I have only lived here for a few years but I used to live in downtown Worcester and would walk all over the center of the city and down to UMass on Lake Ave and I never once got a sense of polluted air or "stinky" emissions beyond what you can notice from cars when walking along a busy street.

There is an air quality measuring device that the state owns located on Summer St just next to 290 in downtown Worcester. The data is freely available on a number of websites, but this one displays it nicely: https://aqicn.org/city/usa/massachusett/worcester/summer-st/

If you scroll down you can see historic PM2.5, PM10, O3, NO2, SO2, and CO pollution patterns.

I'm not sure where you're moving from, but the northeast generally has cleaner air than a lot of the country. For instance, people often think of NYC as having very polluted air but even in Manhattan and the dense industrial areas in Northern NJ, the air is much cleaner than places like Chicago, Houston, LA--even St. Louis, Atlanta, Indiana, etc.

I don't know how sensitive you are but I feel like unless you were next door to the interstate or some industrial site, you should be fine here.