Category: air quality

What should schools do to prevent the spread of SARS-CoV-2 in classrooms – Part 2

Sotirios Papathanasiou2 Comments

In a previous post, I mentioned how important is to monitor the environmental conditions inside a classroom in order to minimize the spread of the virus. Temperature, relative humidity, particulate matter, and carbon dioxide values can serve as indicators, and thanks to them we can have an estimation of the possible propagation of the virus in a classroom.

It seems to me that most people and governments are convinced that the virus is in the air (finally), and although masks work (in most cases), we all know that it is difficult to demand from kids to wear them 8 hours a day without touching their face or each other. Definitely, the virus will affect the psychology of the kids in the classrooms, and most importantly their social skills.

In Madrid, Spain, the authorities have decided to install 6000 cameras in schools. I am totally against this decision. Are they going to fine a kid when he/she touches his/her face? Who is going to watch the footage from 6000 cameras in real-time to determine that a breach of the protocol has occurred? A complete waste of money as later they will have to remove them because of privacy concerns, mark my word on that.

We have to realize that is important to give “some freedom” to kids for their mental sake and for them to grow. Technologically, we can achieve that by offering them the best air possible. In my previous post, a colleague of mine told me that schools in Spain and schools in the UK are not the same because the weather conditions are not the same, and he is right. In south Spain, schools don’t invest in heating, and they could rely on window ventilation, but in the UK (and north Spain) because temperatures drop low earlier, schools need to invest in mechanical ventilation that will recover heat as well.

Either way and although I love an open window for fresh air, I recognize the need for mechanical ventilation systems that will introduce fresh and clean air to a classroom keeping particulate matter and CO2 low and at the same time temperature and relative humility at optimal levels for kids to study and teachers to work.

Hypothetical simulation: Fresh air comes from the back window and stale air exits from the front window, an asymptomatic student is sitting on the front row

The SARS-CoV-2 virus travels inside the tiny droplets we exhale while speaking, sneezing, or coughing. Those droplets aka aerosols have different sizes and can travel from a few centimeters to a few meters far. Most importantly, they can float and be suspended on the air for various minutes depending on their mass, increasing the chances of infection. The conditions inside a room play an important role.

Number and size distribution of the droplets exhaled by talking, sneezing, and coughing

Keep in mind, most of the time, we can’t see the exhaled aerosols below 50μm in diameter.

Currently, there is a lot of debate on which technology should be adopted by schools, medical centers, airports, etc in the area of the ventilation and air treatment as some of them offer some drawbacks.

You see, some of these technologies like pure UVC lamps, ion generators, or similar unregulated photocatalytic oxidation (PCO) technologies may produce a large concentration of unwanted gases like Ozone (O3), which is an irritant for the respiratory tract. CO2 is another by-product that may occur during the oxidation process. Many manufactures (but not all) regulate the concentrations of ozone their purifiers produce to safe levels.

Personally, I have a few important criteria to consider when it comes to which air purification/ventilation system a school should invest. First is the price, public schools can’t afford to install expensive HVAC systems. They need to reply on affordable solutions, and most likely systems that don’t require a lot of hassle to install and maintain (old building, poor infrastructure, no staff), the same applies to some private schools.

Secondly, the performance of the system (air volume m3/h) and the energy it uses (watts/h) must be optimal to keep the energy bill down and get the most out of it in each classroom.

Depending on how air ventilators/purifiers are designed and move the airflow in a room it may increase the chances of spreading the virus before removing it from the room. Simulations have demonstrated that downflow systems are more efficient than overhead systems. In simple words, we need to suck the air from the lower level in a room and introduce fresh and clean air from the top.

Hypothetical simulation: Fresh and clean air is introduced from the ceiling and the stale air is discarded from the vents below

There are so many options right now for someone to choose from. Standalone air purifiers, window ventilators with filtration systems, light fixtures that purify the air while they illuminate the space, central HVAC with quantum plasma that kills 99.9% of the viruses and up to 1000 m3 /hour C.A.D.R, or even special designed devices that can capture all type of particles in outdoor environments like a playground. I can’t tell you which one is the best because it depends on various parameters like the available budget, the infrastructure of the building, location, the size of the classrooms, and the number of students.

An expert is very important during the decision making to plan wisely and deliver the best air for kids. There are a lot of regulations regarding the air ventilation standards in buildings, and each country has its own. For example, in Spain, the UNE-EN 13779 states that a classroom of 45 m² with a height from floor to ceiling of 2.5 meters, occupied by 25 students and a teacher in primary school should renew the air 10.4 times in an hour.

  • 45 m³/h per person (IDA 2) x 26 people = 1,170 m³/h.
  • Classroom volume: 45 m² x 2.5 m = 112.5 m³.
  • Number of air changes in a classroom: (1,170 m³/h) / 112.5 m³ = 10.4 air changes in an hour

The same regulation states that the CO2 concentrations inside a classroom shouldn’t be above 500 ppm. Here come the real-time, low-cost indoor monitors that can measure constant fluctuations and warn teachers about the air quality in a room.

Conclusion

It will be very naive of us to think that only alcohol and masks (which not all of them are equally made) will protect our kids during the course of a day in a classroom. Most importantly, we have to think about their mental health too.

Below you will find a list of companies that have developed various systems for air ventilation and air treatment and each of them offer a different technology and experience.

Many thanks to all for the information you shared with me. Special kudos to caloryfrio.com

Risk of coronavirus transmission in different settings

What should schools do to prevent the spread of SARS-CoV-2 in classrooms

Sotirios Papathanasiou6 Comments

Masks provided decent protection against the SARS-CoV-2 but if a carrier of the virus (40% of them are asymptotic) stays inside a home/business for a long time then the chances of transmitting the virus are higher because some particles may escape.

According to experts the best way to prevent the spread of the virus is to keep introducing fresh air inside a room.

Unfortunately, most rooms don’t meet the recommendation of 8 air changes an hour for a 10 square meter (107 square foot) room occupied by 4 people. A clear example is a classroom that doesn’t meet the recommended ventilation rates. This is a common mistake across all schools in the world.

Read More »

Building an IoT Air Quality Monitor that will survive the competition

Sotirios Papathanasiou7 Comments

Building a hardware startup is a hard business, we are well aware of that. Right now, there are a lot of indoor/outdoor Air Quality Monitors in the market that support low-cost sensors, unfortunately, even when the cost of the materials (aka BOM) is low, companies struggle to survive because of an initial bad business model.

If you want to enter into the game of the air quality or in general of the IoT, you have to ask yourself: How do I turn what I do into a compelling service?

When you sell a product you earn some money, typically three times more of what you have spent. However, your income relies only on that model and the problem with technology is that it evolves constantly, so tomorrow a new company will sell a product a bit better than yours because there will be a new sensor in the market and all future clients will shift their attention towards that device. Then you have to wait for a year or more in order to realize that you have to shut down your product and taking down with you a few hundred to thousand clients that have bought your AQM — More e-waste and frustration for the end-users.

For this reason, you have to invest in software development as well, and here comes my expertise. I have seen a lot of Air Quality Monitors, and I have collaborated with a fair number of companies in the field, but I always see the same mistake.

Some companies believe that they have to give customers free data support and services for life and if they turn their product into a paid service and they ask money based on a subscription model then they will lose costumers, but this is not necessarily correct. You are not going to ask someone to subscribe to your service to get just numeric values of a pollutant, you have to offer them something more than that. Something the competitors can’t offer because this feature is unique in your ecosystem. Maybe it could be restricted with a patent too.

Consumers really value good products especially when they can’t find something similar.

You are going to ask me, “What can I offer them?” You have two options, stay tuned for future articles or contact me in order to discuss how we can collaborate.

 

Review: Airthinx IAQ for Homeowners

Sotirios Papathanasiou5 Comments

This review is dedicated to the end-users (homeowners) as I present the tools (Smartphone app) and functionalities of the device for the average user and some basic features on the dashboard. Later on, I will review the same monitor for businesses where we will have the chance to see and analyze the more advanced tools which are present on the dashboard for all.

Airthinx IAQ is an Air Quality Monitor (AQM) that was built for experts with many communication protocols in order to ensure that users will be able to access air quality measurements from anywhere and air quality sensors that matter in the indoor environment.

Technical Specifications

  • PM1 / PM2.5 / PM10 Sensors (0~500 μg/m3)
  • CO2 Sensor (0~3000 ppm)
  • CH2O Sensor (0~1 mg/m3)
  • TVOC Sensor (1-10ppm of EtOH) (0-1ppm of Isobutylene)
  • Temperature Sensor (-10-85°C)
  • Humidity Sensor (25-90 %RH)
  • Barometer Sensor (300-1100 hPa)
  • Cellular (GSM/GPRS/EDGE/UMTS/HSPA)
  • WiFi (802.11 b/g)
  • Bluetooth 4.0
  • Zigbee
  • GPS
  • Accelorometer 16g (13-bit resolution)
  • 2 Micro-USB Power Ports

Read More »

UV Filtration During COVID-19 with BRISE C200 Air Purifier (English/Español)

Sotirios Papathanasiou3 Comments

(Scroll down for the Spanish version/Desplácese hacia abajo para la versión en español)

Two years ago I reviewed the BRISE C200 and I have been using it everyday but I had never thought before that the UV sterilization process will come so handy. It provides an extra layer of protection in a house or in small office especially during this covid-19 pandemic.

I don’t know about your experience during the lockdown, but mine was quite frustrating when I had to go out for grocery shopping and return home or even when I ventilate my house. A lot of things had been written about the SARS–CoV–2 virus, like that it could survive on clothes, on surfaces (keys, phones, money, etc) and that it can be an airborne pathogen.

Airborne means that a virus is transmitted between people through respiratory droplets and contact routes.Read More »

Why is it so hard to ditch private vehicles from cities?

Sotirios Papathanasiou2 Comments

We all know that cars contribute a lot to air pollution in urban environments, like particulate matter and nitrogen dioxide, among the most common. I see many fellow environmentalists who try to push cities towards a future without cars, but I think with the current means it is very difficult to win the battle.

The automotive industry spends millions on advertising, and they always target the emotional connection that forms between a driver and a car. They will never tell you that cars are important tools that will help you on your work or any other everyday tasks, but they will tell you that a car will offer you freedom as you will be able to escape away from your problems or it will make you a powerful human being and so on.

Take, for example, the first three ads I got as a result when I googled “Car ads”. Powerful subliminal messages to lure you into thinking that a car will make you a new person.

car ads
Just by Googling “Car ads”

When environmental scientists urge communities to leave cars behind they don’t actually do a great job of spreading the message around because they are not trained to do this kind of task. Allow me to elaborate on that. Atmospheric scientists are good at their job which is the study of the Earth’s atmosphere and its various inner-working physical processes. They are able to investigate cases and write papers base on actual facts and among experts, we are able to understand what they want to share but we miss the science of physiology, something that the automotive industry relies on for a century now.

Every day people are not going to read those papers and studies, and if they do, they aren’t going to understand a lot. By giving them the information in a form that they can understand, and without alarming them, we have more chances of making them understand the issue.

Conclusion

When carmakers launch new cars on the market, they are going to involve many more experts on how to make their product more appealing to the costumers, aka everyday people, as a result, we have to fight with the same tools and team up with marketing experts.

Examples of campaigns, we can deploy if we want more people to join the #CarFree movement. Feel free to share them!

Bicycle Power3

Bicycle Power2

Bicycle Power1

Dear city of Almeria (Spain) or any other city in the world (English/Español)

Sotirios PapathanasiouLeave a comment

(Scroll down for the Spanish version/Desplácese hacia abajo para la versión en español)

I am writing this article because I would like to help you understand the importance of the issue as the whole province and consequently my city Almeria doesn’t have an official air quality station with a sensor capable of measuring particulate matter with an aerodynamic diameter of 2.5 μm or less (PM2.5) in real-time.

What is Particulate Matter (PM)?

Particulate Matter (PM) are solids material (sometimes liquid too) that float in the air. Some PM is released directly from a specific source − combustion in Diesel engines − while others form in complicated chemical reactions in the atmosphere.

Particles in the PM2.5 size range can travel deeply into the respiratory tract, reaching the lungs. Studies also suggest that long term exposure to fine particulate matter may be associated with increased rates of chronic bronchitis, reduced lung function and increased mortality from lung cancer, and heart disease. People with breathing and heart problems, children and the elderly may be particularly sensitive to PM2.5.

The Problem

In the province and city of Almeria, there are three Air Quality Stations that measure many pollutants one of which is PM2.5. Unfortunately, these sensors are outdated and the results we get are ONE daily average value which is basically useless in my opinion. Apart from that, we need to wait for a month to get the results back after filing a form. I guess the same thing applies to the 68 stations all around Andalucia in total.

Citizens need real-time data in order to take action and reduce their exposure to air pollution. They also need better tools and maps where they can visualise where pollution is in order to avoid harmful exposure. There are already many studies supporting the correlation between air pollution and COVID-19 cases.Read More »

Review: Node-S by Clarity

Sotirios Papathanasiou11 Comments

I love clean air and even when we are indoors the air we breathe comes from the outdoor environment, like streets, small neighborhoods, city superblocks, etc. There are high probabilities that you, the reader, live in a city and the air you breathe isn’t clean enough to support your healthy lifestyle.

Most cities in Europe, as far as I know, have two state reference stations (a background and an urban) for air quality monitoring. They are great, with highly accurate and expensive equipments inside. Unfortunately, most of the time they are old and outdated which limit their ability to engage people to look into the air quality problems we are facing.

My city hosts around 200,000 people and the one urban reference stations we have isn’t capable of measuring PM2.5, at least not as most people will expect. It registers ONE daily average PM2.5 measurement (and not always). Data are free but in order to get these daily measurements you need to file a form and wait a month as manually a lab examines the filters were PM2.5 particles are captured.

Of course this is a tedious way to report data in 2020 at least in my opinion, I understand the “accuracy” obsession that surrounds some scientists, they can keep doing that but also they need to report real-time data to citizens if they want them to change the way they think and behave. I mean, what can I do if I learn that the air was dirty a month ago?

Here comes a outdoor monitor like Clarity Node-S. In my opinion, cities have no excuse not to install such monitors around the city and allow citizens to see the air they breathe. Literally, it is so easy to pick a place in a city and install a monitor. Clarity takes advantage of the low-cost sensors and has developed a solution hard to resist.

Read More »

Air Quality data that make sense for the average users

Sotirios Papathanasiou2 Comments

Have you ever used an app that will help you relax? Well I have, one of them is Apple’s Breathe app that can be found in the Apple Watch since WatchOS 3. The idea behind the app is that a steady breathing technique will help you relax and hopefully reduce heart rate pulses. Great app but I think Apple or any other developer should combine Air Quality (AQ) data with their breathing/meditation app.

In a mockup that I designed based on Apple’s Breathe app (I chose Apple’s Breathe app for its simplicity and effectiveness), I placed the Air Quality Index (AQI) information inside the app and depending on the AQ at that period the user will be prompted to avoid breathing deeply when the AQ is unhealthy or to adjust the duration when the AQ is good and start. In case the AQ is unhealthy a reminder will notify the user to come back for a breathing session later when the air is healthy enough for deep breaths.Read More »

Low-Cost Portable Monitors vs Reference Monitors Part2

Sotirios Papathanasiou1 Comment

A long time has passed since I wrote Part 1, and I presented the results for NO2 and PM2.5 measurements between the low-cost sensors and the reference monitors. Due to the COVID-19 pandemic, laboratories were closed for 2 months so they couldn’t send me the results but since the 1st of June, I have the results in my hands.

Dates  PM 2.5 Mediterráneo
31/01/2020 15,83 µg/m3
03/02/2020 17,35 µg/m3

These are the data they sent me. Two daily average values for the 31st of January and the 3rd of February. Data for the 1st and 2nd of February weren’t available for a validity reason.

I know it is ridiculous for an urban state reference station to give you just two values for four days. I am curious to learn what exactly they do with these values, what kind of studies (rolling my eyes now).

Unfortunately, I am unable to compare the PM2.5 low-cost sensors with the BAM results as I wanted, so the only thing I could do is to average the values from the low-cost sensors for the specific days and place them side by side. However, it won’t do it as it will create a huge confusion.

Conclusion

You start evaluating portable low-cost sensors, and you end up finding that the official city station is so outdated (accurate but outdated). This is the reason I am going to review an outdoor monitor (Clarity) that is designed specifically for cities that lack real-time PM2.5 monitoring, and it can offer a denser spatial coverage.

Regarding the Atmotube Pro and Flow 2, I will also compare them against the outdoor monitor in order to get a better idea about the PM2.5 monitoring capabilities.