PREFACE 



Aerobiology is usually understood to be the study of passively airborne 

 micro-organisms — of their identity, behaviour, movements, and survival. 

 One characteristic, which it shares with many other population studies 

 in biology, is that the ultimate relevant unit consists of the individual 

 cell or small group of cells. Analysis at the molecular or sub-atomic level 

 is irrelevant to our present purpose. Like geography, aerobiology is an 

 agglutinative study, drawing information from many kinds of scientific 

 research. Although it already has its patron saint, Pierre Miquel, and its 

 martyr, Fred C. Meier, aerobiology is best regarded as an activity whose 

 material will in due course be incorporated into the main body of bio- 

 logical science — without, I hope, any necessity for splinter societies, 

 journals, and international conferences. 



This book amplifies and extends a course of Intercollegiate Lectures 

 given to botanical students in the University of London in 1956. The 

 theme, which has occupied me for over fifteen years, is as follows. Trans- 

 port through the atmosphere is the main dispersal route for such organic 

 particles as the spores of many micro-organisms. How do the properties 

 of the atmosphere, and the properties of these particles themselves, 

 affect their dispersal? How do the particles get into the air? How far, 

 and in what numbers, are they dispersed? By what processes do they 

 become grounded, so that they can continue growth ? What is in the air, 

 and how can we measure it ? What are the practical consequences of this 

 process for the micro-organisms themselves, and for man, other animals, 

 vegetation, and crops ? 



Although there are one or two other books on airborne microbes, this 

 is the first to treat the subject as a world-wide phenomenon. It is, perhaps, 

 inevitable that it should be attempted by a mycologist. Few other biologists 

 find their material so dominated by the atmosphere, and no other micro- 

 organisms have so thoroughly exploited the possibilities of aerial dispersal as 

 the fungi. One of the fascinations of the subject is the impact of facets of its 

 knowledge on such apparently diverse topics as artificial rain-making, allergy, 

 smoke screens, effluent of nuclear power-stations, crop protection, icing of 

 aircraft, air hygiene, and many other topics. This book treats of the 

 development and principles of aerobiology rather than applications; yet 

 the stimulus to nearly all aerobiological work comes from applied science. 



In this book the term 'microbe' is used freely when a general word is 

 wanted; but, like the word 'spore', it has admittedly been stretched 

 beyond its normal meaning. Airborne pollen of flowering plants must be 



