Method development, speciated measurements and culculated reactivities of benzine, toluene, ethylbenzene and xylenes from vehicle exhaust

Zakaria, Norasalwa (2001) Method development, speciated measurements and culculated reactivities of benzine, toluene, ethylbenzene and xylenes from vehicle exhaust. Masters thesis, Universiti Putra Malaysia.

[img] PDF
2101Kb

Abstract

Mathematical modeling of ambient air photochemistry requires comprehensive speciation of hydrocarbons from mobile source emission. The objective of this study is to develop a simple and reliable method for analyzing tailpipe emission focusing on benzene, toluene, ethylbenzene and xylenes (BTEX). The method consists of sampling, qualitative analysis and quantitative analysis. The samples were collected in Tedlar bags at cold start and hot start conditions and were injected manually using a gas-tight syringe into Gas Chromatograph-Mass Spectrometer (GC-MS) operated on Electron Impact Ionization (EI) mode. The method developed has demonstrated ability to produce rapid and reliable separations of exhaust hydrocarbons. An approximate of 50 hydrocarbon compounds were identified in the exhaust ranging from C₄ to C₁₂. It was found difficult to analyze C₁ to some of the C₄ hydrocarbons without the required accessories for volatile organic gases analysis. The emission rate of BTEX was emphasized because of its potential carcinogenicity and toxicity. High concentration of BTEX was observed during cold start and hot start. The mean concentrations of BTEX at cold start were as follows: benzene (55.4 ppm), toluene (184.7 ppm), ethylbenzene (50.2 ppm), m-xylene (143.9 ppm), p-xylene (59.0 ppm) and o-xylene (65.4 ppm). The mean concentrations ofBTEX at hot start were as follows: benzene (82.4 ppm), toluene (198.3 ppm), ethylbenzene (40.0 ppm), m-xylene (184.0 ppm), p-xylene (62.1 ppm) and o-xylene (50.3 ppm). The concentrations of BTEX in weighted percentages for all cars were fairly constant. The weighted percentages concentration was used to estimate the photochemical ozone reactivity by applying the Maximum Incremental Reactivity (MIR) factors to the concentrations. The ozone forming potential as a result ofBTEX emission from vehicle exhaust were estimated as follows: 3.07 g O₃/g benzene, 74.64 g O₃/g toluene, 13.0 g 0₃/ g ethylbenzene, 145.8 g O₃/g m- and p-xylene, and 50.97 g O₃/g 0- xylene. The results suggested that BTEX emitted from the vehicle exhaust increases the formation of photochemical ozone in the atmosphere significantly.

Item Type:Thesis (Masters)
Subject:Photochemistry
Subject:Motor vehicles - Pollution control devices
Chairman Supervisor:Dr. Puziah Abd. Latif
Call Number:FSAS 2001 10
Faculty or Institute:Faculty of Science and Environmental Studies
ID Code:9213
Deposited By: Tuan Norasiah Tuan Yaacob
Deposited On:13 Jan 2011 10:10
Last Modified:28 Oct 2014 01:42

Repository Staff Only: Edit item detail


Universiti Putra Malaysia Institutional Repository

Universiti Putra Malaysia Institutional Repository is an on-line digital archive that serves as a central collection and storage of scientific information and research at the Universiti Putra Malaysia.

Currently, the collections deposited in the IR consists of Master and PhD theses, Master and PhD Project Report, Journal Articles, Journal Bulletins, Conference Papers, UPM News, Newspaper Cuttings, Patents and Inaugural Lectures.

As the policy of the university does not permit users to view thesis in full text, access is only given to the first 24 pages only.