This paper presents the temporal characteristics of toxic fine particulate matter (PM2.5) emissions from a 30-year old municipal solid waste (MSW) dumpsite and associated health risks. The daily average concentrations of PM2.5 monitored near the MSW dump site were found to be 52.78 ± 23.22, 72.34 ± 24.90, 45.82 ± 13.91 μg/m3 respectively during monsoon, winter and summer seasons. The concentration of toxic heavy metals (THMs) such as As, Cd, Cu, Cr, Ni, Pb, Se and Zn were observed to be higher in the PM2.5 samples of dumpsite as compared to other urban locations. Results also confirmed that emissions of THMs were from burning of mixed waste (no source separated segregation). The ionic composition of PM2.5 indicated the dominance of SO4 2− (>25%) and NH4 + (>20%) ions which suggests the occurrence of frequent fires and organic decomposition of municipal wastes. The toxic organic functional groups of aldehyde and ketone, carbonyls were also detected by infrared attenuated total reflectance (IR-ATR) spectra. The analysis of PM2.5 samples collected at dumpsite indicated that ambient air is more toxic during winter periods. The estimated inhalation cancer risks associated with PM2.5 bound THMs indicated the adverse health implications in the neighboring communities. Source apportionment of PM2.5 by UNMIX model showed the significant contribution from mixed garbage burning, re-suspension of soil dust and sea salt. © 2018