Pollution detector designed to protect heritage sites

A simple detector could help conservators at World Heritage sites in the developing world understand and protect against atmospheric pollutants that can damage valuable artefacts. The pollutant-measuring device has been prototyped by Henoc Agbota, an engineer at University College London, United Kingdom, and presented last week (30 October) at a conference marking the end of a five-year funding programme for heritage science run from the university. Agbota’s work was prompted by last year's decision by UNESCO (the UN Educational, Scientific and Cultural Organization) that its World Heritage Committee would begin asking their certified sites to provide yearly figures for atmospheric pollutant levels. In response, Agbota surveyed 25 correct developing world sites and found that few had the capacity to do this. At the Royal Palaces of Abomey, the historical seat of the rulers of the Kingdom of Dahomey in modern-day Benin, conservators care for artefacts such as stone bas-reliefs, wooden thrones and metal weapons. Urbain Hadonou, one of the conservators, tells SciDev.Net that he runs a project called museum school through which local cultural researchers come to study the artefacts. But such projects could be at risk unless artefacts are protected from harmful pollution.

Almost three-quarters of the respondents to Agbota’s survey reported observing damage to objects that they attributed to pollution. This took the form of particle deposits, corrosion and the formation of ‘black crusts’ on artefacts. Agbota hopes his device will help to avoid this damage. His instrument consists of a series of so called piezoelectric quartz crystals — which generate electric currents as they expand or contact by minute amounts — coated with varying thicknesses of copper, iron, nickel or tin. As pollutants absorb to these metallic surfaces, they change the crystals’ mass, altering the electrical output and allowing pollution levels to be calculated.  continued