Just came across this....those things that bite /sting all the time are 'mold' spores I think. The city has had an ongoing problem with 'black soot'. It was diagnosed as only 'harmless mold'!!!! Now it is all starting to come together....It has made the front page at least 3 times this year with residents demanding to know what this 'black stuff' was. There have been numerous followups...but no 'definitive' answer....I reckon this is what is causing the problem.. It is pretty horrible stuff....as I said, I have been hemouraging for 53 days...ekkk! It is pretty toxic stuff which breaks down the immune system allowing these oportunistic 'critters' to invade....