Volatile Organic Profiles and Photochemical Potentials from Motorcycle Engine Exhaust

Abstract

This study surveyed emissions from 2-and 4-stroke new and in-use motorcycles. Emission tests were carried out on a dynamometer following the designated test procedure of the Economic Commission for Europe (ECE). Samples were derived during various driving stages, which included idle, acceleration, 30 km/hr cruise, 50 km/hr cruise, and deceleration. All test motorcycles (10 new and 15 in-use) complied with Taiwan Environmental Protection Administration's Phase III Motorcycle Emission Standards. The dominant volatile organic carbon (VOC) species were isopentane (53 and 295 mg/km, 2-and 4-stroke, respectively), 2-methylpentane (75 and 83 mg/km), 3-methylpentane (34 and 66 mg/km), and toluene (30 and 100 mg/km). The VOC emission factors for the 2-/4-stroke motorcycles were 311/344 (new) and 1479/433 (inuse) mg/km, respectively. In addition, the dominant carbonyl species for the new and in-use motorcycles were formaldehyde (0.4 and 0.7 mg/km, respectively), acetaldehyde (0.6 and 1.2 mg/km), and acetone (0.5 and 0.7 mg/km). The carbonyl compound emission factors for the 2-and 4-stroke motorcycles were 3.2/3.1 (new) and 5.3/ 4.6 (in-use) mg/km, respectively. The ozone formation potentials, based on an ECE test cycle, show that the values from the in-use motorcycles were higher than those from the new motorcycles. The dominant VOC species for the ozone formation potential were propylene (65 and 502 mg-O 3 /km, respectively), isopentane (98 and 501 mg-O 3 /km), 2-methylpentane (152 and 167 mg-O 3 / km), 3-methylpentane (79 and 253 mg-O 3 /km), and toluene (127 and 398 mg-O 3 /km). Further, the dominant carbonyl species were formaldehyde (4.1 and 6.2 mg-O 3 / km, new and in-use, respectively) and acetaldehyde (4.8 and 9 mg-O 3 /km).

Comparison of Real-World Emissions from Two-Wheelers and Passenger Cars

“…It may be supposed that two-wheelers clock most of their mileage in good weather conditions. As these conditions are also conducive to the formation of tropospheric ozone, emissions of HC and NOx gain additional significance (12). It must therefore be borne in mind that the ratios presented here refer to an average value over the year and are probably higher on ozone-critical days.…”

A Pilot Study to Quantify Volatile Organic Compounds and Their Sources Inside and Outside Homes in Urban India in Summer and Winter during Normal Daily Activities

“…Compounds defining this factor include 2-methylpentane, 3-methylpentane, methylcyclopentane, hexane, acetone and 2-ethyloxetane. Some of these compounds have been measured in the exhaust of 2wheelers [66], which were commonplace in the streets near these homes, while others have been measured in vehicle exhaust in general [67]. These profiles-with some representation indoors-point to the ability of ambient pollutants to infiltrate homes, especially when doors and windows remain open for extended periods of time (e.g., in May).…”