Breathing Index 🫁

Pollen and breathing

Every pollen app can tell you pollen is high. In April that's true every single day, which makes it about as useful as a weather app that says "yep there is weather." If pollen messes with your breathing, you need to know which plant is your mortal enemy.

Breathing Index helps you identify your mortal enemy(s). This page explains why you can have a whole tree species as a mortal enemy.

Hay Fever vs Allergic Asthma

Pollen sets off two conditions that can get lumped together. Hay fever (allergic rhinitis, if you're billing insurance) lives in your nose and eyes: sneezing, itching, congestion--I personally get this from pine pollen, which you don't need fancy data APIs for; you just have to notice a slight breeze blowing through a loblolly pine tree and producing a giant cloud of yellow dust. Allergic asthma is the other condition, and you can even have allergic asthma without so much as a sniffle, though most folks with allergic asthma get the nose stuff too. It happens when airways get inflamed and the muscle around them clamps down, leaving less room for air, which causes breathing to get difficult. Plenty of people have both, and a bad pollen day can cause either or both; the ACAAI has a good plainspoken rundown of the hay fever half.

Identifying the plants that hate you

Allergies are specific--they run in plant families, not in "tree pollen" as a category (or, if you're somehow allergic to all of it, I hope you can afford to move to a desert). If you go to an allergist, they're gonna test you for oak, maple, juniper, and friends separately, because different plant families make different proteins, and your immune system keeps separate grudges. Oak and maple pollen both proliferate in April across the northern half of the country (down south, oak can get going as early as February). If oak is your trigger and maple isn't, a "tree pollen: high" banner is wrong for you half the time!

Even if they both happen in April, oak and maple rise and fall on their own schedules, so there are days oak pollen counts are high while maple counts are low. If you rate your breathing on enough days, the app may find that it's only oak that triggers your asthma. Or maybe it's truly both and you can declare war against trees.

Saruman raising his arm as Isengard's army marches: the last guy who declared war on trees.

One honest limit: the app can tell oak from juniper, but it can't tell birch from alder--those are such close cousins that your immune system doesn't really distinguish them, and neither will your breathing log.

Pollen counting is complicated

Real pollen counting is surprisingly manual: stations run by the National Allergy Bureau catch grains on a greased rod or a strip of sticky tape and count them under a microscope, in grains per cubic meter of air. Raw counts are difficult to interpret because the thresholds differ per plant on the NAB's reporting scale: twenty grains of grass per cubic meter already counts as high, while a 'high' level of tree pollen requires ninety grains. A thousand grains might be routine or apocalyptic depending on the species.

So the app uses a 0–5 index instead, where the scale means the same thing across species: 0 is none, 5 is as bad as that plant gets for the people it affects. The steps describe people, not grains; at 1, only seriously pollen-sensitive folks notice anything, and by 4 most people with that allergy are having a day. Today's values come from Google's pollen model, which simulates what's in the air from land cover, plant seasons, and weather rather than counting grains directly. When there's no live value to show, the app will show you a season calendar with historical data instead, since it's better than nothing.

The calendar is broad: it has nine US regions, three species, month granularity, and 'no data' where a species isn't present. The full table and elaboration are on the calendar page.

What to do with all this

If you're reading this mid-flare: I'm sorry, I know exactly how that goes. When you can, open the app and rate your breathing from 1 to 4. Do that for a few weeks and it starts showing you which of these plants hates you, and at least next time you'll be able to plan for & mitigate it.

Breathing Index is a breathing lens on public air data — not medical advice. Trust your symptoms and your asthma action plan over anything on this screen.

Sources