- Environment, general 6
- Atmospheric Protection/Air Quality Control/Air Pollution 4
- Climate Change/Climate Change Impacts 4
- Hydrogeology 4
- Soil Science & Conservation 4
- Water Quality/Water Pollution 4
- Ecology 3
- Geography, general 3
- Earth Sciences, general 2
- Analytical Chemistry 1
- Computer Applications 1
- Environmental Management 1
- Monitoring/Environmental Analysis 1
- Natural Hazards 1
- Nature Conservation 1
- Urban Ecology 1
- Water, general 1