I do not remember this growing up here in Oregon. I graduated high school in 1998. I remember around this time always feeling really bad for my sneezing coughing little sister, but the things that made her sneeze always seemed invisible. Now I see pollen clouds being blown across the landscape. Multiple places along the sidewalk where a prior pollen-filled puddle has dried up there is now a literal pollen stain on the path. This is wild. Am I just feeling that there’s more pollen because I now have allergies and notice it? Or is there actually more pollen? It turns out that science has told us that there is absolutely more pollen, and the culprit is climate change. Climate change is leading to longer pollen seasons and more intense pollen. There’s actually a great deal of disturbing research on how pollen is changing, from becoming both less nutritious for our pollinators, as well as more allergenic, and plants are producing greater amounts of it. This interacts in all sorts of concerning ways with increasing carbon dioxide in the atmosphere. I’m always trying to learn more about this and will continue to explore it in future posts, but there’s too much to cover at once about all the different ways that climate change is affecting our respiratory health. Today I’m focusing on the pollen season. The US Department of Agriculture has a massive economic interest in this, as all of us rely on pollen and pollinators for our food. So changes to pollen are a big deal. One scientist there has been studying this for quite a while- Lewis Ziska, PhD a research plant physiologist at the USDA. I have really loved looking at his studies while learning more about this topic. They are very practical and look at real world data and scenarios.

One study he and his group did looked at why allergies have been increasing in the United States over the last 30 years. They note that this is a very important question to answer since we spend around 21 billion dollars a year on allergies in the United States. They focused on the Ambrosia species, also known as ragweed, since it is a very common cause of allergies. Around 10% of the US population is sensitive to ragweed, and they noted that around 27% of allergic individuals had ragweed sensitivity according to two other large studies.

I did not know this, but the National Allergy Bureau has 8 different locations in the United States between Austin, Texas and Fargo, North Dakota and has been recording the pollen records in these sites. Combining this with a software program from Texas A&M looking at the closest weather stations, the researchers were able to look at pollen counts and temperature trends. They also looked at a couple Canadian locations with similar information. They examined multiple factors, including seasonal precipitation, and found that it was the delay in the cold start of fall and the decrease in days with frost that correlated most significantly with increasing pollen.