Real Life Experiment – Indoor vs Outdoor Air Quality

There are countless times that I stretch the importance of monitoring and managing indoor air quality by keeping an eye on the outdoor air quality/conditions.

In this experiment, I want to demonstrate that it is hard to manage indoor air. I want to state that indoor spaces should be subject to 24/7 monitoring and not a periodic inspection.

The graph below demonstrated that indoor AQ gets influenced by outdoor air and on top of that, the polluted air lingers for a longer time indoors unless there is a mitigation plan (aka filtration) in place.

The graph shows PM2.5 data during a period of 48h hours of continuous monitoring with an indoor and outdoor air quality monitor. The house uses natural ventilation to keep CO2 and VOC concentrations low. During poor air quality events, windows and doors were kept closed.

Once the neighbor started a domestic fire (for an unknown reason) both indoor and outdoor environments were equally influenced. Unfortunately, as automation wasn’t active, it was too late to stop outdoor air from coming indoors. Outdoor air improved faster due to winds and faster dilution of the pollutants, but the indoor air was above WHO AQGs recommended levels (5 μg/m3) for the rest of the day.

Then another fire event of a bigger magnitude occurred, and once more it influenced indoor air in a great extent. The overall 48h average PM2.5 values for the outdoor and indoor air were 8.6 μg/m3 and 13 μg/m3, respectively.


All in all, my exposure to fine particulates was higher indoors, even though the source was outside the house (about 60 meters away). Air purifiers or a central ventilation system with high-quality HEPA filters are recommended. I have found from past experiments that a positive pressure solution is more effective (in most cases) as it keeps VOCs and CO2 at low levels indoors.

Spring Is Around the Corner & Allergies too

I love spring as it marks the return of warm weather, outdoor activities, the blossom of flowers, and life in general. However, pollen becomes abundant everywhere there are plants and trees, as a result, the flare of allergy-related health issues too. I am allergic to some kind of pollen and although I can manage it without medication, some people are suffering to a greater extend and they need better ways to mitigate pollen out of their immediate environment.

Unfortunately, on earth, there are only a few special Air Quality monitors that can measure and classify pollen. Satellites also track the progress of pollen but do you know where to find this kind of information? I bet no, for this reason, I will tell you in a bit.

Remember, the first step is always quantifying the pollutants/allergens (pollen in this case) before mitigating them from indoor spaces. The reason is simple, once we have the proper information, we can take better decisions. For example, should I exercise outdoors today or go outside for some errands or is this the right moment to ventilate my house?

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Review: SODAQ AIR – An Air Quality Monitor for Your Bike/Your Lungs

More and more people choose to ride a bike for their daily commutes and although SODAQ AIR is not the first air quality monitor for a bike, it is the first to have collected over 20M data points. This is particularly import for the development of an IoT air quality monitor as the developers have enough information to debug and develop a super stable product that needs very little troubleshooting from its users.

SODAQ is not a new company as it was founded back in 2013, and they have been working on this particular project (SODAQ AIR) alone since 2015. It seems that consumer satisfaction is always their priority, which is very important nowadays as we need sustainable products that will last for a long time.

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Review: Kunak Air PRO – Ambient Air Quality Monitor

Time to talk seriously about ambient air pollution and how technology can help us see and consequently mitigate it. According to a 2016 report, the annual cost of air pollution has to the global health care system has risen to US$ 176 billion from US$ 21 billion in 2015 and the number of workdays lost to air pollution-related illness bounces to 3.7 billion from 1.2 billion. According to another report, ambient air pollution kills more than 3 million people across the globe every year but more importantly causes health problems that increase the annual health care budget.

Unfortunately, air pollution is not taken very seriously by governments and society because we tend to dismiss things we can’t see or understand. Here comes Kunak which is one of the leading companies in the field of monitoring air pollution accurately. Recently, the monitor Kunak Air PRO has been rewarded at the AirLab Challenge 2021 as the most accurate multi-pollutant ambient monitor and it is made in Spain.

Experts, academics, the city, and policymakers all need air quality monitors in order to quantify the ambient air, get the right conclusions about the situation, and finally, make the right decision on how to mitigate the pollution and the health care costs. As you can understand the accuracy of the monitor is very crucial and Kunak delivers great results.

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AirGradient DIY Indoor & Outdoor Air Quality Monitor

Countless times I have mentioned that we need to monitor indoor and outdoor air quality. This is an essential step in order to have a holistic approach to air pollution that surrounds us in both environments. Unfortunately, not everybody can afford to buy two monitors but thanks to the community and AirGradient there are two DIY solutions that can help us monitor the air quality quite accurately and of course, manage the air we breathe better.

AirGradient’s DIY solution is more appealing than the competition for many reasons. First of all, you can buy directly the DIY Kit with all the electronic components from them including the PCB. The PCB is the board where we will deploy all the sensors, WiFi module, and display. That is a huge benefit because you don’t have to search on the internet and purchase the components one by one. The well-designed PCB will also help us keep the monitor neat and small without unnecessary cables. Secondly, Air Gradient’s DIY AQ Monitor is very customizable allowing us to build an indoor monitor with an NDIR CO2 sensor but another one without a CO2 sensor or display for the outdoor environment. If you don’t want temperature/humidity sensors you can easily omit them too, but I highly recommend them. Moreover, there is software support as a community of passionate people have been improving the firmware constantly. Finally, the solution comes with a web dashboard where you can manage all the monitors and take advantage of the histograms and tools like the alerts.

Additionally, the devices which are connected to the cloud and the dashboard can broadcast the measurements back to a separate display (Viewport) which allows us to see the air quality indoors and outdoors like in the example below. Isn’t that very cool?

It has been a long time since I soldered something, so I was very happy to build the monitor. I built two monitors by following the fairly easy instruction here. There is also a video with the instructions here by Jeff Geerling.

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Outdoor Air Quality Monitors 2021Q4

What’s new? Well, lots of new Outdoor Air Quality Monitors have been released into the market for various purposes and different budgets. Air quality monitors for professional use in cities and industrial sites and homeowners who want to supervise the ambient air quality outside their houses/apartments.

This time, I have included the General Star Score from the AIRLAB Challenge 2021 for the monitors that took part. The Ethera NEMo Outdoor monitor scored the highest with 4.5 Stars out of 5.

uRADMonitor with the Smoggie and City models scored 4/5 and 3.5/5, respectably. Also the Kunak Air Pro which I will review soon scored 4/5. It is great to see that all these solutions deliver accurate results.

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Breathe Helmet – Angel Investor


I have teamed up with a great product designer Nathan Hassanali in our effort to offer clean air to the commuters that need to move around the cities where combustion engine vehicles are unfortunately still a priority over sustainable alternative methods.

The Problem – Air Pollution

One of the biggest challenges of the 21st century will be to mitigate the negative effects of transport – greenhouse gases, air pollution, and noise – while ensuring positive aspects of mobility. Meanwhile what can dwellers do to protect themselves from the toxic air that is present in the streets all around the world?

Although air pollution has decreased over the last two decades, it is still a major problem in many areas. ‘EURO standards’ for vehicles have not succeeded in reducing Nitrogen Dioxide (NO2) emissions and “defected” vehicles (aka Dieslegate) still circulate without meeting the levels set out in the legislation. Recently, the World Health Organization updated the Air Quality Guidelines (2021 AQGs) which sets the bar for human health high because according to new methods for evidence synthesis and guideline development they found proof of health effects occurring at lower levels than previously understood.

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In & Out – Airthings & Airly

Countless times, I have said that it is very important to monitor our indoor air quality side by side with the outdoor air quality. A collaboration between Airthings and Airly brought the best of both worlds, ambient air quality and indoor air quality monitoring in one place. Unfortunately, this solution is available only to the business customers but we can always hope that the demand will drive the feature to the consumer clients as well.

Why in & out AQ monitoring is important?

Our indoor air quality depends on many factors like building material, furniture, and indoor activities (cooking in a home or printing documents in an office, the perfumes people wear, etc). All of these factors will determine indoor air quality from the inside but indoor air quality is subject to outdoor conditions too. Vehicle traffic, marine traffic (in case you live near a port), wood-burning, industrial activities in the area, and wildfires are some of the reasons that will affect indoor air quality as buildings need to breathe or ventilate if you want.

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Ranking of Cities by Air Pollution! Nope!


I have come to the conclusion that rankings of cities by air pollution are not accurate and they don’t reflect the real situation in large communities because if you are unlucky enough to have a careless neighbor that burns wood/garbage/etc or you live outside the Low Traffic Neighborhoods (LTNs) and official AQ stations are far away from you then you are screwed!

Basically, your health is a subject of what others want, and there is little you can do to protect yourself. You can always stay indoors with purifies all over the house 24/7 and unable to open a window for oxygenated air to come inside. That is not correct as your freedom to open a window or walk outside your house and the right to breathe clean air are taken from you.

There are many studies talking about inequality in low-income communities. In a recent study researchers have even identified the fact that there are less trees around poor communities than in high-income ones.

Politicians marginalize the work-class constantly by refusing to find solutions to their problems. Some laws protect us from air pollution but they are not enforced. So far scientists have gathered hundred of evidence that tells us firmly that air pollution kills – more than 7 million people have died prematurely worldwide due to air pollution. Personally, death doesn’t scare me, but living a life with many medications and unable to function as a human being (Alzheimer’s among some of the most common diseases) is my biggest fear and air pollution can decrease the quality of life. It is hard to quantify morbidity which means the condition of suffering from a disease or medical condition. This is not the future I want for myself and the people around me and you shouldn’t too.

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Thailand School sets the AQ bar high – An example to be followed

On Earth, there are over 7 billion people but very few of them have a clear vision of a future and how important air quality is for our health. You will find politicians that are unwilling to enforce air quality laws, you will find educators scared to share with parents the indoor air quality, and you will find lots of people unaware of what they breathe or what they burn.

Among all of them, you will find very few people that want to make things right for the rest. In this case, the Head of School at Prem Tinsulanonda International School in Chiang Mai, Thailand was brave and educated enough to recognize the power of air quality data.

Chiang Mai is a city in exotic Thailand that always ranks in the top polluted cities in the world between March and April. The reason is the burning season. I was taught about the 4 seasons (Spring/Summer/Autumn/Winter) at school but it turns out that they have a fifth season − normally in March and April − when crop waste burning and forest fires fill the air with particles, PM2.5 levels can reach 300 μg/m³.

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