San Diego Common Pollens
Local tree pollens such as from cottonwoods, grass pollens, and ragweed pollens are particularly common in the San Diego region. The allergen seasonality varies with the weather, moisture conditions and length of each growing season. Pollen made by flowering plants helps form seeds and is carried mostly by insects. Interestingly, insect-pollinated flowers produce a stickier pollen grain that may be carried on their bodies and these are very different from wind-dispersed pollens and pollen allergens. In wind-pollinated plants like grasses and trees, the flowers are very small and inconspicuous, producing enormous quantities of lightweight dry pollen that is readily blown into the atmosphere and carried for long distances. The largest quantity of pollen will be released on sunny, dry, windy days, and San Diego Santa Ana conditions are perfect for that.