International Peer-Reviewed JournalOpen AccessISSN 2456-8880
irejournals@gmail.com+91-7433024337

Home / Current Issue / Paper 1711389

1711389 Vol 9 · Issue 4 Download Paper

Oxidative Potential, Health Risk Assessment, And Pollution Indices of Heavy Metals in Indoor and Outdoor Dust from Residences in A Southwest Nigerian Metropolis

Abidemi Omofoyeke Oyediran Oluwatoyin Michael Sunday

Subject area: Science,Engineering and Technology  ·  Area of research: Air Pollution

Abstract

One of the major air pollutants of concern is dust, which have become a global problem due to its impact on both humans and the environment. In this study, we investigated the heavy metals concentration in the settled dust obtained from residential indoor and outdoor environment in Akure metropolis, Nigeria. The oxidative potential (OP) of the dust to trigger oxidative stress upon inhalation and the health risks associated with the heavy metal content in the dust were also evaluated. A total of eight samples were collected from indoor and outdoor settled dust at different locations within the city. The heavy metal contents and water extracts of the settled dust were determined using atomic absorption spectrophotometer. The OP of the water extracts were determined using ascorbic acid (AA) assays. The mean concentration of heavy metals in the digested and extracted dust was in the order Zn> Cu> Fe> Cr> Mn> Pb> Cd > As, with Zn>Cu>Fe>Cr>Mn being more frequently detected in indoor and outdoor samples. The differences between the heavy metal content of indoor and outdoor samples were not significant. The results of the pollution indices using both contamination factor and pollution load index classifies the dust samples as having low heavy metal contamination. In the current study, the OP values in indoor and outdoor samples based on AA assay was 5 ? 1 AA nmol/min. ?g and 4 ? 1 AA nmol/min.?g dust, respectively. The OP values are in the lower range of values reported for dust samples from other cities. The target hazard quotient (THQ) calculated for each heavy metal was generally less than 1, suggesting no adverse health risk associated with the heavy metal content of the samples. Overall, the result of this study demonstrates that the dust samples have low heavy metal contamination and there is no significant health effect associated with the metal content of the sample The differences between the heavy metal content of indoor and outdoor samples were not significant. The results of the pollution indices using both contamination factor and pollution load index classifies the dust samples as having low heavy metal contamination. In the current study, the OP values in indoor and outdoor samples based on AA assay was 5 ? 1 AA nmol/min. ?g and 4 ? 1 AA nmol/min.?g dust, respectively. The OP values are in the lower range of values reported for dust samples from other cities. The target hazard quotient (THQ) calculated for each heavy metal was generally less than 1, suggesting no adverse health risk associated with the heavy metal content of the samples. Overall, the result of this study demonstrates that the dust samples have low heavy metal contamination and there is no significant health effect associated with the metal content of the samples.

Keywords

Air Pollution, Reactive Oxygen Species and Settled Dust.

References

[1] Abbasi S, Keshavarzi B, Moore F, Hopke PK, Kelly FJ, DominguezAO (2020). Elemental and magnetic analyses, source identification,and oxidative potential of airborne, passive, and street dustparticles in Asaluyeh County, Iran. Science of The Total Environment707:136132

[2] Aryal R, Lee BK, Beecham S, et al (2015) Characterisation of road dust organic matter as a function of particle size: a PARAFACapproach. Water Air Soil Pollut. Https: //doi.org/10.1007/s11270-014-2289-yBai et. al., 2007

[3] Ayres, J. G.; Borm, P.; Cassee, F. R.; Castranova, V.; Donaldson, K.; Ghio, A.; Harrison, R. M.; Hider, R.; Kelly, F.; Kooter, I. M.; Marano, F.; Maynard, R. L.; Mudway, I.; Nel, A.; Sioutas, C.; Smith, S.; Baeza-Squiban, A.; Cho, A.; Duggan, S.; Froines, J.,( 2008). Evaluating the toxicity of airborne particulate matter and nanoparticles by measuring oxidative stress potential - A workshop report and consensus statement. InhalToxicol20, (1), 75-99.

[4] Bai N., Khazaei M., Eden S. and Laher I. (2007). The pharmacology of particulate matter air pollution-induced cardiovascular dysfunction, Pharmacol. Ther. 113, 16–29.

[5] Chien, L.C., Hung, T.S., Choang, K.Y., Yeh, C.Y., Meng, P.J., Sheieh, M.J., Han, B.C., (2002). Daily intake of TBT, Cu, Zn, Cd and As for fishermen in Taiwan. Sci. Total Environ. 285, 177–185.

[6] Chen, X., Guo, M., Feng, J., Liang, S., Han, D., & Cheng, J. (2019). Characterization and risk assessment of heavy metals in road dust from a developing city with good air quality and from Shanghai, China. Environmental Science and Pollution Research, 26, 11387–11398. https://doi.org/ 10.1007/s11356-019-04550-2 Clementi, E. A., Talusan, A., Vaidyanathan, S., Veerappan,

[7] Cho, A. K.; Sioutas, C.; Miguel, A. H.; Kumagai, Y.; Schmitz, D. A.; Singh, M.; Eiguren-Fernandez, A.; Froines, J. R., (2005). Redox activity of airborne particulate matter at different sites in the Los Angeles Basin. Environ Res 99 (1), 40-47.

[8] Cohen, A. J.; Brauer, M.; Burnett, R.; Anderson, H. R.; Frostad, J.; Estep, K.; Balakrishnan, K.; Brunekreef, B.; Dandona, L.; Dandona, R.; Feigin, V.; Freedman, G.; Hubbell, B.; Jobling, A.; Kan, H.; Knibbs, L.; Liu, Y.; Martin, R.;Morawska, L.; Pope, C. A., III; Shin, H.; Straif, K.; Shaddick, G.; Thomas, M.; van Dingenen, R.; van Donkelaar, A.; Vos, T.;Murray, C. J. L.; Forouzanfar, M. H., (2017). Estimates and 25-year trends of the global burden of disease attributable to ambient air pollution: An analysis of data from the global burden of diseases study 2015. The Lancet 2017, 389 (10082), 1907- 1918. doi:10.1016/s0140-6736(17)30505-6.

[9] DiStefano, E., Eiguren-Fernandez, A., Delfino, R.J., Sioutas, C., Froines, J.R., Cho, A.K., (2009). Determination of metal-based hydroxyl radical generating capacity ofambient and diesel exhaust particles. Inhal. Toxicol. 21, 731-738.

[10] Dockery, D. W., Pope, C. A., 3rd, Xu, X., Spengler, J. D., Ware, J.H., Fay, M. E., Ferris Jr., B. G., and Speizer, F. E. (1993): An association between air pollution and mortality in six U.S. cities, N. Engl. J.Med., 329, 1753–1759.

[11] Dominici F., McDermott A., Zeger S. and Samet J. (2003). Airborne particulate matter and mortality: timescale effects in four US cities, Am. J. Epidemiol., 157, 1055–1065.

[12] Donaldson, K., Brown, D. M., Mitchell, C., Dineva, M., Beswick, P.H., Gilmour, P., and MacNee, W. (1997): Free radical activity of PM10: iron-mediated generation of hydroxyl radicals, Environ. HealthPerspect, 105, 1285–1289.

[13] Du, Y.R., Gao, B., Zhou, H.D., XX, Ju, Hao, H., Yin, S.H., (2013). Health risk assessment of heavy metals in road dusts in urban parks of Beijing, China. Procedia Environ Sci18, 299–309.

[14] Emmanuel, A., Cobbina, S.J., Adomako, D., Duwiejuah, A.B., Asare, W., 2014. Assessmentof heavy metals concentration in soils around oil filling and service stations in theTamale Metropolis, Ghana. Atmos. Pollut. Res. 5, 270–282.

[15] Ferrante M, Fiore M, Conti GO, Fiore V, Grasso A, Copat C, Signorelli SS (2017) Transition and heavy metals compared to oxidative parameter balance in patients with deep vein thrombosis: a case-control study. Mol Med Rep 15(5):3438–3444

[16] Ferreira-Baptista, L., & De Miguel, E. (2005). Geochemistryand risk assessment of street dust in Luanda, Angola: Atropical urban environment. Atmospheric Environment,39, 4501–4512. https:// doi. org/ 10. 1016/j. atmos env.2005. 03. 026

[17] FNEGhR, (2011). Final NEGhReport:‘Existing Default Values and Recommendations for Exposure assessment – A Nordic Exposure Group Project 2011′ published by the Nordic Council of Ministers, VedStranden 18, 1061 Kǿbenhavn K; Tema Nord2012:505; ISBN 978-92-893-2316-1.

[18] Gakidou, E.; Afshin, A.; Abajobir, A. A.; Abate, K. H.; Abbafati, C.; Abbas, K. M.; Abd-Allah, F.; Abdulle, A. M.; Abera, S. F.; Aboyans, V., (2017). Global, regional, and national comparative risk assessment of 84 behavioural, environmental and occupational, and metabolic risks or clusters of risks, 1990–2016: A systematic analysis for the global burden of disease study 2016. The Lancet 2017, 390 (10100), 1345-1422.

[19] Garba, S. T., Akan, J. C., & Ahmed, I. (2014). Spatial Distribution of the Heavy Metals: Ni, Fe, Cr, and Mn in Roadside Soils of Maiduguri Metropolis, Borno State Nigeria. Global Journal of Science Frontier Research: H Environment & Earth Science, 14(1), 1-5.

[20] Godri K.J., Duggan S.T., Fuller G.W., Baker T., Green D., Kelly F.J., Mudway I.S. Particulate matter oxidative potential from waste transfer station activity (2010). Environ Health Perspect 118(4):493–498

[21] Goldbohm, R.A., Tielemans, E.L., Heederik, J.P., Rubingh, D., Dekkers, C.M., Willems, S., Kroese, E.D., (2006). Risk assessment for carcinogens based on epidiological data: astructured approach, illustrated by an example of 22 chromium. Regul. Pharmacol.44, 294–310.

[22] Hoek G, Beelen R, de Hoogh K, Vienneau D, Gulliver J, Fischer P, Briggs D (2013) A review of land-use regression models to assess spatial variation of outdoor air pollution. Atmos Environ 42(33):7561–7578

[23] Iyer K.S and Klee W.A (1973). Direct Spectrophotometric measurement of the rate of reduction of disulphide bonds. The Journal of Biological Chemistry vol 248, No 2, Issue of Jan 25 pp 707-710 1973.

[24] Janssen, N. A. H.; Yang, A. L.; Strak, M.; Steenhof, M.; Hellack, B.; Gerlofs-Nijland, M. E.; Kuhlbusch, T.; Kelly, F.; Harrison, R. M.; Brunekreef, B.; Hoek, G.; Cassee, F., (2014). Oxidative potential of particulate matter collected at sites with different source characteristics. Sci Total Environ 472, 572-581.

[25] Janssen, N. A. H., Strak, M., Yang, A., Hellack, B., Kelly, F. J., Kuhlbusch, T. A. J., Harrison,R. M., Brunekreef, B., Cassee, F. R., Steenhof, M., and Hoek, G.( 2015): Associations between three specific a-cellular measures of the oxidative potential of particulate matter and markers of acute airway and nasal inflammation in healthy volunteers, Occup. Environ. Med., 72, 5 49–56, 2015.

[26] Li QF, Wyatt A, Kamens RM. Oxidant generation and toxicity enhancement of aged-diesel exhaust. Atmos Environ. 2009a; 43:1037–1042

[27] Malakootian, M., Mohammadi, A., Nasiri, A., Conti, G., & Faraji, M. (2022). Correlation between heavy metal concentration and oxidative potential of street dust. Air Quality, Atmosphere & Health, 15, 731–738. https://doi.org/10. 1007/s11869-021-01130-7

[28] Massimi L., Simonetti G., Buiarelli F., Filippo P. Di, Pomata D., Riccardi C., RistoriniM.,.Astolfi M. L and Canepari S., (2020). Spatial distribution of levoglucosan and alternative biomass burning tracers in atmospheric aerosols, in an urban and industrial hot-spot of Central Italy, Atmos. Res.,  239, 104904 

[29] McWhinney RD, Gao SS, Zhou SM, Abbatt JPD (2011). Evaluation of the effects of ozone oxidation on redox-cycling activity of two-stroke engine exhaust particles. Env Sci Technol. 2011; 45:2131–2136. [PubMed: 21341691]

[30] Morakinyo, O.M.; Mokgobu, M.I; Mukhola, M.S.; Hunter, R.P; (2016). Health outcomes of exposure to biological and chemical components of inhalable and respirable particulate matter. International journal of environmental research and public health 13 (6), 592

[31] Mudway, I., Duggan, S., Venkataraman, C., Habib, G., Kelly, F., and Grigg, J (2005). Combustion of dried animal dung as biofuel results in the generation of highly redox active fine particulates, Part. FibreToxicol., 2, 6, doi:10.1186/1743-8977-2-6, 2005.

[32] Naraki H, Keshavarzi B, Zarei M, Moore F, Abbasi S, Kelly FJ,Dominguez AO, Jaafarzadeh N (2021) Urban street dust in theMiddle East oldest oil refinery zone: oxidative potential, sourceapportionment، and health risk assessment of potentially toxicelements. Chemosphere 268:128825

[33] Nasr, S.M., Okbah, M.A., Kasem, S.M., 2006. Environmental assessment of heavy metal pollution in bottom sediment of Aden port, Yemen. Int. J. Ocean Oceanogr. 1 (1), 99–109.

[34] Nawrot, T. S., Kuenzli, N., Sunyer, J., Shi, T. M., Moreno, T., Viana, M., Heinrich, J., Forsberg, B., Kelly, F. J., Sughis, M., Nemery,B., and Borm, P.(2009): Oxidative properties of ambient PM2.5 and elemental composition: Heterogeneous associations in 19 European cities, Atmos. Environ., 43, 4595–4602.

[35] Obioh I.B., EzehG.C,Abiye O.E, Alpha A,Ojo E.O &. Ganiyu A.K (2013). Atmospheric particulate matter in Nigerian megacities, Toxicological & Environmental Chemistry, 95:3, 379-385, DOI: 10.1080/02772248.2013.790970

[36] Ogundele L.T., Oyediran K.O., Hopke P.K., Olise F.S. (2017). Heavy metals in industrially emitted particulate matter in Ile-Ife, Nigeria. Environmental research 156 (2017) 320-325. www.elsevier.com/locate/envres.

[37] Onabowale M.K., Oyediran K.O (2015). Assessment of Residential Indoor-Outdoor Airborne Particulate Matter in Ibadan, Southwestern, Nigeria. Donnish Journal of Physical Sciences vol1 (1) pp.001 -007. October, 2015. www.donnish journals.org/djps

[38] Oyediran K. Owoade, Olusegun G. Fawole, Felix S. Olise , Lasun T. Ogundele , Hezekiah B. Olaniyi , Marta S. Almeida , Manh-Dung Ho & Philip K. Hopke (2013) Characterization and source identification of airborne particulate loadings at receptor site-classes of Lagos Mega-City, Nigeria, Journal of the Air & Waste Management Association, 63:9,1026-1035, DOI: 10.1080/10962247.2013.793627

[39] Pant, P., Baker, S.J., Shukla, A., Maikawa, C., Godri Pollitt, K.J., Harrison, R.M., (2015). The PM10 fraction of road dust in the UK and India: Characterization, source profiles and oxidative potential. Sci. Total Environ. 530–531, 445–452.

[40] Sam, R.A., Ofosu, F.G., Atiemo, S.M., Aboh, I.J.K., Gyampo, O., Ahiamadje, H., Adeti, J.K., Arthur, J., 2015. Heavy metal contamination levels in topsoil at selected autoworkshops in Accra. Int. J. Sci. Technol. 4 (5), 222–229.

[41] Sauvain, J.-J., Deslarzes, S., and Riediker, M. (2008): Nanoparticle reactivity toward dithiothreitol, Nanotoxicology, 2, 121–129, doi:10.1080/17435390802245716.

[42] Schiavo Benedetto, Diana Meza‑Figueroa, Efrain Vizuete‑Jaramillo, Agustin Robles‑Morua, Aracely Angulo‑Molina, Pablo A. Reyes‑Castro, Claudio Inguaggiato, Belem Gonzalez‑Grijalva (2022). Oxidative potential of metal‑polluted urban dustas a potential environmental stressor for chronic diseases.Environ Geochem HealthJournal.https://doi.org/10.1007/s10653-022-01403-9

[43] Shi, T., Knaapen, A. M., Begerow, J., Birmili, W., Borm, P. J., and Schins, R. P (2003). Temporal variation of hydroxyl radical generation and 8-hydroxy-2’-deoxyguanosine formation by coarse and fine particulate matter, Occup. Environ. Med., 60, 315–321, 2003.

[44] Shien, H., Barakat, A. I., and Anastasio, C.: Generation of hydrogen peroxide from San Joaquin Valley particles in a cell-free solution, Atmos. Chem. Phys., 11, 753–765, doi:10.5194/acp-11-753-2011, 2011

[45] Shima H, Koike E, Shinohara R, Kobayashi T. (2006). Oxidative ability and toxicity of n-hexane insoluble fraction of diesel exhaust particles. Toxicol Sci. 91:218–226.

[46] Simonetti G, Conte E, Massimi L, Frasca D, Perrino C, Canepari S (2018) Oxidative potential of particulate matter components generated by specific emission sources. J Aerosol Sci 126:99–109. https://doi.org/10.1016/j.jaerosci.2018.08.011

[47] Taylor S.R., McLennan S.M., (1985). The geochemical evolution of the continental crust, Reviews of Geophysics, 33(2): 241-265.

[48] Tunde, O. L., & Oluwagbenga, A. P. (2020). Assessment of heavy metals contamination and sediment quality in Ondo coastal marine area, Nigeria. Journal of African Earth Sciences, 170, 103903.

[49] United States Environmental Protection Agency (USEPA) (2000). National water Quality Inventory. http://www.epa.gov/305b/2000report/retrieved August 6, 2003.

[50] US-EPA, (2011). Human Factors Handbook. EPA/600/R-090/052F, September 2011〈https://cfpub.epa.gov/ncea/risk/recordisplay.cfm?Deid=236252〉

[51] Verma V, Pakbin P, Cheung KL, Cho AK, Schauer JJ, Shafer MM, Kleinman MT, Sioutas C. (2011). Physicochemical and oxidative characteristics of semi-volatile components of quasi-ultrafine particles in an urban atmosphere. Atmos Environ. 2011; 45:1025–1033.

[52] Vidrio E, JungH, Anastasio C. (2008). Generation of Hydroxyl Radicals from Dissolved Transition Metals in Surrogate Lung Fluid Solutions. Atmospheric Environment (Oxford, England 994), 01 Jan 2008, 42(18):43694379DOI: 10.1016/j.atmosenv.2008.01.004 PMID: 19148304 PMCID: PMC2626252

[53] Vidrio, E., Phuah, C.H., Dillner, A.M., Anastasio, C., (2009). Generation of hydroxyl radicals from ambient fine particles in a surrogate lung fluid solution. Environ. Sci. Technol. 43, 922e927.

[54] Wang Y.; Arellanes, C.; Curtis, D.B.; Paulson, S.E., (2010). Probing the Source of Hydrogen Peroxide Associated with Coarse Mode Aerosol Particles in Southern California. Environ Sci Technol 2010, 44, (11), 4070-4075.

[55] Wang, T. W. (2012). A Study of the Air Pollution Index Reporting System, School of Public Health and Primary Care The Chinese University of Hong Kong, Tender Ref. AP 07-085.

[56] Weichenthal, S., Crouse, D. L., Pinault, L., Godri-Pollitt, K., Lavigne, E., Evans, G., van Donkelaar, A., Martin, R. V., & Burnett, R. T. (2016). Oxidative burden of fne particulate air pollution and risk of cause-specifc mortality in the Canadian Census Health and Environment Cohort (CanCHEC). Environment Research, 146, 92–99. https:// doi.org/10.1016/j.envres.2015.12.013

[57] Yadav, I.C.; Devi, N.L.; Singh, V.K.; Li, J.; Zhang, G. (2019). Spatial distribution, source analysis, and health risk assessment of heavy metals contamination in house dust and surface soil from four major cities of Nepal. Chemosphere 2019, 218, 1100–1113.

[58] Yadav S., Phuleria H.C., (2020). Oxidative Potential of Particulate Matter: A Prospective Measure to Assess PM Toxicity. In: Gupta T., Singh S., Rajput P., Agarwal A. (eds) Measurement, Analysis and Remediation of Environmental Pollutants. Energy, Environment, and Sustainability. Springer, Singapore. https://doi.org/10.1007/978-981-15-0540-9_16

[59] Yang, A., Jedynska, A., Hellack, B., Kooter, I., Hoek, G., Brunekreef, B., Kuhlbusch, T. A. J., Cassee, F. R., & Janssen, N. A. H. (2014). Measurement of the oxidative potential ofPM2.5 and its constituents: The efect of extraction solvent and flter type. Atmospheric Environment, 83, 35–42. https://doi.org/10.1016/j.atmosenv.2013.10.049

[60] Zhao H, Zhao J, Yin C, Li X (2014) Index models to evaluate the potential metal pollution contribution from wash off of road-deposited sediment. Water Res 59:71–79. Https: //doi.org/10.1016/j.watres.2014.04.012

How to cite this paper

Abidemi Omofoyeke Oyediran, Oluwatoyin Michael Sunday "Oxidative Potential, Health Risk Assessment, And Pollution Indices of Heavy Metals in Indoor and Outdoor Dust from Residences in A Southwest Nigerian Metropolis" Iconic Research And Engineering Journals Volume 9 Issue 4 2025 Page 2006-2017
Abidemi Omofoyeke Oyediran, Oluwatoyin Michael Sunday "Oxidative Potential, Health Risk Assessment, And Pollution Indices of Heavy Metals in Indoor and Outdoor Dust from Residences in A Southwest Nigerian Metropolis" Iconic Research And Engineering Journals, vol. 9, no. 4, Oct. 2025
Abidemi Omofoyeke Oyediran, Oluwatoyin Michael Sunday (2025). Oxidative Potential, Health Risk Assessment, And Pollution Indices of Heavy Metals in Indoor and Outdoor Dust from Residences in A Southwest Nigerian Metropolis. Iconic Research And Engineering Journals, 9(4).
Abidemi Omofoyeke Oyediran, Oluwatoyin Michael Sunday "Oxidative Potential, Health Risk Assessment, And Pollution Indices of Heavy Metals in Indoor and Outdoor Dust from Residences in A Southwest Nigerian Metropolis" Iconic Research And Engineering Journals, vol. 9, no. 4, Oct. 2025.
@article{1711389,
      author = {Abidemi Omofoyeke Oyediran, Oluwatoyin Michael Sunday},
      title = {Oxidative Potential, Health Risk Assessment, And Pollution Indices of Heavy Metals in Indoor and Outdoor Dust from Residences in A Southwest Nigerian Metropolis},
      journal = {Iconic Research And Engineering Journals},
      year = {2025},
      volume = {9},
      number = {4},
      pages = {2006-2017},
      issn = {2456-8880},
      url = {https://www.irejournals.com/formatedpaper/1711389.pdf},
      abstract = {One of the major air pollutants of concern is dust, which have become a global problem due to its impact on both humans and the environment. In this study, we investigated the heavy metals concentration in the settled dust obtained from residential indoor and outdoor environment in Akure metropolis, Nigeria. The oxidative potential (OP) of the dust to trigger oxidative stress upon inhalation and the health risks associated with the heavy metal content in the dust were also evaluated. A total of eight samples were collected from indoor and outdoor settled dust at different locations within the city. The heavy metal contents and water extracts of the settled dust were determined using atomic absorption spectrophotometer. The OP of the water extracts were determined using ascorbic acid (AA) assays. The mean concentration of heavy metals in the digested and extracted dust was in the order Zn> Cu> Fe> Cr> Mn> Pb> Cd > As, with Zn>Cu>Fe>Cr>Mn being more frequently detected in indoor and outdoor samples. The differences between the heavy metal content of indoor and outdoor samples were not significant. The results of the pollution indices using both contamination factor and pollution load index classifies the dust samples as having low heavy metal contamination. In the current study, the OP values in indoor and outdoor samples based on AA assay was 5 ? 1 AA nmol/min. ?g and 4 ? 1 AA nmol/min.?g dust, respectively. The OP values are in the lower range of values reported for dust samples from other cities. The target hazard quotient (THQ) calculated for each heavy metal was generally less than 1, suggesting no adverse health risk associated with the heavy metal content of the samples. Overall, the result of this study demonstrates that the dust samples have low heavy metal contamination and there is no significant health effect associated with the metal content of the sample The differences between the heavy metal content of indoor and outdoor samples were not significant. The results of the pollution indices using both contamination factor and pollution load index classifies the dust samples as having low heavy metal contamination. In the current study, the OP values in indoor and outdoor samples based on AA assay was 5 ? 1 AA nmol/min. ?g and 4 ? 1 AA nmol/min.?g dust, respectively. The OP values are in the lower range of values reported for dust samples from other cities. The target hazard quotient (THQ) calculated for each heavy metal was generally less than 1, suggesting no adverse health risk associated with the heavy metal content of the samples. Overall, the result of this study demonstrates that the dust samples have low heavy metal contamination and there is no significant health effect associated with the metal content of the samples.},
      keywords = {Air Pollution, Reactive Oxygen Species and Settled Dust.},
      month = {October},
  }