Exhaust Fumes on Block

Starting when the weather turned cold last week, there’s been a persistent smell of exhaust fumes on our block in the center slope. I can’t say whether it’s from a diesel generator or an oil burning furnace, but I’d guess it’s one of the two. It’s so bad that creeps in through closed windows. I don’t remember anything this bad in prior years.

Before I call the DEP (311), anyone have any experience investigating this type of issue?