The air circulation on the A380 goes from cabin, to cargo , then overboard. No chance of fumes from the cargo entering the cabin.
Its the same on most big jets. I had an incident on a B767. There was a smell incident in the rear galley. One of the four cabin crew working there was incapacitated by the smell, and was taken off the aircraft by the paramedics and stayed in hospital overnight. The other three crew in that galley were not really concerned. I went to investigate, and finally found that the toilet/galley vent exhaust fan in the back of the bulk cargo hold had burnt out and tripped its CB. So I removed the plug and the aircraft departed (there are two fans). The steward that went to hospital was really bad, and he smelt the fumes from this burnt out motor in the galley about 1.5 meters above the fan.
The other 3 crew standing beside him were OK.
We wonder at times what they are thinking.