The most important things to know

to choose meaningfully.


Air quality monitors are devices created with the scope of tracking and informing about the presence of pollutants in the air.

Air quality has an impact on the health of our planet and plays a fundamental role in the health of the people. For instance, at the residential level, poor indoor air quality can be the origin of asthma, allergies, skin irritation, cancer and many other health issues, being still one of the significant causes of household death in the world.

The pollutants that can be found in the air include physical, chemicals and biological pollutants. Examples of these pollutants are noise, electromagnetic fields, particulate matter (PM), carbon monoxide (CO), carbon dioxide (CO2), methane (CH4), lead (Pb), asbestos, volatile organic compounds (VOCs), formaldehyde (CH2O), ozone (O3), sulphur dioxide (SO2), nitrogen dioxide (NO2), radon (Rn) and ionising radiations (beta and gamma particles). Their origin varies and includes sources like outdoor pollution, ventilation systems, candles, tobacco smoke, fireplaces, stoves, furniture, electrical equipment, construction materials, cleaning products or personal care products. On the other side, temperature and humidity are two environmental factors that influence the presence and development of pollutants.

Having one or more air quality monitors at home can be helpful to identify pollution trends, to understand the type of activities that create pollution, to get alerts when a certain level of pollution is overpassed, to minimise exposure to contaminants. When connected to the internet, the air quality monitors can trigger other connected devices, like air humidifiers, air purifiers, thermostats or fans, to decrease the concentration levels of pollutants.


  • 0%


No direct impact on time savings.

  • 0%


No direct impact on the physical environment.

  • 0%


Peace of mind increased thanks to automatic notifications in case of overpassing acceptable healthy limits.

  • 0%


No direct impact on home costs.


Air quality monitors can be classified considering several criteria. For instance, it can be distinguished between internet and non-internet connected devices, battery and hard-wire powered devices or monitors that track a specific type of pollutant. However, the technology used by air quality monitors is what puts one type apart from the other as it does not just define the type of pollutant that can be monitored, but it also impacts its’ performance:

Used generally to monitor VOCs, these detectors rely on the resulting electrical current of a circuit. They are made of two separated electrically charged metal plates and a radioactive substance. This substance converts the air molecules flowing between the two plates into charged molecules, closing in this way the electrical circuit. When gases enter into the detector, the flow of icons between the two electric plates breaks, opening in this way the electronic circuit and activating an alarm.

Used generally to monitor CO and CO2, these detectors rely on the absorption of infrared light. They are made of a light sensor and LED that emits a light beam in a straight direction. In normal conditions, the light beam does not impact the sensor. Instead, when gases enter into the detector, the light beam is interrupted. This brings some of the reflections to impact the light sensor, and as a consequence, an alarm goes off.

Used generally to monitor CO, NO, NO2, O3 and SO2, these detectors work based on a chemical reaction that occurs when gases enter into the detector. The chemical reaction generates an electric current and is by measuring it that the concentration of a gas is determined. Based on the readings, an alarm then goes off.

Used generally to monitor CO, these detectors work based on a gel that changes colour when in contact with certain gases. The colour change is then identified by a separate sensor that processes the information to the central processor, which in turn makes the alarm goes off.

Used generally to monitor CO, NO2 and O3, these detectors rely on the change of resistivity of a metal oxide surface. When gases enter in contact with the metal oxide surface, it reduces the resistivity. This change is then read by the central processor, which activates the alarm.

Used generally to monitor PM, these detectors rely on the light dispersed by particles.

There are some detectors in the market that combine more than one technology in a single device.


Before buying an air quality monitor that enables you to take action against air pollutants, there are some variables that you may want to consider:

To identify a more extensive number of pollutants, it is advised to select a device that combines several detection technologies.

While most air quality monitors track environmental factors like temperature and humidity, not all of them track the same type of air pollutants. Depending on the contaminants that you want to detect, you may choose one device or another. Hereafter follows an overview of the essential air characteristics to be monitored in a household:

Aspect What is it? Where can be found? Which are the risks?
Particulate Matter (PM)

- They are a complex mixture of solid and/or liquid particles suspended in the air.

- Particles are classified attending their diameter in coarse particles

(diameter between 2.5 μm and ten μm), fine particles (diameter ≤ 2.5 μm) and ultra

-fine (diameter ≤ 0.1 μm).

- Particles that are 10 micrometres in diameter or smaller are especially dangerous as they are inhalable.

- Cooking.

- Heating through inefficient stoves and heaters.

- Smoke from candles, fireplaces, tobacco.

Coarse particles can go deep into the lungs and even into the bloodstream. There is a correlation between exposure to particulate matter and a variety of effects on people's health, from irritation of the nose, throat and eyes, to the aggravation of the symptoms of respiratory and cardiovascular diseases, causing premature death in people with lung or heart disease.
Carbon Monoxide (CO) Colourless, odourless and toxic gas.

- Unvented and poorly maintained combustion devices (boilers, furnaces, chimneys, etc.).

- Gas stoves and water heaters.

- Wood stoves and fireplaces.

- Gasoline-powered equipment.

- Exhaust pipes from combustion vehicles.

- Tobacco smoke.

Depending on the concentration levels and time exposure, carbon monoxide can cause fatigue, chest pain, headaches, confusion, reduced brain function and even death.
Carbon Dioxide (CO2) Colourless, odourless and toxic gas.

- Human breathing.

- Combustion processes (stoves, fireplaces, etc.).

Exposure to moderate levels of carbon dioxide can cause headaches, fatigue, confusion, burning eyes and skin, sleepiness, ringing in the ears and high concentrations, even death.
Nitrogen Dioxide (NO2) Highly reactive oxidant and corrosive gas.

- Tobacco smoke.

- Unvented and poorly maintained combustion devices (boilers, furnaces, chimneys, etc.).

- Welding.

- Kerosene heaters.

Exposure to nitrogen dioxide cause irritation to the eyes, nose and throat. Continued and high-dose exposure can result in chronic bronchitis, pulmonary oedema and lung injury.
Volatile Organic Compounds (VOCs) Organic chemicals that, at standard conditions of temperature and pressure, are emitted by solids and liquids in the form of gas.

- Wood preservatives, paints, solvents, glues.

- Cosmetics and aerosol sprays.

- Pesticides, repellent for insects and air fresheners.

- Detergents, disinfectants, dry-cleaned fabrics.

- Building materials and furniture.

- Office equipment and supplies as printers, corrective liquids, glues and adhesives and permanent markers.

Exposure to VOCs can irritate the eyes, nose and throat, headaches and even cancer.

- Colourless, flammable and water-soluble gas.

- It is a type of VOC that because of its’ widespread use is presented separately.

- Building materials and insulation.

- Resins in composite wood products, glues, lacquers and finishes.

- Dishwashing detergents and fabric softeners.

- Cosmetics.

- Paints and coatings.

- Tobacco smoke.

- Unvented combustion devices.

- Fertilisers and pesticides.

Exposure to formaldehyde cause irritation to the eyes, nose, skin and throat. High-dose exposure can result in cancers.
Lead Heavy, soft and malleable metal.

- Batteries.

- Gasoline.

- Cosmetics.

- Paints.

- Ceramics.

- Pipes and plumbing.

Lead is distributed through the body and accumulated in the bones. In adults, lead has cardiovascular effects, like heart diseases. In children, lead has a higher impact at the neurological level, triggering learning and behavioural problems,  slowed growth and lowered IQ.
Radon - Colourless, odourless, tasteless radioactive gas present in nature. - It comes from the natural decomposition of uranium in the subsoil, in rocks and water.

- Soil gas infiltrations.

- Building materials extracted from the underground.

Radon is considered the number one cause of lung cancer for non-smokers, and the second major cause of lung cancer overall.
Noise Unwanted sounds that interfere with the development of a regular activity like sleeping or reading.

- Outside sources like land, railway and air traffic, industries, sirens, neighbours, etc.

- Indoor sources, like home appliances and other installations.

Depending on the level and duration of exposure to noise, it can create stress, speech disorders, sleep disturbance or even hearing loss.
Temperature Presence of heat in an object.

- Air presence.

- Radiant temperature and relative humidity.

Exposure to too cold or too warm environments creates discomfort, can trigger asthma and increase the emission of pollutants.
Humidity Amount of water vapour present in the air.

- Inadequate heating, ventilation or insulation.

- Structural building faults.

- Water leaks.

Exposure to too high or too low humidity levels can trigger asthma and irritate eyes, lungs, nose, skin and throat.

While two different air quality monitors may track the same pollutants, the detection range and the accuracy level of the readings can be different. For instance, in the case of temperature monitoring, the detection range can go from 0ºC to 45ºC, and the accuracy level varies of ±1ºC.

While some air quality monitors collect data in continuous mode, some others may make the measurements at time intervals. You may not need to know the environment conditions at every single moment, but you may do not want either a device that measures pollution once every hour.

Some air quality monitors can use your geographic location to know how outdoor conditions of your neighbourhood, town or closer available monitor are. Based on internal and outdoor readings, air quality monitors can provide more customised recommendations.

Because air quality monitors are thought to track air pollutants in a given specific space, most devices are directly wired to the electrical grid of your home. In case that you want to monitor and share it among different areas, then look for battery-powered devices. 

There are air quality monitors that combine different types of alerts so to adequately warn you of a potential safety issue both when you are at home and when you are away. The most common type of signals are audible alerts (emit a sound), visual alerts (emit light) and remote mobile alerts (send a push notification, email and others).



Place air quality monitors close to contaminants sources as the concentration of pollutants decreases rapidly when going away from the origin. Kitchens, living rooms and bedrooms are ideal home spaces where air quality monitors can be installed. Avoid their exposure to sunlight and other environmental factors, like airflow that can influence the readings. Place the devices on an elevated surface, one or two meters above the ground, and if possible, in a room-centred location.


Consumer air quality monitors are generally pre-calibrated. Consequently, the settings are usually limited to the set-up of the different automation rules that you want the device to trigger. Taking some initial measurements can help you at identifying a good monitoring location. Naming each air quality monitor with a talking name like “Mike’s Bedroom”, “Living-Room” or “Kitchen” will enable easier identification of each room.


Pollutant concentrations may vary on an hourly, daily and seasonal basis depending on the humidity and temperature levels and the type of activity performed. It is a good practice to monitor how the concentrations of pollutants change and correct potential bad habits. To decrease the number of contaminants, you may want as well to follow some general advice:

- For cooking and other combustion activities, use appliances vented to the outdoors (kitchen hoods, fireplaces, stoves, heaters and furnaces).

- For stoves and fireplaces, use natural, dried and certified wood.

- For kerosene heaters, use proper fuel.

- Do not leave the car on the idle run while in the garage.

- Ventilate spaces frequently to decrease the concentration of CO2.

- Provide fresh air when using VOCs.

- Avoid storing non-used or remaining VOCs after their use.


Air quality monitors do not generally require any type of extraordinary maintenance except for wireless ones, which need a periodical replacement or recharge of the batteries. Keep the devices up to date with the last version of the software.

Torna su