41.   The FTC, however, has previously challenged overly broad claims for indoor air filters and purifiers.

42.   The homes will have such features as energy-efficient mechanical systems, additional insulation, and air handling systems that increase indoor air quality.

43.   The key is maintenance and control of indoor air pollutants, experts say.

44.   The latter are the most energy efficient, acting as supplemental heaters, but there are safety issues about their effect on indoor air quality.

45.   The quality of indoor air can be far worse than it is in the great outdoors, especially if a smoker is present.

46.   The researchers conducted tests that indicated that vented stoves cut levels of indoor air pollution by two-thirds.

47.   The poisonous mold, Stachybotrys atra, has been associated with sick building syndrome, an often mysterious collection of maladies that involve indoor air pollution.

48.   The simplest and most effective way to avoid polluting the indoor air with tobacco smoke is to ask all smokers to smoke outdoors.

49.   The Reuters building also includes filters to improve indoor air quality and glass that resists ultraviolet rays, reducing the amount of power needed for cooling.

50.   The syndrome refers to a collection of maladies in people, including runny eyes and noses and flulike symptoms caused by indoor air pollution.