That's because modern landfills are designed, according to law, to minimize the entry of sunlight, air, and moisture into the landfill. This helps to prevent pollutants from the garbage from entering the air and drinking water supplies, but also greatly slows decomposition. Even organic materials like paper and food may take decades to decompose in a landfill. In contrast to landfills, composting takes advantage of degradability. Some people compost yard trimmings and some food scraps in their backyards.
Many communities collect leaves, grass, and other yard trimmings for composting.
A very small number of communities are experimenting with large-scale composting of all the organic materials in collected garbage. CFCs are chemical substances called chlorofluorocarbons that can deplete the earth's protective ozone layer. They are used to provide coolant in air conditioners and refrigerators, to clean electronic parts, and to make certain plastic foam products. In 1978, CFCs were banned for use as propellants in nearly all consumer aerosol products. HCFCs, or hydrochlorofluorocarbons, are sometimes used as substitutes for CFCs.