(just cruised in from looking for another subject)
RUN!! RUN to the nearest source of public health information!!
I shared a rental house during college (~1979-80) in Adirondacks of New York, and the furnace was fuel-oil fired (very similar to diesel). About mid winter we started waking up with a fine layer of soot on everything; including our nasal mucous membranes. When we blew our noses, the tissue was filled with black flecks. YUCK!!! Sorry to gross everyone out, but that's the facts.
We did get the landlord to get the furnace checked by his contracting company; the tech. said "It's a wonder you guys didn't wake up one morning to not waking up!"
The furnace was seriously compromised, and spitting soot into the warm air and our breathing air.
So,,, pester your landlord. Pester him again. A A minor amount of soot is probably ok, but not 'a ton'. Ask your landlord WHEN and WHO cleaned it.
Be firm. This is your health at stake.