My office building (the company owns it) is four stories. We have a backup diesel generator that is run every week during business hours for 1 hour. And every w

My office building (the company owns it) is four stories. We have a backup diesel generator that is run every week during business hours for 1 hour. And every week the fumes waft upwards towards the air handlers on the roof. My first week I was shocked by how bad it smelled; kind of like a mown lawn that had rotted. After a few years, I stopped noticing it.