Indoor AQ Monitors 2018Q2

Some new AQM on the market and some older devices changed positions from pre-order to order and some others unfortunately they didn’t make it and now they are unavailable. A PDF version of the table is available here: SeeTheAir_Comparison_AQM 2018_Q2

comparison air 2018 Q1

  • Prices may vary during time.
  • Some Companies don’t specify on their data sheet if their devices are capable to measure PM2.5 or PM10 and they just mention the word dust.
  • Some other companies say: Our product goes beyond CO₂ by analyzing substances that directly affect your well-being by measuring VOCs. They aren’t clear if their devices have CO₂ sensor.
  • Some of the devices are AQI Monitors and Air Purifiers Combo. On this list you can only read the features as an AQI monitor.

Giveaway AQ Monitor

It has been over a year since the last time I used the Awair an Air Quality Monitor. As a result, I believe it is time for someone else to use it instead of waiting inside its box. I am offering it for free to a lucky reader of my blog.

It is not a new product but it has been well maintained by me. It is a great AQ Monitor with a lovely design for monitoring CO2, Temperature and Humidity. You can read my comparison tests 12 and 3. It features a PM sensor which unfortunately isn’t very good (Don’t rely on the PM sensor too much) and a VOC sensor in case you would like to get a broader picture of gases inside your house. The device comes with a EU Type C plug.


To be able to win the AQ Monitor you have to follow me on Twitter and retweet the original tweet that includes the hashtag #SeeTheAirAQM.

Additionally, for those who will leave a comment below they will have double chances of winning, remember to mention your twitter name.

The winner of the prize draw will be selected at random on 15th April 2018 at 12pm.

Shipping costs and possible customs fees are not included. The winner has to pay for the parcel and he/she is free to choose a postal service of his/her choice. The box with the device and cable weighs 920grams/2.03pounds.

VOC & Formaldehyde Correlation

Many times I have mentioned that a simple VOC sensor isn’t enough to determinate if the air quality is good or not especially in interior environments. Formaldehyde CH2O is a VOC and since I have an AQ monitor uRAD A3 that features both a Formaldehyde sensor and a VOC sensor I will try to find out if there is a correlation between them.

I have been monitoring my house for Formaldehyde for over a month now by leaving the AQM on including while I was out on a trip for 4 days and during that time the house was well closed. This kind of experiment allowed me to determinate if my furniture, paint, etc outgassing Formaldehyde.Read More »

uRAD A3 vs AirVisual

I have featured both devices on my blog uRAD A3 & AirVisual and since both devices allow the user to download a .csv/.txt file with all the registered measurements and as they both have a laser PM2.5 sensor and a CO2 sensor, I decided to compare both of them farewell.

Although I connected both devices side by side on 28/02/2018 at 10:40 am, I will compare the measurements from 5th March 2018 to 7th March 2018 because I wanted to allow the devices to adjust on the new environment, which was my bookcase.

Each device takes measurements at a different time rate. AirVisual, for example, was set to take measurements every 10-15min and uRAD every minute. Unfortunately, I couldn’t set both devices at the same time rate.

Read More »

Review: uRAD Monitor A3

Who says that everything is made in China or USA? Well, let me introduce you the uRAD Monitor A3 an Air Quality Monitor which is made in Romania, Europe since 2012. The design, firmware design, server software and big data database maintenance and development are all made there and amazingly enough even the unit that I have on my hands is made personally by the CEO Radu Motisan. As a result I am very proud to review it and talk about the cons and pros.


  • Temperature Sensor -40°C to +85°C / 40°F to 185°F
  • Humidity Sensor RT 0-100%
  • Air Pressure Sensor 300-1,100mbar
  • VOC Sensor 0 mg/m³ to 100 mg/m³ reducers – 10 mg/m³ oxidizers
  • PM2.5 Sensor 0 μg/m³ to 1000 μg/m³
  • Formaldehyde Sensor 0 ppm to 5 ppm
  • Carbon Dioxide Sensor 400 ppm to 5000 ppm
  • γ (gamma), x-rays Sensor 0.01μSv/h to 9999.99μSv/h
  • WiFi or LoraWAN or Ethernet or GSM
  • Built-in Speaker
  • LED Light

Read More »

How NO2 affects your health?

I can guess with high accuracy that your answer to the question of the image above is the Healthy Lung. If I guessed right, which I did, then I will advise you to be careful about what you breathe.

These are some gases that chemically poison the body’s oxygen transport systems, preventing oxygen from reaching the body tissues like the Carbon Monoxide CO, which combines with haemoglobin and blocks its ability to carry oxygen around the body, but there are some other gases that cause asphyxiation by producing severe irritation in the air passages and lungs like the Nitrogen Dioxide NO2.

NO2 dissolves in the moisture on any moist tissue surfaces, and forms strong acids or alkalis which then burn the delicate tissues. Health effects are related to its ability to dissolve in moisture to produce Nitric Acid which is a strong mineral acid.Read More »

3 Technologies to Measure Particulate Matter

In this article we will analyze all the available Technologies to Measure Particulate Matter such as PM1, PM2.5 and PM10. This article is trying to answer which type of technology is better and how they work.

First: The Laser Diffraction

Many companies use this kind of technology for their PM sensor like IQAir-AirVisual, Xiaomi, Dylos, Kaiterra-LaserEgg etc. With this technology the sensor is able to figure out the size of the particles and the quantity. This technology is also known as Optical Light Scattering because each time a particle passes and hits the laser beam then an optical sensor, like a camera’s sensor, and with the help of an algorithm will translate how many particles were in the air at that moment. This technology is very stable and the sensor can take measurements fast, typically between 3-10 seconds.

One of the problems that the laser diffraction technology has is how each pollutant is determined by the sensor. For example Black Carbon BC which is an absolute black colored pollutant will absorb some of the light from the laser beam, so it doesn’t react the same as will do a white colored particle which will reflect more light. This problem can be solved with the right algorithm but again the device won’t be able to use the right algorithm for the right pollutant unless we told it which one to use.

Second: The Infrared

The infrared technology is common in less expensive indoor AQ monitors like Foobot, Awair etc. Basic the sensor is a small chamber with two holes on opposite directions which allow the air to pass through. An infrared light is crossing the air there and an infrared sensor is able to determine the light intensiveness. Dimmer light means that pollution is passing through the holes.

One of the problems that the infrared technology has is the estimation of the particles, this technology can’t count particles, it is just guessing. There could be 1200 PM2.5 particles or 300 PM10 particles or 1 gram of sand, either way the infrared sensor will give the same measurement.

Third: The β Beta Attenuation Mass

The β Beta Attenuation Mass technology or BAM is as big and expensive as the length of its name and very uncommon to be found in an indoor environment. Governmental bodies use this kind of instrument like in UK, China etc. Basically, it samples air on a blank piece of filter paper. Then the trapped PM pollution on the paper will be bombarded with some beta radiation. Some of the PM2.5 pollutants absorb the radiation, and the differences on the other side are measured. After that, some mathematical equations are used to determine how the weakening of the β rays translates into a mass of PM2.5. Attenuation is a general term that refers to any reduction in the strength of a signal and in this case the β radiation. The BAM technology is far more accurate than the other two technologies.

There are some disadvantages with this technology too. Humidity can affect the results so proper calibration is always needed.

Some general info to have in mind that applies to all three technologies. If you have two units of the same technology side-by-side, you will still get small variations in results even between 2 BAM monitors. That’s simply because particles in air, especially PM10, aren’t necessarily uniformly dispersed.