Comparative study of single particle characterisation by Transmission Electron Microscopy and time-of-flight aerosol mass spectrometry in the London atmosphere

Size fractionated airborne particle samples were collected from the top of the BT Tower and a ground-based site in Regents Park in London by deploying MOUDI instruments at the two locations. Particles were examined by Transmission Electron Microscope (TEM), Energy Dispersive X-Ray Analysis (EDX) and selected area electron diffraction patterns to determine the morphology, crystallinity and composition of individual particles in aggregated and non-aggregated forms. Eight different types of particles were observed which were common both to the ground-based location and some 160 m above the conurbation of London at the top of the BT Tower. Of these different types, amorphous carbonaceous aggregates (soot-like) containing C and O and often extending to the inclusion of Ca, K and Fe were the most common type of particles that occurred across all stages of the impactors but were most common in the fractions