WHO GUIDELINES FOR INDOOR AIR QUALITY WHO GUIDELINES FOR INDOOR AIR QUALITY: WHO GUIDELINES FOR INDOOR AIR QUALITY: When sufficient moisture is available, hundreds of species of bacteria and fungi – particularly mould – pollute indoor air. The most important effects of exposure to these pollutants are the increased prevalence of respiratory symptoms, allergies and asthma, as well as disturbance of the immune system. Prevent- ing (or minimizing) persistent dampness and microbial growth on interior surfaces and building structures is the most important means of avoiding harmful effects on health. This book provides a comprehensive overview of the scientific evidence on the health problems associated with this ubiquitous DAMPNESS AND MOULD DAMPNESS DAMPNESS pollution and provides WHO guidelines to protect public health. It also describes the conditions that determine the presence of AND MOULD mould and provides measures to control its growth indoors. World Health Organization Regional Offi ce for Europe Scherfi gsvej 8, DK-2100 Copenhagen Ø, Denmark Tel.: +45 39 17 17 17. Fax: +45 39 17 18 18 E-mail: [email protected] Web site: www.euro.who.int WHO guidelines for indoor air quality : dampness and mould Keywords AIR POLLUTION, INDOOR - adverse effects - prevention and control FUNGI HUMIDITY - adverse effects - prevention and control ENVIRONMENTAL EXPOSURE RISK ASSESSMENT GUIDELINES ISBN 978 92 890 4168 3 Address requests for publications of the WHO Regional Office for Europe to: Publications WHO Regional Office for Europe Scherfigsvej 8 DK-2100 Copenhagen Ø, Denmark Alternatively, complete an online request form for documentation, health information, or for permission to quote or translate, on the Regional Office web site (http://www.euro.who.int/pubrequest). © World Health Organization 2009 All rights reserved. The Regional Office for Europe of the World Health Organization welcomes requests for permission to reproduce or translate its publications, in part or in full. The designations employed and the presentation of the material in this publication do not imply the ex- pression of any opinion whatsoever on the part of the World Health Organization concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its fron- tiers or boundaries. Where the designation ‘country or area’ appears in the headings of tables, it covers countries, territories, cities and areas. Dotted lines on maps represent approximate border lines for which there may not yet be full agreement. The mention of specific companies or of certain manufacturers’ products does not imply that they are en- dorsed or recommended by the World Health Organization in preference to others of a similar nature that are not mentioned. Errors and omissions excepted, the names of proprietary products are distinguished by initial capital letters. The World Health Organization does not warrant that the information contained in this publication is complete or correct and shall not be liable for any damages incurred as a result of its use. The views ex- pressed by authors or editors do not necessarily represent the decisions or the stated policy of the World Health Organization. Edited by: Elisabeth Heseltine and Jerome Rosen. Cover photos (from top): © Heger/Müller, © Szewzyk, © UBA, picture taken by Moriske. Book design: Sven Lund. Printed in Germany by Druckpartner Moser. WHO guidelines for indoor air quality : dampness and mould Abstract Microbial pollution is a key element of indoor air pollution. It is caused by hun- dreds of species of bacteria and fungi, in particular filamentous fungi (mould), growing indoors when sufficient moisture is available. This document provides a comprehensive review of the scientific evidence on health problems associated with building moisture and biological agents. The review concludes that the most important effects are increased prevalences of respiratory symptoms, allergies and asthma as well as perturbation of the immunological system. The document also summarizes the available information on the conditions that determine the presence of mould and measures to control their growth indoors. WHO guide- lines for protecting public health are formulated on the basis of the review. The most important means for avoiding adverse health effects is the prevention (or minimization) of persistent dampness and microbial growth on interior surfaces and in building structures. Cont ents Contributors vii Acknowledgements x Foreword xi Executive summary xii 1. Introduction 1 1.1 Background 1 1.2 Scope of the review 3 1.3 Preparation of the guidelines 5 1.4 Guidelines and indoor air quality management 6 2. Building dampness and its effect on indoor exposure to biological and non-biological pollutants 7 2.1 Frequency of indoor dampness 7 2.2 Effects of dampness on the quality of the indoor environment 9 2.3 Dampness-related indoor pollutants 13 2.4 Exposure assessment 20 2.5 Summary and conclusions 29 3. Moisture control and ventilation 31 3.1 Introduction 31 3.2 Sources of moisture 34 3.3 Mould and mites as indicators of building performance 37 3.4 Ventilation performance 41 3.5 Ventilation systems 42 3.6 Outdoor and other sources of pollution related to ventilation 49 3.7 Ventilation and spread of contaminants 51 3.8 Moisture control in buildings 55 3.9 Measures to protect against damage due to moisture 58 3.10 Conclusions and recommendations 61 4. Health effects associated with dampness and mould 63 4.1 Review of epidemiological evidence 63 4.2 Clinical aspects of health effects 78 4.3 Toxicological mechanisms 84 4.4 Synthesis of available evidence on health effects 89 5. Evaluation of human health risks and guidelines 93 5.1 Summary 93 5.2 Conditions that contribute to health risks 93 5.3 Guidelines 94 6. References 97 Annex 1. Summary of epidemiological studies 133 Annex 2. Summary of in vitro and in vivo studies 215 VII Co ntributors Participants in the working group meeting in Bonn, 17–18 October 2007 Alireza Afshari Danish Building Research Institute, Copenhagen, Denmark Hugh Ross Anderson1 St George’s Hospital Medical School, University of London, London, England Aaron Cohen1 Health Effects Institute, Boston, United States of America Eduardo de Oliveira Institute of Mechanical Engineering, Fernandes Faculty of Engineering, University of Porto, Porto, Portugal Jeroen Douwes Centre for Public Health Research, Massey University, Wellington, New Zealand Rafal Górny Institute of Occupational Medicine and Environmental Health, Sosnowiec, Poland Maija-Riitta Hirvonen National Public Health Institute, Helsinki, Finland Jouni Jaakkola Institute of Occupational and Environmental Medicine, University of Birmingham, Birmingham, United Kingdom Séverine Kirchner1 Centre Scientifique et Technique du Bâtiment, Marne la Vallée France Jarek Kurnitski University of Technology, Helsinki, Finland Hal Levin Building Ecology Research Group, Santa Cruz, United States of America Mark Mendell Lawrence Berkeley National Laboratory, Berkeley, United States of America Lars Mølhave1 Department of Public Health, University of Aarhus, Aarhus, Denmark Lidia Morawska International Laboratory for Air Quality and Health, Queensland University of Technology, Brisbane, Australia Aino Nevalainen1 National Public Health Institute, Helsinki, Finland VIII WHO GUIDELINES FOR INDOOR AIR QUALITY: DAMPNESS AND MOULD Malcolm Richardson University of Helsinki, Helsinki, Finland Peter Rudnai National Institute of Environmental Health, Budapest, Hungary Hans W. Schleibinger Institute for Research in Construction, National Research Council of Canada, Ottawa, Canada Per E. Schwarze Norwegian Institute of Public Health, Oslo, Norway Bernd Seifert1 Consultant, Berlin, Germany Torben Sigsgaard University of Aarhus, Aarhus, Denmark Weimin Song Fudan University, Shanghai, China John Spengler1 Harvard School of Public Health, Boston, United States of America Regine Szewzyk Federal Environment Agency, Berlin, Germany Sadras Panchatcharam Sri Ramachandra University, Chennai, India Thyagarajan Giulio Gallo European Commission, Brussels, Belgium Manfred Giersig (observer) European Chemical Industry Council (CEFIC) and Bayer Material Science AG, Leverkusen, Germany Co-authors who did not participate in the working group meeting Jakob Bønløkke University of Aarhus, Aarhus, Denmark Kerry Cheung Centre for Public Health Research, Massey University, Wellington, New Zealand Anna G. Mirer Lawrence Berkeley National Laboratory, Berkeley, United States of America Harald W. Meyer Hillerød Hospital, Hillerød, Denmark Marjut Roponen National Public Health Institute, Helsinki, Finland 1 Steering Group member CO NTRIBUTORS IX Reviewers who did not participating in the working group meeting Olaf Adan Eindhoven University of Technology and Netherlands Organization for Applied Scientific Research (TNO), Eindhoven, Netherlands Gwang Pyo Ko Seoul National University, Seoul, Republic of Korea WHO Regional Office for Europe Matthias Braubach Otto Hänninen Michal Krzyzanowski (project leader) Secretariat: Andrea Rhein, Deepika Sachdeva None of the people listed declared any conflict of interest. X Acknowledgements Preparation of the guidelines was supported by funds received by the WHO Eu- ropean Centre for Environment and Health (Bonn Office) from the German Federal Environment Ministry and from the United Kingdom Department of Health, which are gratefully acknowledged. The input of Jeroen Douwes was supported by a Sir Charles Hercus Fellowship funded by