Discussion Qs

I have 2 question discussions

1) Provide one example of human activity disturbing the hydrological cycle.

There are 4 major processes of hydrological cycle, 1. evaporation and transpiration, 2. condensation, 3. precipitation, and 4. gravitational flow (infiltration, surface runoff). Human activities can disturb any of these processes. Please give ONE example of how a process is affected human activity with necessary description. 

Example: 

1 point answer: Deforestation will affect transpiration.  

5 point answer: Transpiration is water moving to the atmosphere through plants, deforestation eliminates plants in the forest, resulting in reduced transpiration.

2) What are the possible causes of PM2.5?

The causes of PM 2.5 pollution is highly complicated. Search Google Scholar for possible sources of PM2.5 in different locations around the world. Please note that there might be multiple sources for one location, also PM2.5 pollution can be outdoor or indoor. Post you answer with citation and a link to the reference.