Investigating the temporal dynamics of sub-micron particles and particle-bound transition metals in indoor air of a metropolitan city

The present study portrays an association between particle-bound transition metals and children's health. The indoor air quality of the urban metropolitan city households was monitored for four PM sizes, namely PM 1.0–2.5 , PM 0.50–1.0 , PM 0.25–0.50 and PM <0.25 , in major seasons observed in the city; summer and winter. Further transition/heavy metals, viz. Cr, Cu, Fe, Mn, Ni, Pb and Zn, were analysed in PM 1-2.5 samples. In order to evaluate the effect, health risk assessment was performed using mathematical and computational model for assessing dermal exposure and dose estimation (multiple path particle dosimetry model version3.0). The study principally targeted the children aged 2–15 years for the health risk assessment. According to the results, for the largest particle size i.e. PM 1.0–2.5 the highest deposition was in the head region (49.1%) followed by pulmonary (43.6%) and tracheobronchial region (7.2%), whereas, for the smallest particle size i.e. PM <0.25 the highest deposition was obtained in the pulmonary region (73.0%) followed by the head (13.6%) and TB region (13.2%). Also, the most imperilled group of children with highest dose accumulation was found to be children aged 8–9 years for all particle sizes. Moreover, the dermal exposure dose as evaluated was found to be preeminent for Ni, Zn and Pb. Besides, seasonal variation gesticulated towards elevated concentrations in winter relative to the summer season. Altogether, the study will provide a conception to the researchers in the fields mounting season-specific guidelines and mitigation approaches. Conclusively, the study commends future work focussing on defining the effects of other chemical components on particles and associated transition metal composition along with proper extenuation of the same.