These are the greenest cities in the US, study shows

What are greenhouse gases?

The U.S. Environmental Protection Agency defines greenhouse gases as those that trap heat in the atmosphere.

A new study reveals which cities in America rise above the rest when it comes to clean energy and other "green" practices.

To identify the greenest areas of the country, WalletHub compared the 100 largest cities across 28 key "green" indicators. Their data set ranged from greenhouse-gas emissions per capita to the water quality to green job opportunities.

For this study, "Green" living referred to those cities which engage in cleaner, more sustainable habits in order to preserve the planet as much as possible.

"There are plenty of things that individuals can do to adopt a green lifestyle, from recycling to sharing rides to installing solar panels on their homes," Chip Lupo, a WalletHub analyst said in a statement, adding, "However, living in one of the greenest cities can make it even easier to care for the environment, due to sustainable laws and policies, access to locally-grown produce and infrastructure that allows residents to use vehicles less often. The greenest cities also are better for your health due to superior air and water quality."

San Diego is greenest city in America, study finds

The study found that San Diego ranked the greenest city in America, in part because it led the country in the number of solar panel installations per capita.

More than 43% of the city’s electricity comes from renewable sources, the seventh-highest percentage in the country.

Solar Array on roof of house and urban garden encircles house. (Credit: Citizen of the Planet/Education Images/Universal Images Group via Getty Images)

The study also found that San Diego had the second-lowest Urban Heat Island Effect Index in the country, which means that there’s only a relatively small amount of difference between the average temperature in the city and its less-developed immediate surroundings. In other words, this suggests that the use of green energy in San Diego has helped keep it from being an excessively hot city environment.

WalletHub also revealed that San Diego had plenty of other environmentally-conscious policies, including a bike-sharing program and bans on plastic bags. The city also led the country when it comes to the number of certified organic farms per capita.

Washington D.C. ranked second, in part because residents often grow their own food or buy it locally. Meanwhile, Honolulu ranked the third-greenest city, boasting the second-lowest greenhouse gas emissions and the third-best air quality in the country.

Top greenest cities in US: Study