I purchased an air quality monitor in late 2021. I was inspired to do so because of bloggers like Andres Gomez Emillson, who has a great video on how many particles the CA wildfires produce, as well as the anonymous blogger Dynomight, who has a fantastic post called better air quality is the easiest way not to die.

The device gives measurements for particles of 2.5 nanometers in length (PM2.5), particles of 10 nanometers in length (PM10), volatile organic compounds (VOCs), and a number for the air quality index, or AQI (which is entirely based on the level of 2.5 nanometer particles present as far as I can tell.)
I’ve had fun messing around with it to both optimize my indoor air quality and to see how polluted different places are.
The problem
If you are consistently exposed to lots of fine particles in the air, you get lung and heart problems.
According to the EPA, a PM 2.5 level of 12 is the upper limit for healthy air. If an area is at an average of a 12 over a 3 year period, they are healthy by EPA standards.
Dynomight says you really want the PM 2.5’s to be at an average of 5 or below to prevent health problems. I haven’t done my own research here. I use the 5 or below upper limit in my home.
It’s a pernicious problem because you can’t tell a difference between healthy and harmful levels. At least, I can’t. I only notice something’s up when it’s obviously smoky in a room. I wonder how many people have no idea they are inhaling PM2.5’s in the 15-40 range every day of their lives. Then they have heart and lung problems at 65, and assume it’s only because of bad luck.
Here is a screenshot from Dynomight summarizing the problem with small particles:

One calculation from that post particularly stood out to me. It refers to how particles shorten life expectancy (A DALY is a disability adjusted life year, or the loss of one year of full health)
A life-long exposure of 33.3 PM2.5 costs 1 DALY […] Moving from somewhere with no particulates to somewhere with a level of 100 costs 3 DALY.
How I clean my air
I have a cuboid, of course! It’s a beast-mode homemade filter unit that costs way less than a comparably powerful unit you can buy pre-made. You lose a lot in the aesthetics department though, so if that’s an issue you gotta pay up.

I also have a three other filters, two in the bedroom and one downstairs in my office. Two of them are small Levoit’s and one is a midsize from Coway. I bought those before I’d seen the cuboid light. They work pretty well, but they are expensive. You can also make cheap and effective filters using box fans, but they are noisy.
NYC can produce some serious pollution. The AQI outside is often between 50-100, which means PM2.5 levels between 12 and 35. When it’s like that, our indoor levels will creep up quickly if we have a window open and no filters running. With our system, PM 2.5 levels stay consistently at 5 or below.

Things that make my air pollution detector go wild
Once you start playing around with the air quality monitor, you realize that evil particles are all around you and constantly trying to kill you. Mostly when you are frying things, or when you leave the window open for too long in the busiest city in the country.
Pan frying buckwheat pancakes
Pan frying just about anything, including just vegetables, throws off some scary numbers.
But Buckwheat is king. Once they get smoking, ol’ TemTop acts like I am standing next to a burning paint factory. Within seconds it cycles from “unhealthy for sensitive groups” to “unhealthy” to “hazardous”. It maxes out the machine and does everything but alert the paramedics.

Buckwheat pancakes are amazing though, it’s all worth it.
The NYC subway
It’s just bad, bad, bad down there.


It’s so bad that Dynomight calculates that a daily commute from Newark to Manhattan takes a 1/2 year off your life expectancy.

Places that are mostly okay
Prospect Park in Brooklyn.

JFK Airport.

Places that are squeaky clean
The Metropolitan Museum of Art

A note on VOCs
VOCs are less of a problem than I would have thought given how much I’ve heard about them in the press. New furniture doesn’t throw many off, nor did our new vinyl flooring in our house. New wall installation was fine. Low VOC paint was as advertised — it made the number go up for a bit but was back down to negligible levels once it dried.
My in-laws basement has really high VOCs for some reason. Cracking a window makes them drop to almost nothing within a minute or two.
I feel like I have a lot more to learn around VOCs, I haven’t spent nearly as much time looking into it as I have small particulate matter.
Stay safe in there!
I didn’t give much thought to indoor air pollution until recently. Now I realize there are simple, low effort ways to breathe cleaner air. That makes me happy.
For the curious (and for those that don’t want to read the Dynomight article I keep going on about), here are that person’s takeaways on how to improve indoor air quality, most of which I didn’t get into here:

Here’s to having clean air in 2023 without obsessing about it and turning into the Howard Hughes of fine particulate matter.