Google Earth is an incredible tool - it certainly goes beyond the novelty of seeing your house from space. The USA Environmental Protection Agency has put together an amazing Google Earth map of air emissions sources in the US, where you can view state, county, and facility-level emission summaries for the six principal air pollutants. Facilities include:

- Cement Facilities
- Chemical Plants
- Power Generation Stations
- Natural Gas Pipelines
- Oil and Gas Production
- Refineries
- Pulp and Paper mills

You can zoom in on each placemark for further information about the facility. To access this map, you'll need Google Earth (free) installed on your computer and also download this file (right mouse button click and select "save as"). Once downloaded, double click on the file and Google Earth will initialize and display the map data.

Emissions data in your region relating to Carbon Monoxide, Lead, Nitrogen Oxides, Volatile Organic Compounds, Particulate Matter and Sulfur Dioxide are also avaialable via the map according to the EPA, but I wasn't able to bring up that information when I tried.

The EPA site also allows you to create your own map, focusing on particular states, emissions sources and pollutants.

I've been using Google Earth extensively while on the hunt for a chunk of Aussie bushland to escape from the rat race to. It gives me a bird's eye view of not only the land, but what surrounds it; which is really important. For example, I've seen some very nice blocks, but they've sometimes been surrounded by other blocks where it's clear there's a great deal of motorbike activity.

What Google Earth has also done for me is to really drive the point home about how much we've changed the face of the planet. I look at our state and beyond Adelaide's city limits I see it much of it carved into squares and rectangles (farms), with rapidly reducing pockets of bushland and rapidly increasing areas that look like moonscapes. It's quite incredible to see this sort of destruction given that Europeans only settled this country well under 300 years ago.