31.   Recent federal and state attempts to pass laws on indoor air safety have failed.

32.   Samples of the indoor air also confirmed the presence of chlorpyrifos.

33.   Seventy percent of schools surveyed reported indoor air quality problems.

34.   Soot on the furniture is a sign that the stove is releasing pollutants into the indoor air.

35.   Sources of indoor air pollution include gas heaters, kerosene heaters, wood-burning stoves and cooking ranges.

36.   Such steps, of course, are aimed at removing the obvious sources of indoor air pollution.

37.   The artificial noses could monitor air quality in building ventilation systems, keeping track of scores of different indoor air chemicals.

38.   The American Lung Association, among other groups concerned about public health, has many suggestions for cleaning up indoor air that residents can implement.

39.   The Cambridge company has maintained an indoor air council for several years to watch out for employee comfort and health issues related to air quality.

40.   The Environmental Protection Agency and the American Lung Association say that indoor air pollution is a major health concern.