IJERD – International Journal of Environmental and Rural Development (2014) 5-1

Research article
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Effect of Ethanol-Blended Gasoline on the Concentration ofPolycyclic Aromatic Hydrocarbons and Particulate Matterin Exhaust Gas of Motorcycle
SOMPORN PLEANJAI*Rajamangala University of Technology Thanyaburi, Pathumthani, Thailand
Email: Spleanjai@gmail.

ITTIPOL PAW-ARMARTAutomotive Air Pollution Division, Pollution Control Department, Bangkok, Thailand

THERDSAK PETBLENGSI
Automotive Air Pollution Division, Pollution Control Department, Bangkok, Thailand

SINGTO SAKULKHAEMARUETHAIRajamangala University of Technology Thanyaburi, Pathumthani, Thailand
Received 3 January 2014

Accepted 1 March 2014(*Corresponding Author)

Abstract This study focuses on the characteristics of polycyclic aromatic hydrocarbons(PAHs) and fine particulate matter (PM) in six four-stroke motorcycle exhaust emissions.
Blend gasoline contains 85% (vol) ethanol (Gasohol E85) and 10% (vol) ethanol (gasohol91) was used as test fuels. The test motorcycle was driven on a Chassis dynamometer toevaluate the effect of ethanol-gasoline blend on gaseous pollutant emissions. The
dynamometer system comprised a cooling fan, a dynamometer, a dilution tunnel, aconstant-volume sampler (CVS) unit, a gas analyzer and a personal computer. The exhaustfrom the test motorcycle was passed to the dilution tunnel. The emissions of PAHs andcriteria air pollutants (THC, CO, and NOx) were measured. Measurements wereperformed on a standard driving cycle. The results show that in comparison to gasohol 91
fuels, the use Gasohol E85 fuels achieved reduction of THC and CO emissions. The
emission of THC from gasohol E85 reduced by 4-60% (average 43%) compared withthose of gasohol 91 fuels. CO emissions also showed a reduction by 40-95% (average75%). The concentrations of naphthalene, Benzo(a)anthracene, Chrysene,Benzo(b)fluoranthene, and Benzo(g, h, i)perylene were also determined.
Keywords ethanol-blended gasoline, polycyclic aromatic hydrocarbons (PAHs),
particulate matter (PM), exhaust emission

INTRODUCTION
Increasing industrialization and motorization have turned polycyclic aromatic hydrocarbons(PAHs) into omnipresent environmental pollutants. PAHs are organic compounds, the derivativesof which are widespread and harmful compounds formed by incomplete combustion. Some PAHs
are potential mutagens and carcinogens, and are probably a significant cause of allergic responses
and cancer. In addition, the oxidized and nitrated reaction products of these compounds have beenfound to be more potent carcinogens and mutagens than their parent PAHs. Motor vehicles are
known to represent a significant source of PAH emissions. Most carcinogenic PAHs have beenfound to associate with particulates, predominately with fine particulates.
The effects of ethanol-gasoline blend on air pollutant emissions had been investigated in manystudies (Al-Hasan, 2003; He et al., 2003; Hsieh et al., 2002; Yüksel and Yüksel, 2004). Most of thestudies indicated that ethanol-blended gasoline produced lower CO and THC levels than unleaded
gasoline on SI engines. Ethanol-blended gasoline also decreased emissions of air toxic, such as
benzene, 1,3-butadiene, toluene, and xylene, with ethanol levels increasing. Air quality issueⒸ ISERD

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caused by emissions from motorcycle in urban area is critical in Asian cities: China, India, Taiwan,Thailand, and Vietnam. Such as motorcycles contributed up to 30% of CO and 70% of THC among
all gasoline powered vehicles in Bangkok (Xie et al., 2004), and account for 28% of CO, 52% ofTHC, and 19% of NOx in Taiwan (TEPA, 2011). Emission from motorcycle correlates with many
parameters, such as fuel property, engine type, driving mode, and exhaust catalyst. However, to ourknowledge, there are no data on the particulate matter and PAHs distribution pertaining toemissions from motorcycles for Bangkok and the surrounding province of Thailand in current
literature.
This study investigated the effects of ethanol-gasoline blends applied in four-stroke
motorcycle on engine exhaust emissions. The Gasohol E85 (E85) and Gasohol 91 (E10) were usedas test fuels. The study was to measure only mass of PM and selected gaseous pollutants (THC, CO,CO2 and NOx). PAHs in the exhaust are also discussed. Emissions inputs are calculated fromThailand’s PCD (Pollution Control Department).
OBJECTIVES
1.
2.

To analyze PAHs from Gasohol E85 and Gasohol 91 in four-stroke motorcycle exhaust
To measure mass of PM and THC, CO, CO2 and NOx emissions

METHODOLOGY
Table 1 Emission analysis system
Measurement
Direct Measurement

CVS Measurement

Weighing

Pollutants
CO/CO2HC
NOx
CO/CO2THC
NOxParticulate Matter(PM)Analyzer
Non-Dispersive Infrared(NDIR)
Non-Dispersive Infrared(NDIR)
Chemiluminescence Detector(CLD)
Non-Dispersive Infrared(NDIR)
Flame Ionization Detector(FID)
Chemiluminescence Detector(CLD)
Micro Balance

Blend gasoline contains 85% (vol.) ethanol (Gasohol E85) and 10% (vol.) ethanol (gasohol 91) wasused as test fuels. These fuels are a commercial fuel in Thailand. There are 6 motorcycles wereselected. The selected four-stroke motorcycles were without any engine adjustment. Themotorcycle was placed on chassis dynamometer. The chassis dynamometer was located in a
certified laboratory within the motorcycle manufacturer. The main dynamometer system comprisesof a dilution tunnel, a constant volume system (CVS) unit, an exhaust gas analyzer and a personalcomputer. Exhaust samples were collected for the entire cycle; the exhaust gas was initially mixedwith air, directed to the CVS unit, and then connected to the sampling bags and analyzer. In thisstudy, the carbon monoxide (CO), unburned hydrocarbons (THC), and oxides of nitrogen (NOx) inthe exhaust filtered samples were measured using a non-dispersive infrared analyzer, a flame
ionization detection analyzer, and a chemiluminescence detection analyzer, respectively.
Particulate matter (PM) emissions were sampled on fiber filters and measured by means ofweighing (see Table 1).
PM and particulate PAHs were collected by quartz microfiber filters (diameter 70 mm, flowrate 60 liter per minute for 20 minutes). Two sets of filter holders were employed in this system.
Back-up filters were used in each holder downstream the sampling filters to check the breakthrougheffects. Two glass cartridges containing polyurethane foam (PUF) plug and XAD-16 resin wereused to collect the gaseous PAHs. Before taking the samples, the cleaned filters were stored in adesiccator for at least 8 h for moisture equilibrium before weighing. After the experiments, thefilters were brought back to the laboratory and put in a desiccator for 8 h to remove moisture. They
were weighed again to determine the net mass of particles collected. After final weighing (only forfilter samples), each PAH-containing sample was extracted with a mixed solvent (acetonitrile:Ⓒ ISERD

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dichloromethane = 10: 90% v/v) by accelerated solvent extractor (ASE). The extract was thenconcentrated by purging with ultra-pure nitrogen 130 psi for 60 second to 2 mL for cleanup
procedure and re-concentrated to 1.0 mL by evaporator. The concentrations of the following PAHs
were determined by a high performance liquid chromatography (HPLC DAD/FLD).
RESULTS AND DISCUSSION

PM (mg)PM (mg)

All motorcycles fueled with gasohol 91 (E10) and gasohol E85 (E85) were tested. The results areshown in Fig. 1-Fig. 5 and Table 2. Figure1 shows that a quantity of PM content in the test
motorcycle exhaust decreases when adding more ethanol in fuel.
Figure 2 shows that THC emission from all motorcycles fueled with E85 decreases by 4-60%
compared to E10 and it was found that the THC emission decreases when adding more ethanol infuel. Figure 3 shows that CO emission from the motorcycles fueled with E85 decreases around 4095% compared to fueled with E10 and it was found that E10 has CO more than E85 because
incompletely burning of oil unfit engine makes more exhaust emission. The result of CO2 emission
is not significant difference as shown in Fig.4. Figure 5 shows that NOx emission from all
motorcycles fueled with E85 is 50-400% higher than E10.

THC (g/km)

Fig. 1 Emission of PM from four-stroke motorcycle with different fuelsFig. 2 Emission of THC from four-stroke motorcycle with different fuelsⒸ ISERD144CO (g/km)

IJERD – International Journal of Environmental and Rural Development (2014) 5-1

CO2 (g/km)

Fig. 3 Emission of CO from four-stroke motorcycle with different fuels

NOX (g/km)

Fig. 4 Emission of CO2 from four-stroke motorcycle with different fuels

Fig.5 Emission of NOx from four-stroke motorcycle with different fuels
Our findings according to previous studies, it was found that ethanol-gasoline blended fuels(3-30 vol.%) and pollutant emissions are correlated. In general, exhaust HC and CO emissions arelower with oxygenated fuels, but comparable or higher NOx emissions are produced (Furey andⒸ ISERD145

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King, 1980; Hsieh et al., 2002; He et al., 2003). The extent of pollutant reduction depends onethanol content, air-fuel ratio (AFR), engine operating conditions, type of cars and whether closedloop fuel is used (Zervas et al., 2002; Al-Hasan). The effect of using an ethanol gasoline blend fuel(ethanol 10 vol.%) on four-stroke motorcycle exhaust emission using chassis dynamometers hadbeen investigated that indicate reductions in CO and HC emissions with an insignificant effect ofethanol on NOx emission(Jia et al., 2005). In addition, the high ethanol-gasoline blend ratio (20%)
resulted in a less emission reduction than those of low ratio blends (<15%)(Yao et al., 2009).
Furthermore, the effect of ethanol blended gasoline fuel on emission was investigated in Thailand(Sukajit et al., 2011). The exhaust emissions tests on four-stroke motorcycle fueled with E0, E10
and E20 results show that the ethanol blended gasoline fuel results in decreasing of CO emission by
40-70% and it was found that CO emission decreases when adding more ethanol in fuel. Otheremissions show no difference.
According to Table 2, it could be seen that many compounds were detected in the exhaustemissions tests on four-stroke motorcycle fueled with E10 and E85. In this study, based onemission amount, the top-5 aromatic hydrocarbons detected were as follows: Naphthalene,Benzo(a)anthracene, Chrysene, Benzo(b)fluoranthene and Benzo(g, h, i)perylene. It was found thatethanol of E10 fuel plays insignificant effect on aromatic emissions, as compared to E85.
Table 2 Emission of PAHs from four-stroke motorcycle with different fuels
PAHs(mg/m3)
Naphthlene
Chrysene
Benzo(a)anthracene
Benzo(b)fluoranthene
Benzo(g,h,i)perylene

MC10.03‹0.025‹0.025‹0.0250.06

PAHs(mg/m3)
Naphthlene
Chrysene
Benzo(a)anthracene
Benzo(b)fluoranthene
Benzo(g,h,i)perylene

MC14<0.025ND
NDND

MC20.05
1.51
1.3
1.33
1.87
MC20.1
1.25
0.96
1.33
2.16Gasohol 91(E10)
MC3MC40.04
0.04
0.15
‹0.025
0.03
ND
0.14
ND
0.47
ND
Gasohol E85 (E85)
MC3MC4‹0.025
0.06
ND
0.04
ND
<0.025ND<0.025ND
ND

MC5MC60.03‹0.025ND‹0.025‹0.025

0.03
0.05
0.03
0.04
0.05

MC50.04
ND
ND
ND
ND

MC60.04
ND
ND
ND
ND

CONCLUSION
This study investigated the emissions of THC, CO, CO2 and NOx emissions for four-stroke
motorcycles using E10 and E85 gasoline/ethanol blended fuels. In comparison with E10, using E85
as fuel reduces the emission of THC and CO by 4-60% and 40-95% respectively. In contrast, theemission of NOx emission is increased by 50-400% using E85. The CO2 emissions are notsignificant difference. The PM and PAHs were analyzed. The results were found that PM
decreases when fueled with E85 and PAHs: Naphthalene, Benzo(a)anthracene, Chrysene,Benzo(b)fluoranthene and Benzo(g, h, i)perylene emissions for four-stroke motorcycles using E10and E85 as fuels are not significant difference.
ACKNOWLEDGEMENTS
This project was financially supported by the Cooperative Education Program - Rajamangala
University of Technology (RMUTT) and Automotive Air Pollution Division, Pollution ControlDepartment (PCD), Thailand. The authors would like to thank staff of PCD who performed thedynamometer tests.
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