At this stage in my research I became completely side-tracked by a persistant question: have humans always lived with air pollution, or is it a modern phenomenon? The answer wasn’t as straightforward as you might imagine. Consider this chapter a pause in the building drama. Let’s take a breath, sit round the campfire and commune with our ancient ancestors a while. When was the year dot for air pollution? And did it do our ancestors any harm, or have we just become modern-day wimps?
‘You can recognise a Neolithic site a mile off,’ says Professor Paul Goldberg. His hands freeze in mid-air on the Skype call. Speaking from an archaeological dig in rural France, in a cave called Pech de l’Azé, his internet connection is, understandably, not great. But I can still hear him. ‘A Neolithic site’, he says, ‘is just completely grey with ash.’ Goldberg, a professor emeritus of geoarchaeology at Boston University, was involved in the discovery of the earliest known site where Homo erectus may have controlled fire. In Wonderwerk Cave, South Africa, Goldberg and his team found remnants of ash dating back to one million years ago. I’m expecting to talk to him about this marking ‘year zero’, the point after which fire and smoke became something quintessentially, enduringly human. But Goldberg and others in his field are not convinced. The archaeological evidence shows that rather than discovering fire and then using it every day, fire use actually comes and goes for vast periods of early human history. Some humans lived their whole lives without it, even after it was a known technology. It is not until we reach the Neolithic, as recently as 12,000 years ago, that sites of human activity are instantly recognisable by the piles of ash they/we left behind. So, what was happening in the roughly 988,000 years in between?
‘Wonderwerk is a one-off!’ exclaims Goldberg, who can’t help but exclaim most points. ‘The most convincing one is still Qesem Cave in Israel, which is [only] 300,000 to 400,000 years old. There you have repeated ashes one on top of another – it is clear, repeated fire … in Europe [and] the Middle East, there seem to be different fire records.’ A paper from the University of Liverpool in 2016 agrees that ‘despite the increasing numbers of [European Palaeolithic] fire sites, their relative scarcity is still notable.’ Evidence of regular fires in any European site older than around 400,000 years is almost non-existent. If African hominins had mastered fire use before migrating into Europe, why didn’t they bring that technology with them?
In 2015, Goldberg was one of 17 researchers invited to a symposium in Portugal called ‘Fire and the Genus Homo’, which focused specifically on the beginning of fire use and its role in our evolution. Among the 17 was Dennis M. Sandgathe, lecturer in archaeology and human evolutionary studies at Simon Fraser University in Canada and the University of Pennsylvania. Having spent much of his earlier career specialising in Stone Age tools, in recent years he too became side-tracked by the questions surrounding early human’s use of fire. ‘For the period prior to about 400,000 years ago we have maybe half a dozen sites with any evidence for fire,’ Sandgathe tells me, speaking from his home office in Canada. ‘And it’s not overwhelming at any of these sites – a few tiny fragments of burned bone, a reddened patch of sediment … an incredibly small number of potential examples of fire use for such a long period of time … I am not convinced that any of these sites are related to human behaviour – they might be, but it is just as likely, perhaps more likely, that they are mostly natural fire residues – certainly none of them are demonstrably the product of people using fire. For the period after around 400,000 years ago we do have clear evidence of people using fire,’ and again he points to Qesem Cave in Israel.
The difference between Qesem Cave and all earlier sites is the presence of a hearth – a purpose-built (in this case 4m-square) fire pit. This site, in a limestone ridge 12km (7.5 miles) east of Tel Aviv, Israel, is the current earliest-known site where humans first sat, regularly, around a fire. While the cave was occupied from 420,000 to 220,000 years ago, the hearth is dated from 300,000 years ago. Amazingly, given its age, this site also offers our first window into the effects of regular smoke inhalation. A 2015 paper by Karen Hardy, Universitat Autònoma de Barcelona, studied eight hominin teeth from Qesem Cave for evidence of potential smoke inhalation. She found ‘the earliest evidence of exposure to potential respiratory irritants’, including micro-particles, in human history. The presence of small micro-charcoal fragments in the teeth, particles up to 70nm, entered the mouth through breathing, not eating, ‘indicative of fire and [these] suggest a smoky atmosphere inside the cave’.
Is this 300,000-year-old hearth in Israel, then, our year zero, after which humans and fire would always co-exist? It’s still not that simple, says Sandgathe. He and Goldberg have both recently turned their attention to the use of fire by Neanderthals, the Eurasian contemporaries of the Qesem Cave dwellers until their extinction (or assimilation) around 40,000 years ago. ‘Everyone, including us, assumed Neanderthals always used fire and likely knew how to make it,’ says Sandgathe. ‘Then we excavated … and found that, while they were definitely using fire during some periods, there were long periods of time where they weren’t using fire at these sites … and the layers with little fire evidence are, strangely, associated with cold periods. These layers still have tonnes of artefacts and bones so they are still inhabiting the sites during these periods – it’s not like they stopped using the sites.’ There are at least seven sites in south-west France that match this pattern of reduced fire evidence during cold periods. In layers that date to the last interglacial period between 130,000 and 75,000 years ago, fire was being used quite frequently by Neanderthals, using fully intact hearths. In the layers at the same sites during cold periods, from 75,000 to 40,000 years ago, fire use seems to have disappeared. These archaeological layers are still stuffed with stone tools and butchered animal bones, but none of them are burnt, and there is no hearth. It would suggest that Neanderthals had forgotten how to make fire, were it not for the fact that they had already mastered advanced fire techniques. As well as constructed hearths, lumps of preserved pitch were found in a Neanderthal site in Germany in 2001, dating from roughly 80,000 years ago. Pitch, probably used as a wood glue, can only be made from tree bark kept at a constant high temperature in a controlled fire for several hours.
‘So, there’s lots of interesting questions … maybe they didn’t need fire?’ says Goldberg. ‘And this is much younger [than Wonderwerk] – it’s at the end of [human] history, not at the very beginning.’ So, fire as part of daily human life isn’t necessarily a given? ‘No! That’s the thing. Neanderthals here in France used fire 80,000–90,000 years ago, and then it got cold, and they stopped. We were talking about this idea over breakfast this morning [at the dig site] – the idea that “oh, we discovered fire, and it took off, and everybody was using it” – but it’s not true. It’s simply not true.’
What does this do to the ‘cooking hypothesis’, that cooking food led to our unique brain growth relative to other animals? ‘Well it doesn’t support it, put it that way,’ says Goldberg. ‘If that’s really true, then we should find fire everywhere. And we don’t.’ The alternative theory, therefore, is that for millennia – in fact, if it is right, for the majority of human existence – we’ve been happy to tenderise, pickle or ferment food, rather than cook it over a fire. There is even a possibility that many early humans didn’t want to live in close proximity to fire. I think this is a fascinating challenge to our notion of what it is to be human. I am not suggesting we return to pickling and slow-chewing our food; but what I am suggesting, perhaps provocatively, is that maybe we don’t need fire as much as we think we do? Maybe we can, like our ancient ancestors, pick and choose when we use it?
From the agricultural revolution during the Neolithic period onwards, fire did become central to human civilisation. People started living together in townships, and they managed crops and livestock from fixed abodes. The hearth became not just central to every community, but central to every home. ‘You can spot a Neolithic site a mile away’, repeats Goldberg, when he reanimates over Skype, ‘because all the sediments are grey and ashy … people started sitting down and became sedentary, the whole structure of society changed … probably about 12,000 years ago – it’s just major change … From the point of view of pollution, I would say that’s when it starts – in the early Neolithic.’
Dr Hans Huisman, archaeologist at the Dutch Ministry of Culture and previously a lecturer at Leiden University, is a micromorphologist specialising in the Neolithic. He was part of a study team at Swifterbant, a unique Neolithic site preserved under the Dutch wetlands. For centuries the Netherlands has used dikes to drain the coastal flatlands and turn them into ‘polders’ fit for agriculture. When a wetland at Swifterbant, 50 miles east of Amsterdam, was drained in this way in the 1960s, a complete Neolithic landscape was revealed dating from around 6,000 years ago. At that time, when global seawater was lower, it was a settlement on dry land amid tidal creeks. Among the usual pottery, bones and tools, there was also plenty of burnt stuff. ‘Classical Neolithic settlements of the first agriculturalists’, says Huisman, ‘are rich in ceramics, there is burnt material, there are flints everywhere, it’s very much concentrated … In this region the sites [have] thick, black layers full of archaeological remains that consist mostly of burnt plant material, because this was preserved below water and silt, rather than farmed fields or building sites. ‘What’s interesting [at Swifterbant] is you not only have all the finds, but they are also in exactly the same position where they were 6,000 years ago – so the preservation is really exceptional.’ There were also plenty of well-preserved hearths. ‘Most of these buildings were combined with people and cattle often in the same building, and you would have two-thirds [of the space] for cattle and one-third for the people. You often find one hearth [in the people’s section] and a second one in the centre of the building. In Neolithic conditions, you have daily contact with smoke … in fact fire is burning at least a little bit all day … from the Swifterbant site several striker lights have been found – flints that are specially made to make fire … I think everybody must have been able to make fire and use fire, and you see them using it on the settlement and in the landscape, for food, for heat, for waste disposal, for producing artefacts.’
Pre-dating the mining of fossil fuel, the common fuel of the time would have been wood, ‘and if no wood was available, in this period, it was probably animal dung,’ says Huisman. ‘There is some discussion in Palaeolithic settings whether they also used bone as a fuel – fresh bone is full of fat and that would burn.’ Dried dung, a common fuel at the time and still in many parts of the world today, is very smoky. ‘Even if you have it well dried, it is still very smoky,’ says Huisman. ‘You don’t get a real flame – it sort of smoulders … I know a guy who has been doing experiments on different types of fuel in a reconstructed medieval farm building, and the wood fire and peat fire did not [cause him] many problems, but when he used the animal dung he had to get out because the whole building was full of smoke!’ He laughs, adding, ‘A wood fire you can keep burning in the night as you sleep; a dung fire, you have to put out.’
Another Dutch archaeologist, Dick Stapert, theorised in the 1990s that the evolution of a complex language, involving abstract concepts, may be thanks to daily gatherings and story-telling around the hearth, and even stimulated the development of the arts. Fire also started to appear in proto-religious contexts. People began to be buried with their ‘lighters’ – flint and pyrite kits – presumably for use in the afterlife.
Then, around 7,000 years ago, our mastery of fire sparked arguably the first true industrial revolution: metalworking in copper, bronze and then iron. Decorative copper beads have been found in Çatalhöyük, a large Neolithic settlement in Turkey, dating from around 7500 bc to 5700 bc. Later, bronze was made by heating the ores of copper and arsenic together, producing the first toxic industrial emissions alongside prized bronze tools and ornaments. The earliest known example of metallic lead is a metal figure recovered from the Temple of Abydos in Upper Egypt, from around 6,000 years ago: lead requires not just extracting ore from rock, but smelting – a high-temperature process that burns off the sulphur, binds the ore with oxygen, and reacts with carbon, typically charcoal.
Smelting lead ore to extract silver came with the ancient Greeks, around 1350 bc, before the Roman Empire adopted and massively increased the technology. The world record levels of airborne lead emissions produced during this period would not be topped until the Industrial Revolution a couple of millennia later. Around the time of the birth of Christ, silver mines were producing 80,000 tonnes of lead slag a year – at least 1 per cent of which were particles small enough to mix into the air. Modern ice-core sampling has revealed that around 400 tonnes of lead particles fell on the Greenland ice cap during the 800 years of the Roman Empire (though this is just 15 per cent of the lead that fell during the 60 years of leaded petrol in the twentieth century). The smell of the air also changed. The Roman chronicler Lucius Annaeus Seneca the Younger wrote in ad 61, ‘As soon as I had got out of the heavy air of Rome, from the stink of the chimneys and the pestilence, vapours and soot of the air, I felt an alteration to my disposition.’ One of the few embalmed mummies discovered from ancient Rome, known as ‘the Grottarossa mummy’, shows severe anthracosis – accumulation of carbon in the lungs from repeated exposure to smoke – in a girl who only lived to the age of eight.
I visited the British Museum in late 2017 hoping to see some of the evidence of ancient air pollution first hand. I had arranged to meet Daniel Antoine, Curator of Physical Anthropology, responsible for all the museum’s human remains, and his PhD student Anna Davies-Barrett, under the public glass atrium. Daniel leads us to a side door, turns a key, and takes me behind the scenes. Suddenly the architecture is less Norman Foster, more 1970s council office. We go up a narrow set of stairs, down a corridor, to a door that opens into a surprisingly small room. Two almost complete skeletons are laid out on tables, their bones an orange-brown from desert soil. They are both medieval Sudanese women, who lived next to the Nile river. Volunteer researchers are cleaning their bones and teeth with dry brushes.
These skeletons are around 1,000 years old and are just two of nearly 1,000 skeletons donated by the Sudanese National Corporation for Antiquities and Museums to the British Museum in 2007, excavated prior to the building of the Merowe hydroelectric dam on the Nile. Well preserved by the arid desert environment, the skeletons reveal how these societies lived from 1750 bc to ad 1500. Anna is specifically studying the prevalence of chronic respiratory disease which, in the absence of any remaining lung tissue, means she must look at the bones themselves. ‘If you have inflammation from a respiratory disease you might expect to have new bone forming in the sinuses, or on the inside layers of the ribs,’ she tells me. Lower respiratory tract diseases can cause inflammation near certain points in the ribs, causing new bone growth. Similar rib lesions were found in the skeletons of ancient Romans buried by Vesuvius in ad 79, believed to be caused by long-term smoke inhalation.
‘There’s some partial natural mummification,’ Anna points out. ‘You can see some skin and ligaments here,’ she indicates some papery fragments on the skull. I ask what they know about this individual. ‘You can see from the pelvis it is a female,’ says Daniel. ‘And from the wear and tear of the joints … she was probably a middle adult when she died, so about 35 to 50 [years of age].’ They can also see evidence of disease, including fractured bones, a twisted spine probably caused by tuberculosis, and, somewhat less scientifically, ‘terrible teeth’. In coming days Anna will also check for sinusitis, using an endoscope – a tiny camera on the end of a thin tube, more commonly used in surgery – to avoid any damage to the skull: ‘I often refer to sinusitis as the barometer for air quality,’ she tells me. ‘It is a fairly good indication, if you have really high rates [in a population], because it is your first barrier of defence between your body and the air you breathe … [if] there was inflammation, it is really suggestive that something in the air that you are breathing in is causing that.’
Sinusitis is the inflammation of the lining of one or more of the nasal sinuses – the four pairs of air-filled cavities in the skull above and around the eyes and nose. If the inflammation is chronic and ongoing, then the pressure causes new bone growth – vital tell-tale signs for the future archaeologist. Anna tells me that ‘previous bioarchaeological studies looking at the ribs and the sinuses have found … very high rates of sinusitis that may have been caused by metalworking, suggesting that fine particulates in the air from metalworking was causing the men to have very high rates of sinusitis.’ While she hasn’t yet published her findings when we meet, she has found a high rate of sinusitis among the Sudanese skeletons she has examined thus far.
‘Human remains and their study is allowing us to see evidence of our past human health that other sources don’t provide, whether it’s written texts or material culture,’ says Daniel. ‘It is only by studying human remains that we can get an insight into past states of health … and they are very relevant to today. Cancer and cardiovascular diseases are not new diseases. And by looking at where and how they are being expressed, maybe we can get a better sense of what circumstances and conditions lead to an increase [in disease prevalence] … whether just living in a certain environment can lead to a higher rate of respiratory disease.’
Daniel, who also looks after the Egyptian mummies in the British Museum, tells of similar findings within that collection too: ‘For Egyptian mummies, they would remove the lungs as part of the embalming process, sometimes they would put them in canopic jars [used during mummification to preserve important body organs]… Some research has looked at the lungs in [the museum collection] canopic jars and found evidence of silicosis [silica or sand inflammation, most likely from dust storms] and anthracosis, exposure to carbon, and finding particles of both carbon and sand in the lungs … What’s interesting is that the mummified people would have been the very wealthy people. And even [in] them, who are not obviously involved in specific [work] activity, we are finding evidence of respiratory diseases and conditions.’ The next planned study, he says, is to use CT scans of the mummies to look for evidence of atherosclerosis – the fat in arteries that leads to strokes, and around which, as Newby discovered, inhaled nanoparticles can accumulate.
When ancient Greece and Rome held sway, wood remained the primary fuel source. But then came coal. While there are recorded uses of surface-level coal in ancient China and Rome, there is little suggestion of coal being a primary fuel until the heyday of the eleventh-century Chinese Sung capital Kaifeng (500km or 310 miles south of Beijing). Kaifeng is thought to have been the first city in the world to convert its energy supply from wood to coal thanks to river and canal transport that gave it direct access to emergent coal mines. At its peak Kaifeng was a true mega-city with almost one million inhabitants – probably the largest city in the world at the time – with all its cooking and heating fuelled by the new black gold. This early urban smog proved short-lived, however. The city was sacked by Jin Dynasty troops in 1127 and ravaged by a double whammy of Mongol troops and the plague in the following century. It dwindled to little more than a village. The industrial potential of coal, however, with an energy density (the amount of energy stored in its mass) twice that of wood, was now an open secret. By the thirteenth century, coal mining was well established in Europe, and coal was carried by boat into the heart of London.
The first documented record of British air pollution appears when Queen Eleanor, wife of Henry III, cut short her visit to Nottingham in 1257 because of the city’s overwhelming coal fumes. Edward I, her son, attempted the first environmental regulation to control it, setting up a commission in 1285 to come up with a solution. His subsequent attempt to ban coal, however, didn’t have much effect and was soon rendered obsolete when – as with Kaifeng – the Black Death ravaged the country, killing off a quarter of the population; forest began to reclaim the abandoned farmland as entire farming communities were wiped out by plague, and wood became cheaper and more abundant again than coal. Professor Peter Brimblecombe, whose 1987 book The Big Smoke records the history of air pollution in London, comments that this sequence of events has been repeated many times since: rapid population growth, urbanisation, increases in population density, fuel shortages, followed by embracing new fuels which turn out to be much more polluting than their predecessors.
Two centuries later, the pattern was repeated: the population recovered, wood and charcoal became scarce, and coal – specifically sea coal, a low-quality, smoky coal from the sea floor found in abundance around the coast of Scotland – returned. Once again, the monarch – this time, Elizabeth I – complained of being ‘greatly grieved and annoyed with the taste’ of coal smoke. Shakespeare’s ‘man of the people’ character Falstaff bemoans the ‘reek’ of coal-fuelled lime-kilns. Brimblecombe estimates that coal imports into London between 1580 and 1680 increased 20-fold. Tudor houses that still stand today typically have beautifully ornate, but comically tall, chimneys; like trees competing for canopy space they were trying to rise taller than each other, wafting their own foul smoke as far away as possible.
Over 400 medieval skeletons from two burial sites in the UK were examined for sinusitis in a 1995 study, in much the same way as I had seen at the British Museum. In Wharram Percy, an abandoned medieval agricultural village in Yorkshire, the residents’ lives would have been far from smoke-free, with charcoal, coal and dung probably burned to heat their homes. But St Helen-on-the-Walls, an urban parish in the city of York, housed poor workers who lived with the same pollution at home plus the industrial emissions from the foundry, apothecary, tanning and brewery factories they worked in. Of the skeletons from the village with sinuses preserved, 39 per cent had evidence of sinusitis; from the urban site, over half (55 per cent) of the individuals had sinusitis, a 12 per cent difference which researchers from the University of Bradford attributed to ‘industrial air pollution’.1
In the Americas, toxic air pollution arrived with the Spanish conquistadors. Ice-core samples taken from the Quelccaya ice cap in Peru have traced ancient metallurgy and mining in South America back to ad 798 and the sprawling Inca Empire, but the levels of pollution were low, from metal smelting undertaken as a relatively minor cottage industry, using small furnaces. After the Europeans came in the sixteenth century, however, they brought with them the technique of extracting silver using liquid mercury. The toxic dust it created fell all over South America. Some describe sixteenth-century Bolivia, where the Potosí silver mine was the largest in the world at the time, as the start of the Anthropocene – the geological era in which human activity began to have a significant impact on the natural world. The air would never be the same again.
Less than a hundred years later, the diarist John Evelyn chose the smoke-filled air of London as the subject for his new-found gentleman’s pursuit: science. A founder member of the Royal Society of Science, in 1661 Evelyn undertook what is thought to be the first scientific study of air pollution. Addressed to King Charles II, the pamphlet, entitled Fumifugium, or The inconveniencie of the aer and smoak of London dissipated together with some remedies humbly proposed by J.E. esq. to His Sacred Majestie, and to the Parliament now assembled, appeals to the King’s ego as well as his intellect: ‘Your Majesties only Sister, the now Dutchesse of Orleans … did in my hearing, complain of the Effects of this Smoake both in her Breast and Lungs, whilst She was in Your Majesties Palace,’ wrote Evelyn. ‘I cannot but greatly apprehend, that Your Majesty (who has been so long accustom’d to the excellent Aer of other Countries) may be as much offended at it, in that regard also, especially since the Evil is so Epidemicall; indangering as well the Health of Your Subjects, as it sullies the Glory of this Your Imperial Seat.’ Evelyn foresaw health impacts that would only be proven centuries later, in stating: ‘Aer that is corrupt insinuates itself into the vital parts immediately … passing so speedily to the Lungs, and virtually to the Heart itself.’ He also had the backing of fellow gentleman scientist Sir Kenelm Digby, who took note of Londoners dying from ‘pulmonary distempers, spitting blood from their ulcerated lungs’.
Among the remedies Evelyn proposed was the public planting of shrubs and flowers on a grand scale: ‘[that] all low-grounds circumjacent to the City, especially East and South-west … be elegantly planted, diligently kept and supply’d, with such Shrubs, as yield the most fragrant and odoriferous Flowers’. Shrouded in jasmine and lavender, London’s air could be the envy of the world. Charles II actually agreed to it; sadly, Parliament did not, and the Great Fire of London just five years later saw Evelyn’s planting scheme plummet down the list of priorities. He submitted a grand plan to rebuild the devastated city in line with his principles, with smoke-emitting industries banished downriver, but it was rejected – as was Christopher Wren’s – in favour of simply rebuilding the city where it had stood.
By the Industrial Revolution, however, even Evelyn’s wildest shrubbery scheme wouldn’t have stood a chance. The English astrologer John Gadbury noted an increase in London’s fogs in his weather diary from 1668 to 1689. By comparing Gadbury’s diary with the official records of deaths, Peter Brimblecombe found that when a ‘Great Stinking Fog’ (Gadbury’s expression) appeared, the number of deaths in the city doubled. At that time, London had a population of roughly 500,000, many of whom still lived and worked within the original ‘Square Mile’, encircled by Roman walls. Records of atmospheric CO2, methane and nitrous oxide in the modern ice-core record start to rocket upwards from the point that, as the authors Seinfeld and Pandis suggest, coincides ‘more or less with the invention of the steam engine in 1784’2. A tombstone in Kensal Green Cemetery commemorates a certain ‘LR, Who died of suffocation in the great fog of London 1814’. This particular fog, which lasted from 27 December 1813 to 3 January 1814, was reported by The Scots Magazine as being full of the ‘smoke of the city; so much so that it produce[s] a very sensible effect on the eyes, and the coal tar vapour [was] … distinctly perceived by the smell’.
By 1860 London had grown to over three million inhabitants and had sprawled to new suburbs, many far from the River Thames, such as Clapham, New Cross, Tottenham and Walthamstow, all connected by steam-powered trains burning coal. Industries belching coal smoke were now in the heart of every industrial town and city, and every home within them was heated by coal. London became famous for its black umbrellas – the only colour that didn’t show the blackened rain. It was the biggest city in the world from 1831 to 1925, and its skyline, filled with giant chimney stacks and black clouds that never went away, had set the blueprint for the modern world. The northern industrial city of Sheffield, believed to have produced 90 per cent of the world’s steel at the time, was described simply as ‘black’ in the travelogue Rural Rides by William Cobbett in 1830: ‘All the way along, from Leeds to Sheffield, it is coal and iron, and iron and coal. It was dark before we reached Sheffield; so that we saw the iron furnaces, in all the horrible splendour of their everlasting blaze.’
It wasn’t until 1905 that someone came up with a catchier name than ‘Great Stinking Fogs’. On the opening day of the Conference for Smoke Abatement held in London in December 1905, Dr Des Voeux suggested combining the words smoke and fog to become ‘smog’. It was a throwaway line, one that the assembled delegates, probably including Des Voeux himself, thought little of compared to the important proceedings on the three-day itinerary (such as the ‘Final Report of the Royal Commission on Coal Supplies’). But the press picked up on it, and the word ‘smog’ quickly entered the English language on both sides of the pond.
In the US, Dr Devra Davis is one of the most important names in the modern fight against air pollution. A leading academic with numerous papers to her name on the link between health and pollution (long before it was a topic that attracted the funding bodies), she has lectured at universities including Carnegie Mellon and Harvard, medical schools in Jerusalem, Turkey and London, and advised on government boards nationally and internationally. She also happened to be a child in Donora in the 1940s, during one of the world’s most infamous air pollution episodes.
In the first half of the twentieth century, Donora, a small American mill town in Pennsylvania, was well accustomed to dirty air. The sun often didn’t shine for days, blocked out by fumes from the steel mills, coke ovens, coal stoves and zinc furnaces, trapped in the valley by the surrounding hills. Davis tells me that the chemicals in the air could produce ‘astonishingly beautiful sunsets’. But Friday 28 October 1948 was anything but beautiful. A pocket of air pressure caused a temperature inversion, with a layer of warm air trapping the colder boundary layer close to the surface. The pollutants were stuck in a stagnant layer of air only a few metres from the ground. One eye witness, the town’s attorney Arnold Hirsh, told Davis that he saw a steam engine on the tracks as the smog formed: ‘It issued a big blast of black smoke that went up about six feet in the air and stopped cold. It just hung there … in air that did not move.’ The air soon became a thick, yellow soup of sulphuric acid, nitrogen dioxide and fluoride gas, mostly emitted from the zinc smelting plant. It lasted for four days. The company operating the Donora Zinc Works finally ordered the plant to shut down at 6 a.m. on Sunday morning; the next day, the smog had gone. Twenty people died during the incident, and 7,000 (almost half the town’s population) were hospitalised, with a further 50 dying soon after. Autopsies revealed that the inhalation of fluoride gas – released from the smelting of fluorspar in the zinc factories – was the primary cause of death.
In the years that followed, the townsfolk never talked about the disaster, recalls Davis. The plants stayed open and life continued as if it was any other small town in America, with neat lawns, white picket fences and pink curtains – the difference being that the grass rarely survived, the picket fences would quickly turn black, and Davis’s mum preferred venetian blinds to curtains because ‘they were easier to wipe’. Hairdressers would go from home to home ‘to take care of the little old ladies’, remembers Davis, ‘but these were women in their fifties – they were bedridden because it was hard for them to go up and down the stairs because there was so much heart disease … The fact that the skies were brown and we didn’t see the sun for days at a time – that was just normal. Especially in the fall. And the dirt that was always on us, from being outdoors – we used to call it the ‘Donora measles’ because you’d get black spots.’ While she was only two at the time of the disaster, she later interviewed a number of survivors, including her family, for her book When Smoke Ran Like Water, published in 2002. ‘I interviewed a man who had just come back from the war in Europe, and was in excellent physical condition – he talked about gasping for breath during this episode … one of the first clues that something was wrong was that the funeral homes ran out of caskets, and the florists ran out of flowers, and drugstores ran out of drugs. People knew that something was going on.’ A high-school football game went ahead despite the kickers not being able to see where the ball ended up. Mid-game, a Donora player was told over the tannoy that he needed to go home immediately. By the time he got home, his father, an iron worker, had died. The mill owners American Steel and Wire Works never admitted any responsibility, calling the chemical-filled fog ‘an act of God’. The plants stayed open until 1962.
For as long as humans have burned things, then, air pollution has been a killer. But as our industrial practices became more advanced, the wood smoke of our ancient ancestors in Wonderwerk and Qesem morphed into something entirely different. The daily proximity to smoke persists, but rather than from an open hearth it pours from thousands of combustion engines and industrial furnaces. Modern economies began discovering and burning more and more chemical compounds, and the smoke became deadlier. A physician from the University of Cincinnati, Clarence A. Mills, wrote in the journal Science in 1950, ‘Let us hope that the Donora disaster will awaken people everywhere to the dangers they face from pollution of the air they must breathe to live.’ His hopes were not realised. Instead, by the early twenty-first century, humans have unwittingly turned the air into the largest known environmental health risk. The pattern that Peter Brimblecombe identified reappeared once again: rapid population growth, urbanisation, increases in population and a new fuel that turns out to be more polluting than its predecessors. This time, the fuel was diesel.