Fear of sickness from "night air" persisted in the US until just a century ago

Wired - Fantastically Wrong: Why People Were Terrified of Nighttime Air Until the 1900s

A summary of a summary: this article mainly summarizes the essay from Peter Baldwin's "How Night Air Became Good Air" in Environmental History. The speculation is that humans have a biological fear of the dark (or, at the very least, an apprehension), and that it was this fear that continued to influence our thinking about the "night air" even once we moved past the hunting-gathering stages of our history and into agrarian and urban civilization. According to the essay, Americans suspected the night air of carrying sickness, a combination of a fear of "miasma" emanating from swamps and other decaying (organic) bodies and the coolness of night "moisture, which brought the chills. There were skeptics, as proved by John Adams' recollection of an attempt to shut himself into a room he was sharing with Benjamin Franklin, who refused, and lectured him about the silliness of the dread deep into the night. Further dissent came when examining the air within houses that were poorly ventilated: this air was worse due to the excrement we give off from exhaling and through our pores, argued Catherine Beecher and Beecher-Stowe. This led to the belief that the higher the concentration of people, the worse the air: the urban slums would be the worst. Thus in the 1800s the early examples of the affluent fleeing the urban core. Perhaps, however, there was some wisdom in the practice of shutting up the house since (at least in North America), native mosquitoes are most active at night and can carry many serious diseases. Ultimately, the blame was turned to mosquitoes, and interesting methods of eliminating them were tried, including, notably, pouring huge amounts of kerosene into lakes, ponds, and un-drained swamps to discourage breeding!