Plastic, steel, wood and cement constitute the modern basic industrial materials. And it occupies an important position in the national economic development. Considering of its advantages, it is widely used in industry, agriculture and people's daily life. The correct understanding of using plastic has important significance to environmental protection and resource utilization.

1. The environmental impact of waste plastic

It is cheap and convenient; so it is widely used in all kinds of product packaging. With the development of modern plastic industry and improvement of the consumption, most of the packaging are disposable supplies, disposable after use, this leads to serious environmental pollution.

The plastic always is taken into the city landfill. And landfill treatment is the main method of dealing with the waste plastic. With the rapid development of plastic industry, waste plastic production is proportional to the plastic production. The environmental problem is increasingly outstanding. Firstly, landfills occupy limited arable land, it seriously make a waste of land resources. Secondly, the plastic material is very difficult to decay. Thirdly, after the landfill, plastic garbage is washed by the rain for a long time, making a large amount of harmful substances into the human living environment, and also causing harm to future generations.

2. The environmental impact of burning the waste plastic

In the process of plastic pyrolysis, it releases a large amount of harmful gas. Such as polystyrene plastic,when it is under 80 ℃ ,it can keep unchanged composition, but when the temperature exceeds 280 ℃, its molecular weight began to decline, then producing volatile gas, gas of styrene monomer which containing 44%, 22% catamaran, three body and a small amount of toluene, etc. This is very harmful to the environment.