Researchers asked each resident to write down any scented candles, air fresheners and cleaning products they used and how often, and then tested the air in each home.
The team says the chemical it found the most of was limonene, a substance used to give products that citrus smell. The homes that used the most scented candles and cleaning products also had the highest levels of that chemical.
Now, limonene itself isn't particularly dangerous, but when it's released into the air, it reacts with ozone to create formaldehyde.
And that's definitely not good, considering the National Cancer Institute has said formaldehyde is associated with several types of cancer.
But fortunately, the researchers say you can control the amount of limonene in the air by using fewer scented products and opting for fragrance-free cleaning agents.
And we should note: More than six houses are likely needed before the researchers' findings on limonene can be considered conclusive.