Blame it on the mulberry, birch, and oak trees if you’re in Manhattan, said Guy Robinson, Ph.D., where Fordham University maintains the only official pollen monitoring station in the city. Those three species dominated Robinson’s latest sample slides heading into what’s traditionally the peak pollen weeks of the season—the first two weeks of May.

Robinson maintains and collects pollen samples from the station, located at Fordham’s Lincoln Center campus on 60th Street east of Columbus Avenue, as well as another station at Fordham’s Louis Calder Center in Armonk, New York. Throughout the spring and summer, he feeds the data to the National Allergy Bureau of the American Academy for Allergy, Asthma & Immunology and posts a spreadsheet on @FordhamPollen on X as a public service.

Robinson has been at it for 25 years, while teaching biology and paleoecology in the Department of Natural Sciences, first as a senior lecturer at Fordham College at Lincoln Center, now as a visiting scholar. Once a week, on Tuesdays, he hops up on a wall outside the McMahon residence hall on 60th Street and unwraps a clear inch-wide strip of tape from a cylinder in the Burkard spore trap. The cylinder makes one complete turn in a week. The top of the machine spins like a weather vane, capturing the microscopic particles that cause the seasonal suffering of so many.

After coiling the tape into a metal canister, he carries it to a biology lab in Lowenstein. There Robinson snips the tape into segments—one for every 24-hour period. Then he begins the tedious process of counting pollen particles. 

On April 30, peering through a microscope while working a rudimentary clicker counter with his left hand and making notes with his right, Robinson said that by now, he recognizes most of the different tree pollens “just at a glance.” That’s how he gets the number we all know as the “pollen count”—the number of pollen particles per cubic meter of air. 

He added, “Humans are still better at counting pollen than any machine.” 

No More Sycamores

Robinson has a paper in review now for the Urban Design and Planning Journal suggesting that municipalities should take into consideration the effects of allergens when creating their tree-planting plans.

“They do not need to be planting sycamores in the city,” he said, noting that the species is highly allergenic. Fortunately, the sycamore pollen numbers are already subsiding for this season.

Trees like cherry, hawthorne, and pear, with noticeable flowers, he said, are not major contributors to allergies because they are insect pollinated (the pollen is not carried by the wind).

Those wreaking the most allergy havoc are oak, birch, alder, walnut, sycamore, and elm. Pine pollen is not a major allergen, although pines produce a lot of pollen, he said.

Every year is slightly different in terms of timing and quantity of pollen, said Robinson. But tree pollen nearly always peaks in the same order each year, with sycamore pollen appearing first. 

So what can you do if you are allergic to pollen?

“What we learned during COVID is that what does seem to have helped is wearing a mask,” Robinson said.  “Even the cheapest ones filter out most of the pollen.”

Listen here:

Patrick Verel: This is Patrick Verel, and today I’m speaking with Guy Robinson, a senior lecture in the department of Nashville Sciences at Fordham. What is typically the worst time of year for pollen and how does this year compare to that?

Guy Robinson: This is typically the worst time of year. So late April to early May is usually when the middle of the season is getting underway and what you’ll start to get is a co-occurrence of Birch, and then with Oak, and these are usually the largest numbers that we get of pollen throughout the year, in face.

Patrick Verel: Now there’s typically a certain sequence that the plants follow, right?

Guy Robinson: Yes, absolutely. There is a set sequence, so in that respect the pollen every year is very predictable. So we’ll start out, sometime as early as February we’ll start to see Cyprus pollen that may be mixed in with Elm and Alder and sometimes a bit of Maple. The Maple will then continue to increase and the Cyprus will probably hit it’s peak sometimes in March. Then you start to see other species begin to join in as the Cyprus’s are declining.

Patrick Verel: Talk to me about catkins, which sounds like a delightful cartoon character.

Guy Robinson: Catkins are actual the technical term we use for these structures, the structures that carry many flowers on the trees as they’re releasing the pollen into the air. But what I noticed last week, I noticed in Manhattan here that there were just huge amounts of catkins that had already fallen from the Oak trees. Now this tells me that probably we’re passed the peak for Oak and this tells me also that we’re probably past the peak for pollen in the Manhattan area. There may still be a peak to come in the northern suburbs but I think we’re passed some of the worst of it already, because so many of them are already on the ground, which tells us that the trees have already released the pollen and have dropped the structures that do the job of releasing them.

Patrick Verel: So it’s fair to say to say that if you’re somebody who’s allergic to this type of pollen, that if you’re walking around in the park and you see these on the ground, that might bring you a little bit of sense of relief. Okay, the peak has passed, I might be feeling better in the next few weeks.

Guy Robinson: Yeah that’s true. Certainly if you’re allergic to Oak. If you’re allergic to Hickory, well your trouble is about to begin.

Patrick Verel: Now you monitor a couple of different stations around the New York city area. Can you talk to me a little bit about the differences that you see between the two of them?

Guy Robinson: So we have a station in here in midtown Manhattan on 60th street ,and we have another one up in Armonk, up in the northern suburbs. Now typically, we’re going to see the same sequence of pollen occurring as the season kind of unfolds. So the same sequence of different species will come one after another in a very predictable pattern. The main difference I would say is that typically the 60th street midtown station will start seeing things a day or two early. It doesn’t always happen that way, but usually they’ll be just a little bit earlier.

Patrick Verel: Is there any one kind of pollen that is the one that really drives people nuts when you think about allergies, because this is often what gets people talking about it is when there’s high counts of this stuff.

Guy Robinson: Yeah the ones that are often the real trouble makers … There’s several actually, but the big ones probably are birch and oak and I would say there is also ash, which you don’t usually think about a great deal. There’s also London plain, which is common in the city because so many street trees are London plains. They’re otherwise known as Sycamore, but we also get a lot of Pine pollen, but those don’t tend to me troublesome in terms of allergies.

Patrick Verel: So going forward, what kinds of pollen will we be seeing?

Guy Robinson: We’ll be getting a little bit of grass. We’ve seen a little bit this month already, which is not unusual, but it’ll start to increase towards the end of the month. The grasses, and then will continue into June. There’ll be a second season for grasses that occurs after the summer, so there’s usually a gap in the summer where we don’t get any pollen at all, then we come to a second grass season, which usually starts in around September or October, and then we get the largest amount of grasses. But for the rest of this month, we’ll start to see those grasses coming in for that first season, and then we’ll start to see hickory and walnut and a couple of other late season trees.

Patrick Verel: Is there anything about the northeast that’s unique when it comes to pollen?

Guy Robinson: I wouldn’t say unique exactly, but when you get into what we call the mid latitudes, you tend to get a lot of wind pollinated species. As you go further south, into the subtropics and then the tropics particularly, many more species are pollinated by insects, and those tend to be much less troublesome. Most people who have allergies badly up here in the northeast, if they were to go to the Caribbean for a vacation, they would probably find they don’t get allergies there.