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Toxicity and elemental composition of particulate matter from outdoor and indoor air of elementary schools in Munich, Germany
Author(s) -
Oeder S.,
Dietrich S.,
Weichenmeier I.,
Schober W.,
Pusch G.,
Jörres R. A.,
Schierl R.,
Nowak D.,
Fromme H.,
Behrendt H.,
Buters J. T. M.
Publication year - 2012
Publication title -
indoor air
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.387
H-Index - 99
eISSN - 1600-0668
pISSN - 0905-6947
DOI - 10.1111/j.1600-0668.2011.00743.x
Subject(s) - environmental chemistry , particulates , toxicity , indoor air , chemistry , ultrafine particle , ventilation (architecture) , environmental science , toxicology , environmental engineering , meteorology , biology , physics , organic chemistry
Outdoor particulate matter (PM 10 ) is associated with detrimental health effects. However, individual PM 10 exposure occurs mostly indoors. We therefore compared the toxic effects of classroom, outdoor, and residential PM 10 . Indoor and outdoor PM 10 was collected from six schools in Munich during teaching hours and in six homes. Particles were analyzed by scanning electron microscopy and X‐ray spectroscopy (EDX). Toxicity was evaluated in human primary keratinocytes, lung epithelial cells and after metabolic activation by several human cytochromes P450. We found that PM 10 concentrations during teaching hours were 5.6‐times higher than outdoors (117 ± 48 μg/m 3 vs. 21 ± 15 μg/m 3 , P < 0.001). Compared to outdoors, indoor PM contained more silicate (36% of particle number), organic (29%, probably originating from human skin), and Ca‐carbonate particles (12%, probably originating from paper). Outdoor PM contained more Ca‐sulfate particles (38%). Indoor PM at 6 μg/cm 2 (10 μg/ml) caused toxicity in keratinocytes and in cells expressing CYP2B6 and CYP3A4. Toxicity by CYP2B6 was abolished with the reactive oxygen species scavenger N ‐acetylcysteine. We concluded that outdoor PM 10 and indoor PM 10 from homes were devoid of toxicity. Indoor PM 10 was elevated, chemically different and toxicologically more active than outdoor PM 10 . Whether the effects translate into a significant health risk needs to be determined. Until then, we suggest better ventilation as a sensible option. Practical Implications Indoor air PM 10 on an equal weight base is toxicologically more active than outdoor PM 10 . In addition, indoor PM 10 concentrations are about six times higher than outdoor air. Thus, ventilation of classrooms with outdoor air will improve air quality and is likely to provide a health benefit. It is also easier than cleaning PM 10 from indoor air, which has proven to be tedious.