Home smog sensors are small devices that are designed to inform you of the level and type of pollution in your immediate surroundings using a built-in mechanism. If you want to know how a smog sensor works, which smog sensor to buy for a gift, or are wondering whether a handheld smog sensor will be right for you, the following article will clear up your doubts.
Smog sensor - why invest in one?
Air quality sensors are increasingly popular devices in Poland, appearing both in public spaces and in many homes. This is because there is a growing awareness of air pollution - we want to know what we are breathing and harm ourselves as little as possible. The smog created by car emissions, home heating and home heating adversely affects your health. Laser smog detectors are designed to inform you of the pollution levels around you. This gives you an awareness of what you are breathing and, within your own capabilities, you can fight against unwanted particles.
Types of smog detectors
The air meter models available on the market are most easily divided into those for outdoor and indoor measurements. Indoor sensors allow you to check indoor air quality. It is worth remembering that the concentration of pollutants indoors and outdoors will always be different, so an indoor sensor will allow you to determine exactly what kind of air you are breathing at home or in your workplace. Due to their design and specifications, indoor sensors are not suitable for use in atmospheric conditions where they are exposed to precipitation, strong sunlight and wind.
Outdoor sensors are small devices, adapted to changes in weather conditions, connected to a larger network of sensors. The Chief Inspectorate of Environmental Protection has around 200 deployed meters in the country, which test the air quality on the streets of towns and villages. In addition to the public units, many private companies also set up their sensor grids on the basis of which they determine the air quality in the country. Companies distributing outdoor sensors include: Airly, Looko2 or Synegos.
How do smog sensors work?
The outdoor smog sensor works on the principle of examining a supplied air sample, which is sucked into the unit by means of a special pump, where the air components are analysed. This is done by means of a built-in laser, which analyses the particles in the sucked air. The sensor can monitor air quality in real time and continuously or provide data periodically. The second option saves the device's battery power, so it can be efficient for longer periods.
What do home air quality sensors measure?
When scanning the air taken inside the sensor, laser beams pick up dust (PM10 and PM2.5), volatile organic compounds (TVOCs), and formaldehyde. The measurements allow small particles to be identified in order to determine what quality of air you are breathing and what measures need to be taken to make being in your home as harmless as possible.
PM10 and PM2.5 are airborne particles that are less than 10 and 2.5 micrometres in size respectively. Three standards have been set for PM10 (data given as daily average):
- 50 µg/m3 as the limit level;
- 200 µg/m3, as an information level;
- 300 µg/m3, as an alert level.
According to the WHO assessment, the limit threshold should not be exceeded for more than 35 days per year. The limit for PM2.5 in the air, according to EU recommendations, is 25 μm. Formaldehyde and TVOC, on the other hand, are chemical compounds with carcinogenic and respiratory effects, whose concentrations should not exceed 0.05 and 5 μm respectively.
Comparison of professional and home smog detectors
As well as being designed to check the state of air quality, professional and domestic sensors have different applications. Professional sensors are usually used to check the state of air quality outdoors and are interconnected to form a nationwide network, on the basis of which pollution levels in individual towns and cities and the country as a whole are determined. In Poland, there are several professional networks of laser smog sensors monitoring pollution levels in the country and making their measurements available. The first is the GIOŚ, mentioned earlier, which shares data on its website, as well as with apps available for smartphones. Private projects involved in building networks of air quality sensors include Airly and LookO2.
Both companies produce their own measuring devices, which are installed in various locations, once purchased by private consumers. The devices are permanently connected to a WiFi network so that they can communicate with each other, and all the measurement information goes to the cloud. This allows you to use special portals displaying pollution maps and the state of pollution at specific locations. Airly has its own app, where you can check the readings from your own sensor and other devices logged into the network in real time. In a similar way, you can use Synegos' infrastructure. In addition, the data is also made available for public use, sometimes forming part of the data of other air quality monitoring applications, such as Canary.
Personal smog sensors are designed for indoor use only (mains sensors are designed for outdoor use) - battery-powered or rechargeable. These small devices provide real-time information on the state of air quality. They can be a fully independent station or be linked to their manufacturers' apps. Some can be portable - you can take the smog sensor with you and check how the air quality changes depending on where you are. They will also work well as smog monitors when you are training outside.
Home sensors are also simpler devices than professional measuring stations. They usually measure the concentration of PM10 and PM2.5 dust (there are also models that take only one measurement). In comparison, GIOŚ sensors index PM10 and PM2.5 as well as the compounds SO2, NO2, O3. Air quality data is additionally assessed on the basis of the Polish Air Quality Index.
Prices of home smog detectors
Prices for home smog detectors start at around 100 PLN, and some of the more expensive ones on the market will require a budget of up to 2 000. The difference in prices is mainly due to the quality and accuracy of the equipment made available for home use. The price will be further influenced by the number of additional features or the fact that the sensor may be built into an air purifier.
Products on the market are characterised by their compact size. Smog sensors are usually square or rectangular shaped devices that can be laid down or placed at eye level, in a place where you often look. This allows you to monitor how the air quality in your surroundings is changing in real time.
The price of a home smog sensor will also depend on its level of sophistication. The simplest products, such as the Xiaomi-branded sensor, whose price does not reach more than £150, only analyse data related to the intensity level of PM2.5 particles. More expensive products, which examine the concentration of more particles and also measure temperature, humidity and pressure, will be more expensive, in the price range of £200 and above.
How to read and interpret smog sensor data?
Home smog sensors provide information about the current state of the air via the app that runs the device or a display built into the sensor. The information shown is measurements presented as a colour or numerical scale. Depending on the product, data will be updated hourly, once a day or when changes in air quality are recorded.
The device is usually automatically calibrated according to WHO recommendations and the standards they set. A measurement indicating the amount of smog in the air is often mapped on a colour scale, where green indicates that the current air level is indicated and red indicates poor air quality. The scale can also take intermediate colours.
Typically, contamination at the level of:
- 0-20 (PM10) / 0-13 (PM2.5) indicate very good air quality;
- 20.1-50 (PM10) / 13.1-35 (PM2.5) are indicative of good air quality;
- 50.1-80 (PM10) / 35.1-55 (PM2.5) are indicative of moderate air quality;
- 80.1-110 (PM10) / 55.1-75 (PM2.5) are indicative of sufficient air quality;
- 110.1-150 (PM10) / 75.1-110 (PM2.5) are indicative of poor air quality;
- >150 (PM10) / >110 (PM2.5) are indicative of very poor air quality.
The data comes from the GIOŚ website.
The devices, especially if linked to a mobile app, send alerts to their users along with changes in air quality, indicating that it is a good time to go for a walk, the air quality in the home is worryingly poor or the home should be ventilated (assuming cleaner air from outside than the air in the room).
The most popular smog detectors - which model to choose?
When deciding on a smog sensor, whatever you require of it, it is worth betting on quality at a price commensurate with the product's capabilities. The basic value that the sensor should measure is the level of PM2.5, as this is the most harmful and dangerous substance included in smog. It is also worth noting how home smog sensors are calibrated. Depending on the standards that have been coded, the level of harmful pollutants may be recorded by the sensor at a level that significantly exceeds WHO standards. When deciding on a sensor, choose one that has been programmed according to the guidelines. 
If you are only interested in products that inform you of specific parameters, look for the simplest sensor, while not overpaying for extra features. These are usually small devices whose dimensions allow you to take them with you on walks and carry them in your bag. You can find these types of devices from brands such as Xiaomi, Fine Air or Noklead. They are usually characterised by their small size and battery-powered, so they can accompany you during the day as mobile smog sensors, testing the air quality wherever you go.
For those interested in measuring stations that examine more air quality factors, products from, for example, the Dienmern, Air Visual, Webber and EcoLife brands are ideal. In addition to measuring PM2.5 and PM10 particulate matter, the measuring stations also have VOC level testing within their capabilities and are equipped with a humidity sensor, pressure sensor and thermometer.
DIY fans will also find something for themselves - there are many modules available on the market for measuring harmful dust in the air, which you can turn into a measuring station yourself, testing exactly the parameters you want. Creating your own station based on an Arduino or other platform is certainly no small amount of entertainment, combined with useful knowledge of your immediate environment. There is no shortage of tutorials on the internet explaining how to make a smog sensor yourself. Those interested in the state of the air outside the home, ready to spend more than a few hundred zloty, can invest in an outdoor station, such as the Airly, LookO2 or Synegos brands. In addition to being able to monitor the air quality in your immediate surroundings, you can become part of a network monitoring the air quality in your city.
Smog and air quality sensors are devices that allow us to monitor the state of the air in our environment, its quality and, consequently, our health. Smog is a mixture of pollutants with haze, formed particularly often in cities. The resulting cloud mixes with the air we breathe, introducing a number of harmful substances into the body. The damage that smog causes is not immediately apparent, and the problem of smog in cities is related to its long-term persistence in areas of high population density, harming the majority of the population.
Smog detectors, can partly solve the problem by raising public awareness, moreover, the fight against smog is about reducing its formation. More and more service companies (couriers, suppliers) are using non-emission vehicles - you yourself can ensure that you choose services and shops that consciously reduce environmental damage when shopping.
