Fresh white flowers in spring, zesty citrus in the summer and warm cinnamon in the winter, there are so many fragrances to choose from for every occasion or situation, whether this is in the form of perfume, a scented candle, room spray or a diffuser for your home. But apart from smelling divine, do these home fragrances actually have any benefits or do they bring along a flurry of health risks?

Fragrance manufacturers promise their scents will make it easier to relax and concentrate, while psychologists say they can evoke memories and feelings in us. The sense of smell has long been strongly associated with memory.

"In countries like France, the U.K. or the U.S., home scents have been popular for a long time," says Nicolette Naumann, division manager at the Ambiente consumer goods fair. However, sales have intensified during the COVID-19 pandemic.

Harnessing the effect

Many people want to feel good when spending a lot of time at home, especially with a total lockdown now upon us. For others, essential oils can help them relax or concentrate better.

Biologist and physician Hanns Hatt believes both are possible: We smell a scent via small nerve cells in the nose, which are directly connected to the brain, acting as a trigger for emotions. The smell gets saved in the memory center – so by strolling happily through a field of flowers, the next time you catch a whiff of flowers you'll think of this joyful feeling.

There are also other scent detectors in the body. We don't smell with them, but they still react to scents. According to Hatt, this explains why lavender can have a calming effect – not only when you smell it, but also when you eat it.

The effect of fragrances on the body is the same for most people – in contrast to smell, which everyone perceives differently. So home fragrances that we associate with something positive can indeed have a mood-enhancing effect.

The importance of fresh air

Scent expert Maria Kettenring is convinced that certain room scents such as lemon, lemongrass, myrtle and thyme can purify the room air and thus create a better atmosphere. At the same time, Kettenring, who has already written several books on the use and healing powers of essential oils, emphasizes the importance of ventilation and opening the windows: "The basis for using essential oils should always be fresh air."

The German Environment Agency and the German Allergy and Asthma Association take a more critical view: additional fragrances can have an adverse effect on the air quality of indoor spaces.

"Even if it smells better, it doesn't improve the air quality," says Silvia Pleschka from the Allergy and Asthma Association. On the contrary: "Fragrances merely mask stale and polluted air," says the chemist.

The risk of allergy

"Even if there are no immediate health effects, fragrances can affect everyone," Pleschka said. Some ingredients can cause allergies, and over time, frequent use can lead to fragrance sensitivity. This can easily be observed in crowded spaces such as offices.

Symptoms of fragrance intolerance tend to be mild, such as headaches, circulation problems or sweating, but it can also lead to restlessness, migraine-like headaches and even asthma attacks.

Experts agree that the quality of home fragrances plays a major role. Synthetic fragrances often contain chemical additives and solvents that can cause discomfort when breathed in, Hatt said.

High-quality natural-derived fragrances tend to be a bit more expensive, in part because manufacturers need large quantities of the ingredients for these fragrances. If you're not sure, you can get advice at a pharmacy or a health food shop, Kettenring said.

If you suspect you have an allergy, you should get tested by a doctor and get an allergy passport – with all the substances to which you are allergic. Getting tested means you can check ingredients for your intolerance when making purchases. Allergenic substances in fragrances must be marked on the packaging, Pleschka said.

Kettenring recommends using only natural essential oils and checking packaging instructions and warning symbols. You also shouldn't let the undiluted oils come into contact with the skin.

A good formula to prevent yourself from going overboard with the fragrance is to use eight to 15 drops of essential oils maximum in distilled water for a room of about 18 square meters (190 square feet).

Which scent is or becomes your favorite is a matter of taste, the fragrance expert said. Orange, lavender, pine and grapefruit are among the most popular scents.