Particulate Aerosols, Incinerators and Health

Even the most modern municipal waste incinerators (MWIs) emit an aerosol of ultrafine particles which current bag filter technology cannot abate. Collection efficiencies for particles < 2.5 μm are between 5 and 30 per cent. For particles of < 1 μm, collection efficiency, most particles will pass unabated. Ultrafine particles have been found to be chemically highly reactive, even when originating from a relatively unreactive bulk material. The massive surface area associated with a small mass of nanometre-sized particles can act as a catalytic surface for the secondary formation of organic compounds.Recent research has shown that the inhalation of ultrafine particles is associated with changes in the coagulability of the blood and this has been connected with epidemiological findings of increased cardiovascular disease in populations exposed to higher than average PM₁₀ exposure. The relative toxicity of ultrafine particles arising from different processes remains unresearched. However, metal nanoparticles have been shown to be particularly chemically reactive and it can be argued that MWIs, which have a heterogeneous input, high in heavy metals and halogenated organic materials, will tend to produce a more toxic ultrafine particulate aerosol than, say, a coal fired power station.There is an urgent requirement for research into the environmental and health impacts of the particulate aerosols emitted by current incinerators, which, because of the large volumes of gas they produce, have a significant local effect on air quality. Severe restrictions on the emissions of particulate aerosols, in the light of current health data, should become an integral part of future authorisations for the operation of MWIs.