Girl smelling air
Girl smelling air
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What does clean air smell like?

For many people, the smell of clean air is the scent of the air outdoors after a thunderstorm. That scent is so alluring that the makers of one particular air cleaner describe their machine as a “thunderstorm in a box.”

For many people, the smell of clean air is the scent of the air outdoors after a thunderstorm. That scent is so alluring that the makers of one particular air cleaner describe their machine as a “thunderstorm in a box.”

What the makers of the “thunderstorm in a box” neglect to mention is that the fresh, post-storm (and also pre-storm) aroma they promote is largely the scent of ozone, deliberately produced by their “air cleaning” machine. In a thunderstorm, ozone originates from nitric oxide that is produced by the electrical charge in the storm. The nitric oxide combines with other airborne chemicals to form ozone, which is pushed close to the ground by the storm. 

Unfortunately, inhaling ozone can damage the lungs. It can cause a variety of health effects including chest pain, coughing, shortness of breath and throat irritation. And it can also worsen chronic respiratory diseases such as asthmas.

While the concentrations and short duration of ozone in the air before or after a storm are not considered harmful, the ozone from a “thunderstorm in the box” definitely is.

About those clean household scents

For other people, the smell of clean air may mean something completely different. For some, it’s the sweet smell of a fragrance such as pine or cedar. Those who grew up or live in the Hawaiian Islands may associate the scent of fresh flowers with clean air.

Unfortunately, in most modern homes the fresh scent of pine, cedar, lemon or flowers has been replaced with fragrance designed to replicate those scents. That fresh scent may come from cleaning products that kill germs or from air fresheners that contain a particular scent. Scented candles are popular products to add a scent at home.

Unfortunately, many of these products contain chemicals such as limonene, a Volatile Organic Compound (VOC) that produces the pleasant and familiar smell. Limonene gives candles and spray cleaners a lemony smell. A pine scent often comes from pinene, a similar chemical.

The problem with limonene

Outdoors, airborne limonene and other VOCs react with ozone to form secondary organic aerosols (SOAs) – microscopic particles that become suspended in the air and contribute to the haze commonly known as smog. Indoors, limonene also becomes aerosolized. The chemical combines with other airborne pollutants to form formaldehyde. 

Limonene is not associated with adverse health effects, but formaldehyde is. Formaldehyde exposure can cause watery eyes, burning sensations in the eyes, nose and throat, coughing, wheezing, nausea and skin irritation. At sufficient levels, formaldehyde is carcinogenic.

Other “clean” household scents can contain other chemicals, equally or even more dangerous than formaldehyde. For example, many detergents and other “fresh scent” detergents contain phthalates, a class of chemicals linked to breast cancer, infertility, decreased thyroid hormone production, reproductive problems and other health problems.

So what should clean air smell like? Nothing.

Despite all of our best intentions to make a home smell clean, the truth is that clean air should smell like … well, nothing at all. The sure sign of clean air in a home is the lack of anything in particular to smell.

Where odors do exist, it’s smart to remove them rather than mask them with other scents. The best strategy is to prevent odors from occurring in your home in the first place. But if you share your home with pets or cook indoors frequently, it may be difficult to stop odors at the source.

Well-designed ventilation systems, including high-performance kitchen range hoods that ventilate to the outside can help. A high-performance air purifier with gas and odor filtration, such as the IQAir HealthPro 250 or the GC MultiGas, will also remove odors, and can easily be moved from room to room.

By addressing odors in your home instead of masking them, the air in your home will be cleaner and healthier. And if your household guests comment on how clean and fresh your house smells, you can take satisfaction that they are smelling the true scent of clean air.

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