A hole in the ozone story?
Searching the internet for UV-C disinfection products you will often see ‘produces ozone’ highlighted as a potential benefit. Ozone is a gas that is produced by the interaction of ionising radiation and oxygen in the atmosphere. Ozone does have disinfection properties, but it is also harmful to humans and animals even in quite low concentrations.
UV-C emitting products that claim to produce ozone use lamps that are incorrectly shielded, and caution should be exercised when considering these units as safe for your application. Operating such products, particularly in poorly ventilated spaces, can quickly generate an ozone PPM count that can cause respiratory irritation or worse.
According to the US Environment Protection Authority ozone can:
Cause coughing and sore or scratchy throat.
Make it more difficult to breathe deeply and vigorously and cause pain when taking a deep breath.
Inflame and damage the airways.
Make the lungs more susceptible to infection.
Aggravate lung diseases such as asthma, emphysema, and chronic bronchitis.
Increase the frequency of asthma attacks.
Some of these effects have been found even in healthy people, but effects can be more serious in people with lung diseases such as asthma. They may lead to increased school absences, medication use, visits to doctors and emergency rooms, and hospital admissions.
Long-term exposure to ozone is linked to aggravation of asthma, and is likely to be one of many causes of asthma development. Studies in locations with elevated concentrations also report associations of ozone with deaths from respiratory causes.
The HSE in the UK and the Control of Substances Hazardous to Health (COSHH) regulations explicitly set limits for the PPM maximum safe exposure levels for ozone
The current Working Exposure Limits or WEL for ozone is 0.2 ppm in air (averaged over a 15-minute reference period). If exposure to ozone cannot be prevented then the principles of good control practice need to be applied (see Schedule 2A of COSHH regulation 7.7) to ensure that the workplace exposure limit is not exceeded, this may mean using equipment that generates ozone sparingly for short periods of time.
Further the COSHH guidelines mean that any ozone generating equipment must be assessed for risk including:
where is ozone likely to be generated?
is exposure likely?
who is likely to be exposed?
can the exposure be prevented?
if the exposure cannot be prevented, estimate the potential level of exposures (in some cases this may involve personal exposure monitoring). If you can demonstrate that your estimate of exposure is unlikely to exceed the WEL, you do not need to take any further action;
if exposures exceed or are likely to exceed the WEL, decide what control measures are needed and take appropriate action.
So the use of UVC products that generate ozone also means the business has to assess the risk and may mean that these units are only capable of very limited use to ensure the WEL is not exceeded; ozone is not only hazardous for employees but its presence can put an extra burden, liability and cost on the company.
Uvisan cabinets and whole-room systems use only UV-C sources that are shielded and proven to produce no ozone.
The Uvisan range can be used safely in any environment, regardless of ventilation or room size.
