re walter's post :
They described a "global dimming" in particular over south and east Asia, South America, Australia and Africa, while visibility remained relatively stable over North America and improved over Europe, the researchers said.
i believe i read somewhere that some scientists are concerned about the air over europe becoming "too clean" , and not filtering out enough UV rays ?
if i recall correctly , it was expected that this "anomaly" would correct itself within a few years/decades ?
can airmasses really be that stable ?
i always assumed that the air all over the world was constantly shifting .
i know that at certain times of the year , air pollution from coal fired power stations in the southern U.S. moves all the way into northern canada .
we also have been effected by large forest fires in northern quebec when north-westerly winds have brought smoke all the way into eastern ontario and new york state .
i also recall that swedish authorities claimed that "exhaust" from the large nickle and copper smelters near sudbury/ northern-ontario drifted as far as sweden and caused their lakes to acidify .
(i know that the smokestacks at the smelters were fitted with "extensions" after a few years of operation to allow the exhaust "to punch" through the lower atmosphere and prevent the dirt and dust from falling on adjacent land around sudbury - apparently it worked very well - for a while .
all smokestacks have now been fitted with scrubbers and sudbury has truly become a "green community " . i remember driving up there in the 70's and there wasn't much in the way of grass , living trees etc. to be found within 30 miles of the smokestacks) .
any scientific explanation for these conflicting occurences ?