"1. moisture (water vapor) in the air near the surface
2. instability - relatively large decrease of air temperature with height
3. lift - some process (such as a front) that forces air to rise"
The air is dry during the summer and any moisture amount is increased in the afternoon as the temperature cools.
Answer:
1. Location
2. Place
3. Human-environment interaction
4. Movement
5. Region
I think it's climate or humidity
Motor vehicles are a HUGE source of pollution in big cities
