Understanding Diesel Fuels
Diesel fuel is more efficient than gasoline because it contains 10% more energy per gallon than gasoline. But there are a few kinds of diesel fuel: Just as gasoline is rated by its octane, diesel fuel is rated by its cetane, which indicates how easy it is to ignite and how fast it burns.
Diesel fuel is safer than gasoline because its vapors don’t explode or ignite as easily as gasoline vapors.
When the exhaust from conventional diesel fuel was found to cause cancer, clean diesel engines were developed. Although thousands of conventional diesel fuel-burning vehicles are still on the road, public pressure and environmental organizations have prodded individual states and the federal government to enact legislation and fund replacement programs to take them out of use as quickly as possible.
Standard diesel fuel
Standard diesel fuel (sometimes called diesel oil) comes in two grades: Diesel #1 (or 1-D) and Diesel #2 (or 2-D). The higher the cetane number, the more volatile the fuel. Most diesel vehicles use fuel with a rating of 40 to 55. You won’t have to worry about which type to use because all diesel automakers specify Diesel #2 for normal driving conditions. Truckers use Diesel #2 to carry heavy loads for long distances at sustained speeds because it’s less volatile than Diesel #1 and provides greater fuel economy.
Diesel fuel also is measured by its viscosity. Like any oil, diesel fuel gets thicker and cloudier at lower temperatures. Under extreme conditions, it can become a gel and refuse to flow at all. Diesel #1 flows more easily than Diesel #2, so it’s more efficient at lower temperatures. The two types of oil can be blended, and most service stations offer diesel fuel blended for local weather conditions.
If you plan to drive in very cold weather, choose diesel fuel rated at least 10 degrees lower than the coldest temperatures you expect to encounter. Consult your owner’s manual for specifics.
Because emissions from conventional diesel fuel have been found to be extremely toxic to humans and other living things, until safer forms of this fuel are developed, be careful not to inhale the fumes while pumping it into your fuel tank. (The same goes for gasoline!)
Biodiesel fuels
Biodiesel fuels derived from agricultural materials have the potential to provide a clean-burning alternative to dwindling sources of petroleum.
Rudolph Diesel’s first engine was designed to run on peanut oil, and Henry Ford envisioned plant-based fuel as the primary fuel for transportation and partnered with Standard Oil to develop biofuel production and distribution. However, currently the only type of biodiesel fuel that can be used in vehicles in the United States and Canada without violating manufacturer’s warranties is B5, a blend of 5 percent biodiesel and 95 percent regular diesel. Most diesel engines run just fine on blends of up to 30 percent biodiesel.

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acid rain
A mild acidic solution that falls in rain or as dry particles caused when fossil fuel burning produces sulfur dioxide and nitrogen oxides. Acid rain has been linked to damaging effects on waterways and forests.

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active solar design
A strategy for designing high-performance, ultra-energy-efficient buildings. Active solar incorporates all the elements of a passive solar design with additional mechanical equipment, such as pumps or fans, to take advantage of the heat from the sun.

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alternative energy sources
Wind, hydro (water), biomass (fuel from natural material such as crops and agricultural waste), and solar power.

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biodegradable
Made from materials that will decay and break down into naturally occurring elements in a fairly short amount of time.

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biomass
Fuel made from natural material such as crops and agricultural waste.

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Bokashi
A Japanese term referring to a process of fermenting organic matter

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carbon emissions
Carbon released when many substances — particularly fossil fuels such as oil, gas, and coal — are burned by vehicles and planes; by the manufacturing processes of many consumer goods; and by the heating, cooling, and electricity for your home.

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carbon neutral
The state of reducing a person’s carbon emissions as much as possible and balancing the remaining carbon emissions by offsetting them with processes that consume carbon.

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carbon offsets; carbon credits
Paying for or participating in programs that reduce the carbon in the atmosphere. Purchased shares go toward reducing the same amount of environmental costs that an activity expends. Carbon offset programs or projects often involve tree planting because trees have a huge capacity to absorb carbon from the atmosphere. Other programs involve everything from supporting solar and wind power to replacing fossil fuel–burning stoves in developing countries with more sustainable energy sources.

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carcinogen
A cancer-causing substance.

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carpooling
Reducing the number of vehicles going to the same destination by having two or more people ride in the same vehicle. In most cases, carpoolers take turns being the driver and using their own vehicles.

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car-sharing
A system in which a person pays a fee that gives them access to a vehicle (or a pool of vehicles), usually parked in an easily accessible location. Car-sharing can eliminate the need for a personal vehicle.

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climate change; global warming
Changes in the concentrations of various gases in the atmosphere that are affecting the planet’s climate. Many scientists believe that the increase of carbon dioxide is a primary contributor to global warming, which occurs when gases trap warmth in the earth’s atmosphere instead of letting the atmosphere release it.

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compact fluorescent CFL bulbs
Fluorescent light bulbs that fit into a standard light bulb socket and use a fraction of the energy of their incandescent counterparts.

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compost
Decayed plants and other organic matter that breaks down into rich soil.

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core aerating
Poking small holes in the top few inches of lawn to encourage the flow of air, water, and nutrients.

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corporate social responsibility
Principles adopted by a business to make sure that its operations harm no one and instead benefit everyone around it and involved in it.

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daylighting
Bringing natural light into a home.

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ecosystem
A community of living organisms and nonliving materials.

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ecotourism
Sustainable and ethical travel in a natural environment.

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Energy Star
The federal government system for rating energy efficiency in appliances.

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Environmental Protection Agency EPA
Federal agency that regulates environmental laws.

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Fairtrade
System to ensure that workers and producers receive fair value for their products and that mandates sustainable practices in producing those products.

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food miles
The distance food travels from where it’s produced to the consumer.

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foodprint
The amount of land that various diets require to sustain them.

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fossil fuels
The energy-rich organic substances, traced back to the remains of organisms that lived 300 to 400 million years ago, that modern societies burn to provide power.

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geothermal
Energy within the Earth in the form of heat.

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greenhouse effect
The warming of the planet caused by gases in the atmosphere trapping the sun’s heat instead of letting it get through to space. This action is very similar to what happens in a greenhouse.

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greenhouse gases
Gases such as carbon dioxide, methane, and nitrous oxide produced by the burning and processing of fossil fuels and that contribute to global warming and acid rain.

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greywater
Water already used for washing, laundry, or showering that is appropriate for household functions from toilet flushing to watering plants.

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Leadership in Energy and Environmental Design LEED
A scoring system to rate how ecologically friendly buildings are.

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light shelves
White or light-colored horizontal fins above windows that bounce sunlight up onto the ceiling to bring it deeper into the room.

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light-emitting diode LED
A tiny semiconductor that emits light.

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natural gas
An energy source that burns cleaner than coal and oil but still releases carbon dioxide when it burns and methane during production, storage, and transportation.

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organic
Of living things; in food, grown without chemical fertilizers or pesticides or genetically modified organisms.

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passive solar design
Building design that takes advantage of the fact that the summer sun is higher than the winter sun. Overhangs shade the building from the summer sun and allow the lower winter sun to enter the building and heat it.

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petrochemicals
Chemicals derived from petroleum.

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phantom load; standby power
Energy drawn by a plugged-in appliance even when the appliance is turned off.

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plastic identification code
A triangle with a number from 1 to 7 inside indicating what type of plastic an item is made from.

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PV cell
A photovoltaic cell; a cell with a thin semiconductor that converts solar power into electricity.

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recycling
Collecting goods that have reached the end of their lives and processing them, their parts, or some of their parts, into the raw materials from which new goods are made.

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renewable energy
Energy from sources that cannot be used up, such as wind, water, and the sun.

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skylight
A rooftop window that brings in twice the light of a traditional window of the same size.

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solar panel
A panel containing cells that convert sunlight into electricity.

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sun tunnel
A passage that brings light into a room by bouncing sunlight through a small dome skylight on the roof connected to another skylight on the ceiling of the room. (Also known as a sun tube, sun pipe, and solar tube.)

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sustainable
Using natural resources in a way that allows for continued viability.

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thermal hole
An opening such as a window that leaks heat and air-conditioning energy.

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thermal mass
The ability of a material to absorb and store temperature.

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three Rs
The environmental practices of reducing consumption, reusing items, and recycling.

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top-dressing
Applying a light scattering of compost, other mulch, or sometimes fertilizer, over soil surfaces to add organic matter or nutrients without digging it in

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toxic waste
Disposed materials that can cause harm to people, animals, or the environment.

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vermicomposting
Composting with worms.

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xeriscaping
Landscaping for water conservation; a practice of garden planning and maintenance.