- Environment, general 7
- Demography 2
- Environmental Physics 2
- Population Economics 2
- Public Health 2
- Sociology, general 2
- Soil Science & Conservation 2
- Climate Change 1
- Ecology 1
- Engineering, general 1
- Environmental Engineering/Biotechnology 1
- Industrial Pollution Prevention 1
- Renewable and Green Energy 1
- Waste Management/Waste Technology 1