The Latest in Wearables Is the Flow Air Pollution Monitor

CC BY 2.0. Flow and app/ Lloyd Alter

I want to know what I am breathing and I don't leave home without it.

We talk a lot about air quality on TreeHugger, and lately we have been preoccupied with particulate matter, the tiny bits called PM2.5 that get into your lungs and throughout your body. (See our stories on PM in related links at the bottom.) These are barely regulated, there are few standards for them, and really no minimum threshold for safety. For years, when everyone smoked and burned coal for heat, they were background noise, but recent research has shown them to be a major health hazard, taking years off our lives.

Flow 2 on table

Flow 2 on table/CC BY 2.0So I was really intrigued when I learned about the Flow from Plume Labs. It's a little device that measures Volatile Organic Compounds (VOCs, from solvents and chemicals all around us), Nitrous Oxides (NO2, mostly from car exhaust and burning fossil fuels), and Particulate Matter in various sizes (PM1, PM10 and what are probably the deadliest, PM2.5). I was curious about the air quality in my home (particularly when cooking) and in the streets. The new upgraded Flow 2 was just released when I started looking, and costs US$ 159. It was not available in Canada at the time but it now is through a partner.

Flow on my bike

Flow on my bike/ Lloyd Alter/CC BY 2.0

The device itself doesn't look like your usual scientific instrument; it is a nice little bit of industrial design covered with a pattern of holes and a rubber strap so you can fasten it to your pack, belt or bike. It has a tiny fan that goes on and off; for a while it was driving me crazy wondering what that noise in my office was. (Flow says, "If you listen closely, you’ll soothe your eardrum with its gentle whirr." I find it annoying and moved it farther away on my desk.)

And what magic is going on inside that little thing! It measures particulates by firing a laser beam at the air brought in by the fan. "Every time a particle is hit, light is dispersed – disco-ball style. This micro light show is detected by a photovoltaic cell that translates the laser’s deflected beams into electrical current we can measure."

The NO2 and VOC sensor is a sort of toaster.

A tiny membrane is heated up to 350 degrees (!), and mercilessly disintegrates any NO2 or VOC molecules passing through. This lets us measure the variations in energy required to maintain the membrane’s temperature stable as it’s happily toasting away.

They somehow do that with the tiny little battery, then calibrate it all to account for "drift" caused by temperature or humidity. They run programs based on neural networks that detect patterns, turn them into data, and combine them into their Air Quality Index (AQI).

All of this is sent to your phone, tied into the GPS, and sent up into the cloud. "This is how we’ll be able to start layering our users’ data on top of all the maps we’ve already built from public data. And that, my friends, will truly be the next leap forward in air quality monitoring!"

Data download looks like this

Data download looks like this/ Lloyd Alter/CC BY 2.0

Note that this is not anonymous data but is tied to your Flow. My iPhone is set to give the Flow app location data all the time, so somewhere in Paris a bunch of scientists know exactly where I have been and what I have been breathing. (Flow warns you about privacy when you download your data, and their privacy policy is explicit, but this may be a concern for some.)

However, there is a real benefit to sharing this much detail with Plume Labs. I thought some of the numbers were odd and got on a chat with Alexandria in customer support; she and I both looked at the NO2 numbers and were not happy. She suggested that I get the vacuum out and clean out the machine, that perhaps something got stuck in it. Sure enough, the NO2 readings became more consistent. To add to the things I like, really knowledgable and efficient support.

Trip to school

Trip from home to school/ Lloyd Alter/CC BY 2.0

But the show really starts with the app, which is extraordinary. In this shot you can see my trip from home to Ryerson University on 21 January. You can slide your finger across the time scale at the bottom and the spot where the reading is taking place shows up on the map above.

food trucks

Lloyd Alter/ Food trucks at the University of Toronto/CC BY 2.0

I was particularly interested in the air quality in the University of Toronto because I have been complaining for years about the diesel powered food trucks parked on St. George, the main north-south street on campus. But interestingly, according to the Flow, particulates are highest just before I turn south, in a spot where not much was happening at all. Then it all goes green again until I hit a main intersection where there is a lot of construction going on and a lot of traffic (and a lot of Ryerson University students).

Dinnertime spike

Spike in the evening when dinner is on the stove/ Lloyd Alter/CC BY 2.0

I have become obsessed with this and carry it everywhere with me. I see weird spikes of NO2 inside my home, and am checking the gas boiler flue; am I getting backdrafts? But I am also happy to know that I am adding data that will be used to create a map of air quality where I live.

Finally, there is the question: How accurate is it? Flow answers this with their usual style, writing, "Accurate compared to what?" It is not an expensive lab monitor or monitoring station.

Flow was built to be road-worthy, for the streets but not for the labs. As such, the advances in electronics and self-calibration Plume Labs was able to achieve make it a truly best-in-class wearable device in many respects, accuracy included.

What I love about it is that I don't have to do anything, don't have to press a button when I want a reading. I just have to carry it around and it measures all the time. I am not getting lab-grade measurements but I am getting a lot of information that is useful to me; Plume says it is really good at:

  • Helping users understand the pollution levels they are exposed to in terms of thresholds corresponding to different health risks.
  • Providing context and insights to help users understand their exposure in relation to their environment’s average as well as the rest of the population’s average.
  • Accurately detecting variations and peaks - from a personal health perspective, consistent, dependable and real-time detection of air quality suddenly changing thresholds is on the very top of the priority list.

So far, I am very impressed, and will keep carrying it everywhere.