I used to live in an apartment and my son's room had a window that faced on to the driveway. People would pull up to our entrance and idle their cars with the tail pipe right underneath that window.
This bothered me on a host of levels. I feared for my son's health. I was upset about pollution. I felt there was a waste of resources going on. All of those were legitimate concerns.
I was going to write about all the ways idling is bad and fill up this post with facts and figures. Then I discovered that there is an organization called LEAP (Lower Emissions and Particulates) dedicated to reducing the time people spend idling. It is sponsored by an auto parts manufacturer and I am sure they have more expertise in this are than I. So I figured, why reinvent the wheel? I am just going to give you the link to their website.
I found this particular page interesting, but the whole site is information rich. Hope you find it helpful!
Idling Myths & Facts
What's concerning you about the environment at the moment?