What is the best air quality monitor? In this article, we will discuss what the best domestic air quality monitors have to offer and what their limitations are. An air quality monitor uses an internal sensor or sensors, to detect and track the amount of pollution in the air. These monitors can have different types of sensors to detect different types of pollution. The accuracy and reliability of the sensor are important as the better the sensor, the more accurate it will be in detecting and reporting the correct levels of pollution in your environment. There is a wide variety of air quality monitors on the market today to choose from and the accuracy of their performance can greatly vary.
Air quality monitors can be used indoors and outdoors with a plug-in or hand-held versions available. Air quality monitors are mainly used to detect particulate matter (PM), carbon dioxide (CO2), carbon monoxide (CO), temperature and humidity levels. There are also units which detect volatile organic compounds (VOC’s) as well as noise levels (dB). It should be noted that most air quality monitors have the capability to monitor only some of the features listed above. The right air quality monitor needs to be chosen for the intended purpose and to give you the best information on the air quality in the environment you want to test. Most of the air quality monitors on the market today will be using a form of light scatter to measure PM levels in the air. Light scattering is a process whereby light is used to try to detect how many particulates are present in the air. Light from a source, such as a laser, is directed, when it comes into contact with particles in the air, the light is scattered and this is then measured to give the PM reading. The rate at which readings are measured can vary, with some sensors being able to give readings every few seconds whereas others give readings every couple of minutes or more. There are even air quality monitors which claim to give instant readings and others let you set the interval of measurements. This can be useful as it will extend the period when the laser needs to be calibrated.
Due to the relatively recent development of laser sensor technology, there is not yet a certified standard to which laser sensors are held in testing. Light scattering sensors are relatively cheap and can be bought for a few pounds, making them very cost effective when used in air quality monitors. The downside to using such sensors is that their readings may not be accurate.
Properly understanding and interpreting the results from the sensors in an air quality monitor is crucial. This is where a good interface, app and or web site will be able to translate the readings from the air quality monitor and present it in a way which makes it easy to read and understand. Having warnings, in the form of alerts sent to an app, email or text is also a handy feature, which enables you to keep updated on how polluted the levels are in your environment. A good air quality monitor will be able to display the air quality readings on the unit itself as well as having data logging capabilities so that you can track long term patterns. Furthermore, it should be able to discern the cleanliness of air based on a relative measure, i.e. the unit should understand when the air is actually clean, rather than simply report on changes in the air quality. If the number of people smoking in a small room drops from 50 to 20 people, some sensors will determine that the air is now “clean” simply because it has improved.
An air quality monitor that measures for particulate matter (PM), has to specify what size particulate matter it measures at. Particulate matter is a term used to describe a mixture of liquid droplets and particles that are suspended in the air. Airborne particulate matter can include but is not limited to, pollen, traffic soot, viruses, bacteria, mould spores, dust and smoke.
The better the PM sensor in an air quality monitor, the wider the range of pollution it will be able to detect and with greater accuracy. Several air quality monitors can measure a particle range of 0.3 – 2.5 microns but this can vary between models. The particle range of 0.3 - 2.5 microns is able to detect particles such as animal dander, house dust as well as certain types of bacteria. Even with a good air quality monitor, there will always be certain contaminants in the air which the air quality monitor will not be able to detect. Smog and soot particles can go down to 0.01 microns in size, with some viruses going as small as 0.005 microns.
As the price of air quality sensors is becoming cheaper, air quality monitors are becoming more popular and are enabling people to get an idea of the levels of pollution that is in the air they are breathing. Although the best air quality monitors can give you a good indication as to the levels of pollution that is in the air, they should not be considered a substitute for a proper air quality test. Air quality testing is more accurate and has a much wider range when it comes to detecting what contaminants are present in the air. The equipment used is also often of higher accuracy than what is available to be incorporated into domestic air quality monitors.
Although most air quality monitors can give a basic idea of what is in the air, most do have limitations. As an example, particulate contamination from a faulty boiler or diesel exhaust would not be observable from a PM2.5 reading from most air quality monitors.
When looking to purchase an air quality monitor, there are several features that should be looked at that will be able to give a good indication as to the overall quality of air in an environment. Size of particulate matter measured should be one of, if not the most important feature in an air quality monitor. There are some ‘air quality monitors’ on the market that do not monitor PM levels at all, but instead only monitor carbon dioxide, temperature, humidity levels and supposedly VOC’s. PM levels, however, play an integral part if not the most important one in most domestic environments in determining the overall indoor air quality. Purchasing an air quality monitor that does not have this feature would compromise the readings that you get.
Carbon dioxide detection is a useful feature as it indicates when CO2 levels are getting high which means you should take appropriate steps, such as opening the window to ventilate the area and lower it. A build-up of CO2 levels can lead to feelings of dizziness, headaches and even nausea.
Temperature and humidity sensing capabilities are also features which a lot of air quality monitors are equipped with and can be useful to have. High levels of humidity can cause mould and elevated levels of mould spores in the air. Typical associated symptoms are sore eyes, nose and throat irritation as well as coughing and wheezing in people suffering with asthma.
Another important factor in choosing the best air quality monitor is to consider how the readings from the air quality monitor will be communicated. Most air quality monitors have some type of app which can be downloaded and this is where the readings are displayed. Some may even have the option to log in online to view the results this way. This can be a good way of monitoring air quality readings easily and remotely. The use of apps and online access means that data may be able to be logged and viewed over a period of time, which means you can see if there are any patterns emerging. But ideally, the air quality monitor should have a user-friendly LCD screen so that readings can be viewed directly from the unit. Having an easy to read screen means that you can have a look at the screen and know exactly what the air quality is like without the need to use an app or computer.
When it comes to the detection of VOC’s, there is currently no low-cost VOC sensor that can be incorporated into a consumer product at a reasonable price that would be able to provide accurate VOC readings. There are air quality monitors available that market themselves as having VOC sensing capabilities but the accuracy of these sensors should be questioned. To get an idea of how accurate an air quality monitor is, it needs to be compared against more sophisticated air monitoring devices which are often used by professionals to record air pollution levels. These devices will have better sensors along with excellent levels of calibration and their accuracy will be a good comparison to any air quality monitor.
Air quality monitors tend to only measure a limited spectrum of pollution. A good air quality monitor will measure 0.3 to 2.5 microns. This may not always be the case as there could be harmful pollutants in the air which the air quality monitor is not able to detect, due to the particles being outside the measuring capabilities of the device. Most domestic air quality monitors are really best used only in conjunction with a leakage-free air purifier. The air purifier will be able to remove virtually all particulate pollution including ultra-fine particles in the air, even if they are not measured by the air quality monitor. Using an air quality monitor in conjunction with an air purifier means that you can look at the readings of the air quality monitor and know when air contamination has risen, thus allowing you to adjust the air purifier speed setting to lower the levels.
Particle pollution comes in a variety of sizes, with the most commonly discussed particle size being PM2.5 and PM10. However, measuring at 0.3 microns is the most important as particulate pollution at that size has the most negative impact on health. This particle pollution is also most prevalent in cities, due to exhaust fumes caused by the combustion process of automotive vehicles. This level of ultrafine pollution once breathed in, can reach your bloodstream via the lungs.
The reading in the picture below is representative of what air pollution levels can be like on a typical day in London. Over 200,000 particulates per cubic litre and this is on a very warm day where the temperature was into the 20’s.
If you find yourself stuck in traffic or behind other cars for extended periods, you can expect to see that number go even higher. All cars would provide some level of particulate filtration when the car air conditioning ventilation system is activated, but the standard fitted car filters mostly have very low filtration efficiency and do not provide the level of filtration efficiency that you can get from a leakage-free HEPA car air purifier.
Clearly driving around can pose a significant health risk to those that are sensitive to this kind of pollution as there is no easy way to reduce the level of pollution. You can close the windows to limit the amount of pollution entering the car but you will raise the Carbon Dioxide (CO2) levels. The IQAir Atem car air purifier offers HEPA filtration that can be used in the car to reduce pollution levels.
Laser particle scanners or particle counters as they are so known are highly accurate professional devices designed to measure particle pollution. They are much more reliable when compared to most of the air quality monitors on the market today that use cheaper sensors to detect pollution. Some laser particle scanners are capable of measuring different sizes of particulates and can provide instant readings when compared to other devices that provide readings with every few seconds or longer. With laser particles scanners being so accurate, they can tell you where contamination is highest and where it may be coming from. Laser particle scanners are very expensive and would be cost prohibited for most people.
If we look at the Particle Scan Pro, it is capable of measuring different sizes of particle pollution ranging from 0.3 – 5.0 microns in size. The Particle Scan Pro provides data logging capabilities whereby the device stores particle readings of the environment based on user-defined set intervals. This enables the data to be analysed and patterns or trends in particle pollution identified. The Particle Scan Pro also allows measurement data to be logged in real time to the computer via a USB cable or network.