San Francisco Bay Area hay fever sufferers are having particularly severe sneezing fits this year. “The tree pollen count this year is heavier than normal for two reasons,” said Dr. Donald German, chief of allergy at Kaiser Permanente Medical Center. “First, we had a particularly mild winter, which causes the pollination process to last longer in the season. Also, it’s been more windy than normal this spring, and that wind is keeping the pollen in the air where people can breathe it.” German estimated that about 20% of Bay Area residents suffer from some form of allergy, mostly hay fever. German, chairman of the American College of Allergists, said that new medications are making relief possible. Chromylin sodium, a prescription drug approved last year by the Food and Drug Administration, blocks the action of the pollen on the body with no harmful side effects, he said.