Air and climate: an historical introduction

Mike Emanuel, Research Associate at Oxford Brookes University, Department of History, Philosophy and Religion, writes:

In the fifth century BC, Hippocrates, in ‘On the Nature of Man’ and ‘Airs, Water, Places’ saw health as a matter of equilibrium within the body, and illness as a destabilisation of that equilibrium. Interpreted six centuries later and popularised for the next millennium by Galen and his followers, Hippocratic medicine linked the four humours (black bile, yellow bile, blood and phlegm), the four primary natural qualities (hot, cold, dry, and wet) to the four elements (earth, fire, air and water), the four temperaments (melancholy, choleric sanguine, phlegmatic) and finally to the four ages of man (childhood, youth, adulthood and old-age) and the seasons of the year.

So, air was seen from the earliest times as having a critical role in the balance of health, long before any understanding of its role in contributing to that balance existed. Throughout the period and well into the middle ages, Galenical thinking encompassed the concept of miasma (bad air) into its concept of environmental susceptibility, reacting with the individual susceptibility of unbalanced bodily humours. Medical and lay explanations of disease have long attributed importance to air and climate. Margaret Pelling, writing on apprenticeship in seventeenth-century London, quotes the need for ‘better air for apprentice’s health’ and ‘fear of being visited by London’s diseases’. It was understood that plague and smallpox were epidemics that prospered in crowded environments long before any understanding of the germ theory of disease.

The idea of malignant or corrupt air is widespread and central to writing about disease, especially in relation to epidemics. In Coriolanus, Shakespeare writes

As the dead carcasses of unburied men, / That do corrupt my air, I banish you.

Similarly, in Jayne Eyre (1847), Charlotte Bronte attributes the outbreak of a typhus epidemic to the miasmas and mists of the unhealthy climate:

That forest-dell where Lowood lay, was the cradle of fog and fog-bred pestilence; which quickening with the quickening spring, crept into the Orphan Asylum, breathed typhus through its crowded schoolroom and dormitory and, ‘ere May arrived, transformed the seminary into a hospital.

Herzlich and Pierret, in their paper ‘Illness: from causes to meaning’, discuss the factors that made air corrupt as described in the seventeenth century, and describe a

malignant combination of heat and humidity, miasmas from the ground, the marshes in the country, putrid effluvia from the corpses of men and animals, emanations from living bodies and soiled clothing and also stagnant air in excessively narrow town streets.

What caused air to be corrupt was a matter of theological as well as medical argument and any explanation assumed that, in the last analysis, it is God who sends illness to mankind: air is the delivery system of God’s will. Air and climate were inextricably linked and illness was related to any unusual meteorological events as it had been back in biblical times. So Pierre de L’Estoile, writing in 1609, stated,

The disposition of the air was malignant, full of thunder, storms, sudden rain and tempests, symbolising the humours of the century, carried off large numbers of people of all ages, sex and condition.

Debates about contagion as a factor in disease and the corruption of air continued for many centuries. As an example, Frascotoro of Padua wrote extensively on contagion in the early sixteenth century and isolated three kinds; contagion from person to person; indirect contagion from an object to a person; and contagion at a distance through the air. These ideas were the basis of many of the practices of hygiene and isolation used to deal with plague. The idea of transmission without contact is an expression of the quality of the air: healthy air becomes poisoned and transmits the contagion; it becomes all the more virulent because it has overcome healthier air. Nevertheless, without understanding of the process of contagion, medical and political debate in the eighteenth century about the importance of contagion and the dominance of the anti-contagionists lasted until the discoveries of Pasteur in the nineteenth century.

Interested readers might enjoy this podcast of Mike’s recent talk on the Open Air School movement (‘A non-evidenced based experiment in social health‘).