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Fundamentals of growth in indoor environments and strategies for healthy living Fundamentals of mold growth in indoor environments and strategies for healthy living

edited by:

Olaf C.G. Adan Robert A. Samson

Wageningen Academic P u b l i s h e r s This work is subject to copyright. All rights are reserved, whether the whole or part of the material is concerned. Nothing from this publication may be translated, reproduced, stored in a computerised system or published in any form or in any manner, including electronic, mechanical, reprographic or photographic, without prior written permission from the publisher: ISBN: 978-90-8686-135-4 Wageningen Academic Publishers e-ISBN: 978-90-8686-722-6 P.O. Box 220 DOI: 10.3920/978-90-8686-722-6 6700 AE Wageningen The Netherlands www.WageningenAcademic.com Photo cover: [email protected] Robert A. Samson CBS Fungal Biodiversity Centre, The individual contributions in this Utrecht, The Netherlands publication and any liabilities arising from them remain the responsibility of the authors. First published, 2011 The publisher is not responsible for possible damages, which could be a © Wageningen Academic Publishers result of content derived from this The Netherlands, 2011 publication. Preface

Molds play a crucial role in our daily life, affecting our well-being both in a positive and negative way. can be found nearly anywhere, being present outdoors and indoors. They are spoiling food as well as giving it specific flavors, they are digesting plant and animal matter, they cause defacement of interior surfaces and they may release lightweight and fragments that travel through the air.

In our built environment, molds are often associated with dampness, introducing moisture control as the key to mold control. And for many years, molds and their implications to human health have been prominently on the agenda, referring to increased risk of respiratory symptoms, respiratory and exacerbations of .

Today, and moisture, and their associated health effects, are a society- wide problem. The economic consequences of indoor mold and moisture are enormous. Their global dimension has been emphasized in the 2009 Guidelines on : dampness and mould of the World Health Organization, stating that: “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”. Similarly, Krieger et al. (2010) concluded in their review for the US Centers for Disease Control that one of three interventions ready for implementation in houses was: “Combined elimination of moisture intrusion and leaks and removal of moldy items”. These conclusions are in line with the leading principle of this book.

In this era of progress and prosperity, scarcity is now becoming a key problem globally. Scarcity in natural resources, scarcity in energy. In the next decennia, energy efficiency will dominate residential building and construction. First steps in response to the energy crises in the 20th century – i.e. and increased air tightness of the – obviously led to dampness problems. The question rises if next steps in energy efficiency will introduce new risks for adverse health effects of indoor molds.

This book aims to describe the fundamentals of indoor mold growth as a prerequisite to tackle mold growth in present building as well as in future energy efficient building. Without doubt, water is the key factor. A profound understanding of the mold-water relation lays the foundation for control strategies in any building, present and future.

Fundamentals of mold growth in indoor environments 7 The common approach to control mold growth risks on the basis of theambient air alone is no guarantee at all for a “mold-free” environment. Short humidity peaks may result in mold growth. This relation between mold growth and climate dynamics is particularly addressed in this book.

The book brings together different disciplinary points of view on indoor mold, ranging from physics and material science to microbiology and health sciences. The contents have been outlined according to three main issues: (1) fundamentals, particularly addressing the crucial roles of water and materials, (2) health, including a state-of-the-art description of the health-related effects of indoor molds, and (3) strategies, integrating remediation, prevention and policies. The latter has been added, as information dissemination among all relevant stakeholders is an essential step towards strategies for achieving healthy indoor environments.

The editors like to thank the authors for their excellent contributions and particularly David Miller, who also has continuously supported our research. We greatly acknowledge Jeannette Schouw of TNO for her indispensable support in (cross) checking references and editing figures.

Olaf Adan and Rob Samson

References

Krieger J, Jacobs DE, Ashley PJ, Baeder A, Chew GL, Dearborn D, Hynes HP, Miller JD, Morley R, Rabito F and Zeldin DC (2010) Housing interventions and control of asthma-related indoor biologic agents: a review of the evidence. J Public Health Manag Pract 16(5) E-Supp: S11-S20. World Health Organization (2009) WHO guidelines for indoor air quality: dampness and mould. WHO Regional Office for Europe, Copenhagen, Denmark, 228 pp.

8 Fundamentals of mold growth in indoor environments Table of contents

Preface 7

1 Introduction 15 Olaf C.G. Adan and Robert A. Samson

Introduction 15 Why is this book different? 16 The societal context of indoor fungal growth 18 Introduction to indoor fungi 21 Water as the key factor 22 References 33 Appendix 1. Thermodynamic definition of water activity and relative humidity 36

Fundamentals

2 Water relations of fungi in indoor environments 41 Olaf C.G. Adan, Henk P. Huinink and Mirjam Bekker

Introduction 41 Fungal response to long term variations in indoor climate 42 Short term variations in indoor climate 54 Conclusions 63 References 64

3 Fungal growth and humidity fluctuations: a toy model 67 Henk P. Huinink and Olaf C.G. Adan

Introduction 67 A toy model for growth 68 Growth scenarios 73 Comparison with experiments 75 Signposts for a better model 78 Conclusion and outlook 80 References 82

Fundamentals of mold growth in indoor environments 9 4 The fungal cell 83 Jan Dijksterhuis

Introduction 83 Fungal growth 83 The fungal colony as a unity 87 Considerations about aerial hyphae and fungal survival 87 References 98

5 Ecology and general characteristics of indoor fungi 101 Robert A. Samson

Introduction 101 Nomenclature 110 References 114

6 Characteristics and identification of indoor -decaying basidiomycetes 117 Olaf Schmidt and Tobias Huckfeldt

Fungal and significance 117 Dry rot fungi: Serpula species, Leucogyrophana species, Meruliporia incrassata 123 Cellar fungi (“wet-rot fungi”): Coniophora species 135 Indoor polypores: Antrodia species and Oligoporus placenta 139 Diplomitoporus lindbladii 151 Asterostroma species 152 Tapinella panuoides (Paxillus panuoides), stalkless paxillus, oyster rollrim 152 Trechispora species 154 Dacrymyces stillatus, orange jelly 154 Phellinus contiguus 156 Identification and characterization 156 References 169

10 Fundamentals of mold growth in indoor environments Health

7 Health effects from mold and dampness in housing in western societies: early studies and barriers to further progress 183 J. David Miller

Introduction 183 Early large-scale studies linking dampness and mold to health 187 Biomarkers 195 Conclusions 201 Acknowledgements 202 References 202

8 Aerosolized fungal fragments 211 Brett J. Green, Detlef Schmechel and Richard C. Summerbell

Introduction 211 The process of fungal fragmentation 215 Contributions of hyphal fragments and to the environment 218 Collection, enumeration and quantification of hyphal and fungal fragments 224 Implications for human health 231 Conclusions and future perspectives 234 Acknowledgements 234 References 235

9 on building materials 245 Kristian Fog Nielsen and Jens C. Frisvad

Introduction 245 Analytical methods 247 The fungi 249 Exposure 264 Conclusion 265 Acknowledgements 265 References 266

Fundamentals of mold growth in indoor environments 11 10 WHO guidelines for indoor air quality: dampness and mold 277 Otto O. Hänninen

History of who guidelines for air quality 277 Focusing on indoor air 281 State of the scientific evidence 286 Potential global guideline targets 292 Indicators of dampness and microbial growth 292 Chemicals with specific role indoors 294 Relationship of guidelines to health impact assessment and management 296 Interventions 297 Acknowledgements 301 References 301

Strategies – measuring

11 Moisture content measurement 305 Bart J.F. Erich and Leo Pel

Introduction 305 Basics of moisture measurements 305 Measuring the moisture content in materials 313 Measuring moisture content in air 324 Measuring the moisture content on the scale level of the 331 References 333

12 The fungal resistance of interior finishing materials 335 Olaf C.G. Adan

Introduction 335 Present standards to assess fungal resistance of materials for interior applications 336 A new concept to assess fungal growth 341 Next steps for improvement 344 Pilot application on a wide range of materials 346 Towards performance requirements in building codes 349 References 350

12 Fundamentals of mold growth in indoor environments 13 Detection of indoor fungi 353 James A. Scott, Richard C. Summerbell and Brett J. Green

Introduction 353 Environmental sampling 354 Bioaerosols 356 Air sampling 360 References 373

Strategies – remediation

14 Mold remediation in North American buildings 383 Philip R. Morey

Introduction 383 Examples of mold remediation strategies 386 New York City guidelines 395 Containment and suppression during mold remediation 397 Quality assurance during mold remediation 400 North American guidelines on mold remediation 404 References 409

15 Mold remediation in West-European buildings 413 Thomas Warscheid

Introduction 413 Basic causes of indoor mold infestation 414 Risk-assessment of mold growth 415 Sanitation of mold infestations – goals and limits 416 Mold guidelines in Germany 417 Limits and risks of mold guidelines 420 Gaps and necessary improvements in mold guidelines and their analytical approach 422 Challenges for future mold guidelines 424 Health implications of indoor mold 425 Intervention steps in sanitation 426 Future prospects 428 References 430

Fundamentals of mold growth in indoor environments 13 16 Protection of wood 435 Michael F. Sailer and Waldemar J. Homan

Introduction 435 Wood protection by biocides 438 Other ways of wood protection 446 New developments 458 References 459

17 Coating and surface treatment of wood 463 Hannu Viitanen and Anne-Christine Ritschkoff

Introduction 463 Microbial activity on coated surfaces 463 Biocidal protection of paints on wood 468 Novel trends in coating technology 473 Testing the resistance and performance of coatings on wood 481 References 484

Recommendations

18 Recommendations 491 Olaf C.G. Adan and Robert A. Samson

Introduction 491 Fundamentals 491 Health 492 Strategies 492 References 498

Contributors 499

Index 505

14 Fundamentals of mold growth in indoor environments