The mild winter has resulted in a "perfect storm" of pollen in many parts of the United States on the first day of spring, U.S. allergists said.

"The recent rains followed by warm, sunny, summer-like temperatures have created a dangerously high tree pollen count and allergy sufferers should stay indoors, keep the windows closed, use their air conditioners and take their allergy medications," said Dr. Joseph Leija, an allergist at Loyola's Gottlieb Memorial Hospital near Chicago certified by the National Allergy Bureau to perform the daily official allergy count for the Midwest. "Chicago's tree pollen count is dangerously high and the city is officially on alert for poor air quality -- ragweed in March is unheard of in the Midwest; I have never seen an allergy count so unusual."

Allergist Dr. Stanley Fineman, president of the American College of Allergy, Asthma and Immunology, said in the Atlanta area Tuesday's 9,369 particles of pollen per cubic meter of air is 55 percent higher than the old record prior to this week of 6,013, set April 12, 1999.

Anything more than 1,500 is considered "extremely high," and last year, the highest pollen count measured in the Atlanta area was 3,939 March 24.

Dr. Donald J. Leopold of State University of New York College of Environmental Science and Forestry in Syracuse has studied woody and herbaceous native and non-native plants for 27 years. He said he had never seen these species bloom on campus before April 1.

This warm weather might be really pleasant," Leopold said. "But when the weather is really altered from typical conditions, there are always winners and losers among all types of both plants and animals." (c) UPI