A thick layer of pollen covers the windshield of a vehicle in Columbia, South Carolina, on March 25, 2007. According to the Allergic Disease and Asthma Center in Greenville, the pollen count in the Capitol City soared to 4,862 particles per cubic meter of air the last week in March, resulting in what doctors are calling one of the worst allergy seasons in 26 years. The exceptionally high pollen count is largely due to a combination of above-average temperatures and lack of rain.