147, email@example.com, or @sbauers on Twitter. Visit her blog at philly.com/greenspace.