PHYSICAL AND CHEMICAL CHARACTERIZATION OF PARTICULATES FROM IN-USE PASSENGER CARS OPERATING ON DIESEL, GASOLINE, AND CNG

摘要

The new emission regulations are more stringent and applicable for newly manufactured vehicles, but the more population of old in-use vehicles running on the road contribute substantial to the vehicular pollution because of which significant effectiveness to urban air quality has not been seen. This is an unique comparative study carried out in this context specifically for the in use vehicles from Bharat Stage-2 to Bharat stage-4 technology and operating on diesel, gasoline and CNG fuels, in order to get the vital information on particulate matter (PM2.5) and particle number (PN) and their various metrics in terms of their physical and chemical characteristics. This research work focuses on characterization of ultrafine and nanoparticle emissions from diesel, gasoline and CNG vehicles to investigate for their physical characterization in terms of number, size, surface area and volume. Investigations also carried out for their chemical characterization in terms of chemical speciation like SOF, IOF, PAH, aldehydes-ketones, 1-3 butadiene and benzene content as they found responsible for toxicity, mutagenicity and carcinogenicity. Test methodology used to measure PM and PN is based on GRPE-PMP incorporated in European Regulations No.R83 since Euro V+. Engine exhausts particle sizer (EEPS) having fast response was used to measure particle size between 5.6 and 560 nm. Chemical characterization was carried out subjecting particulate extract to GC-HPLC and HRGC analyzers. Study reveals that urban part of the cycle is the most significant contributor to total PN approximately, 66%, 53% and 74% for gasoline, diesel and CNG vehicles, respectively. More than 90% of the total particles emitted are of ultrafine nature and contribution by nanoparticles (< 50 nm) alone is approximately 50%, 94% and 72% for diesel, gasoline and CNG vehicles respectively. Contribution of SOF to PM for gasoline, CNG and diesel vehicles are 73%, 75% and 40% respectively. Investigation provides vital information to ensure effective measures and to address social health concerns raised by WHO.