This is the time of year that Dr. Jonathan Tam keeps an eye out for a layer of pollen on the outside of his car: a telltale sign that tree pollinating season has begun.
There's not much yet, but Tam, an allergy expert, expects to see a lot more in the next few weeks, and that's unwelcome news for allergy sufferers.
While the winter rains may have eased California's drought, "some people are going to have to appreciate it inside their cars or inside their homes," because the increased plant growth also means more pollen in the air, said Tam, Medical Director at the Gores Family Allergy Center at Children's Hospital Los Angeles.
Pollen allergies can cause stuffy nose, itchy eyes, and tiredness. They can be particularly harmful for people who are also asthmatic.
Rain isn’t the only weather condition that affects allergies; winds can blow pollen from one area to another. Even if an individual isn't allergic to the tree pollen in his immediate area, "you get those Santa Ana winds and you get those pollens coming down into the city so you will be affected," said Dr. Richard Barbers, Professor of Clinical Medicine at the Keck School of Medicine of USC.
People with pollen allergens should avoid being outside on windy, high pollen count days. "Make sure you have systems like air conditioning systems that will filter out the pollen from the outside," said Barbers.
The changing climate may lead to higher pollen levels in the future, according to Dr. André Nel, Professor of Medicine, Pediatrics and Public Health at UCLA.
"As the global temperature and CO2 levels increase plant pollination, cycles have become longer and more intense and record pollen counts become routine," he said.
Nel predicted high levels of pollen from trees, grasses and weeds this year. "We can also expect if the drought conditions return in summer we will also deal with very high mold spore counts," he said.
Mold spores, which are a bigger problem than pollen for some people with allergies, readily become airborne during dry periods.