On-field and laboratory measurement of nanoparticle emission in the wake of gasoline vehicle

Nanoparticle emission from gasoline driven vehicles is reported to be significantly lower compared to diesel vehicles. Accordingly, there is no threshold limit implemented by the regulatory authorities in India for gasoline driven vehicles. Recent studies however indicate that this is true as far as the mass concentration of the nanoparticles is concerned. The number concentration of nanoparticles particularly of smaller dimensions is reported to be significantly higher for gasoline driven vehicles under certain operating range of speed and load. Smaller the dimension of the particles more are their residence time in environment and more susceptible are these particles to be inhaled by human respiratory and cardiovascular system. Thus an estimate of the size distribution of nano-sized particulate matter emission from gasoline driven vehicle is of immense importance in context to Indian urban population. In this direction, laboratory measurements are reported for the nanoparticle size distribution emitted from a gasoline engine under different loading conditions. On-field measurements are carried out in the wake of a stationary vehicle under idling and throttling condition. Simultaneous measurement of vehicular acceleration and deceleration is also reported along with nanoparticle distribution in the wake of a moving vehicle. The measurements reported in this paper reveal the need for deciding threshold value of number concentration to be implemented for gasoline vehicles by the Indian regulatory authorities.