Pollen

The world is a complicated system, but yet there are certain natural laws that hold true, two of which are: people and animals need oxygen to live and they exhale carbon dioxide; plants need carbon dioxide and release oxygen. This seemingly great symbiotic relationship, that we all learned pre-high school, in which both fauna and flora benefit, has a kink if you suffer from allergies, and more in particular you have asthma. If you have varied environmental allergies, the cards in the deck may seemed stacked against you as you wheeze your way through the now lengthening pollen season. 

A Close-up Look at Pollen

Scientists have noted that carbon dioxide levels have been increasing. Dr. Joseph Leigra, has been collecting pollen and mold spore from a collection machine on the roof of a suburban Chicago hospital, from where he is now retired, for over 24 years. He, being one of many, has noticed the increase in pollen. Increases in levels of carbon dioxide are mainly (some estimates place it at 87%) attributed to our use of fossil fuels. (Prior to heavy use of fossil fuels carbon dioxide natural emissions are said to have been balanced by natural absorption.) With more carbon dioxide you get more plant growth, with more plant growth you get more pollen, more pollen exacerbates allergies, and in particular those that may suffer from both allergies and asthma. But, because allergy symptoms are similar to those of the common cold, the number of persons with an allergy is likely under-reported. It is reported that 1 in 5 Americans have a ragweed allergy and 1 in 12 have asthma. Federal data indicates a 17% increase in asthma between 2001 and 2012. An allergist at the hospital were Dr. Leigra collects his pollen samples noted that children are being affected with allergies at a younger age, and adult symptoms are becoming more severe. I see this in my spouse, who is allergic to grass and trees, and since pretty much every biome on earth has grass, she may as well be allergic to the environment. The past couple weeks have not been kind to her and if increases in carbon dioxide continue, matters may only get worse.

Study Relating Pollen to Carbon Dioxide Levels; 2060 is an estimate

People with asthma can have trouble breathing—they need oxygen too—and while the causes of asthma have many factors, doctors say the condition is exacerbated by pollen. One study found that high carbon dioxide levels are more likely to trigger an allergic reaction. Proteins on the surface of pollen can vary and this variation can lead to different allergic reactions. Allergist and immunologist Leonard Bielory at Rutgers University says that allergy risk is a convergence of many factors—a person's sensitivity to allergens, seasonal temperature variations, urban development, and varied reaction of plants to different chemicals, among other things. It is known, however, that the number of persons sensitized to pollen has doubled in the last 20 years. Part of this may be related to the hygiene hypothesis—where we are too clean and thus do not develop proper antibodies. Temperature variation, not unlike what we have seen this spring, one day with temperatures in the 30’s another in the 70’s, mixes up the immune system and leads to more suffering. Likewise, more male trees, after all pollen is the sperm, are being planted to avoid the trouble with having to clean up seed pods. Less mess, more pollen. It was on drive full of maple seed "helicopters" that my oldest son years ago spun out on his bike and broke his arm. Wet fall and winter weather also is thought to lead to higher spring pollen counts—after all, plants like water too.

Map of Tree Pollen levels in the Continental United States
on June 4, 2015

While we may think that more plant growth is good, most say the few positive effects are outweighed by the negative effects. The world is complicated and temperature changes, erosion and soil conditions and other effects may limit more than limit the beneficial effects of greater plant growth. With increasing carbon dioxide levels, increasing in pollen days per year (pollen days in Minneapolis has increased 16 days in 14 years), my wife and other allergy sufferers may be seeing a new normal. Of course, because the natural world is complicated more study needs to be accomplished, but it would appear that increasing carbon dioxide is becoming a matter of public health.

Images are from Google Images