Vishnu Kumar's scientific contributions

The mass concentration of diesel particulate matter (DPM) and its elemental constituents (twenty-four) emitted from stationary diesel engine exhaust at ten different sizes (56 nm to 18 µm) increased with rise in engine-operating load. The maximum value of DPM concentration varied from 10.3 ± 2.4 mg/Nm3 at 0% load to 20.4 ± 6.5 mg/Nm3 at 100% load at size-bin of 0.10–0.18 μm. The elements of S, Ca, K, Al, Na, Mg, Fe, and Zn contributed as the major components to DPM mass with more than 90% to total elements at six engine-operating loads. Ca, K, Al, Na, and Mg also showed higher values of EFs compared to Fe, Zn, As, Cr and Ni. Compared to Cu, Mn, Co, Se, Pb, Ba, Sr, fuel-based emission factor (EF) of Ti, Ga, Cd, Bi, and Te showed lower side of the estimated values. The levels of hazardous particulate elements generated from stationary diesel engine exhausts was a matter of concern from human health point of view as these elements showed better potential in causing significant cancer and non-cancer diseases through long-term exposure. The elements in DPM revealed significant deposition in the pulmonary and alveolar region of the human respiratory tract.