['Introduction', 'The', 'public', 'concern', 'over', 'environmental', 'degradation', 'that', 'mounted', 'in', 'the', '1960s', 'and', 'led', 'to', 'the', 'landmark', 'environmental', 'laws', 'of', 'the', 'early', '1970s', 'identified', 'the', 'air', 'pollution', 'problems', 'of', 'greatest', 'concern', 'to', 'be', 'those', 'that', 'were', 'occurring', 'out-of-doors.', 'In', 'the', '1970', 'Clean', 'Air', 'Act,', 'Congress', 'gave', 'the', 'U.s.', 'Environmental', 'Protection', 'Agency', '(EPA)', 'the', 'authority', 'to', 'control', 'and', 'prevent', 'the', 'degredation', 'of', '"ambient"', '--', 'or', 'outdoor', '--', 'air.', 'Neither', 'the', '1970', 'law,', 'nor', 'the', 'major', 'amendments', 'to', 'the', 'law', 'passed', 'in', '1977,', 'addressed', 'the', 'quality', 'of', 'indoor', 'air.', 'Recognizing', 'that', 'air', 'pollution', 'within', 'homes,', 'offices,', 'and', 'schools,', 'on', 'airplanes,', 'and', 'in', 'other', 'enclosed', 'spaces', 'has', 'recently', 'become', 'a', 'matter', 'of', 'growing', 'concern,', 'in', '1986', 'Congress', 'passed', 'the', 'Radon', 'Gas', 'and', 'Indoor', 'Air', 'Quality', 'Research', 'Act', 'as', 'Title', 'IV', 'of', 'the', 'Superfund', 'Bill.', 'Title', 'Iv', 'provides', 'a', 'clear', 'Congressional', 'mandate', 'that', 'the', 'U.S.', 'Environmental', 'Protection', 'Agency', 'conduct', 'an', 'indoor', 'air', 'research', 'and', 'public', 'information', 'program.', 'This', 'booklet', 'is', 'one', 'of', 'the', 'activities', 'within', 'that', 'public', 'information', 'program.', 'ie)', 'A', 'Z', 'The', 'air', 'we', 'breathe', 'indoors', 'as', 'well', 'as', 'outdoors', 'nearly', 'always', 'contains', 'gases,', 'particles,', 'and', 'biological', 'materials', 'in', 'addition', 'to', 'nitrogen,', 'oxygen,', 'carbon', 'dioxide,', 'and', 'water', 'vapor.', 'These', 'other', 'gases,', 'particles,', 'and', 'biological', 'materials', 'are', 'called', '-1-', 'TIMN', '0019576', ' ']