OPPORTUNITIES TO REDUCE MOBILE SOURCE VOC EMISSIONS

Abstract

Brazil is currently facing a growing vehicle population and increasing concerns regarding air quality in large metropolitan areas such as Sao Paulo. Mobile source hydrocarbon emissions are a large contributor to ground level ozone and smog in many urban areas. In order to develop the most cost-effective and meaningful VOC control strategy, from both evaporative and exhaust, one needs to better understand the quantity currently not controlled and the cost impact to advance controls and capture of each. This paper will further evaluate the control opportunities and impacts to the overall goal of reducing mobile source hydrocarbon emissions and improving air quality. INTRODUCTION Brazil is currently facing a challenge regarding mobile source emissions. Vehicle sales year over year in Brazil continue to grow. According to IHS Automotive Scenarios Service, the projected vehicle sales will be 5.2 million by 2020, up over 40percent from 2012 [1]. This growth leads to increases in traffic, congestion, and pollution. In a 2011 study published by CETESB, passenger cars were the largest contributors to total hydrocarbon emissions in Sao Paulo [2]. Additionally in 2012, 98 days were measured where the national standard for ozone, 160 micrograms per cubic meter on a one-hour basis, was exceeded in Sao Paulo [3]. Possible contributors to this ozone formation were identified as the increase in pollutants from mobile sources – namely nitrogen oxides (NOx) and volatile organic compounds (VOC), which contribute to the creation of photochemical smog or ground level ozone.VOC levels must be reduced to reduce ozone. Currently PROCONVE addresses various pollutants with limits on key exhaust and evaporative emissions. Tailpipe emissions have received the majority of attention historically with specific focuses on NOx, sulfur dioxide (SO2), non-methane hydrocarbon (NMHC), particulate matter (PM) and carbon dioxide (CO2).This trend continues in PROCONVE L6 which contains exhaust emissions based on the United States Environmental Protection Agency’s (US EPA) 2004 Tier 2 Bin 7 requirements [4]. Evaporative emission standards lag further behind and currently match closest with the 1980 US EPA standard. There is still much opportunity with regards to VOC emissions controls from mobile sources in Brazil. 1. SOURCES OF MOBILE SOURCE VOC EMISSIONS There are many sources that vehicle engine is shut off and emission sources from a motor vehicle interior, and window washing fluid; however, these paper. Figure 1. Air induction system (AIS) losses occur when gasoline evaporates from the engine. occur from unburned fuel in the cylinders, intake manifold, leaking cylinders, and from the crankcase. AIS emissions are p uncontrolled emissions are approximately during the hot soak [5]. Currently, the low limit of the rig test and vehicle emissions standard requiredby the Air Resources Board (ARB) including partial zero emission vehicle ( vehicles. Evaporative gasoline can migrate through the use of ethanol in gasoline increases the amount of permeation. studies that include over 150 vehicles for permeation. These permeation uncontrolled VOC emissions [ As the vehicle is parked and exposed to daily temperature increases, diurnal tank venting losses occur. Daily evaporated gasoline from the fuel tank can result in day of uncontrolled emission. comprise vehicle emissions, some of which occur when the the vehicle is parked. Figure 1 identifies several of the . Other sources of emissions includ sources arenotdiscussed Major Sources of VOC Emissions rimarily from leaking injectors. It is estimated that these 0,1 grams per diurnal test plus addi in California necessitate control on some vehicles PZEV) vehicles and high performance LEV II plastic fuel system components. In some instances, US EPA reviewed from a range of model years to develop emission factors losses account for 0,01 to 0,311 grams per 6]. one to main e tires, vehicle in detail in this