You might do well to check the trap under the sink. If the trap is loose, then any time sewage moves through that pipe, the smell can come into air in the space and it tends to stick. Likewise if there is a sewer vent near your home the smells could periodically be coming into the air that way.
You might do well to check the trap under the sink. If the trap is loose, then any time sewage moves through that pipe, the smell can come into air in the space and it tends to stick. Likewise if there is a sewer vent near your home the smells could periodically be coming into the air that way.