Abstracts Earth and Environmental Sciences

Measurement and identification of ambient atmospheric metallic nanoparticles

by Paul Sanderson

Physico-chemical characterisation of atmospheric metallic particles collected at six roadside, background and rural sites has been undertaken by multiple methods. Mass-size distributions of total PM mass have been compared between multiple sites and roadside increments calculated in Birmingham, which are found to occur in the size ranges 100-180 nm, 320-560 nm and >1000 nm. Good correlations are observed between Ba, Cu and Fe, but some divergence of sources is evident in small particles. Single-particle analysis by TEM-X-EDS and EELS has classified Fe-dominated particles into two main groups; Fe content >90%/wt and Fe-Mn alloys (Fe ~75%/wt). Both classes are mainly γ-Fe(2)O(3) and α-Fe(2)O(3). Pb-dominated particles have been detected with Zn and Sb. Ce particles have been found as nanoparticles attached to large soot agglomerates. TEM and ICP-MS samples collectedfrom a static brake test rig show changes in mass distributions at different braking forces and between different elements, in particular between Ba, Cu, Fe, Ni and Al. Data from TEM samples of diesel exhaust imply that particles containing Fe, Cr and Ni together may be indicative of this source and that engines are a possible source of submicrometre Cu. Use of Al-alloys in engine design contributes Al-dominated particles to the emitted exhaust.