Let’s talk: IoT Wireless Network Protocols for Air Quality Monitors

Sotirios Papathanasiou4 Comments

The Internet of Things (IoT) describes the network of electronic devices (air quality monitors, purifiers, motion detectors, cameras, etc.) that are embedded with sensors, software, and other technologies for the purpose of connecting and exchanging data with other devices over the Internet.

In this article, I am going to describe some of the available networks and physical layers that are used by Air Quality Monitors (AQM), mainly for consumer-based products, and discuss which technologies make more sense in 2021+ for Smart Homes/Buildings and Businesses.

Wi-Fi IEEE 802.11

IEEE 802.11 is part of the IEEE 802 set of local area network (LAN) protocols and specifies the set of media access control (MAC) and physical layer (PHY) protocols for implementing wireless local area network (WLAN) Wi-Fi computer communication in various frequencies including 2.4 GHz, 5 GHz, and 6GHz.

IEEE 802.11a/b/g/n

This standard wireless network protocol is among the most common protocols for communication between the devices and the internet/cloud. Most devices even today use the ~20 years old 802.11b or 802.11g with a linkrate between 1 to 54 Mbit/s and a frequency of 2.4 GHz for power conservation reasons and good wall penetration. The 802.11n transmits the highest data throughput, but at the cost of high-power consumption at 5GHz.

IoT AQMs do not need a high-speed data throughput because the information they transfer is very little and in the range of a few kilobytes. So protocols like the IEEE 802.11ac and IEEE 802.11ax don’t make a lot of sense because they demand energy and they don’t offer good wall penetration in order to cover an entry house/apartment.

IEEE 802.11ax aka WiFi 6 or 6e

There are some claims that IoT devices will adopt the new WiFi 6e (e stands for enhanced) but I don’t think we will see that happening as bandwidth isn’t relevant for AQMs but the range is more essential and the WiFi 6e is designed to cover approximately 30m/98ft indoors. The 6e operates at 6Ghz, as a result, the highest the frequency the shortest the distance a signal can travel within walls. A positive feature of this protocol is that it supports a Low Power Indoor (LPI) mode. In the multi-user scenario, the WiFi 6 module consumes only one-third of that of the Wi-Fi 4 (802.11n) module and they achieve that by shortening wake-up time.

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Review: HA500 Air Purifier by Healthy Air Technology

Sotirios Papathanasiou13 Comments

It is not always an easy task to keep indoor air free from pollutants, especially, when Nitrogen Dioxide (NO2) is present in indoor environments. In most cases, there is little you can do to eliminate NO2 and other gases like Sulphur Dioxide (SO2), Formaldehyde (TVOC), or even pathogens like H1N1 Influenza A virus (pandemic flu), and Staphylococcus aureus (or similar bacteria).

Here comes the HA500 Air Purifier by Healthy Air Technology which is able to eliminate all of these pollutants/pathogens from indoor environments. It does that thanks to the triple-layered system with a primary filter, HEPA 13 filter, and Pollution Eraser DNO filter. DNO means D-Orbital Nano Oxide which is made of two parts. 

1st part: The Carrier – Activated charcoal. The material that is used in military gas masks, and captures pollutants within the pores of the charcoal.
2nd part: The Transition metal oxides – Transition metal oxides are coated in the activated charcoal to form catalysts, and these catalysts break down pollutants and toxic gases into harmless chemicals and then release these harmless materials back into the atmosphere like water, oxygen, carbon dioxide, etc. The DNO is invented by the founding CTO of Oxford Catalyst plc (a leader in novel industrial catalysts).

HA500 Control Panel and Display
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Penetration of Particles into the Human Body

Sotirios Papathanasiou5 Comments

How deep can pollution particles go into the human body?

Poll: Results Discussion – Air Pollution

Sotirios Papathanasiou5 Comments

Last week I started a brief poll on Twitter because I wanted to obtain feedback from the community. The subject was simple “Which source of #AirPollution affects you the most?”

263 people responded and unfortunately, I can’t say that the results surprise me. Vehicle traffic was voted as number #1 source of air pollution with a massive 53% and it was followed by 32% wood burning for heating like wood-burning stoves, fireplaces, etc. 7% of the users voted that agriculture is the source of air pollution in their communities and an 8% voted other.

I would like to comment about each category individually, but first of all, I would like to make something clear. All sources are equally important, I don’t rank them from most to least important but I classify them based on what people think is the source in their community, and it varies a lot.

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Clarity Node-S Remote Calibration Process

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When you use low-cost monitors for professional reasons, you need to calibrate them in order to obtain the best possible measurements. This process makes data less vulnerable to environmental conditions and more valuable to scientists and policymakers.

Clarity takes this process really seriously, and they dedicate a lot of resources to making sure their devices will measure accurate data (for more on how to assess air quality sensor accuracy, see this blog). I ask Clarity to perform a remote calibration on my Node-S and guide me through the entire the process.

I have discovered something interesting during that process about the local air quality station.

As you may already know from my previous articles, my local air quality station ES1393A is placed inside a park and it is almost surrounded by trees. Trees act as a barrier, and they block pollutants from reaching the monitors. The Clarity team told me that this was an especially complicated calibration. I suspect it has to do with the location of the station and how trees may interact with low-cost sensors.

The type of trees in my city is a variation of a ficus called ficus retusa l. var nitida. These trees release a resin from their leaves which can create interference to the low-cost sensors that do not have a filter to keep them out as the scientific-grade monitors do. Most outdoor scientific-grade monitors come with a debris screen inlet or an Inlet Heater which may capture the resin from the trees.

The problem is not the trees but the location of the air quality station that shouldn’t have been there.

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Shopping Guide: Air Quality Monitors

Sotirios Papathanasiou15 Comments

As you already know, I receive messages from readers of my blog almost every day. Their most common question is which air quality monitor should they choose. Most of the time in their message, they tell me that they go through Amazon to find a product, but they are confused from their reviews.

Carbon Dioxide (CO2) Monitors are a big hit nowadays due to the pandemic and because they are great tools at helping us understand indoor ventilation in order to mitigate the spread of the virus. Many new CO2 monitors pop up every day like mushrooms. Are they good, well …. you have to be careful!

No offense to Amazon or AliExpress or Facebook but most of their products are garbage for two reasons. Firstly, they are cheap products that come from China but without any quality control. Apple products come from China too, but Apple controls the quality of the shipping products. I have reviewed some cheap air quality monitors here on the blog just to justify their low price tag. Secondly, companies that sell these products don’t offer any kind of support nor updates. If the product has a small bug, you will stick with it forever. Many times the language they come with is badly translated or they come in Chinese if you are not careful enough during the purchase process.

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How to Use CO2 Monitors

Sotirios Papathanasiou2 Comments

I see a lot of pictures on social media platforms where people measure Carbon Dioxide (CO2) concentrations in indoor environments incorrectly.

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Review: Envirosuite – Air Quality Management Platform

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In today’s marketplace, there are many ambient air quality monitors capable of measuring multiple environmental parameters and pollutants in real-time. However, air quality monitors aren’t useful unless they are paired with an intelligent software platform in order to extrapolate the information and make it serviceable to operators and communities.

 Envirosuite has succeeded in embedded 30+ years or experience working with complex air quality and meteorology challenges directly into an advanced software platform. Users can make operational decisions based on insights from real-time air quality data and emissions modeling. Furthermore, they can identify the likely sources of air quality pollution from past incidents. 

The platform is currently used by over 500 industrial operations such as mines, oil refineries, maritime ports, construction sites but also for municipal authorities in cities. Noise management capabilities are also used at 200 of the world’s major airports.

Key modules and their functionalities

Envirosuite does just that and it is a global leader in Environmental Intelligence, using proprietary technology and real-time localized data to help industries grow sustainably and communities to thrive. The platform integrates with pre-existing monitoring devices that are capturing data on multiple air quality parameters. It is offered as SaaS (software-as-a-service) subscription supported by AWS cloud technology and is segmented into modular solutions for to assist with specific air quality challenges.

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AQ Monitors meet Apple HomeKit

Sotirios Papathanasiou4 Comments

I really like to have all AQ Monitors and other devices connected to one place in order to make my life easier when I try to figure out what is going on in my house. I am an iOS user which means this post doesn’t concern Android users, however, I will advise you to stick around and read the benefits of having Apple HomeKit.

Not all AQ Monitor manufacturers support HomeKit and here comes HomeBridge which is a platform to bring non-supported devices to Apple’s ecosystem. There are only a few AQM manufacturers that officially support HomeKit, like Kaiterra, Eve and QingPing.

The community of the HomeBridge has allowed others to take advantage of the platform and make the user experience even better by porting many more AQMs into HomeKit.

Which AQMs support HomeBridge?

  • Airthings
  • PurpleAir
  • Awair
  • Sensor Community (aka Luftdaten)

How to set up HomeBridge?

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PurpleAir II (PA-II) Hack

Sotirios Papathanasiou7 Comments

During and after the wildfires on the west coast of the United States the PurpleAir II (PA-II) network of low-cost monitors grew exponentially and has reached a number of about 11000 units. The reason was simple, people wanted to see when it was safe to go outside and/or open the windows.

Although the PA-II is a small cute particulate matter monitor, it has a flaw. The temperature and humidity sensor (Bosch BME280) is placed too close to the rest of the electronic components. As a result, neither the temperature nor the humidity reflects the real values of these environmental parameters. All electronics produce heat, and they may interfere with other sensors, and this is the case with the PA-II.

By the time someone invests money on a device with an array of sensors they want to be able to take valuable measurements for all the parameters. For this reason, I figured out how to improve the temperature and humidity measurements in order to reflect the real conditions outdoors or indoors as some people place the monitors indoors too.

It is easy to take apart the device, as there is only one screw. Once it is unscrewed, you need to pull the sensors out of the white case. Don’t worry because they are holding each other with some stickers.

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