Maher also studies magnetic nanoparticles to track dust impacts on climate change and changes in human health due to particulate air pollution.[1] She was described by Richard Harrison as having "single-handedly developed the field of environmental magnetism".[12] She demonstrated that soils that were exposed to higher rainfall make more magnetite.[1] She has studied how windblown dusts impacted the levels of greenhouse gases.[1] She is interested in magnetic records of Quaternary terrestrial sediments.[13] She launched the Quantifying Uncertainty in the Earth System (QUEST) Working Group on Dust in 2008.[14]
Maher became interested in metal-rich particulate pollution.[15] In 2013 Maher demonstrated that silver birch trees could be used as pollution filters.[16][17] The result was part of an investigation into the impact of roadside trees on the concentration of particulate matter found in people's homes.[18] Silver birch trees are covered in tiny hairs, which can trap the particulate matter whilst allowing clean air to circulate.[16] The matter is washed off the leaves when it rains, allowing the birch trees to trap even more particulate matter.[16] Her work was examined by Michael Mosley and Gabriel Weston on the BBC show Trust Me, I'm a Doctor.[16][19] They found that the pollution collected in houses protected by silver birch trees was 50 - 60% lower than in houses without them.[20][21][22]
In 2016 Maher found toxic, metal-rich nanoparticles in human brain tissue.[23][24][25][26] By studying the nanoparticles using an electron microscope, Maher found they were small and round, some with surface crystallites, indicating that they had been formed at high temperatures, rather than in the brain itself.[27] The nanoparticles comprise a mix of iron-rich, strongly magnetic particles associated with other metals, including platinum, cobalt, aluminium and titanium. Similar metal-rich nanoparticles occur in abundance in urban air pollution, especially at busy roadsides. As the nanoparticles have diameters that are less than 200 nm, they can enter the brain via the lungs and blood circulation, via ingestion and transport through the neuroenteric system, and through the olfactory nerve.[28]Magnetite can produce reactive oxygen species in the brain.[23] Maher became concerned that these magnetite particles could be linked to Alzheimer's disease, mental illness and reduced intelligence.[23][29] Her work on air pollution nanoparticles in human tissues attracts worldwide scientific, and media, attention. She has appeared on numerous BBC News and World Service TV and radio programmes, including BBC Radio 4's Inside Science in 2018, discussing the Government of the United Kingdom Clean Air Strategy.[30] S
^Maher, B. A.; Thompson, R.; Zhou, L. P. (1994). "Spatial and temporal reconstructions of changes in the Asian palaeomonsoon: A new mineral magnetic approach". Earth and Planetary Science Letters. 125 (1): 461–471. Bibcode:1994E&PSL.125..461M. doi:10.1016/0012-821X(94)90232-1. ISSN0012-821X.
^Maher, Barbara A.; Ahmed, Imad A. M.; Davison, Brian; Karloukovski, Vassil; Clarke, Robert (2013). "Impact of Roadside Tree Lines on Indoor Concentrations of Traffic-Derived Particulate Matter". Environmental Science & Technology. 47 (23): 13737–13744. Bibcode:2013EnST...4713737M. doi:10.1021/es404363m. ISSN0013-936X. PMID24215538.
