Many experts think this could be because of global warming. Higher concentrations of CO2 in the atmosphere speeds plant growth, while the warmer temperature that bring Spring and allergy season arrives earlier and earlier.
Spring-like conditions are arriving as much as 14 days earlier in some parts of the U.S. A warmer climate will make allergies worse for most of us. Total pollen counts in many areas of the country are increasing every year. Also industrialized population’s sensitivity to pollen and other irritants is increasing as well.