Safe Scents

Sometimes a sweet-smelling aroma is just what you need to clear the air. But how do you know which scents are safe? "Fragrance products often contain alcohols, aldehydes (like formaldehyde, a common indoor air pollutant and probable carcinogen) and aromatic hydrocarbons, which can be irritating to the eyes and respiratory system," says Joseph Ponessa, Ph.D., an indoor air specialist at the Rutgers Cooperative Extension. "If they are used, moderation should be a guideline."

Also check labels for synthetic scents (signaled by the general term "fragrance"), which can release hormone-disrupting chemicals known as phthalates. For a healthier dose of aromatherapy, try pure essential oils, which are distilled from flowers (lavender, jasmine), woods (sandalwood, cedar), leaves (basil, eucalyptus) and resins (frankincense, myrrh).

Incense and Candles

Fine particulate matter, which can trigger allergies and asthma, is contained in smoke, including that from incense and candles. Researchers also have found high levels of polycyclic aromatic hydrocarbons (PAHs)—carcinogenic by-products of combustion that have been linked to lower birth weights in babies of exposed mothers—in temples and churches where incense is burned frequently. While keeping tapers out of a draft, make sure your breathing space is well ventilated (see "Safety Tips," below). And look for beeswax, soy and vegetable-based waxes scented with pure essential oils, which burn cleaner and greener than petroleum-based paraffin waxes or gels.

Another smoke contaminant you don't want to inhale is lead, a nervous-system toxin often used in wire candle wicks. Choose all-cotton wicks: to run a quick test, examine the tip of the wick and look for a dark, stiff, metal core.

Air Fresheners, Home Fragrances

If you choose to spritz scents around your home, remember to be considerate of others. "Some folks like them, others don't . . . and fragrances, whether natural or synthetic, can be irritants," Ponessa says. Manufacturers don't always reveal a complete list of ingredients, either. Even high-end products can be elusive about labeling. An article in The New York Times Magazine, "Now Let Us Spray," recently praised a variety of boutique-brand fragrances, and when The Green Guide contacted these companies, they would not disclose the ingredients.

A more natural home-fragrance option is to buy pure essential oil-based sprays or mix a few drops of an essential oil mixed with water in a reusable spray bottle. Or just leave out in a bowl some organic potpourri, which can also be scented with essential oil.