Try Mr Google Scholar. You get more scientific results from this.

http://scholar.google.co.uk/

I did some work on this and found... lots of conflicting info.

Some sources - mainly American, state that exposure = certain death (well eventually I suppose that's even true for air)

Other sources think it's one of your 5 a day...

I basically concluded -
1) try and avoid breathing spores - especially if suffering from lung problems such as asthma, noting some people will be more susceptible
2) use a appropriate contractor to remove the mould - obviously there are safety issues structurally if the mould spreads

Not the most helpful of posts, but I'm not sure there is a clear answer, other than - it depends

Good luck :)