East Coast Visibility

I was having lunch with a buddy of mine the other day who has been a pilot
for almost 50 years. We discussed the bad visibility we have in the South
and up the Eastern seaboard in the summer. Haze to 10,000', lateral
visibility frequently under 5 miles, etc.

He said that it is much better now than in the late 60's/early 70's. He
said the airborne pollution in those days was so bad that if you went on a
long X/C you often came back with an oily film covering the leading edges of
the wings. He also added that when he started flying, in the 50's,
visibility was usually far better than it is today.

Any comments?

KB