A customer who had installed UV odor control told me that the greasy smell had faded, but that a whiff of 'swimming-pool disinfectant' occasionally drifted out near the exhaust outlet. That is actually ozone. What lets UV photolysis remove odor is precisely ozone's strong oxidizing power, but ozone is a double-edged sword: used just right it removes the smell, used to excess it becomes a new source of neighbor nuisance, since it is itself an irritant gas. So only when the residual is well controlled is UV being used correctly.
Where Ozone Comes From: The Role of 185nm
A low-pressure UV lamp emits two main wavebands. Around 254nm leans toward photocatalysis and directly breaking molecular bonds; around 185nm is higher in energy and can split the oxygen molecules in the air into free oxygen (O₂ → O + O), and the free oxygen then combines with an oxygen molecule to form ozone (O + O₂ → O₃). Ozone is a strong oxidant that can oxidize grease vapor and odor molecules, converting part of the organics into smaller molecules, so the smell naturally comes down.
That said, keep a realistic view. UV's 'breakdown' effect on heavy fume is actually limited; it is more like odor removal and supplementary oxidation, and the front stage still has to rely on a grease mesh, wet scrubbing, or an electrostatic precipitator to capture the grease-mist particles first. Treating UV as the primary grease-removal workhorse is a very common misconception.
How to Control the Residual
To control residual ozone, there are a few practical directions:
- Match lamp count and power to the airflow: ozone output has to match the treated airflow; over-provisioning only sends the excess ozone out with the exhaust.
- Enough reaction residence time: give the ozone time to react with and be consumed by the pollutants, rather than being exhausted before it has reacted.
- Ozone removal at the back end: add activated carbon or a catalyst after the UV section to adsorb or catalytically break down the residual ozone—a common practice that balances odor removal and safety.
Used well, ozone is a powerful tool; controlled poorly, it becomes a nuisance. So in design you must factor in generation rate, residence time, and back-end treatment together, then fine-tune to the on-site conditions—don't end up 'trading the greasy smell for a chemical one.'
TingHao is deeply rooted in Kaohsiung, Tainan, Pingtung, and across southern Taiwan, handling everything from on-site airflow measurement and capture hoods to purification-equipment selection and scheduled cleaning and maintenance. To find out which setup your kitchen needs, call 07-363-0802 or add us on LINE, and we will visit in person before making a recommendation.