Carpets and rugs retain heat, muffle sound, and offer an easy way to make a home comfortable. But, as anyone who vacuums knows, they also harbor a lot of dirt, as well as whatever else comes in on your shoes. Many carpets are factory-treated with stain protectors, fire retardants, and mothproofing insecticides. Synthetic carpets contain volatile organic compounds (VOCs) -- which account for that "new carpet" smell -- that may cause health problems ranging from allergies to nausea. And virtually all synthetic varieties are backed with a latex mix containing styrene, a possible human carcinogen.
Remove your shoes at the door to minimize the amount of pesticides, car-exhaust particulate, and germs you bring into your living space. Invest in a vacuum cleaner with a HEPA (High Efficiency Particulate Air) filter; the average carpet has nearly 70 grams of dust per square meter, and the HEPA filter will help ensure that the dust doesn't blow around in the air.
Make sure your home is well ventilated to minimize the effect of your carpeting's chemical components or additives. Dispose of any wet carpet (from flooding, for example) right away; the chances of keeping it mold-free are slim.
If you're getting a new carpet, ask the installer to air it out first in a clean, well-ventilated area. Have the carpet tacked down, instead of glued. Leave the house for at least several hours after installation, as synthetic carpets (often nylon and olefin) can emit noxious gases, including VOCs.
According to the Consumer Product Safety Commission (CPSC), the government agency that monitors products that may pose a health risk, you should also open doors and windows, and keep the air circulating throughout your home with window fans and air conditioners. If you have an air-ventilation system -- usually ducts that exchange indoor for outdoor air -- keep it running for at least 48 hours after the carpet is installed (although airing out the house longer certainly won't hurt).
Consider area rugs, which can be less toxic than wall-to-wall carpeting, since the latter is usually glued to the floor with adhesives that can also off-gas fumes.
Consider purchasing carpets and rugs made of sustainable materials, such as sisal, coir, wool, or organic cotton. Look for rugs with jute, latex, or other natural backings that are sewn on, rather than glued with toxic adhesives, and ask for a wool underpad, too.
Many eco-friendly alternatives are available at ecobydesign.com or naturalhomesource.com. Flor offers low-VOC nylon and wool modular floor tiles, with backing made of some recycled materials; the company also recycles its old floor tiles. No matter what material you choose, look for floor coverings that are not treated with fire retardants, stain protectors, or other chemicals. If purchasing a handmade rug, look for the Rugmark label, which certifies that it was made without using child labor.