The development and application for full-flow dilution tunnel sampling and analyzing system for particulate matters from vehicle emission

摘要

A full dilute tunnel sampling system for vehicle emission was developed which is able to meet the requirements to test from motorcycles to heavy diesel vehicles and has been used to test the emission factors of PM10 and PM2.5 from vehicles. Twenty-one elements(S, Ca, et al), 9 ions (SO42-, NH4+ et al), organic carbon (OC) and elemental carbon (EC) in PM2.5 were analyzed, and enrichment factors of elements. The results indicated that the emission factors of PM10 and PM2.5 from light-duty vehicles were 12.88 mg/km and 9.85 mg/km respectively, those that from motorcycles were 68.92 mg/km and 62.14mg/km respectively, and those that from diesel vehicles were 359.04 mg/km and 342.86 mg/km respectively; the emission factors of PM10 and PM2.5 from the vehicles without exhaust control device were higher than those from carburetor type vehicles with exhaust control device, and those from electronic fuel injection vehicles were very low; the ratios of PM2.5/PM10 from light-duty vehicles, motorcycles and diesel vehicles were 76.47%,90.20% and 95.80% respectively. The component analysis results of PM2.5 from light-duty vehicles and diesel vehicles indicated that the ratios of OC in PM2.5 from light-duty vehicles and diesel vehicles were 59.82% and 62.59% respectively, as a result OC was the highest contribution to PM2.5; the ratios of EC in PM2.5 from light-duty vehicles and diesel vehicles were 11.09% and 14.69% respectively, as a result EC was the secondary contribution to PM2.5.the ratios of total inorganic elements tested except S element in PM2.5 from light-duty vehicles and diesel vehicles were 2.86% and 3.05% respectively, and the contribution from the sum of Al、Ca and Fe three elements to total elements was above 70%, which might come from air, exhaust gases of fuel combustion and also come from wear damage or consumption of vehicles components possibly; S, As, Cu, Pb and Zn elements were all enriched obviously. The ratios of SO42- and NO3-" in PM2.5 from light-duty vehicles were 1.28% and 1.34% respectively and those from diesel vehicles were 4.00% and 0.78%.In a word, the ratios of OC, EC, total elements except S and SO42- in PM2.5 from diesel vehicles were higher than those from light-duty vehicles, while that of NO3- in PM2.5 from light-duty vehicles was higher than from diesel vehicles; the ratios of OC/EC in PM2.5 from light-duty vehicles and diesel vehicles were both around 4.5 higher than that in the developed countries which reflected an important emission characteristic in China.