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Magnetic characterisation of London's airborne nanoparticulate matter

2022; Elsevier BV; Volume: 287; Linguagem: Inglês

10.1016/j.atmosenv.2022.119292

1873-2844

Adrian R. Muxworthy, Claire Lam, David C. Green, Alison Cowan, Barbara A. Maher, Tomasz Gonet,

Radioactivity and Radon Measurements

Iron-bearing particulate matter produced by vehicle emissions is known to be toxic. To better quantify potential health risks, we have conducted the first magnetic study of a time-series of London's inhalable particulate matter (<10 μm, PM10), captured by three monitoring stations in central London (Marylebone Road, Earl's Court Road and Oxford Street) through 2010 and 2012. We conducted room-temperature analysis on all the samples, and a limited number of samples were analysed at both high and low temperatures. The high-temperature measurements identified magnetite as the dominant magnetic phase. The low-temperature measurements revealed high numbers of nanoparticles, which, assuming magnetite, are in the grain-size range 1–4 nm. It is estimated that as much as ∼40% of the total magnetic signal at 10 K is from particles 50 nm.