With air purifiers, hay fever sufferers can transform their four walls into an almost pollen-free zone. However, not every cleaner is suitable for fighting pollen. Some even seem counterproductive.

Hay fever sounds harmless, but it can be hell for those affected. The mild cases only have to sneeze, the severe ones struggle with itchy eyes, constant secretion of mucus, inflammation of the paranasal sinuses and conjunctiva and even asthma. For many of those affected, this ordeal lasts longer and longer each year, as climate change means that many things bloom earlier and sometimes well into late summer.

Many grass and pollen allergy sufferers should relieve the home office during the flowering season. You no longer have to go out, but air the room early in the morning and then close the windows. That helps a lot, but the tiny pollen continues to penetrate the house. They slip through the smallest cracks in windows and doors, are blown in when they are aired and carried in with the clothes. When walking through the apartment and due to temperature differences, the particles are then whirled up. Some pests are always there anyway, like the house dust mite. Anyone who suffers from a pollen allergy often also has an allergic reaction to house dust. Although the symptoms are usually much less severe than with bee pollen, the combination of both types of allergy means that the immune system is under constant attack.

HEPA is mandatory for allergy sufferers

In addition to tablets, drops and creams, you can also take technical action against allergic reactions, at least within your own four walls: with an air purifier. Two years ago, these devices were more of a niche product, but the corona pandemic has provided a good boost in new devices in all price ranges and configurations.

The basic principle of the cleaner is simple: air is drawn in, passed through several filters on which particles get caught, and released back into the room cleaned. The cleaners do not have to run continuously. Depending on the volume of the room and the power of the fan, only a few minutes per hour. Rule of thumb: The cleaner should be able to filter approximately twice the actual volume of the room per hour. Some manufacturers indicate the cleaning performance in square meters. Here you should take a closer look at the ceiling height the manufacturer has set.

Pay attention to the follow-up costs for the air purifier

Only devices with a so-called HEPA filter are suitable for allergy sufferers. HEPA stands for “High Efficiency Particulate Absorption”. The filter stage before that is called EPA. The HEPA filters can filter particles smaller than one micrometer out of the air. Pollen with a size of at least five microns reliably gets caught in the membranes, as do mite eggs and even bacteria, mold spores and viruses. HEPA filters can be expensive depending on the manufacturer and device. If you stick to the replacement intervals recommended by the manufacturer, you invest up to 200 euros per year in filtered air. When choosing an air purifier, looking at the follow-up costs is just as important as the purchase price.

So that the expensive HEPA filter does not clog up quickly, it is located behind a pre-filter. A membrane for the rough that blocks hair, dust, lint, insects. Pre-filters are usually not replaced, but cleaned or rinsed with a vacuum cleaner from time to time.

In many models, there is an activated carbon filter between the pre-filter and the HEPA, which is also used in extractor hoods. Their job is to filter odors. Viewed microscopically, coal is very porous, the air flows through it as if through a large labyrinth. On the long journeys, odor particles get stuck and are stored in the charcoal structure. At some point the carbon can no longer absorb particles and the filter must be replaced.

Double Edged Ions

The ionizer, on the other hand, is indestructible. This component in the air purifier charges the air particles electrostatically using UV light. Particles in the air accumulate on the negatively charged particles, form larger clusters that sink to the ground and can be filtered out of the air much more easily. The air looks fresher. The idea is copied from nature. Ions occur in much higher concentrations in nature than indoors. Among other things, they are the reason why we perceive the air from outside as clear and the air in the room as stale.

However, by-product is ozone, a gas with double-edged properties. Ozone consists of three oxygen atoms and is very reactive. In this way, it can break down and neutralize odor molecules, even if they have already been deposited in textiles. In higher doses, however, ozone is harmful to health. The limit values ​​set by the EU are 180 micrograms of ozone per cubic meter. Sensitive people, and these are usually allergy sufferers, react to the chlorine-smelling gas from as little as 40 micrograms. Even if the air purifier stays well below these values, the German Allergy and Asthma Association DAAB advises against ionizers. There is a relationship between the benefit and the risk of discomfort.

Softfoot preferred

Air cleaners suck in the air with a fan and blow the cleaned air out on the other side. What turns makes noise. During the day, the quiet whirring may be lost in the background sound of everyday life, but in the bedroom the cleaner should preferably not be turned up louder than 30 decibels. Many devices offer a night mode with reduced speed and dimmed lighting of the control buttons. The better devices can be controlled via an app. The small programs for the smartphone then also indicate upcoming filter changes.

Some air purifiers can not only filter the air, but also humidify it at the same time. Moist air initially sounds tempting for allergy sufferers with irritated airways, but doctors warn against the air washers. As soon as bacteria and fungal spores accumulate in the water tank, they are released into the room air. In sometimes large quantities, as studies have shown. Possible allergic reactions to fungal spores include sneezing fits, a runny nose, coughing, tiredness, joint pain or headaches, gastrointestinal problems or allergic asthma. Therefore: If in doubt, as an allergy sufferer, it is better to do without air humidifiers.