- Green Glossary - H
- Hair Booms
See Oil Spill Hair Booms.
- Hair Mats
See Oil Spill Hair Booms.
- Hammer Mill
A shredding machine that can be used for various materials and purposes, such as garden waste for composting, garbage disposal, shredding paper and grinding shipping pallets for mulch. Wether for industrial or home use, hammer mills are basically steel drums that have rotating shafts or drums on which hammers are mounted. When the rotors are in motion, material is fed into the machine for shredding.
- Hazardous Air Pollutants
A group of air pollutants classified under the US Clean Air Act as dangerous to human health and detrimental to the environment. Among the Clean Air Act's list of hazardous pollutants are: asbestos, benzene, mercury and vinyl chloride.
- Hazardous Chemical
Any manmade substance that poses a physical danger or health hazard to plants, animals and humans. Carcinogens, toxins and irritants are some examples of hazardous chemicals that affect human health. Some hazardous chemicals that pose physical danger include combustible liquids, explosives and flammables.
- Hazardous Landfill
An area that has been excavated or engineered for depositing hazardous waste. Landfills must be covered and designed to ensure that the hazardous waste it contains does not contaminate the environment or endanger human health.
- Hazardous Ranking System or HRS
The primary assessment tool used by the US Environmental Protection Agency (EPA) to evaluate health and environmental risks posed by abandoned or uncontrolled hazardous waste sites. The HRS calculates a score based on the potential of hazardous substances spreading from the site through the air, surface water, or ground water, and on other factors such as density and proximity of human population.
- Hazardous Waste
Garbage that contains dangerous substances or potentially dangerous materials are classified as hazardous waste. Examples of hazardous waste are lead acid batteries and fluorescent lighting tubes. If not disposed of properly, hazardous waste threaten human health and the environment. US environmental laws classify hazardous waste as 1) flammable 2) reactive 3) corrosive and 4) toxic.
- Heat Capture Technology
Any form of technology or system that traps "wasted" excess heat from gas turbines so it may be used as consumable heat. Combined heat and power plants (CHPs) use these types of technology to not only generate electricity but also utilize the additional heat produced by the process to heat homes and buildings.
- Heat Compression
A type of recycling process, heat compression takes unsorted, clean discarded plastic and loads them into large rotating drums that apply heat and mixes the waste converting them into new plastic material. Heat compression can be used to recycle almost all forms of plastic and allows them to be mixed together. However, energy costs are high due to the rotating drums and heating pipes used.
Also known as 2-Hexanone, methyl n-butyl ketone, MBK, or propyl acetone, it is a clear, colorless liquid with a sharp odor. It dissolves very easily in water, and can evaporate easily into the air as a vapor. It was used in the past in paint and paint thinner, to make other chemical substances, and to dissolve oils and waxes. It is no longer made or used in the United States because it has harmful health effects. It is formed as a waste product resulting from industrial activities such as making wood pulp and producing gas from coal, and in oil shale operations.
Hopenhagen is a movement to create awareness and rally global support for the 2009 Copenhagen Agreement on Climate Change. It is spear headed by the International Advertising Association which created a campaign inviting people from all over the world to sign an online petition supporting the Copenhagen Agreement. Hopenhagen made use of merchandising and traditional mass media along with new social media and internet buzz to draw attention to the climate change cause.
- Household Hazards
Dangerous substances or conditions in human homes that arise from a wide variety of sources. Potential hazards that affect indoor air quality can come from chemical household products, residues and particles from the home's structure (such as Radon and asbestos), and biological pollutants such as viruses, bacteria and fungi.
- Hybrid Car
A hybrid car uses two power sources to move itself -- an internal combustion engine like one used in regular gas-powered cars and, in addition, at least one electric-powered motor. Because a hybrid vehicle has two energy sources, it requires less gas to power itself and produces less green house gas emissions. The Toyota Prius is an example of a hybrid car that produces 90 percent less air pollutants than a fully-gas-powered car.
- Hydroelectric Power
Hydroelectric power is produced by using the push of falling water to turn turbines that generate electricity. A dam is built on a river with a large drop in elevation, water falls with the force of gravity to a penstock inside the dam. The turbine propeller is turned on by the falling water. The shaft from the turbine goes up into the generator, which produces the power. Power lines are connected to the generator that carry electricity to homes and buildings on the grid.
- Hydrofluorocarbons or HFCs
Hydrofluorocarbons (HFCs) do not contain ozone-destroying chlorine or bromine atoms and are therefore used as substitutes for ozone-depleting compounds such as chlorofluorocarbons (CFCs) in such uses as refrigeration, air conditioning, and the manufacture of insulating foams. Though the HFCs do not deplete the ozone layer, they are potent greenhouse gases. Molecule for molecule, all HFCs are more potent warming agents than carbon dioxide, some are thousands of times more potent. HFCs are in the basket of gases regulated under the 1997 Kyoto Protocol, an international treaty to reduce emissions of greenhouse gases.
- Hydrogen Fuel Cells
An alternative power source for engines that can replace carbon-based oil fuels. Hydrogen fuel cells generate power through a hydrogen and oxygen chemical reaction--with no combustion and no resulting pollution. Tests are being made by major vehicle manufacturers on the use of hydrogen in providing energy to various types of engines, from cars to aircraft.
Hydrology is the science of the circulation and distribution of water from the moment it falls as rain until it is returned to the atmosphere by evaporation or transpiration. Studying the hydrology of a watershed can help resource managers understand the flow of water within stream systems and beneath the earth's surface. Water is critical for the survival of organisms--each life stage requiring different hydrological conditions.
- Hydronic Heating
An environmentally-friendly way of heating indoor spaces using water as a heat transfer mechanism. The Hydronic Heating Association states that not only is water the "ultimate transfer medium" but can also be much better for air quality. Older systems that use air can pass dust or other impurities through their system and pollute the air. Hydronic heating does not have this effect--producing cleaner air. The hydronic heating system is also quieter and can be less costly. Plastic tubing used in most hydronic systems are recyclable, adding to its green-living appeal.