Chris Henry, Director of Heritage, and Ken Donaldson, Senior Research Fellow at Surgeons’ Hall Museums, write about artefacts from the museum collections that reveal damage cause by urban air in previous centuries.

Most people, if asked, would be of the opinion that air pollution is worse now than in the past but, perhaps surprisingly, they would be wrong. Electricity and gas were not available in homes until the early to mid 20th century so prior to that households burned candles, oil, wood and coal for light and heat, often under conditions of poor ventilation and with inadequate flues. This resulted in the indoor air of homes being loaded with soot particles derived from these different forms of combustion. The nuisance effect of this polluted indoor environment in staining and damaging curtains, furniture and fittings was well known. As regards outdoor air John Evelyn in his pamphlet Fumifugium in the 17th century had described the highly smoke-polluted nature of London air and James Johnson in his pamphlet ‘Change of air’ said in 1837 that London had a :-

‘..dense canopy of smoke that spread itself over her countless streets and squares, enveloping a million and a half human beings in murky vapour..’

The problem was due in large part to the domestic burning of coal, which had increased 10-fold over the course of the 18th century. Although the advent of electrical and gas power for lighting and heating eventually alleviated the problem indoors, the domestic burning of coal continued to increase, exacerbating the outdoor pollution problem. This eventually lead to the infamous smogs of early and mid 20th century. One of these, the great London smog of December 1952, caused upwards of 12,000 deaths and lead directly to the Clean Air Acts of 1956. This legislation introduced “smoke control areas” in towns and cities in where only smokeless fuels could be used and encouraged cleaner sources of heat such electricity, and gas. The net result was to reduce the amount of emanating from household fires.

Returning to the situation in the early 19th century, particles that are in the air are breathed into the lungs and a proportion of them accumulate there. The anatomists who first carried out regular autopsies in the 18th and 19th centuries noted that, as people aged, their lungs became blacker in colour. A debate ensued in which various suggestions were advanced for the origin of this black matter. The debate should have been ended in 1813 when George Pearson, a Yorkshireman and graduate of Edinburgh University Medical School wrote a seminal paper describing his researches. In his paper Pearson mentions the oft-discussed darkening of the lungs with age:-

‘..As hath been repeatedly observed, the lungs generally become more dark coloured proportionately to their age..’

Pearson them makes the remarkably prescient suggestion that the darkening of the lungs is due to

‘sooty matter taken in with the air at respiration and accumulated in proportion to the duration of life..’

He did not base this supposition on guesswork but, being a skilled chemist he collected the black pigment from some lungs at autopsy and analyzed it. He found it to be pure carbon, or soot and it was on this that he based his hypothesis.

There then ensued about 50 years of argument with two main alternative explanations being put forward – 1) the black pigment was derived from blood; 2) elemental carbon could be precipitated in the lung tissue when the expulsion of carbon dioxide during exhalation went wrong.

A major stumbling block to acceptance of Pearson’s view, which we now know was the correct one, was Rudolf Virchow. As the single most influential figure in the development of modern pathology, it was only in 1868, when Virchow finally accepted that the black matter was inhaled soot, was Pearson’s theory given the general seal of approval.

The museum of the RCSEd has in it a collection lungs from around the time that Pearson was carrying out his work. In order to assess just how sooty lungs were at that time, a lung (G.C.493.2) collected in 1840 was identified, and a block take for histology and assessment of toxic heavy metals that are found in soot. The Figure below shows the huge extent of black soot accumulation in the pink lung tissue of this normal individual. The dustiness of the lung is more like the appearance we would now associate with being a coalminer, underlining just how much soot there was present in the air. The lung tissue was also heavily contaminated with toxic metals such as lead and mercury and research is continuing into the source and consequences of this level of air pollution.

We often view the past, especially the Dickensian past, through rose-tinted glass as ‘the good old days’. However this study, providing as it does a brief window into the heavily-polluted conditions a normal person would encounter in their own home, tends to dispel that sentimental notion.