Bryologists and lichenologists are well aware of the differential sensitivity of bryophytes and lichens to air pollutants. However, governmental agencies and other scientists have not used the wealth of information to the fullest extent. It is hoped that this volume will help bridge the gap between the professional bryologist and lichenologist on the one hand and those who are concerned with assessing biological aspects of air quality issues on the other. In addition, the book will provide a useful reference for anyone embarking on a research project in this area and provides a modern synthesis for those who are already working in the field.

Accordingly the book is roughly organized into four parts. (1) The first two chapters provide background information for those who are not familiar with lichensand bryophytes. (2) Chapters 3-6 emphasize field studies and are arranged approximately in an order of increasing quantitative complexity. (3) Chapters 7-10 provide considerable physiological information derived from laboratory studies that are necessary to establish that lichens and mosses do actually respond to air pollutants. This section also discusses ways by which field and laboratory studies may be integrated to establish a stronger case for establishing that lichens and bryophytes are sensitive to air pollutants. (4) The last two chapters provide specific ways by which governmental agencies may usefully apply information gained from lichen and bryophyte studies. Thus the book is concerned with both air quality effects on lichens and mosses and the way by which air quality may be assessed by studying lichens and mosses.

The origin of this book stems from a symposium on "Assessing air quality with lichens and bryophytes", that was jointly sponsored by the U.S. National Park Service and the American Institute of Biological Science meetings held in August, 1983, at Grand Forks, North Dakota, USA. Most of the original authors expanded their contributions considerably beyond the scope of their original talks. Some of the papers are contributions from new authors.