1700s European cities filthy, smelly, bad air, dead animals in the streets

Every household burnt coal … The smoke from their chimneys made the air dark, covering every surface with sooty grime. There were days when a cloud of smoke half a mile high and twenty miles wide could be seen over the city … Londoners spat black.

In towns in the eighteenth century, the city ditches, now often filled with stagnant water, were commonly used as latrines; butchers killed animals in their shops and threw the offal of the carcasses into the streets; dead animals were left to decay and fester where they lay; latrine pits were dug close to wells, thus contaminating the water supply. Decomposing bodies of the rich in burial vaults beneath the church often stank out parson and congregation.

A “special problem” in London, Stone wrote, was the “poor holes” or “large, deep, open pits in which were laid the bodies of the poor, side by side, row by row. Only when the pit was filled with bodies was it finally covered with earth.” As one contemporary writer, whom Stone quotes, observed, “How noisome the stench is that arises from these holes.” Furthermore, “great quantities of human excrement were cast into the streets at night … It was also dumped into on the surrounding highways and ditches so that visitors to or from the city ‘are forced to stop their noses to avoid the ill smell.’”

The result of these primitive sanitary conditions was constant outbursts of bacterial stomach infections, the most fearful of all being dysentery, which swept away many victims of both sexes and of all ages within a few hours or days. Stomach disorders of one kind or another where chronic, due to poorly balanced diet among the rich, and the consumption of rotten and insufficient food among the poor.

Paris is a horrible place and ill smelling. The streets are so mephitic that one cannot linger there because of the stench of rotting meat and fish and because of a crowd of people who urinate in the streets.

Henry Mayhew, an English social researcher and journalist, found that the Thames contained "ingredients from breweries, gasworks, and chemical and mineral manufactories; dead dogs, cats, and kittens, fats, offal from slaughterhouses; street-pavement dirt of every variety; vegetable refuse; stable-dung; the refuse of pig-styes; night-soil; ashes; tin kettles and pans … broken stoneware, jars, pitchers, flower-pots, etc.; pieces of wood; rotten mortar and rubbish of different kinds."

https://fee.org/articles/the-industrial-revolution-was-dirty-but-pre-industrial-europe-was-worse/