[' ', '  ', ' ', ' ', 'products', 'of', 'human', 'metabolism.19', ' ', 'DISCUSSION', 'i', 'Because', 'of', 'the', 'small', 'number', 'of', 'air', 'samples', 'that', 'were', 'evaluated', 'in', 'this', 'project,', 'one', 'cannot', 'be', 'confident', 'of', 'all', 'the', 'conclusions.', 'It', 'seems', 'very', 'likely', 'that', 'the', 'typical', 'number', 'of', 'organic', 'chemicals', 'found', 'indoors', 'ts', 'much', 'larger', 'than', 'the', 'number', 'present', 'outdoors,', 'and', 'that', 'the', 'difference', 'is', 'largely', 'due', 'to', 'release', 'from', 'consumer', 'products', 'and', 'to', 'human', 'metabolism.', 'If', 'this', 'is', 'true;', 'then', 'it', 'is', 'plaust-', 'ble', 'that', 'site', 'factors', 'leading', 'to', 'increased', 'ventilation', 'with', 'the', 'outdoors', 'will', 'often', 'lower', 'indoor', 'concentrations', 'of', 'many', 'airborne', 'organic', 'chemicals.', 'Still,', '{t', 'is', 'upsetting', 'to', 'see', 'that', 'cigarette', 'smoking', 'anticorrelates', 'with', 'total', 'chemicals', 'found.', 'The', 'smell', 'of', 'cigarette', 'smoke', 'in', 'a', 'house', 'Clearly', 'indi-', 'cates', 'the', 'presence', 'of', 'chemicals,', 'and', 'it', 'is', 'surprising', 'that', 'houses', 'with', 'smokers', 'have', 'fewer', 'total', 'airborne', 'chemicals.', 'Similarly,', 'it', 'is', 'surprising', 'that', 'houses', 'with', 'pets', 'have', 'fewer', 'airborne', 'chemicals.', 'These', 'results', 'were', 'not', 'anticipated', 'and', 'their', 'counter-intuitive', 'nature', 'is', 'unsettling.', 'The', 'conjecture', 'that', 'these', 'houses', 'have', 'fewer', 'chemicals', 'due', 'to', 'increased', 'ventilation', 'is', 'plausible', 'but', 'not', 'proven.', ';', 'The', 'site-factor', 'equation', 'that', 'was', 'used', 'to', 'fit', 'these', 'data', 'does', 'account', 'for', 'about', '50%', 'of', 'the', 'variance,', 'but', 'it', 'would', 'require', 'additional', 'data', 'for', 'verifica-', 'tion.', 'It', 'is', 'presumed', 'that', 'the', 'remaining', '50%', 'variance', 'is', 'largely', 'due', 'to', 'the', 'im-', 'precision', 'in', 'the', 'site', 'factor', 'Variables.', 'For', 'example,', 'rather', 'than', 'just', 'knowing', 'whether', 'or', 'not', 'a', 'house', 'has', 'a', 'fireplace,', 'it', 'would', 'better', 'to', 'know', 'if', 'it', 'is', 'a', 'wood', 'burning', 'fireplace,', 'how', 'often', 'it', 'is', 'used', 'and', 'how', 'much', 'fuel', 'is', 'used.', 'Similarly,', '1t', 'would', 'be', 'better', 'to', 'note', 'what', 'kinds', 'of', 'indoor', 'plants', 'are', 'growing', 'and', 'which', 'particular', 'consumer', 'products', 'are', 'used', '(brand', 'names', 'of', 'polishes,', 'waxes,', 'etc.).', 'Though', 'about', 'half', 'of', 'the', 'individual', 'chemicals', 'found', 'were', 'Statistically', '“correlated', 'with', 'individual', 'site', 'factors', '(probable', 'sources),', 'much', 'more', 'work', 're-', 'mains', 'to', 'be', 'done', 'on', 'this', 'Question.', 'Since', 'about', '127', 'of', 'the', 'chemicals', 'found', 'were', 'Present', 'in', 'only', '1', 'or', '2', 'of', 'the', 'Samples,', 'no', 'convincing', 'statistical', 'conclusions', 'about', 'their', 'correlations', 'could', 'be', 'reached.', 'If', 'the', 'number', 'of', 'samples', 'had', 'been', 'about', '5', 'times', 'larger,', 'Judgements', 'could', 'have', 'been', 'made', 'on', 'about', 'another', '100', 'chemicals.', 'CONCLUSIONS', 'bl', 'le', 'Based', 'on', '44', 'Chicago', 'area', 'air', 'Samples,', 'it', 'was', 'found', 'that:', '1.', 'There', 'were', '303', 'different', 'organic', 'chemicals', 'at', 'concentrations', 'above', '1', 'ppb', '(V/V)', '2.', 'Indoor', 'air', 'samples', 'contain', 'more', 'organic', 'chemicals', 'than', 'outdoor', 'ones', '(48.6', 'chemicals', 'per', 'Sample', 'versus', '19.2)', '3.', 'The', 'molecular', 'weight', 'distributions', 'of', 'the', 'indoor', 'and', 'outdoor', 'chemicals', 'do', 'not', 'differ', 'significantly', '4.', 'Most', 'of', 'the', 'chemicals', 'occur', 'at', 'low', 'frequency.', 'The', 'average', 'chemica)', 'was', 'found', 'in', '5.54', 'samples', 'and', '127', 'of', 'the', 'chemicals', 'were', 'found', 'only', 'in', '1', 'or', '2', 'samples', '5.', 'Some', 'of', 'the', 'chemicals', 'are', 'ubiquitous,', 'such', 'as', 'acetone,', 'benzene,', 'tolu-', 'ene.', '6.', 'Out', 'of', '50', 'site', 'factors', 'Surveyed,', 'only', '10', 'had', 'a', 'significant', 'correlation', 'with', 'total', 'chemicals', 'per', 'site,', 'especially', 'age', 'of', 'house', '(-),', 'smoking', '(-),', 'fire-', 'Place', '(+),', 'houseplants', '(+),', 'dogs', '(-),', 'geographical', 'area', '(+),', 'washer/drier', '(-)', 'and', 'number', 'of', 'occupants', 'aged', '5', 'to', '20', '(-)', '.', '7.', 'Other', 'factors', 'expected', 'to', 'correlate', 'with', 'total', 'chemicals', 'did', 'not:', ' ', ' ', '88hCS', 'l6st', 'NO', ' ']