I thought about this one more time as I sprayed the tub with a bleach-based cleaning agent and took note of all the toxic cleaners I had for various tasks. I live in an area where black mold is a serious threat, so the monthly bleach treatment of wet spaces and the A/C pipes is a must. Our area is also famous for airborne pollen and an annual event called "cedar fever," caused when a cold snap triggers the release of cedar pollen in clouds of reddish dust. Between that, elm, mold, livestock, auto exhaust and whatever else in our semi-rural environs, you'd think outdoor air quality, monitored diligently by our local meterologists, would be worse than in your home. Think again! We recently had to replace our central heating and air system and I was horrified by the grungy condition of the old unit. Because the upstairs air intake is next to our daughter's room and across from the tall hall mirror where she liked to brush her hair, I would "swear" there was a whole head of her hair in that unit! Plus, over 25 years worth of dust bunnies, pet hair and who knows what else clogged the internal filters. I keep insisting that the air ducts should be cleaned, but the kid (very young person) who checked our system prior to its replacement said that was such an unnecessary task. What does he know - all you have to do is look at the dust around the vents to see that there's stuff being blown through by our nice, new, powerful unit. Carpeting and furry pets do not mix. I read somewhere that over 85% of household dirt is tracked in by shoes and pets and it gets ground into the padding of the carpet. So, no matter how much you vacuum and steam clean, all you're doing is creating mud. What a thought! Formaldehyde can also be found in carpeting. Remember that new carpet smell? It can also be found in paneling, cabinetry, upholstery and permanent press clothes. This only scratches the surface of what causes indoor air pollution. The cleaners we use, our pets, improperly filtered vacuum cleaners, even the scents we use are among the daily contributors to poor ambient air quality. The other major contributor is poor ventilation. Proper ventilation allows air flow throughout the house, drying out moisture trapped in the attic and eaves and pushing out stale air while bringing in the fresh. But, how many of us will open the windows every day, especially if it's hot or very cold out? I have a habit of opening windows every morning, regardless the temperature. This drives my husband crazy, but I can't stand stale air and am not fond of masking it with air sprays or candles. Inasmuch as I try to avoid daily use of toxic cleaners, opting for natural products as much as possible, mold, mildew and lime only respond to heavy duty agents. I also have a habit of not making my bed first thing in the morning, turning the duvet down, instead, to air the linens. This dries the linens, thereby killing dust mites. Using filters inside air vents, and changing them regularly, helps trap large particles traveling through the ducts. An electrostatic air cleaner working in tandem with your central air system also helps trap particles. All the same, my house does literally make me sick. We've been slowly replacing the carpeting with wood and tile. One of these days, perhaps the cat will go live with his owner (my daughter). Between the carpeting, the vents and the household products, I'm one of millions suffering from chronic respiratory issues. Indoor air quality affects people with asthma, and might even lead to more serious health concerns. Black mold can kill - yikes! The CDC has a list of resource and reports on air pollution and respiratory health, including indoor air quality issues: http://www.cdc.gov/nceh/airpollution/ind... For more on indoor and residential air pollutants: http://extoxnet.orst.edu/faqs/indoorair/... Also see: Indoor Pollution Control for Your Home: http://www.home-air-care.com/ The Importance of Home Ventilation: http://www.pure-indoor-air.com/ How have you dealt with issues in your home?