Oldest Air Pollution

When you think of ‘air pollution’ you are probably imagining traffic fumes, or the thick photochemical smogs that shroud many modern megacities, or perhaps you even think of the ‘pea soupers’ in London that led to the first Clean Air Act in 1952. Now we know that air pollution is actually almost as old as humanity and the proof has come from a surprising source.

Fossil_Qesem_teeth
The teeth of Qesem Cave. Source: Wikimedia Commons

Hardened tooth plaque, sometimes called ‘tartar’, is usually dealt with by a quick trip to the dentist and most people think of it as little more than an unsightly inconvenience, but it is this tartar which has provided detailed information about a 400,000 year old human population. The teeth in question were discovered in Qesem Cave, Tel Aviv, a site which has already provided a wealth of archaeological finds and is particularly known for its multiple preserved ‘hearths’ which show long-term and repeated use. The teeth revealed that these fires had potentially serious consequences for the inhabitants. Preserved in the dental tartar were tiny particles of charcoal and other ‘particulates’, basically small, solid particles that contribute to poor air quality and can cause irritation of the throat and lungs. Today particulates contribute to air pollution and can trigger numerous respiratory problems. If the inhabitants of Qesem Cave were being exposed to enough charcoal for it to be persevered in their teeth then it would almost certainly have been taking a toll on their health.  Of course there is no evidence from the skeletons alone that would reveal what health impacts these conditions may have had but today, according to the Environmental Protection Agency in the US, particulate exposure has been linked to lung damage and certain cancers as well as exacerbating breathing problems like asthma.

As well as tiny particles of charcoal though there were other things preserved in the tartar that tell us a little about the diet of the time. We know from the discovery of animal bones and butchering tools at Qesem Cave that the inhabitants were eating a lot of meat but there were also traces of fatty acids in the teeth which probably came from nuts and seeds. Alongside these were small quantities of starch which the researchers interpreted as coming from plant fibres which the people of Qesem may have been using to clean their teeth. An alternative interpretation is that this is evidence of the humans using their teeth to hold or manipulate plant fibres to make tools. Either way this is direct evidence of the importance of plants to the inhabitants which was missing from the archaeological record.

Discoveries like this paint a picture of a whole way of life. Its only too easy to imagine these people living in their warm, smoky caves, roasting meat on their communal hearths and supplementing their protein-rich diet with a few nuts and seeds. Whether this exposure actually had any long term health effects is impossible to say for certain but we know from modern experiences that air pollution can have profound health effects and there is no reason to think that this wasn’t also the case 400,000 years ago.

Reference: Hardy, K. Et al. 2015. Dental calculus reveals potential respiratory irritants and ingestion of essential plant-based nutrients at Lower Palaeolithic Qesem Cave Israel. Quaternary International. doi:10.1016/j.quaint.2015.04.033

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