Green chemistry (or sustainable chemistry) is a type of chemical research and engineering. It supports the design of products and processes that use as little dangerous substances as they can. 

Environmental chemistry is the chemistry of the natural environment and of pollutant chemicals in nature. But green chemistry wants to reduce and prevent pollution at its source. In 1990, the Pollution Prevention Act was passed in the United States. This law sought original and new ways to handle pollution. It aims to avoid problems before they happen.

Green chemistry applies organic chemistry, inorganic chemistry, biochemistry, analytical chemistry and even physical chemistry.  While green chemistry seems to focus on just industrial applications, it does apply to any chemistry choice. Green chemists reduce the hazards and increase the efficiency of any chemical choice. It is distinct from environmental chemistry which focuses on chemical phenomena in the environment.

The 12 principles of green chemistry 

1. Prevent waste

Create products without or with minimal wastes so that the wastes do not need to be taken care of afterwards.

2. Design safer chemicals and products

Design chemicals to have little or no toxicity, without affecting effectiveness.

3. Design less hazardous chemical syntheses

Design a way of synthesising products without it being toxic to humans or the environment.

4. Use renewable raw materials

Use renewable raw materials, like plant materials, other than depleting ones, such as Fossil fuels.

5. Use catalysts, not stoichiometric reagents

Use of catalysts because of their ability to be able to be reused and that they are less harmful than reagents.

6. Avoid chemical derivatives

Chemical derivatives generate wastes that can be avoided.

7. Maximize atom economy

Make sure that a greater percentage of the atoms present in the reactants of a chemical reaction are used in the products that are also usable.

8. Use safer solvents and reaction conditions

Avoid using harsh solvents, but if that cannot be avoided, then use benign chemicals.

9. Increase energy efficiency

Use the normal ambient temperature and pressure wherever possible.

10. Design for degradation

Design materials to breakdown into benign substances by bacterial or other environmentally sound ways.

11. Analyse in real time to prevent pollution

Monitor and control the formation of by-products during a reaction.

12. Minimize the potential for accidents

Design chemicals to minimize the potential for accidents.

References

Other websites
EPA Green Chemistry Program Website
Introduction to Green Chemistry and Recent Literature
American Chemical Society Green Chemistry Institute
California Department of Toxic Substances Control, Green Chemistry Initiative 
University of California, Berkeley, Program in Green Chemistry and Chemicals Policy 
Center for Green Chemistry and Green Engineering at Yale University
Green Chemistry Centre of Excellence at the University of York, UK 
Center for Sustainable and Green Chemistry at the Technical University of Denmark 
Mediterranean Countries Green Chemistry Network 
Next Generation Environmental Technologies Published by RAND
Green Chemistry at Tel Aviv University 
Green Chemistry, Journal of the Royal Society of Chemistry
Green Chemistry Book Series published by the Royal Society of Chemistry
Green Chemistry Letters and Reviews, Taylor & Francis

Environmental chemistry