So I am conducting a home experiment by observing the CO2 levels during night and my experiment focus on two fundamental questions.

• Is the atmosphere inside the house getting worse during night?
• Can specific plants help the air quality during night?

This experiment needs time, so you have to be patience till the experiment ends at the end of this month (February).

Stay tuned.

There are so many devices available right now on the market that measure PM2.5 (as we can see on this post) but there aren’t all of them the same. In my opinion PM2.5 is the key for air quality monitoring. Different sensors, different manufacturers and also different software can give different results.

Let’s try to analyze them and see which of them are accurate and which ones aren’t. In order to do that firslty I will present some the sensor manufactures and models. Prices are in USD:

• Novafitness SD011 ∼23$
• Plantower PMS1003 ∼17$
• Plantower PMS3003 ∼17$
• Shinyei PPD42NS Made in Japan ∼10$ (R² ∼.83)
• Shinyei PPD60PV (More expensive than the PPD42 because it allows smaller particle detection) Used by AirBeam
• Samyoung DSM501 Korean copy of the Shinyei PPD42 ∼5$ Used by Speck
• Sharp GP2Y10 ∼15$ (Used by Awair and probably by Foobot) (R² ∼.74)
• TZOA RD02  135$-600$ Used by TZOA Wearable (R² .9253)
• Dylos DC1100 ∼300$ (R² ∼.85)
• DustTrak TSI DRX 8533 ∼3000$ (R² ∼.97)
• Turnkey Instruments Dustmate ∼3200$

 

On the table below there are some of the devices that measure PM2.5 among other stuff and have been reviewed by the Air Quality Sensor Performace Evaluation Center aka AQ-SPEC www.aqmd.gov. Focus on the R² (correlation) values on the last column “Sensors vs FRM/FEM Method”.

An R² of 1 indicates that the regression line perfectly fits the data, while an R² of 0 indicates that the line does not fit the data at all. So, closer to 1 then better results.

 

References:

http://aqicn.org/sensor

http://www.aqmd.gov/aq-spec/evaluations#&MainContent_C001_Col00=2

http://www.davidholstius.com

http://www.howmuchsnow.com/arduino/airquality/

Low cost air pollution sensors: New perspectives for the measurement of individual exposure? Madelin Malika, Duché Sarah

https://www.indiegogo.com/projects/tzoa-wearable-air-quality-tracker#/

New Year and new devices on the market. Here is the new complete list.

• 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.
• The classification of the design between Bad, Good and Very Good is based on the materials (plastic, wood, glass and metal) that they have used and the aesthetic on my personal opinion.

So, I left my home 20 days ago for vacations but I left Awair (one of my Home AQI devices) ON just because I wanted to monitor the house during all that time of absence.

Every day all the values of VOCs, CO2, Temperature and Humidity were stable and normal when suddenly on 5th of January I noticed that the value of the VOCs index climbed from 1 to 2 (Awair dispays VOCs on an index values not into parts per billion). Why did that happen? Well my first thought was that someone has entered the house without my knowledge and indeed my sister in law had entered the house secretly during night to leave some presents (btw high in VOCs) for my nieces because she wanted to hide them before the The Three Wise Men day (a traditional day when Spanish people exchange gifts).

Bottom line my Home AQI device can function more than a simple air quality monitor and gives me a glimpse inside my house even when I am not present. I guess if my house had a flood problem, I could see a spike in the humidity and if a fire started, I could see a spike in CO2.

On my previous post I have talked a bit about the air problems that Greece is facing now. On this post I will talk about my experience in Italy and more specific in Rome.

Great city with great history as well. They call it the eternal city but I will call it the noise city because they are part of the mediterranean temperament. I only had the chance to visit the city and not around but I have noticed that the air quality in Rome isn’t good at all.

Smoking: From one hand people respect and they don’t smoke inside (Strong Law) but from the other hand by the time they exit a building they will smoke and smoke non stop. Cigarette Butt everywhere on the street. I couldn’t walk outside without having someone in front of me smoking.

Cars: Vehicles are a big problem there as well. In Rome they even have many mini cars (one-two seats per car) I guess because of a parking issue that they may facing.

Metro: The air quality inside Rome’s metro was horrible, unhealthy and unbreathable. I guess the ventilation doesn’t work and if it works maybe it’s time to renovate it immediately. In my opinion the metro didn’t have a good aspect at all. The price of the underground was €1.5 per journey or €7 for 24h or €24 for 7 days which I don’t find very attractive for a family and someone that goes to work every day. In Madrid for example the price of Metro is  €1.5 for a single trip but €11.20 for 10 trips which is more good if you work 5 days per week and you need two tickets per day during a labor week.

People have to realise that we need to make changes if we want a healthy future in Rome, in Athens, in London etc.

Winter holidays are here and after a long time I am back in Greece to spend them with my family. Unfortunately the crisis has affected the air quality here too.

Fireplaces: Huge problem because most houses choose them as a heating source, so they burn wood nowadays. Previously they were burning oil but its price climbed up and people tured to wood. PMs inside houses are on high values 20-40μg/m3. The threshold is below 25μg/m3. Outside values are high too with similar values of 18-38μg/m3.

Smoking: One more time Greek people disappointed me with the way they decide to behave in interior places. They smoke everywhere like in cafes, in restaurants etc. There is a law that prohibits that but they don’t follow it at all. How can we make people understand that this is a toxic air? It isn’t about them only but for all the people around them that they choose not to smoke like non smokers and kids. They are so proud smoking inside. Socialy is still something cool in Greece I guess. I asked some friends what will happen if I raise my voice. Will I find justice or will they throw me outside the places? Sadly the answer was that probably they will think I am crazy.

Cars: Yes there was a big scandal about some automobile companies that made-make car that pollute air beyond any consideration but that hasn’t affect how people think and move. People love Cars and traffic apperantly too.

Agricultural Fires: Through my trip from Sterea Ellada to Peloponeso farmers all over the countryside were burning unwanted material, from plastic to wood. I was hopping to breathe some pure air but that wasn’t the case on that trip. I know that there is a law that prohibits that action but I guess people don’t care.

If you are aware about air quality, a wearable device like TZOA is absolutely necessary in case you want to find places with good air quality in Greece or on the rest of the planet Earth.

Both devices are equipped with the basic home-environment sensors.

• Temperature sensor
• Humidity sensor
• VOCs sensor
• CO2 sensor
• Particular Matter sensor.

Carbon Dioxide:

Foobot features all the above sensors except the CO2 sensor, it calcualtes the CO2 through an algorithm and the VOCs sensor which doesn’t make it very accurate. Awair has a dedicated sensor for the CO2 which makes it a winner in this category. Both devices display the CO2 in parts per million (ppm) values.

Volatile Compounds:

Foobot can measure and display the VOCs in parts per billion (ppb) values which make it perfect if you want to have precision into your measurements. Awair from the other hand can display the VOCs in Index values from 0 best to 5 worst. Foobot wins here (Awair could fix that with a simple app upgrade).

Particular Matter:

Foobot measures PM10 and PM2.5 and Awair measures PM10 PM2.5 too. Both measure them in μg/m³. They use  exactly the same Sharp dust sensor, but the readings I get are different!

Temperature/ Humidity:

I had the devices side by side for a week and they always had different indications for temp, humidity and CO2. As you can see on the pictures below.

 Both companies claim that they have tested the devices into a chamber.

Connectivity:

Foobot so far works fine via WiFi network WPA2. Awair has had some trouble staying connected, it looses the connection time to time. Awair features Bluetooth but it is only useful during initial connection with your phone (they told me that they are working to fix the wifi issue).

UI/UX:

Both devices have a unique interface. Foobot history browser is far more advanced and it can remember measurements for a long time although they need to design it a little more intuitive. Awair can’t display the history far from 24h but the main screen is friendlier and easier for the simple user to understand.

Conclusion:

Some of the features can be enchaned during time because they are software based. As a result, for the moment the scores are:

• Awair 5/6
• Foobot 5/6

After all the problems that I had in my bedroom (Part1) (Part2) with air quality I want to share some conclusions and tips.

First of all I placed next to the AQI device a snake plant as I’ve already mentioned. It can suck some of the VOCs in the air but not in a high rate, so don’t wait that it will suck up all the pollution inside the house. An estimated rate is ∼3ppb/10min. The size of my pant is small 18cm wide, 11cm tall and with 16 tiny to small leaves (roots are actually responsible for VOCs’ absorption). The bigger the better of course.

From the other hand it can handle better the CO2 during night sleep, before the snake plant the CO2 readings could reach easily +3500ppm but after the snake plant the CO2 readings are about -2800ppm. Yes I know they are quite high but during night time, windows are close.

The Window is your true friend but trust it with wisdom. Which means that you have to open the window if you want to renew the air and get rid of the VOCs and the CO2 but make sure the air outside is better. It actually doesn’t need to be open for a long time 10-20min per session, 3-4 times per day during winter. In summer I personally leave some windows always open.

As always stay tuned.

 

Last week I decided to move my foobot in my bedroom mostly to check the air quality and humidity during night. I decided to place it in front of my bed between the window and the room door and on top of a chest of drawers that I have.

I was shocked to notice that the readings were too high. At the beginning I thought it was because of the fire of the previous night (Yes, someone decided to start a fire of wood and plastic, almost next to my house I had to call the firefighters the following day because the previous day they didn’t turn it off properly and it was burning slowly all night, I was desperate for clean air). Anyway, so I thought that the air was still polluted from that but the PMs were low 5-10μg/m³ after the fire  something that I couldn’t understand at the moment. The time and the days were passing and the VOCs were still high even with the window open the quality of the air couldn’t get better below safe limits. I had to do an experiment which I did it. As a result I was monitoring the device closely and my conclusion is that the source of VOCs was the chest of drawers under the foobot. The average reading was about ∼730ppb. Yes quite shocking for a furniture.

After that I moved it next to my night stand. The experiment continues, so stay tuned.