Dr Sanja Potgieter-Vermaak

My profile

Biography

I specialise in monitoring and charactersing environmental pollutants and their impact on ecosystems and human health. I have extensive expertise in air pollution, both outdoors and indoors,  specifically in the characterisation of solid environmental particles of respirable/inhalable size, using various state-of-the-art techniques, to determine their bioaccessibilty in the human body. In this way, the groups that I work in chemically characterise dust (road/house/office), airborne particles, and sediments, followed by exposure to artificial body fluids, to ascertain the bioaccessibility if ingested and/or inhaled particles. My international collaboration encompasses China, Nigeria, South Africa, and Brazil. The Brazilian partners and  I work together with German partners on air monitoring and atmospheric chemistry at the Amazonian Tall Tower Observatory (ATTO). I am one of the principal investigators in the HomeBiome group, which is part of the mapmyenvironment initiative, which spans several countries and revolves around citizen science. I have published 100+ peer-reviewed papers in high-impact scientific journals and have an H-factor of 31. 

Visiting and honorary positions

Visiting professor: Xingfa School of Mines, Wuhan Institute of Technology, China, 2019 - 2022

Honorary Associate Professor, University of the Witwatersrand: 2008 – current

Extraordinary Academic Staff, University of Antwerp: 2010 – 2014.

Personal website address

https://scholar.google.com/citations?user=I8xsiewAAAAJ&hl=en

Impact

External examiner roles

External examiner for postgraduate studies

Ph D Chem Eng, University of the Witwatersrand- A.I. Igbafe (2008)
MSc Environmental Science, University of Antwerp - Akhandaf Yasmina (2009)
MSc Environmental Science, University of Antwerp - Van Hoof Wouter (2009)
MSc Applied Science: University of Pretoria – O Sitando (September 2011)
MSc: Manchester Metropolitan University – Al-Modaris (Chemistry Sept 2011)
Master of Engineering: University of Pretoria – GS Woest & I Venter (Dec 2015)
Master of Engineering: University of Pretoria – Yapi (Jun 2017)
MSc: Manchester Metropolitan University – F. Owen (Chemistry Oct 2017)
MSc: University of the Free State - A. Q. Vilakaze (Chemistry September 2017))
MSc (Science – Environmental Studies), University of the Witwatersrand, Johannesburg, SA, Fulufhelo Makhani, An Assessment of BTEX Concentrations from Various Fuel Depots in Parts of South Africa, (2018)
MSc (Chemistry), University of the Free State, Lijo Pius Mona, (March 2019)
MSc (Environmental Management). Salford University, Rebecca Houghton, A comparison in air pollution in different socio-economic areas (May 2019)
Master of Engineering: University of Pretoria – E Ungerer: Verwydering van MoF6 en HF uit ≈â helium-MoF6-gasmengsel (September 2019)
PhD: Manchester Metropolitan University - Mark Frost (Sept 2015)
PhD: (Chem Eng), University of Pretoria, R Pretorius, Development of a Continuous Dry NdF3 Production Process (August 2018)

PhD: Wisdom Adza, University of the West of Scotland, Exploring the relationship between road traffic noise, air quality and hypertension, July 2023

Expert reviewer for external funding bodies

Journals:

Reviewer for: Journal of Radioanalytical and Nuclear Chemistry; X-Ray Spectrometry; Spectro Chimica Acta B; ICCC (International chemistry of cement conference) 2007, refereed proceedings; International
Journal for Coal Geology; Journal of Raman Spectroscopy; Building and Environment; Water, Air and Soil Pollution; Journal of Environmental Monitoring; Fuel; Atmospheric Environment; Desalination & Water Treatment; Corrosion Science; Journal of Chromotography; Water SA; Analytica Chimica Acta; Industrial
and Engineering Chemistry Research; Environmental Science and Pollution Research; Environmental
Engineering and Management Journal; Environmental Earth Sciences; Science of the Total Environment Journal; International Journal of Environmental Analytical Chemistry; Environmental pollution; Journal
of Aerosol Science; Environment, Atmospheric Chemistry, Environment International, Journal of Microscopy
Hydrometallurgy, Molecules

Other reviewing roles:

National Research Foundation of SA (NRF):
• 2014 Prof T VAN REE (DEPARTMENT OF CHEMISTRY, UNIVERSITY OF VENDA), titled: Determination of volatile organic chemicals and solvents in ground and surface waters in Limpopo Province.
• 2017 Mrs. K. Premlal (Department of Chemical and Metallurgical Engineering, Tshwane University of Technology), titled: The enhanced recovery of natural methane gas from coal bed seams through carbon dioxide sequestration in South Africa.
• 2018 -OM Moroeng: (University of Johannesburg, South Africa) The organic geochemistry profile of macerals in South African coals of different origins.
National Research, Development and Innovation Office (NKFIH)
• 2016 Applicant: László Bencs; Title of the proposal: A complex study on aerosols evolved from an electrothermal vaporizer; ID of the proposal: 124779, 2017
Medical Research Council: UK-Kenya Health Research Partnership 2018 Population & Systems Medicine Board
• 2018 Applicant: Dr Suzanne Bartington, University of Birmingham: Investigating the impact of air pollution upon children’s respiratory health in urban Nairobi.
Acted as reviewer for international conferences:

  •  Indoor Air 2016
  •  ICCC (International chemistry of cement conference) 2007, refereed proceeding
  • 37th International Conference of the Society of Geochemistry & Health, 2019. 

Community, charity and NGO links

Collaborating with Airly (a company providing low-cost outdoor air pollution sensors) in the “Let Schools Breathe” programme to help schools develop a plan of action to mitigate air pollution in and around the school campus. Designed an Air pollution Toolkit for primary school children in years 5 and 6 to promote awareness of individual air pollution footprints and how to mitigate it. Building relationships with schools in GM to promote, develop, facilitate, and implement air pollution literacy toolkits, to raise better awareness of individual’s air pollution footprint amongst learners, staff, and the wider community’.

Editorial Board membership

Editorial roles:

Co-ordinating editor: Journal of Environmental Geochemistry & Health (EGAH) (2019 - )

Leading guest editor: Special Edition for EGAH - 37th International Conference SEGH 2019 - 2020

Membership of professional associations

Member RSC UK (2010 – current)
Member of the SEGH (2011 – current); executive board member (2018 – current); Fellow of the SEGH (2019 - current)
Member of the RSC Analytical Division (NW - UK) executive committee (2010 – current) Past President (2012 – 2017)
 

Projects

Current Air Quality projects and applications:

  • Mapmyenvironment.com - Citizen science initiative (Funded by NERC) in collaboration with Northumbria University - collecting house dust across the world to determine the level of pollutants in indoor air. Further characterisation of the relationship between the house dust and the airborne particulate matter
  • Characterising microplastics to determine its bioaccessibility (part of PhD)
  • “Let Schools Breathe” monitoring air pollution at schools to determine temporal and spatial distribution.
  • Investigating Fog Processing of Aerosol in Amazonia and their Climatic Impacts: ATTO project
  • Bridging the gap between measurement and modelling:  pathway to compliance for proposed fine particulate matter target values

Most Recent Previous Air Quality projects and applications:

  • SBRI: monitor and visualise domestic pollution to safeguard health -  application for funding with AirSensa (We aim to build a low-cost indoor air monitor that can be easily installed and provide with the use of Artificial intelligence real-time data to ensure better indoor air quality and safer environments - AIRPOMS)
  • Manchester air pollution monitoring network in partnership with Airsensa, University of Manchester, Salford University, TfGM

Teaching

Why do I teach?

I teach in the chemistry team and is responsible for analytical chemistry delivery across the 4 years of our two degree programmes (BSc chemistry & pharmaceutical chemistry & MChem chemistry). I also teach some specific topics in my research realm - Raman spectroscopy for example to the chemists and air pollution and health to the Environmental science students. In addition, I teach bulk characterisation techniques in our new MSc programme: Advanced Materials 

How I’ll teach you

Benjamin Franklin said: “Tell me and I forget. Teach me and I remember. Involve me and I learn.” That is my teaching philosophy, by dovetailing theory with hands-on experience, new knowledge becomes an easy learning process.  

Why study…

The importance of air quality and its link to early deaths has been in the UK news as recent as February 2016, when a report of the Royal College of Physicians released a figure of 40,000 early deaths in the UK that can currently be ascribed to air pollution. The extent and profile of the ecological footprint of anthropogenic pollution are continuously changing. For example, transport emissions are increasing due to urbanisation, and changing in composition, due to changes in fuel and combustion processes. This causes a differential impact on the environment and humans, dictating continuous monitoring and investigation to assess new and emerging risks. It is for this very reason that my postgraduate training focusses on the impact of pollutants on human health. My group uses the chemistry of particulate matter to elucidate their fate when in-vitro studies are conducted. Specifically, in-depth training on single-particle analysis using micro-Raman spectroscopy and computer-controlled scanning electron microscopy with energy dispersive x-ray detection as well as the hybrid InSEM-Raman will be provided. This will be complemented by experimental skills in various in-vitro approaches (simulated body fluids, COMET assay, chip technology) to determine occupational risks.

Postgraduate teaching

Bulk characterization techniques - MSc in Advanced Materials

Postgraduate training focusses on single-particle analyses of particles with environmental/industrial origin. Specifically, in-depth training on single-particle analysis using micro-Raman spectroscopy and computer-controlled scanning electron microscopy with energy dispersive x-ray detection as well as the hybrid InSEM-Raman are provided. This will be complemented by experimental skills in various other analytical techniques, including ICP-OES/MS, HPLC, GFAAS, and in-vitro approaches (simulated body fluids, COMET assay, chip technology).

My specific focus is assessing air quality (both indoor and outdoor) to determine its chemical composition and how that will impact on human health.

Subject areas

Environmental Analytical Chemistry - focused on environmental particles’ characterisation and fate.

Courses

Supervision

Completed as DoS in the UK:

Nicolle Bain (MSc): Bioaccessibility of Particulate Matter with Special Reference to Potential DNA Damage, Toxic and Carcinogenic Species.

Kate Irvin (MSc): The differentiation and determination of ochre pigments from Blombos Cave, South Africa; using micro-Raman spectroscopy.

Hulya Kars (MSc): POTENTIALLY TOXIC ELEMENTS AND PERSISTENT ORGANIC POLLUTIONS IN HAIR: A CASE STUDY OF GREATER MANCHESTER

Andrew Brown (PhD): Bioaccessibilty of the inhalable fractions of urban road dust.

Leonard Mbgeahuruike (PhD):   STUDIES  OF MULTI-METAL CONTAMINANTS IN SIMULATED SOILS AND THEIR POTENTIAL  BENEFICIATION FOR METAL RECOVERY

IN PROGRESS in the UK:

Kate Irvin (PhD): The creation of a novel predictive model for compounded poly(vinyl chloride) formulations through various characterisation techniques and vibrational spectroscopic mapping. (DoS)

Kate Burns (PhD): An investigation into plasticiser compatibility in PVC (Co-supervisor)

David Jones (PhD): Microplastics in the environment

William Greenwood (PhD): Bridging the gap between measurement and modelling:  pathway to compliance for proposed fine particulate matter target values

Completed  11 Masters and 2 doctoral students elsewhere

Research outputs

My area of research focuses on air quality (both indoor and outdoor) and its impact on human health and the environment. This encompasses monitoring of air pollutants (particulates, gases) in various macro and micro environments followed by chemical quantification and characterisation of the pollutants. I specialise in individual particle analysis using computer-controlled scanning electron microscopy coupled with energy dispersive X-ray detection and Raman spectroscopy with which environmental particles of respirable size are characterised. Using various in-vitro techniques the bioaccessibility of these particles, with reference to toxic and carcinogenic components, are assessed to determine human exposure risks.

I am group leader for the Environmental Change group of the Ecology and Environment Research Centre (EERC). 

Selected research projects:

1. Commissioning of micro Raman Spectrometer at Witwatersrand University as part of setting up a molecular spectroscopy analysis centre for coal and carbon-based materials characterisation.

2. Raman as an on-line tool for mineral characterisation of coal - commissioned by SASOL, SA.

3. Minor and trace elemental analyses of minerals in coal with ICP-MS.
4. Micro Raman spectroscopy interfaced with electrochemical techniques to monitor in-situ corrosion of materials (relevant for CCS operational equipment).
5. CCSEM/EDX of coal – substrate and sample preparation optimisation.
6. SEM/EDX interfaced with micro Raman Spectroscopy for the analysis of macerals in coal.
7. Component-specific toxicity in road dust sediments of respirable size.
8. Bioaccessibility studies of environmental particles
9. SEM/EDX interfaced with micro Raman Spectroscopy:
9.1 Analysis of As containing soils
9.2 Characterisation of titania zeolites for antibacterial applications
9.3 Characterisation of Vanadium catalysts used in the sulphuric industry
9.4 Characterisation of Basal ice particulates
9.5 Characterisation of hydrometallurgically isolated chromium product from UG2 platinum group metal deposits.
9.6 Characterisation of dusts from various originns.

10. Investigating Fog Processing of Aerosol in Amazonia and their Climatic Impacts

  • Chapters in books

    Cardell, C., Urosevic, M., Sebastián-Pardo, E., Horemans, B., Kontozova-Deutsch, V., Potgieter-Vermaak, S., Bencs, L., Anaf, K.W., de Wael, K., Van-Grieken, R. (2013) 'Risks of atmospheric aerosol for cultural heritage assets in Granada (Spain).' Science and Technology for the Conservation of Cultural Heritage. pp. 45-49.

    Potgieter-Vermaak, S., Van Grieken, R., Potgieter, J.H. (2012) 'Integrated analytical techniques for analysing individual environmental particles.' pp. 123-140.

    Potgieter-Vermaak, S., Van Grieken, R., Potgieter, J.H. (2010) 'Integrated analytical techniques for the characterisation of environmental particles.' pp. 12-16.

  • Journal articles

    de Souza Tadano, Y., Potgieter-Vermaak, S., Siqueira, H.V., Hoelzemann, J.J., Duarte, E.S.F., Alves, T.A., Valebona, F., Lenzi, I., Godoi, A.F.L., Barbosa, C., Ribeiro, I.O., de Souza, R.A.F., Yamamoto, C.I., Santos, E., Fernandesi, K.S., Machado, C., Martin, S.T., Godoi, R.H.M. (2024) 'Predicting health impacts of wildfire smoke in Amazonas basin, Brazil.' Chemosphere, 367

    dos Santos Silva, J.C., Potgieter-Vermaak, S., Medeiros, S.H.W., da Silva, L.V., Ferreira, D.V., Godoi, A.F.L., Yamamoto, C.I., Godoi, R.H.M. (2024) 'A Fingerprint of Source-specific Health Risk of PM2.5-bound Components Over A Coastal Industrial City.' Journal of Hazardous Materials, 480

    Moreira, C.A.B., Polezer, G., dos Santos Silva, J.C., de Souza Zorzenão, P.C., Godoi, A.F.L., Huergo, L.F., Yamamoto, C.I., de Souza Tadano, Y., Potgieter-Vermaak, S., Reis, R.A., Oliveira, A., Godoi, R.H.M. (2024) 'Impact assessment of IMO’s sulfur content limits: a case study at latin America’s largest grain port.' Air Quality, Atmosphere and Health,

    da Costa, G., Pauliquevis, T., Heise, E.F.J., Potgieter-Vermaak, S., Godoi, A.F.L., Yamamoto, C.I., dos Santos-Silva, J.C., Godoi, R.H.M. (2024) 'Spatialized PM2.5 during COVID-19 pandemic in Brazil’s most populous southern city: implications for post-pandemic era.' Environmental Geochemistry and Health, 46(1)

    Masnica, J.P., Sibt-e-Hassan, S., Potgieter-Vermaak, S., Regmi, Y.N., King, L.A., Tosheva, L. (2023) 'ZIF-8-derived Fe-C catalysts: relationship between structure and catalytic activity toward the oxygen reduction reaction.' Green Carbon, 1(2) pp. 160-169.

    Burns, K., Ingram, I.D.V., Potgieter, J.H., Potgieter-Vermaak, S. (2023) 'Synthesis and performance evaluation of novel soybean oil-based plasticisers for polyvinyl chloride (PVC).' Journal of Applied Polymer Science, 140(45)

    Burns, K., Potgieter, J.H., Potgieter-Vermaak, S., Ingram, I.D.V., Liauw, C.M. (2023) 'A comparative assessment of the use of suitable analytical techniques to evaluate plasticizer compatibility.' Journal of Applied Polymer Science, 140(30)

    dos Santos Silva, J.C., Potgieter-Vermaak, S., Medeiros, S.H.W., da Silva, L.V., Ferreira, D.V., Moreira, C.A.B., de Souza Zorzenão, P.C., Pauliquevis, T., Godoi, A.F.L., de Souza, R.A.F., Yamamoto, C.I., Godoi, R.H.M. (2023) 'A new strategy for risk assessment of PM2.5-bound elements by considering the influence of wind regimes.' Science of the Total Environment, 872pp. 162131-162131.

    Polezer, G., Potgieter-Vermaak, S., Oliveira, A., Martins, L.D., Santos-Silva, J.C., Moreira, C.A.B., Pauliquevis, T., Godoi, A.F.L., Tadano, Y., Yamamoto, C.I., Godoi, R.H.M. (2023) 'The new WHO air quality guidelines for PM2.5: predicament for small/medium cities.' Environmental Geochemistry and Health, 45(5) pp. 1841-1860.

    Sarmiento, H., Potgieter-Vermaak, S., Borillo, G.C., Godoi, A.F.L., Reis, R.A., Yamamoto, C.I., Pauliquevis, T., Polezer, G., Godoi, R.H.M. (2023) 'BTEX profile and health risk at the largest bulk port in Latin America, Paranaguá Port.' Environmental Science and Pollution Research, 30(22) pp. 63084-63095.

    Mafulul, S.G., Potgieter, J.H., Longdet, I.Y., Okoye, Z.S.C., Potgieter-Vermaak, S.S. (2022) 'Health risks for a rural community in Bokkos, Plateau State, Nigeria, exposed to potentially toxic elements from an abandoned tin mine.' Archives of Environmental Contamination and Toxicology, 83(1) pp. 47-66.

    Irvin, K.S., Potgieter, J.H., Liauw, C., Sparkes, R., Potgieter-Vermaak, S. (2022) 'The quantification of di-octyl terephthalate and calcium carbonate in polyvinyl chloride using Fourier transform-infrared and Raman spectroscopy.' Journal of Applied Polymer Science, 139(24) pp. 52372-52372.

    Watts, M.J., Argyraki, A., Barbieri, M., Brown, A., Button, M., Finkelman, R., Gibson, G., Humphrey, O., Huo, X., Hursthouse, A.S., Kaninga, B., Marinho Reis, P., Middleton, D.R.S., Morton-Bermea, O., Nazarpour, A., Olatunji, A.S., Osano, O., Potgieter-Vermaak, S., Prater, C., Torrance, K., Wong, M.H., Zhang, C., Zia, M. (2022) 'Editorial: The society for environmental geochemistry and health (SEGH): 50 years and beyond.' Environmental Geochemistry and Health, 45(4) pp. 1165-1171.

    Krupnova, T., Rakova, O., Bondarenko, K., Saifullin, A., Popova, D., Potgieter-Vermaak, S., Godoi, R.H.M. (2021) 'Elemental Composition of PM2.5 and PM10 and Health Risks Assessment in the Industrial Districts of Chelyabinsk, South Ural Region, Russia.' International Journal of Environmental Research and Public Health, 18(23)

    Thompson, J.R., Argyraki, A., Bashton, M., Bramwell, L., Crown, M., Hursthouse, A.S., Jabeen, K., Marinho Reis, P., Namdeo, A., Nelson, A., Pearce, D.A., Potgieter-Vermaak, S., Rasmussen, P.E., Wragg, J., Entwistle, J.A. (2021) 'Bacterial Diversity in House Dust: Characterization of a Core Indoor Microbiome.' Frontiers in Environmental Science, 9

    Toubes‐Rodrigo, M., Potgieter‐Vermaak, S., Sen, R., Oddsdóttir, E.S., Elliott, D., Cook, S. (2021) 'Active microbial ecosystem in glacier basal ice fuelled by iron and silicate comminution‐derived hydrogen.' MicrobiologyOpen, 10(4)

    Tadano, Y.S., Potgieter-Vermaak, S., Kachba, Y.R., Chiroli, D.M.G., Casacio, L., Santos-Silva, J.C., Moreira, C.A.B., Machado, V., Alves, T.A., Siqueira, H., Godoi, R.H.M. (2020) 'Dynamic model to predict the association between air quality, COVID-19 cases, and level of lockdown.' Environmental Pollution, 268(Part B) pp. 115920-115920.

    de Oliveira, A., Polezer, G., Godoi, R.H.M., Vermaak, S.P., de Souza, R.A.F., Andreoli, R.V., Yamamoto, C.I. (2020) 'EXPRESS: Atomic Absorption Spectrometry Methods to Access the Metal Solubility of Aerosols in Artificial Lung Fluid.' Applied Spectroscopy, 74(8) pp. 932-939.

    Polezer, G., Oliveira, A., Potgieter-Vermaak, S., Godoi, A.F.L., de Souza, R.A.F., Yamamoto, C.I., Andreoli, R.V., Medeiros, A.S., Machado, C.M.D., dos Santos, E.O., de André, P.A., Pauliquevis, T., Saldiva, P.H.N., Martin, S.T., Godoi, R.H.M. (2019) 'The influence that different urban development models has on PM2.5 elemental and bioaccessible profiles.' Scientific Reports, 9

    Watts, M.J., An, T., Argyraki, A., Arhin, E., Brown, A., Button, M., Entwistle, J.A., Finkelman, R., Gibson, G., Humphrey, O.S., Huo, X., Hursthouse, A.S., Marinho-Reis, A.P., Maseka, K., Middleton, D.R.S., Morton-Bermea, O., Nazarpour, A., Olatunji, A.S., Osano, O., Potgieter-Vermaak, S., Saini, S., Stewart, A., Tarek, M., Torrance, K., Wong, M.H., Yamaguchi, K.E., Zhang, C., Zia, M. (2019) 'The Society for Environmental Geochemistry and Health (SEGH): building for the future.' Environmental Geochemistry and Health, 42(2) pp. 343-347.

    Brown, A.D., Yalala, B., Cukrowska, E., Godoi, R.H.M., Potgieter-Vermaak, S. (2019) 'A scoping study of component-specific toxicity of mercury in urban road dusts from three international locations.' Environmental Geochemistry and Health, 42(4) pp. 1127-1139.

    Brown, A.D., Barrett, J.E.S., Bennett, M., Potgieter-Vermaak, S. (2019) 'An investigation into the use of < 38 µm fraction as a proxy for < 10 µm road dust particles.' Environmental Geochemistry and Health, 42(4) pp. 1117-1126.

    Borillo, G.C., Tadano, Y.S., Godoi, A.F.L., Pauliquevis, T., Sarmiento, H., Rempel, D., Yamamoto, C.I., Marchi, M.R.R., Potgieter-Vermaak, S., Godoi, R.H.M. (2018) 'Polycyclic Aromatic Hydrocarbons (PAHs) and nitrated analogs associated to particulate matter emission from a Euro V-SCR engine fuelled with diesel/biodiesel blends.' Science of the Total Environment, 644pp. 675-682.

    Amaibi, P.M., Entwistle, J.A., Kennedy, N., Cave, M., Kemp, S.J., Potgieter-Vermaak, S., Dean, J.R. (2018) 'Mineralogy, solid-phase fractionation and chemical extraction to assess the mobility and availability of arsenic in an urban environment.' Applied Geochemistry, 100pp. 244-257.

    Chiweshe, T.T., Potgieter-Vermaak, S., Purcell, W. (2018) 'Characterization of Chromium (III) Compounds Isolated from Different Mineral Ores Using Ammonium Phosphate as Flux.' Mining, Metallurgy and Exploration, 36(2) pp. 441-450.

    Naqvi, Q.A., Ratova, M., Klaysri, R., Kelly, P., Edge, M., Potgieter, S., Tosheva-Jivkova, L. (2018) 'Tuning the composition of porous resin-templated TiO2 macrobeads for optimized photocatalytic performance.' Catalysis Today, 326pp. 54-59.

    Godoi, A.F.L., Grasel, A.M., Polezer, G., Brown, A., Potgieter, S.S., Scremim, D., Godoi, R.H.M., Yamamoto, C. (2017) 'Human exposure to hydrogen sulphide concentrations near wastewater treatment plants.' Science of the Total Environment, 610pp. 583-590.

    Godoi, R.H.M., Polezer, G., Borillo, G.C., Brown, A., Valebona, F.B., Silva, T.O.B., Ingberman, A.B.G., Nalin, M., Yamamoto, C.I., Potgieter-Vermaak, S.S., Penteado Neto, R.A., de Marchi, M.R.R., Saldiva, P.H.N., Pauliquevis, T., Godoi, A.F.L. (2016) 'Influence on the oxidative potential of a heavy-duty engine particle emission due to selective catalytic reduction system and biodiesel blend.' Science of the Total Environment, 560-56

    Brown, A., Barrett, J.E., Robinson, H., Potgieter-Vermaak, S. (2015) 'Risk assessment of exposure to particulate output of a demolition site..' Environmental Geochemistry and Health, 37

    Romero-Pastor, J., García-Porras, A., Van Grieken, R., Potgieter-Vermaak, S., Coll-Conesa, J., Cardell, C. (2015) 'New insights in technology characterization of medieval Valencia glazes.' X-Ray Spectrometry, 44

    Borillo, G.C., Tadano, Y.S., Godoi, A.F.L., Santana, S.S.M., Weronka, F.M., Penteado Neto, R.A., Rempel, D., Yamamoto, C.I., Potgieter, S.S., Potgieter, J.H., Godoi, R.H.M. (2015) 'Effectiveness of Selective Catalytic Reduction (SCR) systems on reducing gaseous emissions from an engine using Diesel and Biodiesel Blends.' Environmental Science and Technology, 49(5) pp. 3246-3251.

    Dirtu, A.C., Buczyńska, A.J., Godoi, A.F.L., Favoreto, R., Bencs, L., Potgieter-Vermaak, S.S., Godoi, R.H.M., Van Grieken, R., Van Vaeck, L. (2014) 'Methods, fluxes and sources of gas phase alkyl nitrates in the coastal air.' Environmental Monitoring and Assessment, 186

    Buczynska, A.J., Krata, A., Van Grieken, R., Brown, A., Polezer, G., De Wael, K., Potgieter-Vermaak, S. (2014) 'Composition of PM2.5 and PM1 on high and low pollution event days and its relation to indoor air quality in a home for the elderly.' Science of the Total Environment, 490

    Potgieter, J.H., Olubambi, P., Potgieter-Vermaak, S.S. (2014) 'The Corrosion Behaviour of WC-Co-Ru Alloys in Aggressive Chloride Media.' International Journal of Electrochemistry, 2014

    Hellar-Kihampa, H., Potgieter-Vermaak, S., de Wael, K., Lugwisha, E., van Espen, P., van Grieken, R. (2014) 'Concentration profiles of metal contaminants in fluvial sediments of a rural-urban drainage basin in Tanzania.' International Journal of Environmental Analytical Chemistry, 94(1) pp. 77-98.

    Godoi, R.H.M., Godoi, A.F.L., de Quadros, L.C., Polezer, G., Silva, T.O.B., Yamamoto, C.I., van Grieken, R., Potgieter-Vermaak, S. (2013) 'Risk assessment and spatial chemical variability of PM collected at selected bus stations.' Air Quality, Atmosphere and Health, 6(4) pp. 725-735.

    Godoi, R.H.M., Godoi, A.F.L., Gonzalves, S., Paralova, S.L., Potgieter-Vermaak, S.S. (2013) 'Healthy environment — indoor air quality of Brazilian elementary schools nearby petrochemical industry.' Science of the Total Environment, 463-464pp. 639-646.

    Mmari, A.G., Potgieter-Vermaak, S.S., Bencs, L., McCrindle, R.I., Van Grieken, R. (2013) 'Elemental and ionic components of atmospheric aerosols and associated gaseous pollutants in and near Dar es Salaam, Tanzania.' Atmospheric Environment, 77pp. 51-61.

    Godoi, R.H.M., Godoi, A.F.L., de Quadros, L.C., Polezer, G., Silva, T.O.B., Yamamoto, C.I., van Grieken, R., Potgieter-Vermaak, S. (2013) 'Risk assessment and spatial chemical variability of PM collected at selected bus stations.' Air Quality, Atmosphere and Health, pp. 1-11.

    Machio, C.N., Konado, D.S., Potgieter-Vermaak, S., Potgieter, J.H., Van der Merwe, J. (2013) 'Corrosion of WC-VC-Co Hardmetal in Neutral Chloride Containing Media.' ISRN Corrosion, 2013

    Potgieter-Vermaak, S., Rotondo, G., Novakovic, V., Rollins, S., Van Grieken, R. (2012) 'Component-specific toxic concerns of the inhalable fraction of urban road dust..' Environ Geochem Health, 34(6) pp. 689-696.

    Jacobs, L., Buczynska, A., Walgraeve, C., Delcloo, A., Potgieter-Vermaak, S., Van Grieken, R., Demeestere, K., Dewulf, J., Van Langenhove, H., De Backer, H., Nemery, B., Nawrot, T.S. (2012) 'Acute changes in pulse pressure in relation to constituents of particulate air pollution in elderly persons.' Environmental Research, 117pp. 60-67.

    Godoi, R.H.M., Hirata, P.Y., Bitterncourt, A.V.L., Godoi, A.F.L., Jafelicci, M., dos Santos, F.J., Bini, R., Zara, L.F., Cunha, C.L.N., Soares, A.P.K., Gobbi, E.F., Potgieter-Vermaak, S., Gardolinski, J.E.F.C., Reis Neto, J.M., Rotondo, G.G., van Grieken, R. (2012) 'Geochemical Assessment of a Subtropical Reservoir: A Case Study in Curitiba, Southern Brazil.' Clean - Soil, Air, Water, 40(4) pp. 364-372.

    Hellar-Kihampa, H., Potgieter-Vermaak, S., van Grieken, K., Rotondo, G.G., Kishimba, M., Van Grieken, R. (2012) 'Elemental composition of bottom-sediments from Pangani river basin, Tanzania: Lithogenic and anthropogenic sources.' Toxicological and Environmental Chemistry, 94(3) pp. 525-544.

    Potgieter-Vermaak, S., Horemans, B., Anaf, W., Cardell, C., Grieken, R.V. (2012) 'Degradation potential of airborne particulate matter at the Alhambra monument: A Raman spectroscopic and electron probe X-ray microanalysis study.' Journal of Raman Spectroscopy, 43(11) pp. 1570-1577.

    Delport, D.J., Potgieter-Vermaak, S.S., McCrindle, R.I., Potgieter, J.H. (2011) 'Potentiometric determination of free chloride in cement paste - An alternative method for low-budget laboratories.' South African Journal of Chemistry, 64pp. 251-253.

    Potgieter, J.H., Delport, D.J., Verryn, S., Potgieter-Vermaak, S.S. (2011) 'Chloride-binding effect of blast furnace slag in cement pastes containing added chlorides.' South African Journal of Chemistry, 64pp. 108-114.

    Potgieter, J.H., Thanjekwayo, N., Olubambi, P., Maledi, N., Potgieter-Vermaak, S.S. (2011) 'Influence of Ru additions on the corrosion behaviour of WC-Co cemented carbide alloys in sulphuric acid.' International Journal of Refractory Metals and Hard Materials, 29(4) pp. 478-487.

    Worobiec, A., Potgieter-Vermaak, S.S., Berghmans, P., Winkler, H., Burger, R., Grieken, R.V. (2011) 'Air particulate emissions in developing countries: A case study in South Africa.' Analytical Letters, 44(11) pp. 1907-1924.

    Chabalala, V.P., Wagner, N., Potgieter-Vermaak, S. (2011) 'Investigation into the evolution of char structure using Raman spectroscopy in conjunction with coal petrography; Part 1.' Fuel Processing Technology, 92(4) pp. 750-756.

    Potgieter-Vermaak, S., Maledi, N., Wagner, N., Van Heerden, J.H.P., Van Grieken, R., Potgieter, J.H. (2011) 'Raman spectroscopy for the analysis of coal: A review.' Journal of Raman Spectroscopy, 42(2) pp. 123-129.

    Potgieter-Vermaak, S.S., Mmari, A., Van Grieken, R., McCrindle, R.I., Potgieter, J.H. (2011) 'Degradation of galvanised iron roofing material in Tanzania by atmospheric corrosion.' Corrosion Engineering Science and Technology, 46(5) pp. 642-650.

    Potgieter-Vermaak, S., Chabalala, V. (2010) 'Raman spectroscopy and petrographic analysis for the study of char structure.' AIP Conference Proceedings, 1267pp. 459-460.

    Konadu, D.S., Merwe, J.V.D., Potgieter, J.H., Potgieter-Vermaak, S., Machio, C.N. (2010) 'The corrosion behaviour of WC-VC-Co hardmetals in acidic media.' Corrosion Science, 52(9) pp. 3118-3125.

    Ignat, M., Van Oers, C.J., Vernimmen, J., Mertens, M., Potgieter-Vermaak, S., Meynen, V., Popovici, E., Cool, P. (2010) 'Textural property tuning of ordered mesoporous carbon obtained by glycerol conversion using SBA-15 silica as template.' Carbon, 48(5) pp. 1609-1618.

    Worobiec, A., Potgieter-Vermaak, S., Brooker, A., Darchuk, L., Stefaniak, E., Van Grieken, R. (2010) 'Interfaced SEM/EDX and micro-Raman Spectrometry for characterisation of heterogeneous environmental particles - Fundamental and practical challenges.' Microchemical Journal, 94(1) pp. 65-72.

    Bencs, L., Krata, A., Horemans, B., Buczyńska, A.J., Dirtu, A.C., Godoi, A.F.L., Godoi, R.H.M., Potgieter-Vermaak, S., Van Grieken, R. (2009) 'Atmospheric nitrogen fluxes at the Belgian coast: 2004-2006.' Atmospheric Environment, 43(24) pp. 3786-3798.

    Potgieter, J.H., Bada, S.O., Potgieter-Vermaak, S.S. (2009) 'Adsorptive removal of various phenols from water by South African coal fly ash.' Water SA, 35(1) pp. 89-96.

    Stranger, M., Potgieter-Vermaak, S.S., Van Grieken, R. (2009) 'Particulate matter and gaseous pollutants in residences in Antwerp, Belgium.' Science of the Total Environment, 407(3) pp. 1182-1192.

    Stranger, M., Potgieter-Vermaak, S., Sacco, P., Quaglio, F., Pagani, D., Cocheo, C., Godoi, A.F.L., Van Grieken, R. (2009) 'Analysis of indoor gaseous formic and acetic acid, using radial diffusive samplers..' Environ Monit Assess, 149(1-4) pp. 411-417.

    Avigo, D., Godoi, A.F.L., Janissek, P.R., Makarovska, Y., Krata, A., Potgieter-Vermaak, S., Alfoldy, B., Van Grieken, R., Godoi, R.H.M. (2008) 'Particulate matter analysis at elementary schools in Curitiba, Brazil.' Analytical and Bioanalytical Chemistry, 391(4) pp. 1459-1468.

    Potgieter-Vermaak, S., Stranger, M., Godoi, A.F.L., Jacobs, W., Godoi, R.H.M., Van Grieken, R. (2008) 'Volatile organic gaseous pollutants in various indoor environments.' pp. 1-49.

    Stranger, M., Potgieter-Vermaak, S.S., Van Grieken, R. (2008) 'Characterization of indoor air quality in primary schools in Antwerp, Belgium.' Indoor Air, 18(6) pp. 454-463.

    Godoi, R.H.M., Potgieter-Vermaak, S., Godoi, A.F.L., Stranger, M., Van Grieken, R. (2008) 'Assessment of aerosol particles within the Rubens' House Museum in Antwerp, Belgium.' X-Ray Spectrometry, 37(4) pp. 298-303.

    Bada, S.O., Potgieter-Vermaak, S. (2008) 'Evaluation and treatment of coal fly ash for adsorption application.' Leonardo Electronic Journal of Practices and Technologies, 7(12) pp. 37-48.

    Idris, A.M., Eltayeb, M.A.H., Potgieter-Vermaak, S.S., Van Grieken, R., Potgieter, J.H. (2007) 'Assessment of heavy metals pollution in Sudanese harbours along the Red Sea Coast.' Microchemical Journal, 87(2) pp. 104-112.

    Worobiec, A., Stefaniak, E.A., Potgieter-Vermaak, S., Sawlowicz, Z., Spolnik, Z., Van Grieken, R. (2007) 'Characterisation of concentrates of heavy mineral sands by micro-Raman spectrometry and CC-SEM/EDX with HCA.' Applied Geochemistry, 22(9) pp. 2078-2085.

    Potgieter, S.S., Marjanovic, L. (2007) 'A further method for chloride analysis of cement and cementitious materials - ICP-OES.' Cement and Concrete Research, 37(8) pp. 1172-1175.

    Potgieter-Vermaak, S.S., Potgieter, J.H., Worobiec, A., van Grieken, R., Marjanovic, L., Moeketsi, S. (2007) 'Fingerprinting of South African ordinary Portland cements, cement blends and mortars for identification purposes - Discrimination with starplots and PCA.' Cement and Concrete Research, 37(6) pp. 834-843.

    Worobiec, A., Stefaniak, E.A., Kiro, S., Oprya, M., Bekshaev, A., Spolnik, Z., Potgieter-Vermaak, S.S., Ennan, A., Van Grieken, R. (2007) 'Comprehensive microanalytical study of welding aerosols with x-ray and Raman based methods.' X-Ray Spectrometry, 36(5) pp. 328-335.

    Smekens, A., Godoi, R.H.M., Vervoort, M., Van Espen, P., Potgieter-Vermaak, S.S., Van Grieken, R. (2007) 'Characterization of individual soot aggregates from different sources using image analysis.' Journal of Atmospheric Chemistry, 56(3) pp. 211-223.

    Stranger, M., Potgieter-Vermaak, S.S., Van Grieken, R. (2007) 'Comparative overview of indoor air quality in Antwerp, Belgium.' Environment International, 33(6) pp. 789-797.

    Potgieter-Vermaak, S.S., Potgieter, J.H. (2006) 'Metakaolin as an extender in South African cement.' Journal of Materials in Civil Engineering, 18(4) pp. 619-623.

    Stefaniak, E.A., Worobiec, A., Potgieter-Vermaak, S., Alsecz, A., Török, S., Van Grieken, R. (2006) 'Molecular and elemental characterisation of mineral particles by means of parallel micro-Raman spectrometry and Scanning Electron Microscopy/Energy Dispersive X-ray Analysis.' Spectrochimica Acta - Part B Atomic Spectroscopy, 61(7) pp. 824-830.

    Potgieter-Vermaak, S.S., Potgieter, J.H., Belleil, M., Deweerdt, F., Van Grieken, R. (2006) 'The application of Raman spectrometry to the investigation of cement: Part II: A micro-Raman study of OPC, slag and fly ash.' Cement and Concrete Research, 36(4) pp. 663-670.

    Potgieter-Vermaak, S.S., Potgieter, J.H., Van Grieken, R. (2006) 'The application of Raman spectrometry to investigate and characterize cement, Part I: A review.' Cement and Concrete Research, 36(4) pp. 656-662.

    Godoi, R.H.M., Potgieter-Vermaak, S., De Hoog, J., Kaegi, R., Van Grieken, R. (2006) 'Substrate selection for optimum qualitative and quantitative single atmospheric particles analysis using nano-manipulation, sequential thin-window electron probe X-ray microanalysis and micro-Raman spectrometry.' Spectrochimica Acta - Part B Atomic Spectroscopy, 61(4) pp. 375-388.

    Potgieter-Vermaak, S.S., Potgieter, J.H., Monama, P., Van Grieken, R. (2006) 'Comparison of limestone, dolomite and fly ash as pre-treatment agents for acid mine drainage.' Minerals Engineering, 19(5) pp. 454-462.

    Potgieter, J.H., Kabemba, M.A., Teodorovic, A., Potgieter-Vermaak, S.S., Augustyn, W.G. (2006) 'An investigation into the feasibility of recovering valuable metals from solid oxide compounds by gas phase extraction in a fluidised bed.' Minerals Engineering, 19(2) pp. 140-146.

    Potgieter-Vermaak, S.S., Van Grieken, R. (2006) 'Preliminary evaluation of micro-Raman spectrometry for the characterization of individual aerosol particles.' Applied Spectroscopy, 60(1) pp. 39-47.

    Potgieter, J.H., Potgieter-Vermaak, S.S., Kalibantonga, P.D. (2006) 'Heavy metals removal from solution by palygorskite clay.' Minerals Engineering, 19(5) pp. 463-470.

    Potgieter-Vermaak, S.S., Potgieter, J.H., Kruger, R.A., Spolnik, Z., Van Grieken, R. (2005) 'A characterisation of the surface properties of an ultra fine fly ash (UFFA) used in the polymer industry.' Fuel, 84(18) pp. 2295-2300.

    Potgieter-Vermaak, S.S., Godoi, R.H.M., Grieken, R.V., Potgieter, J.H., Oujja, M., Castillejo, M. (2005) 'Micro-structural characterization of black crust and laser cleaning of building stones by micro-Raman and SEM techniques..' Spectrochim Acta A Mol Biomol Spectrosc, 61(11-12) pp. 2460-2467.

    Potgieter, J.H., Potgieter-Vermaak, S.S., Modise, J., Basson, N. (2005) 'Removal of iron and manganese from water with a high organic carbon loading. Part II: The effect of various adsorbents and nanofiltration membranes.' Water, Air, and Soil Pollution, 162(1-4) pp. 61-70.

    Potgieter, J.H., Potgieter, S.S., McCrindle, R.I. (2004) 'A comparison of the performance of various synthetic gypsums in plant trials during the manufacturing of OPC clinker.' Cement and Concrete Research, 34(12) pp. 2245-2250.

    Potgieter, S.S., Potgieter, J.H., Panicheva, S. (2004) 'Investigation into methods of chloride analysis of South African cement and cement-related materials with low chloride concentrations.' Materials and Structures/Materiaux et Constructions, 37(3) pp. 155-160.

    Potgieter, J.H., Potgieter, S.S., Mbaya, R.K.K., Teodorovic, A. (2004) 'Small-scale recovery of noble metals from jewellery wastes.' Journal of The South African Institute of Mining and Metallurgy, 104(10) pp. 563-571.

    Potgieter, S.S., Panichev, N., Potgieter, J.H., Panicheva, S. (2003) 'Determination of hexavalent chromium in South African cements and cement-related materials with electrothermal atomic absorption spectrometry.' Cement and Concrete Research, 33(10) pp. 1589-1593.

    Potgieter, J.H., Potgieter, S.S., Strydom, C.A., Gheevarhese, O. (2003) 'The influence of various common ions on the slaking of some South African limes.' Water SA, 29(4) pp. 433-436.

    Potgieter, J.H., Potgieter, S.S., McCrindle, R.I., Strydom, C.A. (2003) 'An investigation into the effect of various chemical and physical treatments of a South African phosphogypsum to render it suitable as a set retarder for cement.' Cement and Concrete Research, 33(8) pp. 1223-1227.

    Abonyi, J., Tamás, F.D., Potgieter, S., Potgieter, H. (2003) 'Analysis of trace elements in South African clinkers using latent variable model and clustering.' South African Journal of Chemistry, 56pp. 15-20.

    Potgieter, J.H., Potgieter, S.S. (2003) 'Mining backfill formulations from various cementitious and waste materials.' Indian Concrete Journal, 77(5) pp. 1071-1075.

    Potgieter, J.H., Potgieter, S.S., McCrindle, R.I., Tamas, F.D. (2003) 'Fingerprinting of South African cement clinkers and gypsum as a tool for cement identification purposes.' Advances in Cement Research, 15(2) pp. 45-50.

    Potgieter, S.S., Potgieter, H. (2003) 'Hexavalent chromium speciation in a cement matrix.' American Laboratory, 35(4) pp. 26-28.

    Potgieter, J.H., Potgieter, S.S., De Waal, D. (2003) 'An empirical study of factors influencing lime slaking Part II: Lime constituents and water composition.' Water SA, 29(2) pp. 157-160.

    Potgieter, S.S., Strydom, C.A., Gheevarhese, O. (2003) 'The effect of ultrasonic energy on lime slaking.' Minerals Engineering, 16(8) pp. 767-770.

    Potgieter, J.H., Potgieter, S.S., McCrindle, R.I., Tamas, F.D. (2003) 'Fingerprinting of South African cement clinkers and gypsum as a tool for cement identification purposes.' Advances in Cement Research, 15(2) pp. 45-50.

    Potgieter, J.H., Horne, K.A., Potgieter, S.S., Wirth, W. (2002) 'An evaluation of the incorporation of a titanium dioxide producer's waste material in Portland cement clinker.' Materials Letters, 57(1) pp. 157-163.

    Potgieter, J.H., Potgieter, S.S., Loubser, M., Kearsley, E., Strydom, C.A. (2002) 'Stabilisation of a ferro-industry waste in various solid matrices.' Journal of Chemical Technology and Biotechnology, 77(3) pp. 311-314.

    Potgieter, J.H., Potgieter, S.S., Moja, S.J., Mulaba-Bafubiandi, A. (2002) 'An empirical study of factors influencing lime slaking. Part I: Production and storage conditions.' Minerals Engineering, 15(3) pp. 201-203.

    Gheevarhese, O., Strydom, C.A., Potgieter, J.H., Potgieter, S.S. (2002) 'The influence of chloride and sulphate ions on the slaking rate of lime derived from different limestone deposits in South Africa.' Water SA, 28(1) pp. 45-48.

    Potgieter, J.H., Potgieter, S.S., Moja, S.J., Mulaba-Bafubiandi, A. (2002) 'The standard reactivity test as a measure of lime's quality.' Journal of The South African Institute of Mining and Metallurgy, 102(1) pp. 67-69.

    Legodi, M.A., de Waal, D., Potgieter, J.H., Potgieter, S.S. (2001) 'Rapid determination of CaCO3 in mixtures utilising FT-IR spectroscopy.' MINERALS ENGINEERING, 14(9) pp. 1107-1111.

    Potgieter, J.H., Potgieter, S.S., Legodi, B. (2001) 'Proposed modifications to the method for the determination of available lime.' Minerals Engineering, 14(5) pp. 515-523.

    Legodi, M.A., De Waal, D., Potgieter, J.H., Potgieter, S.S. (2001) 'Technical note rapid determination of CaCo3 in mixtures utilising FT-IR spectroscopy.' Minerals Engineering, 14(9) pp. 1107-1111.

    Potgieter, J.H., Howell-Potgieter, S.S. (2001) 'A plant investigation into the use of treated phosphogypsum as a set-retarder in OPC and an OPC/FLY ash blend.' Minerals Engineering, 14(7) pp. 791-795.

    Coetzee, P.P., Yacoby, M., Howell, S., Mubenga, S. (1998) 'Scale reduction and scale modification effects induced by Zn and other metal species in physical water treatment.' Water SA, 24(1) pp. 77-84.

    Coetzee, P.P., Yacoby, M., Howell, S. (1996) 'The role of zinc in magnetic and other physical water treatment methods for the prevention of scale.' Water SA, 22(4) pp. 319-326.

    Coetzee, P.P., Gouws, K., Pluddemann, S., Yacoby, M., Howell, S., Den Drijver, L. (1995) 'Evaluation of sequential extraction procedures for metal speciation in model sediments.' Water SA, 21(1)

  • Non-peer reviewed articles / reviews

    Argyraki, A., Watts, M.J., Abdou, M., Ahmad, W., Ajayi, F.F., An, T., Barbieri, M., Biswas, J.K., Gaberšek, M., Gibson, G., Hashmi, M.Z., Humphrey, O.S., Hursthouse, A.S., Kaninga, B., Laniyan, T.A., Monteiro, C.E., Morton-Bermea, O., Olajide-Kayode, J., Olatunji, A.S., Onyangore, F., Osano, O., Potgieter-Vermaak, S., Prater, C., Purchase, D., Torrance, K. (2024) Editorial: Charting achievements: a two-year retrospective of the society for environmental geochemistry and health (SEGH) and the evolving strategies.

  • Conference papers

    Potgieter, J.H., Potgieter-Vermaak, S., Purcell, W. (2017) 'Quantification of scandium in columbite-tantalite tailings and other scandium compounds.' 4. pp. 1797-1807.

    Potgieter, J.H., Wagner, N., Potgieter-Vermaak, S., Mohamed, W. (2016) 'The use of microwave energy to desulphurize S.A coal.' 2016-August.

    Potgieter-Vermaak, S., Maledi, N., Potgieter, J.H., Sparkes, R., Wagner, N. (2016) 'Organic and inorganic characterisation of different coals by single particle analysis.' 2016-August.

    Worobiec, A., Potgieter-Vermaak, S., Darchuk, L., Vishnyakov, V., Potgieter, H., Van Grieken, R. (2010) 'Behavior of semi-volatile particles under a laser and electron beam - Influence on the quality of analytical results.' 1267. pp. 523-524.

    Potgieter-Vermaak, S., Potgieter, J.H., Van Grieken, R. (2010) 'Is the micro-Raman-SEM-EDX combination the answer to surface analysis? A case study of atmospheric corrosion.' 1267. pp. 521-522.

Press and media

Media appearances or involvement

BBC Manchester radio interview to talk about air pollution reduction after COVID-19 lockdown. 

Granada Reports TV interview on NOx reduction three weeks into COVID-19 lockdown in Manchester