Indoor Air Quality: What can be measured in the air?

Good indoor air quality offers many benefits: It creates attractive and safe workplaces and helps to save costs in the long term. Thus, good indoor air quality determines the productivity, health and performance of employees – and helps to reduce costs in building management in the long term.

  1. The importance of oxygen (O2) indoors
  2. Monitor and reduce indoor CO2 levels
  3. Humidity as an influencing factor in indoor air quality
  4. Measure Indoor Air Quality – and create efficient and safe places with the right measures



What is Indoor Air Quality?

It influences health and well-being – both at home and at work: Indoor Air Quality, also called IAQ. Indoor Air Quality can be described as perfect indoor air when there is an optimal relationship between temperature, humidity, CO2, and oxygen.

The purer the air, the higher the quality.


People spend 90% of their time indoors and therefore the importance of clean and healthy air is of great value for personal well-being and work performance.

Unfavorable air humidity and temperature, unpleasant odors, and pollutants are among the unwelcome guests in indoor air. Frequent consequences are concentration difficulties, states of exhaustion, and headaches. Thus, indoor air quality affects cognitive performance and leads to lower productivity and a higher number of sick days among employees.

The economic and professional challenge for those responsible: to ensure healthy indoor air quality in order to create healthy and safe workplaces while also ensuring efficient building use with low operating costs.

Not an easy task. The good news is that indoor air can be measured – and thus optimized – on the basis of various factors.


The importance of oxygen (O2) indoors

The concentration of various vapours, gases and particles determines the condition of the air quality in your indoor spaces – for example in offices, during meetings in the conference room or in break rooms.

Oxygen (O2) is of great importance for the air you breathe indoors. The gas helps keep the brain functioning and the body working.

What happens to oxygen in the body?

Oxygen first reaches the lungs from the ambient air, from where the gas makes its way into the body's bloodstream. A process known as cellular respiration takes place; the body generates energy. In the process, it inhales about 21 percent oxygen – and exhales about 16 percent.

Good to know: If inhalation takes place via the nose, the inhaled air can be filtered, humidified, and warmed somewhat beforehand. As soon as the oxygen concentration drops below 17 percent, the consequences of an undersupply are imminent: The reaction time is prolonged and the person becomes tired. It is possible that the error rate will now increase for tasks in the job that are part of the daily routine.

The following symptoms, among others, indicate a lack of oxygen, for example at workplaces:

  • Reduced concentration
  • Decreased absorption capacity
  • Fatigue
  • Tiredness
  • Headache
  • Nausea
  • Feeling of weakness
  • Dizziness
  • Aggravation of existing health problems (e.g. allergies, asthma)

Optimize oxygen content: What helps?

The more people are indoors in an office, in schools and clinics or in other workplaces, the higher the oxygen consumption.

You may know it from your private life: The more family members are in the bedroom or children's room, the quicker you are usually overcome by the desire to open the window after a while. Fresh air should flow in. After all, more oxygen has now been consumed.

Targeted and regular ventilation is the means of choice for improving the oxygen content in indoor spaces.


Especially in heated rooms, when the body loses even more fluid through the breath and the skin, it is of great importance against emerging fatigue. Because: Dryness causes less supply with blood and not enough oxygen to the brain.

Carbon dioxide (CO2) indoors

Another indicator of indoor air quality: carbon dioxide (CO2). The odorless gas is a natural component of our air atmosphere. CO2 is not only produced during the combustion of fossil fuels, but also in the body – for example, when you exhale or digest.

Many people are familiar with CO2 as a greenhouse gas in the climate debate. Yet carbon dioxide, as it occurs naturally, is not a culprit per se. On the contrary: CO2 is part of the earth's natural protective cover.

The big problem: Too much CO2 in the air, as caused by human intervention in the natural atmosphere, poses a danger in the long term; temperatures on earth are rising ever faster, the planet is getting hotter.

Too much CO2 is also a problem indoors: In the air we breathe, carbon dioxide is considered hazardous to health. When you breathe, it is combined with oxygen. This means: you breathe in oxygen and exhale carbon dioxide.

In the body, CO2 is therefore a waste product. If the levels are too high indoors, it poses a danger to the body. Possible consequences include:

  • General indisposition
  • Headache
  • Concentration problems
  • Reduced productivity
  • Decreased responsiveness


Monitor and reduce indoor CO2 levels

Indoor air ventilation plays an important role in reducing carbon dioxide levels in, for example, offices, schools, or medical facilities. The level of CO2 concentration depends on the following factors, among others:

  • Number of people in the room
  • Activities carried out
  • Physical exertion
  • Size of the room
  • Duration of stay
  • Combustion processes, e.g. by candles or smoke

The motto when it comes to carbon dioxide indoors is: reduce the CO2 content and let fresh oxygen into the room. Correct monitoring helps to reduce the amount of CO2 indoors and allows you to take appropriate measures in the short and long term.

The aim of a measurement in the air is therefore to detect too high concentrations in time and also to prevent them.


VOC: Volatile Organic Compounds Indoors

The collective term VOC stands for volatile organic compounds, which can be measured in the air of your workspace. They could for example enter the indoor air when a liquid product dries.

Additionally, when a liquid starts to evaporate, volatile organic compounds are created in the room. But that's not all: VOCs are also formed during biological processes, such as plant decomposition processes.

In the case of interiors in particular, however, the sources of VOCs can often be traced back to specific items of equipment – such as flooring, furniture, adhesives, and ceiling materials. In addition, they can often be in materials used in the construction of industrial and commercial buildings.

Likewise, if there is improper use of certain building products, the VOC concentration increases.

The problem with VOCs

Volatile organic compounds that can be measured in indoor air are considered hazardous to health. As a rule, the compounds do not pose a problem at low concentrations.

As soon as the period of time during which the human body is exposed to these compounds increases, it is not uncommon for side-effects of high VOC exposure to occur, such as:

  • Odour nuisance
  • Irritation of the respiratory tract
  • Irritation of the eyes
  • Intensification of allergies
  • In the long term: effects on the nervous system

Important: Some VOC compounds are also suspected of being mutagenic and carcinogenic.

How can VOCs in indoor air be reduced?

Although regular ventilation also helps to reduce the VOC concentration in indoor spaces, preventive measures in particular promise a positive effect on health and well-being.

After all, if indoor spaces are contaminated with VOCs, the first step is to take measurements to find the sources and remove them. Particularly if the pollutants are building materials as remediation requires time and money.

In order to create a healthy indoor climate and a safe workplace, more and more companies are relying on continuous indoor air monitoring so that they can act in good time if VOC concentrations are high or rising.

Pollutants that influence indoor air quality

High levels of indoor pollutants have a significant impact on air quality. Whether it's tobacco smoke, pollutants that enter rooms through outside air, or certain older building materials still found in commercial properties: Pollutant sources are many and varied. They also include bacteria, fungi, and viruses

Especially for employers today, it is therefore important to monitor Indoor Air Quality in order to create safe and productive workplaces.


Good to know: The various sources of pollutants, such as VOCs, biocides, or carbon monoxide, can often be found indoors. However, the outside air must also be taken into account. For example, the location of an office can also play a role in measuring indoor pollutant levels.

Example: The building is located directly on a busy road in the city center – and there is no intelligent ventilation system. The risk of the pollutant level increasing when ventilating is high.

Possible contaminant sources:

  • Older building materials
  • Certain floor coverings
  • Electronic devices
  • Airtight (modern) buildings
  • Special furniture
  • Room scent sprays
  • Cleaning agents and detergents
  • Flame retardants
  • Certain plastics, lacquers, textiles
  • Cigarette smoke

What you should consider when measuring pollutants

A conscious approach to pollutants helps to improve indoor air quality. The following applies: The results of a measurement are usually different, depending on the field of activity. However, pollutants occur almost everywhere.

This means that not only crafts or industrial professions are affected, which is an often-underestimated topic.

Strategic monitoring helps to create an attractive and safe working environment, to use space intelligently and to save costs in the long term.



Humidity as an influencing factor in indoor air quality

Rooms that are too humid or too dry: both lead to pathogens settling in offices. But that is not all. Because the right level of indoor humidity makes a significant contribution to maintaining buildings. If the indoor humidity level is too high or too low, it woudld result in a risk of long-term health and economic problems.

What is humidity?

Humidity measurement determines how much water is in the air of your indoor rooms. Important: Experts distinguish between absolute and relative humidity. While absolute humidity describes the actual content of water vapor in the room air, relative humidity shows how high the degree of saturation of water vapor in the air is. As a general rule, relative humidity should ideally be in a range between 30 and 60 percent. Factors that influence the humidity can be, for example, electronic devices in a room that give off heat. People who are in a room also release moisture into the interior through breathing.

Dry air – and its effect on indoor air quality

Especially during the wintertime, when you heat your rooms, regulating the air humidity is not an easy task. Incorrect ventilation behavior or inadequately adjusted ventilation systems can lower indoor air quality. As soon as the air humidity drops significantly, the following consequences are imminent, for example:

  • Impairment of the body's ability to breathe
  • Headaches
  • Drying out of the mucous membranes
  • Higher risk of catching a cold due to a weakened immune system

Effects of too high air humidity

High humidity occurs, for example, in offices or rooms where several people are present. The air we breathe condenses and water vapour is produced. Risk factors also include inadequate building insulation and incorrect ventilation behavior. The consequences:

  • Sweating
  • Increased risk of mold growth
  • Higher risk of illness

Regulating Humidity for Higher Indoor Air Quality

Be careful not to overheat indoor spaces to prevent dryness. In addition, proper ventilation habits help regulate indoor humidity.

In order to warm buildings efficiently and save costs at the same time, the right heating behavior is also required. This is how you prevent the formation of mold.

Humidity measurement helps you to take appropriate measures and create a safe and inviting working atmosphere.


Temperatures indoors: How do they influence indoor air quality?

If you are always sweating or shivering, you cannot concentrate optimally on your work. It is, therefore, all the more important that many companies pay attention to an appropriate room temperature for their employees.

The general recommendation is that the room temperature in the office should be at least 21 degrees Celsius. Those who work predominantly in a seated position produce less heat

By comparison, activities that require more movement usually also result in a higher body temperature. In this case, a room temperature of around 19 degrees Celsius may be perceived as more pleasant.

Correct measurement and setting of the room temperature are therefore also dependent on the type of activity.

What happens if the temperature in the workplace is not right?

If a temperature measurement shows an indoor temperature that is too high or too low, the following risks may be increased:

  • Concentration problems, reduced performance
  • Freezing or increased sweating
  • Tiredness
  • Increased risk of catching a cold
  • Headaches
  • Skin problems
  • Dizziness

Creating the right indoor climate

In order for employees and workers to perform at their best and stay healthy, regulating room temperature is essential for high indoor air quality.

Hot spells, for example, present particular challenges when the height of summer puts a strain on indoor air quality. Remedies include not only cooling drinking water, but also installing a cooling unit or fans if needed.

Employers should also take care to avoid constant draughts at workplaces. In the long term, this means that monitoring and measuring the room temperature is a must when it comes to creating safe places to work.

The concentration measure PPM

PPM is an abbreviation of parts per million. The formula: PPM indicates the amount of parts per million. It plays a role as a concentration measure in the measurement of indoor air quality - and serves as an auxiliary measure for the specification in volume percent. An equation can be made with the indication ml/m³. Basically, the following applies: 1 ppm results in 1 of 1,000,000 parts.

PPM example

A CO2 measurement takes place in the central city area. The outside air shows a value of 0.040 in volume percent. Converted, this means that the measurement gives a value of 400 ppm. The CO2 content in the air in ppm is therefore 400.

PPM as a unit of measurement for calculating the CO2 content indoors

Not only to increase energy efficiency, but also to increase productivity, the monitoring of CO2 levels in the workplace is considered particularly important.


Guide values for indoor rooms:

If the CO2 level is below 800 ppm, it is generally considered good. The aim should be for the CO2 content to be below 1,000 ppm. It should not exceed 1,400 ppm (maximum value). If the value is above this, it is essential to check the ventilation behavior. One problem is that human perception only notices that the air quality is poor at a value of 2,000 ppm, but cognitive performance drops significantly even before that.

Be sure to take steps to protect employees when the level is above 2,000 ppm. Then there is a serious risk to the health of everyone who is in rooms with a hygienically conspicuous carbon dioxide content.


Measure Indoor Air Quality – and create efficient and safe places with the right measures

Fresh and clean air, an inviting room atmosphere, and a pleasant temperature to work at: Indoor air quality determines the attractiveness and safety of workplaces.

Those who take the right measures, therefore, contribute to the well-being of the staff on the one hand. On the other hand, efficient and long-term cost-reducing building management takes place.

Important: Although the right heating and ventilation behavior already works wonders to improve indoor air quality, ideally you should rely on long-term monitoring. This way, you can keep an eye on all values – and create an inviting and safe room atmosphere.