Reactive species are the working chemistry of cold plasma. They are extremely short-lived, high-energy molecules that react almost instantly with whatever they touch, and they are formed from nothing more than the oxygen, nitrogen and moisture already in the air.
Why they are called reactive
A stable molecule, such as the oxygen you breathe, has its electrons neatly paired. A reactive species is missing that stability. Some are free radicals with an unpaired electron; others are molecules that readily give up or take oxygen. Either way, they are chemically restless: they react with the first suitable molecule they meet, and in doing so they change its structure.
That instability is exactly what makes them useful. When a reactive species meets an odor molecule, a volatile organic compound (VOC) or the outer surface of a microorganism, the reaction can break bonds and alter or disable it.
The two families AURA relies on
| Family | Examples | Formed from |
|---|---|---|
| Reactive oxygen species (ROS) | Hydroxyl radical (•OH), superoxide (O₂⁻), hydrogen peroxide (H₂O₂), ozone (O₃) | Oxygen and water vapor in the air |
| Reactive nitrogen species (RNS) | Nitric oxide (NO•), nitrogen dioxide (NO₂), peroxynitrite (ONOO⁻) | Nitrogen in the air, reacting with oxygen species |
Together these are often called RONS. Scientists also study reactive halogen, carbon and sulfur species in other settings, such as water disinfection, but AURA's air-based process is built around reactive oxygen and nitrogen species.
Three properties that matter
They are short-lived
Most reactive species exist for microseconds to seconds before they react with something nearby. They do not drift around the room for hours, and they do not build up over time the way a fragrance or a chemical spray would.
They are high-energy
Their chemical instability is what lets them break down a contaminant's molecular structure, rather than simply moving it somewhere else.
Concentration and exposure time matter
The more reactive species reach a contaminant, and the longer the exposure, the stronger the effect. That is why results depend on room size, airflow, distance from the unit and how long it runs, and why laboratory figures always come with their test conditions.
Familiar chemistry
None of this chemistry is new. Your own immune cells produce reactive oxygen and nitrogen species to fight infection. In the atmosphere, the hydroxyl radical is so effective at breaking down pollutants that atmospheric chemists call it the detergent of the troposphere, and lightning produces nitrogen oxides in every storm. Cold plasma recreates a small, controlled amount of this natural oxidation process inside a chamber.
What happens next
Reactive species act on contaminants through three pathways: they charge fine particles, they oxidize odors and VOCs, and they can inactivate certain microorganisms. Each is explained in How cold plasma treats the air.
Reactive species can inactivate certain bacteria, viruses and fungi under tested conditions. Performance depends on design, concentration, airflow and exposure time. AURA is not a medical device.
