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How can you possibly control for traffic pollution in a way that is independent from traffic noise?

Skimming the article [0], it looks like they compared outcomes of people who lived closer to the road against people who lived farther away from the road, in the same building.

I think the idea is that people living in the same building should all have roughly the same particulate and pollution exposure, but people living on a road-facing side of the building will have more exposure to road noise. It's an extremely clever study design.

0: https://www.bmj.com/content/374/bmj.n1954

If the assumption is that people in the same building have the same exposure to pollution but differential exposure to noise based on distance, I would prefer that it were tested. I am sceptical that this is the case, as I would expect folk on the road facing side to be exposed to more particulates and pollution and noise.

That's a good point, and I didn't read far enough in the paper to see if they tested that assumption or not. It seems like they developed some kind of model of noise exposure as a function of elevation and proximity to the road, so it's possible they developed a similar model for pollution.

With ear plugs apparently. But then you have an entirely different control problem.

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