Dirt: The Filthy Reality of Everyday Life, Wellcome Collection, London

Miasma. Foul air. Stench. These were the words that sent terror into the urban soul of centuries past, when what everyone should have been afraid of was the contents of the jug on their bedroom washstand. But it wasn't until the mid-19th century, after countless thousands of cholera deaths, that the link began to be made between public health and contaminated water.

A "ghost map" of early Victorian Soho drawn up by a London doctor is by no means the most interesting exhibit in the Wellcome Collection's latest exhibition, Dirt: The Filthy Reality of Everyday Life, but it's one of the most significant. Using tiny black blocks, Dr John Snow marked the homes of individual victims of the infection. A dark cluster of marks lining the streets around a particular water pump identified for the first time the devastating link between disease and drinking water polluted with human faeces.

History is rich with progressive victories over dirt, and the exhibition proposes six different places and times to explore changing attitudes, including a Dutch home in 17th-century Delft, a street in early Victorian London and a Glasgow hospital in the 1860s. There are also rooms devoted to Dresden in the early 20th century, present-day Delhi and a future New York landfill site, but somehow this visitor managed to emerge from the show having missed these (perhaps from poor or absent signage – she's at a loss to say how it happened).

One of the smallest exhibits is the world-changing, single-lens microscope designed by Delft scientist Antonie van Leeuwenhoek, through which he discovered microbes, some of them in what he called the "batter" scraped from his teeth. A plasma screen, showing the very varieties of microbe he found in their different wrigglings and jostlings, makes clear why he termed them animiculae, or "little animals". A magnified dust mite, with its glistening pale-pink carapace and scuttling legs, holds a similar fascination.

It's surely no coincidence that the town of Delft also became famous for its ceramic sanitary wares, and there are exquisite examples displayed of early blue-and-white tiles, and an ingenious chamber pot with a spout.

The question of who would have emptied that chamber pot is also addressed, the frontline battle against dirt having always been fought largely by a half-seen underclass of domestics and cleaners. Victorian photography fleshes out the story at this point, documenting the fantastic variety of sanitising tasks undertaken, many of them with a built-in commercial aspect, as in the case of bone grubbers, mudlarks, and the euphemistically named "pure finders" who collected dog faeces for use in tanneries.

The Victorians' ingenious transformation of dust heaps and other debris into housebricks inspires the show's most intriguing contemporary project. The artist Serena Korda invited institutions and members of the public to gather dust from their immediate environment and submit it in a labelled envelope. She then incorporated the material in specially fired terracotta bricks, each imprinted with the donor's initials. The RNIB's brick includes "dog hair from guide dogs", while one that Stephen Geers contributed has "fluff from under my fridge". Less convincing is the "ritualising" of the bricks in a choreographed dance, shown on film. The project culminates in the bricks' burial – dust to dust – completing the circle.

The Wellcome Collection describes itself as "a free destination for the incurably curious". It would take a dullard, indeed, to prefer that this topic be swept under the carpet.

Until 31 Aug (020-7611 8545)

Exhibitions Choice

The potters, printers and cabinet-makers take pride of place in The Cult of Beauty, the V&A's sprawling survey of the Aesthetic Movement, but it's the South Kensington museum's smaller section devoted to the grace and grandeur of the painters – Leighton, Rossetti, and most notably Whistler – that makes it worth a visit (until 17 Jul).