For a considerable time, the significance of fresh air to our health has been acknowledged, even in moments when the underlying reasons were not entirely comprehended.

The New Brunswick legislature recently passed a motion to improve indoor air quality in the province’s public buildings “to reduce the spread of airborne illnesses, such as COVID-19.”

There are many ways to improve the air we breathe indoors, including filtration and ventilation: bring fresh air in, send exhaled air and contaminants out. And we have good reasons for looking at indoor air quality.

From wildfire smoke, to industrial pollution, many of us have felt the impacts of poor air quality and turned to air filters and respirators to cope.

The White House held a summit last year on improving indoor air quality to reduce the transmission of COVID-19. This September, there will be a similar meeting in Europe organized by the World Health Organization.

How new is all this? Well, it is and it isn’t. Eighteenth-century physicians were big advocates for ventilation as a way of reducing the transmission of contagious diseases, though not entirely for sound reasons.

Ventilation and eighteenth-century medicine

I teach about eighteenth-century literature and medical writing in the British Isles. In the 1700s, British physicians took advantage of new scientific approaches but had little technology to see what was going on.

They believed that most contagious illnesses spread through smelly decaying matter, or miasma, from rotting food, sick bodies and so on. This is called “miasma theory,” and it was eventually replaced by germ theory.

Miasma theory meant that physicians associated bad smells with disease. But they also had the evidence of their eyes. Eighteenth-century physicians saw diseases spreading easily in crowded, poorly ventilated structures, from ships and jails to the homes of the poor. Ventilation made sense as a way to make people safer: blow out the bad air. It also seemed to make a difference when they used it..

So they acted. In 1756, the British Navy ordered the installation of recently invented ventilators on ships. A naval hospital required “doors and windows to be opened for the purposes of ventilation.” In 1802, the British parliament passed legislation requiring factories to have enough “Windows and Openings…to insure a proper Supply of Fresh Air.”