How much can one little letter do to help improve air quality? In week 2 of our six-week Project Smog series, Jesse McLean asks just that. He looks at the AQHI (Air Quality Health Index), a new index that has replaced the AQI (Air Quality Index) in parts of B.C. and Toronto. What’s different? From the story:

Where the existing system reflects a region’s air quality in relation to provincial standards, AQHI will rate air quality based on its risk to human health–and that might make all the difference.

Click here to read the rest of the article, and remember to check back each Wednesday for the next instalment.