Pollution Prevention in Transportation
Around the world, the need for transportation is vital in driving the economy, business and society. One of these nations on the move is the US with 29% percent of the country’s’ energy consumption coming from the transportation of goods and people in 2016. There are several sources for this energy consumption such as:
- Gasoline used in cars, motorcycles, light trucks, and boats.
- Diesel fuel (or distillate fuel) used mainly by trucks, buses, and trains and in boats and ships.
- Kerosene is used in jet airplanes and some types of helicopters.
- Natural gas used as compressed natural gas and as liquefied natural gas in cars, buses, and trucks. Most of the vehicles that use natural gas are in government and private vehicle fleets.
- Propane (a hydrocarbon gas liquid) is used in cars, buses, and trucks. Most of the vehicles that use propane are in government and private vehicle fleets.
- Electricity is used by public mass transit systems and by electric vehicles.
piechart blabla – source: biodiesel website
Understandably, the majority of pollution in form of greenhouse gas emissions from transportation are carbon dioxide (CO2) emissions, which is the result of combustion of petroleum based products like gasoline. The largest sources of transportation-related pollution include passenger cars and light-duty trucks, including sport utility vehicles, pickup trucks, and minivans. These sources account for over half of the emissions from the sector.
Urban mobility accounts for 32% of energy consumption and for 40% of all pollution of road transport and up to 70% of other pollutants from transport. The congestion of urban roads is responsible not only for the increase in environmental pollution and energy consumption, but also for increasing the length of journeys.
This causes a 1% Gross Domestic Product (GDP) lose in the European economy. Consequently, there is evidence showing that traffic emissions are responsible for 70% of all cancerous and other dangerous substances.
With more than half the population living in cities, the benefits for lowering one’s carbon footprint in the midst of global warming is essential in preserving one’s’ life and the lives of future generations. Possible solutions are: Fuel Switching, Improving Fuel Efficiency with Advanced Design, Materials, and Technologies, Improving Operating Practices and Reducing Travel Demand.
There are several different types of alternative fuel used, the most commonly known is electricity followed by biodiesel, hydrogen, natural gas as well as the lesser known ethanol and propane. For countries like the US that imports around 25% of its petroleum, the move to biodiesel would be able to help the country depend less on foreign petroleum supplies,? which risks trade deficits, supply disruption, and price changes. Biodiesel is produced in the US and can be used in conventional diesel engines. Therefore, directly substituting or extending supplies of traditional petroleum diesel. In addition, biodiesel has a positive energy balance meaning that biodiesel yields 3.2 units of energy for every unit of fossil energy consumed over its life cycle whilst biodiesel and petroleum diesel only yield 0.98 units of energy. This means that the life cycle consumption of petroleum will drop by 95%. [ “Life Cycle Inventory of Biodiesel and Petroleum Diesel for Use … – EPA.
Despite its positive effects on air quality biodiesel also has its drawbacks in that it increases some amount of air pollutants as well, making it a complex situation. Engines manufactured in 2010 and later have to meet the same emissions standards, whether running on biodiesel, diesel, or any alternative fuel. Selective catalytic reduction (SCR) technology in diesel vehicles, which reduces nitrogen oxide (NOx) emissions to near zero levels, makes this possible. These engines are some of the cleanest engines on the road, and the emissions from diesel fuel are comparable to those from biodiesel blends.
Using biodiesel reduces greenhouse gas emissions because carbon dioxide released from biodiesel combustion is offset by the carbon dioxide absorbed from growing soybeans or other feedstocks used to produce the fuel. Life cycle analysis completed by Argonne National Laboratory found that biodiesel reduces carbon dioxide emissions by 74% compared with petroleum diesel.
However, biodiesel in comparison to petroleum diesel increases the amount of NOx which is being produced from the vehicle’s tailpipe. NOx is an irritant gas, which at high concentrations causes inflammation of the airways. In situations wherein nitrogen is released during fuel combustion it combines with oxygen atoms to create nitric oxide (NO). This further combines with oxygen to create nitrogen dioxide (NO2). Nitric oxide is not considered to be hazardous to health at typical ambient concentrations, but nitrogen dioxide can be. Nitrogen dioxide and nitric oxide are referred to together as oxides of nitrogen (NOx). NOx gases react to form smog and acid rain as well as being central to the formation of fine particles (PM) and ground level ozone, both of which are associated with adverse health effects. NOx is usually responsible for respiratory conditions and long term exposure can cause the decrease in lung function.
Furthermore, high levels of NOx can have a negative effects on vegetation, including leaf damage and reduced growth. It can also make vegetation more susceptible to disease and frost damage. A study of the effect of nitrogen dioxide and ammonia (NH3) on the habitat of Epping Forest revealed that pollution is likely to be significantly influencing ecosystem health in the forest. The study demonstrated that local traffic emissions contribute substantially to exceeding the critical levels and critical loads in the area. The critical level for the protection of vegetation is 30 µg/m3 measured as an annual average. NOx also reacts with other pollutants in the presence of sunlight to form ozone which can damage vegetation at high concentrations.
In spite of some of its negative drawbacks, it is important to note that engines made by car manufacturing companies were until recently primarily geared towards lowering pollution in form of CO2 emissions and were meant for normal diesel consumption. Hence, NOx that is a much smaller molecule would still be able to pass through the car engine. If companies create an engine for the purposes of biodiesel consumption, I predict the NOx emission levels of the alternate fuel will also be reduced.
On the topic of engine, it should be emphasised that biodiesel improves fuel lubricity and raises the cetane number of the fuel. Diesel engines depend on the lubricity of the fuel to keep moving parts from wearing prematurely. One unintended side effect of the federal regulations, which have gradually reduced allowable fuel sulfur to only 15 ppm and lowered aromatics content, has been to reduce the lubricity of petroleum diesel. To address this, the ASTM D975 diesel fuel specification was modified to add a lubricity requirement (a maximum wear scar diameter on the high-frequency reciprocating rig [HFRR] test of 520 microns). Biodiesel can increase fuel lubricity to diesel fuels at blend levels as low as 1%.Therefore, also allowing your car engine to last longer, saving an individual both time and money in car maintenance.
It is important for anyone who plans or is thinking of switching to biodiesel, to first check your engine manufacturer recommendations to determine what blend is optimal for your vehicle (example: 2% biodiesel)
Electric as an alternative fuel has been praised and written about for years; from 2006 onwards the increase in electric vehicles (EV’s) has made lithium ion batteries as the dominant technology. Subsidies and tax incentives by governments provide a supportive environment for technology investment and customer adoption, and therefore are most often seen as central in the transition towards sustainable mobility. Yet, the batteries actually cause significant environmental damage because of the high cost of manufacturing. One example of such engines are Tesla cars, whose batteries are larger and more powerful than its competitors. In fact, many electric vehicles contain rare-earth minerals that are costly to extract. The extraction of such minerals undoubtedly produce pollutants that poison the air but drilling for oil is no better, and has taken a worser turn with industries now interested in mining the deep sea in hopes of finding valuable minerals and maybe striking another oil well. At the very least both alternative fuels are a step towards a better environment and taking control of your carbon footprint.
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