Tag: air quality

Get yourself an air purifier

The air quality in the Midwest sucks a lot right now, due to smoke coming from forest fires in Canada. You need an air purifier to clean the air inside your home.

I’ll describe what I personally look for in an air purifier and guide you to a couple of models. I can only recommend the one I have, since it’s one of two that I’ve used, but I would rather have a different model.

I use a Coway Airmega 200S. I bought it for about $180. I bought this model because it can cover a large room (my entire studio is about 550 s.f.), has “auto” and “eco” modes, an air quality sensor, and three filters (a washable screen, a charcoal filter to remove odors, and a HEPA filter).

ComEd customers should look for Energy Star-rated air purifiers because there is a $50 rebate. Even if the manufacturer doesn’t specify or show the blue logo, it may still be rated, including the Coway Airmega 200S!

What I look for in an air purifier

  • Auto mode. I want the machine to have a sensor to turn itself on to clean the air when it detects the air is dirty, and to run at the fan speed commensurate with the dirtiness.
  • Eco or sleep mode. This runs the fan at an even slower speed and I use this when I’m not home.
  • Washable screen or pre-filter. This catches larger objects like dirt and hair and presumably prolongs the life of the other filters. It also satiates the desire to clean and know that things are clean after you’ve cleaned them.
  • HEPA filter. This should go without saying. If it doesn’t have this, it shouldn’t be labeled an air purifier.
  • Reasonable filter prices, and available. I am skeptical of the proliferation of identical looking air purifiers on Amazon and their ability to consistently stock replacement filters six months and 12 months from now. I don’t want to be in the position where I’m questioning if a given filter is the right one for my air purifier model.
  • Filtration rate, expressed as CADR (higher numbers are better). There are many ways that air purifier companies will describe this, the most common or first shown being the floor area of a room. The floor area, however, is not a filtration rate. My favorite way is when the manufacturer has a graphic showing how many air changes per hour the air purifier can manage.

In the graphic below, the air purifier was advertised as being able to cover a living area up to 1,837 s.f., which is the size of a four-bedroom apartment, but it could only change the air once per hour, which is too slow to respond to changes in air quality. On the other hand, in a 527 s.f. space, which is about the size of my studio apartment, the air purifier can manage five air changes per hour – I think that’s more than sufficient.

Which air purifier should you get

Note that many air purifiers have a “smart” option, which means they come with wifi and an app. Sometimes these apps connect to Google or Alexa voice assistants. Rarely will they connect with Siri, due to higher Apple licensing or certification costs. This is unnecessary but could be fun to use to track PM2.5 levels in your home if you don’t have a standalone air quality measuring device.

All models listed are Energy Star rated and are ones I would get my for studio apartment

IKEA also sells air purifiers but I haven’t determined if they are Energy Star rated.

ComEd customers can apply for their $50 rebate as soon as they purchase an Energy Star rated air purifier.

I ran errands and measured the CO2 concentration everywhere I went

I am starting to take my Adanet CO2 concentration monitor everywhere because I want to see which stores, restaurants, and offices have “fresher” air. The other day on December 20, 2022, I visited a BMO Harris bank branch and a Target store, and I took note of the measurements in three locations within my apartment building.

My goal is to take two readings in each location and photograph the second reading. The photograph provides the proof of the reading in the location I specified as well as a timestamp and GPS that only I can see.

I also took an outdoor reading to establish what the ambient level was that day:
421 parts per million (ppm), which is exactly what the global ambient level is!

Keep in mind that a typical reading in my studio apartment is around 650 ppm.

An outdoor reading of 421 ppm, for reference.

BMO Harris bank branch – 115 S LaSalle St

This is a large bank branch with half a dozen teller stations and a significant business banking area. There were two tellers, a handful of other staff, and myself and another customer – the person density was very low.

Reading: 614 parts per million (ppm)

The CO2 reading was 614 ppm at a BMO Harris bank branch in downtown Chicago.

Target – 1 S State St

A busy department store is where I was most excited to take several readings. I took four readings, all on the second floor.

  1. Men’s clothing department, three minutes after entering the store: 646 ppm
  2. Another area in the men’s clothing department, three minutes later: 785 ppm
  3. A dressing room, six minutes after the previous reading: 913 ppm
  4. Automotive accessories aisle, 15 minutes after: 961 ppm

To give you another reference point, the readings have regularly exceeded 800 ppm – and have exceeded 1,000 ppm if I burn some food – when I’m cooking in my studio apartment. As I write this from there, the reading is 623 ppm.

I was pleased with these numbers at Target; I’m not an expert on assessing air quality but the Centers for Disease Control writes “that indoor CO2 concentrations no greater than 700 parts per million (ppm) above outdoor CO2 concentrations will satisfy a substantial majority (about 80%) of occupants” in office environments – or about 1,121 ppm.

My apartment building

I took three readings in my apartment building:

  1. One of the two bike rooms: 619 ppm
  2. An elevator (I had to visit a lot of floors to wait until I could get a second reading, which also meant the door opened a lot): 788 ppm
  3. Gym (which has two rooms, and I took the reading in the larger room that had fewer people at the time): 596 ppm

Say hello to Adanet, my new CO2 concentration monitor

I acquired a homemade and open source Adanet carbon dioxide (CO2) monitor from a friend in Chicago and tested it on a short trip on the Brown Line ‘L’. The Adanet monitors the concentration of CO2 in the air, in parts per million, which is a proxy for how “fresh” the surrounding air is.

Monitoring CO2 concentration became a more common activity and point of discussion since the COVID-19 pandemic began. A key way to reduce risk of transmission is to have “fresher” air. I’ll establish that “fresher” air is replacing air that has people’s outgoing CO2 with air that has less CO2, namely outdoor air.

(Another reason to monitor CO2? Excessive CO2 can lead to a decline in cognitive ability and sleep quality.)

I conducted an unscientific test of the “freshness” of the air inside a single Brown Line car on my trip between the Western and Belmont stations. I took five readings, which was the most I could take given that the Adanet refreshes every three minutes.

Map showing gray markers indicating where readings were taken. The trip started at the Western Brown Line station and the last reading was taking just before the train pulled into the Belmont station.

The ambient global measurement of CO2 is 421 ppm, measured in May 2022.

On the transit trip, the lowest reading was 475 ppm, which was taken while the device was in my coat pocket before I boarded the train at the outdoor station.

The highest reading was 680 ppm, when the train car had the most people on it during my short trip.

I have been checking the Adanet since getting home two hours ago.

  • I left it in the hallway outside my apartment and a single reading was 556 ppm.
  • Inside my studio readings have been around 650±20 ppm.
  • The highest reading since I got home has been 830 ppm and this is because I partially burned a quesadilla, releasing additional carbon into the air (my standalone air filter also turned on automatically to deal with the reduction in air quality).
  • I opened the balcony door to let fresh air in and 15 minutes later the reading dropped to between 671 and 692 ppm (the more readings the better).