| Environmental source | Major causative antigen |
| Humidifier fever | Thermoactinomyces spp (T vulgaris, T sacchari, T candidus) |
| Klebsiella oxytoca | |
| Naegleria gruberi | |
| Acanthamoeba polyphaga | |
| Acanthamoeba castellanii | |
| Unventilated shower | Epicoccum nigrum |
| Hot-tub lung (mists; mold on ceiling and around tub) | Cladosporium spp |
| Mycobacterium avium complex | |
| Sauna taker's lung | Aureobasidium spp, other sources |
| Summer-type pneumonitis | Trichosporon cutaneum |
| Lifeguard lung | Microbial contamination of pool water sprays and fountains |
| Contaminated basement (sewage) pneumonitis | Acremonium spp (formerly Cephalosporium) |
