hey everybody

this may sound like a stupid rather scientific like question,but since it is spain related why not right. :p there is an exception to this because while in madrid and alcala de henares the sunny sky did look quite amazingly blue to what im used to here in new york.in the northern provinces of spain on the rare ALL sunny days i never really saw this phenomenom.does anybody have any suggestions on why the spanish sky is so blue and why is never is in new york. oh and i heard madrid is more polluted these days but i still see this phenomenom.any ideas?