Why the sky changes color?

[emilyscience]

I am doing a project on why,how,when the sky changes color and how this effects us. I need an expert to answer some Questions for me and was wondering if you could do that for me?
Questions:
1.Who monitors the colors in the sky/atmosphere or what group of scientists study this and what studies have been done?
2. What factors are there that contribute to the changes in the color of the sky(such as pollution,climate,etc.)?
3.Are there times when the changes in color are more prevalant than others and if so when?
4.Are there times when the change in the color of the sky is a bad thing 5. What can we do to change any negative effects we are having on the atmosphere that is causing these changes?

If you can't answere these questions can you direct me to a source where I can get these questions answered. I have done some research but I am not having much luck finding someone. Thank you for your time.
Emily G.

[Lise Byrd]

Emily,

Here are some links that might help you:
http://mynasadata.larc.nasa.gov/P11.html
http://mynasadata.larc.nasa.gov/P12.html (has some other factors)
http://www.newton.dep.anl.gov/askasci/w ... a00180.htm (info about seasonal sky color, but doesn't have to do with pollution)

I know the NOAA (National Oceanic and Atmospheric Administration) monitors atmospheric temperature and humidity extensively. They may also monitor air pollution.

Hope this helps!
Sonia