The survey by the Economist Intelligence Unit looked at 31 variables, such as mobility, air and water quality, land use, and energy to determine the ranking. That the result covers a broad geographic spectrum is a clear indication of the narrowing "environmental gap between the West and East coasts [...] in the last decade," writes Wendy Koch for the USA Today.
What about Canada?
"The American cities tend to be fairly wealthy and thus able to afford new projects. When wealth was taken into account, the survey finds that the five Canadian cities, including Vancouver (No. 2 overall) and Toronto (No. 9), outperform their U.S. counterparts," Koch points out.
The Economist Intelligence Unit is a research division of The Economist.