The First Smart Air Quality Tracker?

It is now almost 50 years since the first microprocessor, but it continues to revolutionize new areas. (First MPU = Intel 4004, in 1971, which Intel designed for a calculator company!) In concert with Moore’s Law and now ubiquitous wireless two-way wireless data transmission (thanks, Qualcomm!). smartphones have become a basic building block of many products.

A companion to explain what’s in your air, anywhere. Flow is the intelligent device that fits into your daily life and helps you make the best air quality choices for yourself, your family, your community.

Source: Flow, by Plume Labs | The First Smart Air Quality Tracker

Here is a quick review I wrote of the “Flow” pollution meter, after using it for a few months.  I wrote it as a comment on a blog post by Meredith Fowlie about monitoring the effects of fires in N. California.

I started with a particulate meter (a handheld model, not PurpleAir). Now I also have a Plume Labs unit running full time. It measures PM2.5, but also PM10, NO2 and Volatile Organic Compounds (smog components). https://plumelabs.com/en/flow/
After a few months of use, I am impressed by the hardware. It shows very sharp peaks when we are cooking or something else disturbs indoor air. Sensitivity and consistency are both high.
Another advantage is that it is very portable. It’s actually designed to be worn on your belt while commuting, to discover local hot spots. All data is GPS flagged if you turn that feature on. I think their hope is to build time/location history for many major cities, using crowdsourced data.

Accuracy is harder to assess. The PM2.5 readings are much lower than on my other meter, and are usually below 5. We keep it in our bedroom, and while we use a Roomba frequently, I am skeptical about such low numbers. Readings above 20 happen less than once a week. But as usual with these devices, because outside meters (as discussed in the article) vary so much there is no way to calibrate it against other information.

The software that goes on your phone is “slick,” but it presents the information in a very limited format. It is optimized for use by commuters/runners. If you want to look at your data differently, such as over multiple days, you are out of luck.
Price is about $180. I compare alternatives for quite a while before selecting this one. It is considerably less expensive than other sensors that go beyond particulates.

Modern smartphones now allow revolutionary advances in portable measurements and in citizen science. They have huge computational power with highly standardized interfaces for application-specific hardware, such as pollution monitors, to link to. Instrument makers now need nothing more than a Bluetooth radio to give their devices graphical displays, real-time tracking and alerting, location flagging, months of data storage, and many other features that used to add hundreds or thousands of dollars to instrument prices.

Pollution measured over the course of a day as the owner travels. This is the display shown on my phone.

One Day, a Machine Will Smell Whether You’re Sick – The New York Times

Sniffing disease markers is a fundamentally promising concept. We know that dogs have very good smell, so that is an existence proof that something interesting can be detected in the air. (In my family’s experience, human smell can also become amazingly good, at least for pregnant women!) In fact, if B.F. Skinner were still alive, I wonder if he would be training pigeons to sniff out disease?

But although air is feasible, it does seem like blood is a better choice because it is likely to have stronger signals and lower noise. Air-based sensors would be non-invasive, so perhaps that is why some groups are pursuing air.

…a team of researchers from the ..Monell Chemical Senses Center and the University of Pennsylvania [are working] on a prototype odor sensor that detects ovarian cancer in samples of blood plasma.

The team chose plasma because it is somewhat less likely than breath or urine to be corrupted by confounding factors like diet or environmental chemicals, including cleaning products or pollution. Instead of ligands, their sensors rely on snippets of single-strand DNA to do the work of latching onto odor particles.

“We are trying to make the device work the way we understand mammalian olfaction works,” … “DNA gives unique characteristics for this process.”

Judging by research at UCSD and elsewhere, I envision tests like this eventually be run as add-on modules to smartphones. Buy a module for $100 (single molecule, home use) up to $5000 (multiple molecules, ambulance use), and plug it into your phone. Above $5000, you will probably use a dedicated electronics package. But that package might be based on Android OS.

This is also another example of Big Data science. It could be done before, but it will be a lot easier now. Blood collected for other purposes from “known sick” patients could be used to create a 50,000 person training set. (The biggest problem might be getting informed consent.)