There are many environmentally unfriendly aspects to our modern world—gas-guzzling cars, pollution-spewing industry and apathetic consumers. Looking beyond the usual suspects, many would be surprised to find out that something as mundane as a parking lot could also be bad for the environment. We know that the cars we drive and park on them can be detrimental to the environment, but little did we know that our need to sprawl out and “pave paradise” may be contributing to the problem as well.

It turns out that Americans are paving more space than ever. This was evidenced by a 2005 study by researchers from Purdue University which counted parking spaces in Tippecanoe County in Indiana. In a county of 155,000 residents, there were 355,000 parking spaces, which had paved an area bigger than a thousand football fields. Tippecanoe is reflective of many other counties in the US, where suburban strip malls, schools and businesses are creating the need for more parking lots.

Parking lots can be bad for the environment for many obvious reasons. Increasing need for more parking lots may indicate that more cars are on the road, which means that more gas is being consumed and more pollutants exhausted into the air. More pavement means less green space, thereby reducing the number of trees and plants that serve as natural “air cleaners” by absorbing carbon dioxide in the air and releasing oxygen. More pavement also means less open soil that can collect rainwater, which helps to replenish natural aquifers. Areas that have less of a natural groundwater supply suffer even more from an overabundance of parking lots.

Cars are dirty pieces of machinery and leak all sorts of toxic liquids onto parking lots. Oil, grease, coolant and other fluids collect on the asphalt and sit until rain washes it into storm drains which may drain to lakes and streams. The runoff from parking lots is often highly polluted.

Another negative effect of parking lots is called the urban heat island. The asphalt or concrete in parking lots more readily absorbs and retains the heat from the sun’s rays than the surrounding ground. This in turn raises surrounding temperatures a few degrees, affecting what is called the “urban growing season.”

For those looking for fewer parking lots and more open green space, Keweenaw County in Michigan was found to have the most space between paved roads and parking lots. Washington D.C. has the most pavement with the least amount of open green space.