Outdoor air vs. indoor air: Which is dirtier?

Why indoor air is often more polluted than outdoor air

Whether at home, in the office, in the classroom, or in the car: people today spend around 80 to 90 percent of their time indoors. This makes the quality of indoor air all the more important, as it has a direct impact on health, well-being, and performance. Nevertheless, indoor air is often more polluted than outdoor air.

One of the main reasons for this is building materials and furnishings. New furniture, carpets, paints, or varnishes can release volatile organic compounds (VOCs) into the air, which accumulate in closed rooms over time. In addition, everyday activities such as cooking, heating, burning candles, or using cleaning products produce further pollutants and fine dust particles.

The people present also influence the air quality. Breathing releases CO₂, which increases humidity. In poorly ventilated rooms, this can promote the growth of microorganisms and mold. This problem is particularly acute in modern, energy-efficient rooms, as they are built to be very airtight.

When is outdoor air dirtier?

Of course, there is also pollution outside: traffic, industry, heating, or natural sources such as pollen or dust contribute to particulates, nitrogen dioxide (NO₂), and other pollutants.

Near busy roads or industrial facilities, the outdoor air can even be more polluted than the indoor air for short periods of time, especially if the rooms are regularly ventilated.

Nevertheless, most people breathe indoor air more frequently and for longer periods of time, so its quality is more crucial to their health.

What causes indoor air pollution?

Air pollution arises from many different sources and mechanisms:

• Everyday activities such as cooking, heating, cleaning, or burning candles release pollutants and particulates.
• Moisture and mold: High humidity can promote mold growth, which further pollutes the air.
• Tight construction / insufficient air exchange: Fresh air can hardly circulate in modern, well-insulated buildings.
• Building materials, furniture, textiles: Furniture, carpets, paints, and varnishes emit harmful substances over many years.
• External sources: Pollutants from the outside air enter through windows, doors, or ventilation systems.

What are the consequences of poor air quality?

Poor indoor air quality can have a wide range of health effects: short-term headaches, fatigue, eye and throat irritation; long-term respiratory diseases, allergies, and cardiovascular problems. Children, older people, and people with pre-existing conditions are particularly at risk.

Since we spend so much time indoors, clean indoor air is crucial for our health and well-being.

Measures for better air quality

There are simple strategies for improving air quality:

• Ventilate regularly: several times a day, briefly and intensively: bursts of ventilation bring in fresh air, provided that the outside air is not too polluted.
• Reduce sources of pollutants: Use low-pollutant furniture, paints, and materials; use fewer scented candles and avoid aggressive cleaning agents and solvents.
• Control humidity: Measure humidity, dry laundry properly, ventilate after showering or cooking.
• Air purification/filtering: HEPA filters or air purifiers can also remove particles and pollutants from the air.
• Monitor air quality: Keep an eye on indoor air quality using suitable air quality measuring devices so that you can take action as quickly as possible.

How air-Q can help

The air-Q is a smart air quality monitor that helps to specifically monitor and sustainably improve indoor air quality. The device continuously measures important parameters such as pollutants, particulates, CO₂ concentration, humidity, and other relevant factors in indoor air in real time. Based on this data, the air-Q provides recommendations and indicates when ventilation is advisable in order to effectively improve indoor air quality. At the same time, it becomes clear how effective measures such as regular ventilation or the use of an air purifier actually are, as changes in air quality can be tracked immediately. This allows users to maintain control over their indoor air at all times and actively contribute to protecting their health, well-being, and performance in their living and working spaces.

Indoor spaces are often hidden hotspots for pollutants, while outdoor air is not automatically "dirtier." With a little attention, the right measures, and an air quality monitor such as the air-Q, air quality can be significantly improved.

Because clean air not only means well-being, but also better health for you and your family.

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