PM1 (particles having aerodynamic diameter < 1.0 µm) concentrations were measured at a sampling site inside the Indian Institute of Technology (IIT) Kanpur campus for 11 months from July, 2008–May, 2009. The sampling was carried out for all the major seasons of India and a total of 90 samples were collected. The chemical speciation data in terms of element and anion concentrations of all the collected samples were closely studied for any seasonal phenomena and different source contributions to PM1 mass. Average PM1 concentration was found to be highest (199 µg/m3) during winter and lowest (31 µg/m3) during monsoon season. Concentrations of different elements and anions also followed similar trend as PM1 concentration. Nitrate and sulfate were the two most predominant anionic species contributing to almost 80%–90% of total anionic concentrations. Crustal elements (Ca, Mg, and Fe) were the main contributors within the total elemental concentrations. Overall, it was found that anions contributed up to 35% of the total PM1 mass. Factor Analysis of chemical speciation data and UNMIX (Version 6) revealed that secondary sources and vehicular emissions were the two main sources contributing to PM1 mass with minor contributions from paved road dust and coal combustion sources.