Compositional Characteristics Of Road/Air-Conditioner Dust And Their Health Risk Assessment In Urban-Industrial Environment

Anthropogenic activities caused serious environmental issues in water,land and air that disturbed the normal habitat around the world faced by both developed and developing countries.Poor indoor and outdoor air quality is one of the leading health hazards in modern world and is categorized in top five environmental hazards.Dust stands out to be the most imperative supporter toward air pollution.Dust is an aggregate of solid particles released as results of different activities including processing of material mechanically,crushing and grinding,detonation,construction,demolition and decrepitation of inorganic/organic substances like ore,rocks and metals.Atmospheric dust in urban-industrial environments act as a significant sink for potentially toxic elements,black carbon and Nano particles that can pose a variety of health problems in both indoor and outdoor environments.In present study,a total of 442 samples were collected including road dust(162),air conditioner filter dust(110),hair(85)and nails(85).The dust samples were analyzed and characterized to find out 20 PTEs pollution status,black carbon and dominant Nano particles using array based techniques(ICP-MS,SEM/TEM/EDS/SAED,XRD,TOR,EDS,XPS,BET,Elemental analyzer and particle size analyzer)and their health risk assessment.The hair and nails samples were analyzed using ICP-MS for bio monitoring of PTEs content in human body.In case of road dust the mean concentrations of most elements were markedly higher in industrial area as compared to background values.In case of urban areas,mean contents of As,Sn,Sb,Cu and Pb were 2.05,1.67,1.47 and 5.99 times higher as compared to the industrial area.Geo-accumulation index(Igeo)showed Pb,As and Ga were in the range of moderate to heavily contaminated in industrial areas.However,in the case of urban areas,Cu,Zn,Sb and Ga were ranked as moderately to heavily contaminated.In case of AC dust the mean concentration of PTEs like Al,As,Cd,Cu,Li,Pb,Sb,Se,Sn,Ti,V and Zn exceeded the corresponding background value.Pb,As,Sn,Sb,Cd were categorizing under geo-accumulation index class IV.The mean value of BC was found to be 126 mg g-1.A strong correlation was found between black carbon and total potential toxic elements content(R2= 0.79).The particles size distribution and variation with increasing altitude showed that most of the particles were<100 tm and it decreased significantly with increase in floor altitude.A significantly negative correlation was found between particles size and PTEs concentration showing a significant increase in PTEs content with decrease in particles size.The XPS results showed dominant peaks for TiO2,Ti-O-N,As2O3,Fe+3,Fe+2,Al-OH and Al2O3.Additionally,As,Pb,Si and Fe were dominant metallic nanoparticles identified using SEM/TEM along with EDS.The mean concentration of Elements followed descending order of Zn>Mg>Fe>Cr>Al>Sn>Sr>Ti>Cu>As>Cd and Mg>Zn>Fe>Cr>Al>Sn>Ti>Cu>Sr>As>Cd in hair and nails,respectively.Overall,the concentration of elements was found to be high in female subject as compared to male.The concentration of PTEs in hair and nail exceeded the maximum permissible limits in most cases.Furthermore,health risk assessment revealed negligible non-cancerous health hazard in all sites including urban,periurban and industrial areas.The HQ and HI values for all exposure routes(ingestion,inhalation,and dermal contact)were<1 except for chromium with HI value of 1.06E+00 in industrial areas.Moreover,the non-carcinogenic health risks were found to be high in case of children compared to the adults.The risk order through the exposure routes was HQing>HQdermal>HQinh.The cancer risk from As,Co,Cr,Ni,and Pb was found to be in safe levels as the RI values were below the safe limits(1.00E-6 to 1.00E-4).