Bad smells  in the home can certainly be caused by mold , but it's not the only source. There are several surprising causes of poor indoor air quality , and luckily, they’re usually cheap to correct. Before you get worked up over the possibility of an expensive and intensive mold remediation , check into the other possible odor sources and try the following inexpensive solutions for bad smells.
Mysterious bathroom smells: Without proper ventilation, a bathroom  can easily be a haven for moisture, mold and mildew. But if the ventilation is more than adequate and your bathroom has a persistent sour smell  even after it’s cleaned top to bottom, take a closer look. A disintegrating toilet bowl seal, for example, is often an outlet for unpleasant smells, and a common problem during exceptionally warm weather. The solution is to replace the wax bowl ring that joins the toilet bowl to the drain pipe , and you’ll seal out an array of bad smells that can otherwise travel into your bathroom and masquerade as a mold threat.
Indoor air quality expert Jeff May  has another tip based on the experience of a client who had done all of the above with his guest bathroom and was still wrestling with a bad smell.
“The culprit was a sink overflow that was full of mold and bacteria,” says May. “He poured a mild bleach solution down the overflow, and the problem was solved.”
May also recommends looking to furnishings or fixtures that could be off-gassing a chemical smell into the bathroom atmosphere. The same client who had that stinky sink  overflow discovered that a wicker basket in another bathroom was releasing a strong varnish odor, and getting rid of the basket helped get rid of the smell .Alt=
Misdirected exhaust: Back on the exhaust  issue, it’s vital to have proper ventilation in moisture-prone areas  of the home like bathrooms, the kitchen and the laundry zone. You also want to make sure that each room’s ventilation system includes balanced supply and exhaust outlets; otherwise, odorous air can escape into other living areas and cause a big stink. The solution to ventilation issues is a pretty cheap trick for bad smells, and especially important as the stuck-indoors days of winter draw near.
Unclean cleaning products: The fact that you’ve cleaned a surface or an entire room doesn’t mean you’re in the clear where air quality and safety are concerned. Disinfectants that contain formaldehyde, usually as a fungicide or germicide, are a definite threat to air quality, and other cleaners you’re using may also release harmful smells. Green your cleaning routine by switching to disinfectants and sanitizers with citrus or hydrogen peroxide bases, and look to either homemade natural cleaners  or retail products that carry the Green Seal  logo. Green Seal is an independent verification program that bestows its mark upon products that meet stringent standards for safety, human health and all-around greenness.
Also, make sure you’re changing your cleaning sponges and cloths on a regular basis, because these can quickly fill up with odor-emitting bacteria that transfers to surfaces and creates more bad smells around the house. There's no cheaper solution than getting rid of your stinky sponges!
Odorous décor and building products: A remodel  or room redecoration may look great but can be the source of bad smells if materials off-gas into the new living space. Plasticizers in vinyl-based products can emit persistently unpleasant odors, adhesives and fungicide-featuring treatments contribute to indoor air pollution , and that new-carpet smell can actually harm your health. Save yourself a lot of hassle and money by working closely with your contractor to choose products that will preserve indoor air quality and prevent additional redos down the line. Think ahead and air out carpeting and other treatments before installation, and be aware of potentially harmful product contents as you shop for accessories and furnishings to complete the look.
With a little bit of sleuthing and these cheap solutions for bad smells, you’ll be able to improve and maintain indoor air quality at home with little effort or money.