A B S T R A C TThis study assesses temporal variability and source contributions of PM 1 (particles with aerodynamic diameter 5 1.0 mm) samples (n051; November 2009ÁFebruary 2010) from an urban location at Kanpur (26.308N; 80.138E; 142 m above mean sea-level) in the Indo-Gangetic Plain (IGP). A study period from November to February is preferred owing to massive loading of particulate matter in entire IGP. PM 1 varies from 18 to 348 (Avg9SD: 113972) mg m (3 in this study. A total of 11 trace metals, five major elements and four water-soluble inorganic species (WSIS) have been measured. Mass fraction of total metals (ametals 0 tratrace ' major) centres at 18914 %, of which nearly 15 % is contributed by major elements. Furthermore, aWSIS contributes about 26 % to PM 1 mass concentration. Abundance pattern among assessed WSIS in this study follows the order: NH 4 ' :SO 4 2 ( ! NO 3 ( ! Cl ( . The K-to-PM 1 mass fraction (Avg: 2 %) in conjunction with air-mass back trajectories (AMBT) indicates that the prevailing north-westerly winds transport biomass burning derived pollutants from upwind IGP. A recent version of positive matrix factorisation (PMF 5.0) has been utilised to quantify the contribution of fine-mode aerosols from various sources. The contribution from each source is highly variable and shows a strong dependence on AMBT. Events with predominant contribution from biomass burning emission ( !70 %) indicate origin of air-masses from source region upwind in IGP. One of the most interesting features of our study relates to the observation that secondary aerosols (contributing as high as Â60 % to PM 1 loading) are predominantly derived from stationary combustion sources (NO 3 ( /SO 4 2 ( ratio: 0.3090.23). Thus, our study highlights a high concentration of PM 1 loading and atmospheric fog prevalent during wintertime can have a severe impact on atmospheric chemistry in the air-shed of IGP.