Question

What steps have the United States and Canada taken to improve air and water quality?

Answer 1

Air Quality:

Portland, Oregon has been specially designed to conserve air quality. It is purposefully compact, so that people living on the rural-urban fringe do not need to travel far (By car - a polluting practice) to reach the CBD (Central Business District).

Hydrogen fuel stations are also becoming more abundant, to support hydrogen-fuelled cars, which are less polluting than petrol cars as they only emit water vapour (not co2 - a harmful greenhouse gas).

Water quality:

Recycling schemes to reduce waste dumping in the oceans. 

Research into fertiliser alternatives which, when washed into water, disrupt ecosystems by affecting the nitrogen cycle.

Hope that helps!