mouldy outside walls in tropical country

I need advice on how to stop my compound walls going green and black with mould in the rainey season. They were perfect white in April before the rain. What worries me is the thought of scraping off the mould . Is it dangerous to inhale?? and because its Africa specialist paints are not available and I dont think it will be easy to spray fungicide on such a big area. The walls are breeze blocks covered in I dont know what and the paint is local emulsion. Cant bear the thought of having to do this job every year !!! HELP !! Trisha View media item 5547 View media item 5548

Are you using exterior paint? You can't use normal emulsion on outside walls.....

well its the only paint available in gambia they call it plastic emulsion and its what everyone uses on their walls but some walls seem to survive better than others. What worries me is getting rid of the mould from such a large area. I could always ship some paint over which I have done before for the inside. Might just go around and find people who have really white walls and ask them how they've done it !!!