So here’s an issue no official sources seem to be talking about: Plane Tree dust.
I work as a gardener in Central London and for me, and all gardeners who work beneath plane trees, the orange dust from Platanus hispanica causes huge issues. It leads to not just sneezing and itchy eyes, but uncontrollable coughing fits. I see colleagues of mine brought to their knees by coughing. I see their red eyes and hear constant sneezing. I’ve even heard cyclists complaining about it to each other as they whizz past.
Most worrying is that I think it may be getting worse, but there seems to be very little official recognition that there is a problem. A scout around the internet for information turned up almost nothing. The occupational therapist at my work had never heard of it. So I wanted to find out what is actually happening? Is this really only a problem for gardeners? Is climate change increasing the problem? And how worried should we be about it?
In this blog is everything I’ve discovered and I’ll be contacting anyone who might be able to tell me more, but if any of you out there have personal experiences or professional knowledge about plane tree dust, then please comment on here, or write to me – my email is at the bottom of the page.
Plane trees are beautiful, with their flaky bark, palmate leaves and dangly seed pods. They were planted in great number in London in the 18th century and are considered of great importance because they provide a huge canopy, are generally tough and resistant to pollution. There are roughly 115,000 in London. That makes up 1.4% of the capital’s tree population, but due to their huge canopies, they make up the biggest leaf area of any London tree species.
However to anyone working outside in London, they are known as serious trouble. Every gardener I have spoken to has described them as being their biggest hindrance to doing their job. Plus I know of a tree surgeon who refuses to work with them after being put in hospital with asthmatic fits. Around Chelsea Flower Show time, people talk about the Chelsea Cough. In Australia there have been protests and demands that the trees are banned.
There is some dispute over what causes this problem. When I started looking into this, I found plenty of research into Platanus pollen, but pollen isn’t the problem, it is the orange dust that floats down like snow and gets into the grass and coats the soil. The dust is largely made up of a fluffy coating in the seed pods (it helps the seeds float, like dandelion (Taraxicum officinale) seeds) but it also contain trichomes, tiny hairs that coat the leaves. These trichomes are thought to be the main cause of coughing. As James Wong explains here, antihistamines won’t work against trichomes, they are an irritant, which is more serious than an allergy.
The Reasearch
I found three studies into the effect of plane trees on the public. They include research from Australia, France, Spain and Italy. The effect of plane trees is acknowledged as often extreme, however all these studies focus on the effects of pollen. Some mention that it is odd that the reaction to plane trees happen outside of the pollen season, all find that plane tree pollen only affects a few people.
There are also scientific studies into trichome regulation, but these don’t seem linked to allergies.
Conclusion
Well, that’s all I have and it’s not much at all.
What worries me is that I think with the change in climate, this problem is getting worse. Because there are no studies I’m only going by what long-standing colleagues say, but the effects are so extreme and the awareness so small it makes me think it can’t have been as bad in the past.
Is global warming having an effect on the production of trichomes and the seed bristles?
And if so, do trichomes have an effect that lasts beyond the coughing fits – since prolonged exposure to dust can lead to long term health issues, should we be worried?
I shall continue to investigate and update later, but if you have information or personal experience, then either comment below or contact me via email on
therealtetrapod @ gmail .com
Tentative Plant Scientist 
These awful trees make me sicker every year because they get bigger and bigger and bigger with each year and the canopy spreads more and more.
it’s like being drowned in a shower of irritants that land me in the hospital many times unable to breathe. Unfortunately those in charge of the trees refuse to even thin the overreaching branches and God forbid reduce the canopy some so that we could survive their onslaught of irritants they drop every year ! The shade is unbearable so much that the house is like a dark little cave where nothing grows.
In the garden everything is buried below unending biomass piled up from the ever larger plane trees. if any little shoots do get through, the shade quickly kills that effort. This ever spreading dense canopy ensures there’s no damn light below. I hate the four trees that each alone is twice the size of my modest house!
That sounds awful, I’m so sorry. And you’re right, the leaves just don’t rot down like other leaves which can be a bit of an environmental nightmare.