Journal of Environmental Protection, 2013, 4, 74-82 http://dx.doi.org/10.4236/jep.2013.48A1010 Published Online August 2013 (http://www.scirp.org/journal/jep) Measurement of Emissions from a Passenger Truck Fueled with Biodiesel from Different Feedstocks Natchanok Pala-En 1 , Melanie Sattler 2 , Brian H. Dennis 3 , Victoria C. P. Chen 4 , Rachel L. Muncrief 5 1 Automotive Air Pollution Division, Pollution Control Department, Bangkok, Thailand; 2 Department of Civil Engineering, The Uni- versity of Texas at Arlington, Arlington, USA; 3 Department of Mechanical and Aerospace Engineering, The University of Texas at Arlington, Arlington, USA; 4 Department of Industrial and Manufacturing Systems Engineering, The University of Texas at Arlington, Arlington, USA; 5 International Council on Clean Transportation, Washington DC, USA Email: sattler@uta.edu Received May 17 th , 2013; revised June 19 th , 2013; accepted July 25 th , 2013 Copyright © 2013 Natchanok Pala-En et al. This is an open access article distributed under the Creative Commons Attribution Li- cense, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. ABSTRACT Biodiesel has generated increased interest recently as an alternative to petroleum-derived diesel. Due to its high oxygen content, biodiesel typically burns more completely than petroleum diesel, and thus has lower emissions of hydrocarbons (HC), carbon monoxide (CO), and particulate matter (PM). However, biodiesel may increase or decrease nitrogen oxide (NO x ) and carbon dioxide (CO 2 ) emissions, depending on biodiesel feedstock, engine type, and test cycle. The purpose of this study was to compare emissions from 20% blends of biodiesel made from 4 feedstocks (soybean oil, canola oil, waste cooking oil, and animal fat) with emissions from ultra low sulfur diesel (ULSD). Emissions of NO x and CO 2 were made under real-world driving conditions using a Horiba On-Board Measurement System OBS-1300 on a highway route and arterial route; emissions of NO x , CO 2 , HC, CO, and PM were measured in a controlled setting using a chassis dynamometer with Urban Dynamometer Drive Schedule. Dynamometer test results showed statistically significant lower emissions of HC, CO, and PM from all B20 blends compared to ULSD. For CO 2 , both on-road testing (arterial, highway, and idling) and dynamometer testing showed no statistically significant difference in emissions among the B20 blends and ULSD. For NO x , dynamometer testing showed only B20 from soybean oil to have statistically signifi- cant higher emissions. This is generally consistent with the on-road testing, which showed no statistically significant difference in NO x emissions between ULSD and the B20 blends. Keywords: Alternative Fuel; Biodiesel; Diesel; Emissions; On-Road Testing; Portable Emission Measurement System (PEMS); Dynamometer 1. Introduction As global population increases and developing countries industrialize, energy demand around the world is in- creasing markedly. World energy consumption is ex- pected to increase by 50% by 2020 [1]. According to the Energy Information Administration’s (EIA’s) Interna- tional Energy Outlook, world demand for crude oil is expected to grow from 84 million barrels/day in 2005 to over 114 million barrels/day in 2030 [2]. Biodiesel has generated increased interest in the US and elsewhere recently as an alternative to petroleum- derived diesel. Because it can be produced from domestic natural sources such as soybeans, canola, and recycled cooking oil, biodiesel can help reduce dependence on petroleum fuel from foreign sources, and thus foster en- ergy independence [3]. Due to its high oxygen content, biodiesel typically burns more completely than petro- leum diesel, and thus has lower emissions of hydrocar- bons (HC), carbon monoxide (CO), and particulate mat- ter. Since biodiesel is essentially free of sulfur, SO 2 emissions are negligible. However, a B20 blend of bio- diesel may increase or decrease nitrogen oxide (NO x ) emissions (from +12% to −13%) and carbon dioxide (CO 2 ) emissions (from +1% to −67%), depending on biodiesel feedstock, engine type, and test cycle [3-7]. Biodiesel feedstocks that reduce NO x would be bene- ficial to US regions facing problems with ground-level ozone, fine particulates, and/or acid precipitation. From the viewpoint of climate change, all regions should avoid biodiesel from feedstocks that increase CO 2 emissions. Therefore, determining which biodiesel feedstocks in- Copyright © 2013 SciRes. JEP