How good are air purifiers? - in the air-Q Test

Admittedly, the terms air filter and air washer seem misleading and at first glance they are also very similar. Nevertheless, the devices differ. The respective designation also reveals which device is responsible for which function.

What can an air filter do?

Air purifiers filter the room air and remove dust, pollen or cooking odours from it. There are different types of filters for this purpose: for example, carbon filters or so-called "High-Efficiency Particulate Air/Arrestance" - HEPA filters for short. Carbon filters are found, for example, in extractor bonnets that have no outlet to the outside. But HEPA filters can do even more and circulate the room air, so to speak. They can filter air particles that are only fractions of a micrometre in size.

What can an air washer do?

With air washers, the room air is actually washed. Unlike air purifiers, however, the air is not cleaned by filters but by a water bath. Allergy sufferers know this too well: when there is a high pollen load outside, nothing helps as much as a heavy rain shower. After that, breathing becomes easier again.

Venta AH902 Professional K: The mobile air washer with air humidification

Our test device, the Venta AH902 Professional K, is an air washer. The room air is sucked in via a fan and fed into the air washer filled with water. Stacks of plates rotate in the device and hold pollutants such as dust or pollen. The air is cleaned in the water and pollutants are collected in the air washer. Hygienically clean water is evaporated into the room via the plates. In our air-Q Lab, we found that the air purifier removes both VOC and particulates particles from the room air.

What are VOCs?

VOCs (Volatile Organic Compounds) are the group of volatile organic compounds. These include gaseous and vaporous substances of organic origin that are found in our air. For example, these are hydrocarbons, alcohols, aldehydes and organic acids. Many solvents, liquid fuels and synthetically produced substances can occur as VOCs. But also numerous organic compounds that are formed in biological processes (for example during mould formation) belong to the VOCs.

If the VOC concentration exceeds the limit values, this can lead to an altered smell and taste perception or manifest itself as irritation of the eyes or mucous membranes. Other effects include poor concentration, exhaustion, dry skin, eczema and headaches. The Federal Environment Agency has set guideline values for the concentration of certain VOCs in indoor air.

	Konzentrationsrange [mg TVOC/M³]	Hygienestatus	CO2 Concentration (ppm)
Level 1	<= 0,30 mg/m³	hygienically unthinklich	< 1.000 ppm
Level 2	0.30 - 1.0 mg/m³	hygienically still unpossible, as long as there are no guidelineoverwritetions for individualsubstances or fabricgroups are present
Level 3	1.0 3.0 mg/m³	hygienically ondue	1,000 - 2,000 ppm
Level 4	3.0 - 10 mg/m³	hygienical considerationlich
Level 5	> 10 mg/m³	hygienically inaccepttabel	> 2,000 ppm

Source: Federal Environment Agency

What is particulates?

Particulate matter (PM) is the term used to describe a part of airborne dust. This includes the particles in the air that do not immediately sink to the ground. Depending on the particle size of the different particles, suspended dust is divided into different groups: PM1 includes all dust particles whose aerodynamic diameter is smaller than 10 micrometres (that is 10 millionths of a metre). This PM10 fraction of suspended dust is generally called particulates.

Air purifier AH902 K from Venta in the air-Q test

In our test, we artificially polluted the air in a room with a size of 20 m² with an incense candle. We lit the candle at eleven o'clock. We checked our test with the air-Q pro air measuring device with a total of 14 different measured values. The data was monitored live on the smartphone via the air-Q app during the test. We then exported the data and analysed it on a PC using a statistics program (see diagram). Just ten minutes later, the values rose rapidly and peaked after about 20 minutes. Both the VOC and particulate matter levels in the room were drastically increased.

When the air-Q indicated strong air pollution and high VOC values by means of the red LED lights, we activated the Venta air purifier. As we could see in the evaluation on the PC, the particulates pollution dropped quickly and steadily. After barely half an hour, both the VOC and the particulates values had halved.

Diagram air measurement VOC with the air measuring device air-Q — Visible increase in VOC values in the air-Q Lab

Diagram air measurement particulates with the air-Q — Increase in particulate matter levels in the air-Q Lab

Result of our air-Q Lab

The Venta air purifier was able to reduce the very strong contamination by half after only 30 minutes. In continuous operation, the device ensures that excessive levels are not reached in the first place. Our check is available here as a short video: