Beginner Gardening: Spruce Tip Curl, 1 by GardenNes

GardenNes wrote:
I'm a little confused by the information I've already come across. We live in a rural area (although granted, near a highway) so I find it quite surprising that our tip curl would be caused by air pollution.

Also the branches curl down not up and aren't loosing any needles (all these trees are quite healthy).

Is there another explanation for what is going on with these trees?

And if there is anything I could do?