Allergies, pollen, and palynology

by Radio Somewhere

I am lucky to not suffer overly from allergies of any kind. I cannot eat shellfish — but as I’m a vegetarian that is rather moot. And when I was a child, up-close examinations of certain caterpillars brought my fingers out in a nasty rash. Encounters with poison ivy have resulted in extreme reactions that require a prescription of those tiny little cortisone tablets. But these are things I have learned to avoid. I suspect I might have become allergic to mold after I moved to Seattle. My apartment has a terrible mold problem in winter, but it can be managed with care. Even so, for several winters I was troubled with horrible nasal congestion that did respond to prescription Flonase. Then I lost my health insurance and had to do without it — and was pleasantly surprised to have no symptoms for the last two winters. It might be that my system figured out a way to deal with it naturally — but it might also be that I have cut way back on a very heavy wine-drinking habit that perhaps didn’t help things. Anyway, compared with many people I know, I am fortunate in that I rarely suffer.

That is not to say that I don’t sneeze though! At this time of the year, I let out sneezes that probably register on University of Washington seismometers. But when people ask if I have a pollen allergy, I flatly deny it — and if time permits, I tell them a little bit about pollen.

A long time ago, when I was still smart and industrious, I did a PhD in geography. One of my favorite classes was Quaternary Geography, in which we learned about the various ways in which one can reconstruct past environments from evidence such as tree rings, isotope ratios, sediments — and pollen grains!

Pollen is handy stuff, because first, plants issue tons and tons of the stuff, trees especially. Second, pollen grains are very long lived on account of their tough outer layers, or exines, which do not break down even in strong acid! Insects which consume pollen have an enzyme which will break down the outer shell, but in just about any environment, pollen grains remain not only intact, but identifiable by species, for a very long time — tens of thousands of years possibly! This is of great utility to a palynologist who can extract a sediment core from the muck at the bottom of a lake, with layers representing periods in history going back thousands of years. By sampling the core at intervals, and examining the buried pollen grains under a microscope, palynologists can make inferences about how the environment at that location has changed through time. For example, an assemblage dominated by grass pollen might suggest relatively warm, dry conditions while a cooler, wetter climate might be indicated by more tree pollen. In the Holocene, i.e. the modern human era, changes in pollen assemblages over time also indicate roughly when the hunter-gatherer lifestyle gives way to agriculture. But enough of that! Just look up “palynology” if you wish to know more. (You can find a very nice and quick overview here.)

With regard to allergies, you need only know one thing: the outer shells of pollen grains do not break down even in strong acid! And, pollen grains can survive intact for thousands of years. OK, that’s two things. But suffice is to say, if pollen manages to make it down inside your respiratory system, then it is probably going to be down there a long time — which is why you are prompted to sneeze aggressively and expel as much of the stuff as possible! The sneezing and watery eyes are just nature’s way of keeping that stuff out of your lungs — and taking medication to “relieve” those symptoms might allow too much pollen to take up residence inside you — and perhaps stay there! So, I really feel it is important to allow yourself to sneeze — and not to get started on the annual ritual of allergy medication, which might just be making things worse in the long run.

So far this spring, I’m not sneezing much. In Seattle, weeds are extremely busy right now. Trees have yet to start pumping out their load, grasses are pretty light, but weeds are going mad! I’ll know when the trees get going. We have a lot of spruce around here, and I think that’s the pollen that really gets me sneezing!