Air disinfection

What air disinfection covers

In practice "air disinfection" means several different things, and it is worth separating them:

• Treating the room air with ozone or fog — a one-off, intensive treatment.
• Treating ventilation grilles and the accessible part of the ducts — dust, grease and moisture build up there.
• Air recirculation units with filters or UV-C — continuous, lower intensity.
• Assessing the air exchange — whether the ventilation works at all.

The last point is the most important and the most often skipped. If the air in a room barely changes, any air treatment is a one-off event after which the situation returns to where it was.

Why air exchange is the first question

Air in a room is not static. People, cooking, showering, drying laundry and even houseplants constantly add moisture and volatile compounds to it. If that air is not replaced, the moisture builds up, settles on the cooler surfaces and creates conditions in which biological growth begins. This is one of the most common causes of mould in flats generally.

The key mechanism is simple: extract ventilation only works if there is an air supply. In a block of flats the air went out through the kitchen and bathroom ducts, while it came in through draughty wooden windows. When those windows are replaced with airtight ones, the extract loses its supply and effectively stops. Nothing looks different, but the air exchange has ceased.

Airing in the heating season

In the Latvian climate this shows up most clearly during the heating season. Cold outdoor air holds little moisture; when it warms up indoors its relative humidity falls, so airing in winter dries the space out. That is exactly why short, intensive bursts of airing in winter work better than leaving windows ajar for hours: the air is replaced, but the walls do not have time to cool down.

Ventilation ducts

Over the years dust, kitchen grease deposits and moisture build up in ventilation ducts. That combination is a good environment for micro-organisms and is often exactly the source of the stale smell coming into a room. In that case the duct is no longer just a route — it has itself become a source of contamination.

In blocks of flats the ducts are shared, so smells travel between flats. If the flow reverses somewhere in the riser — most often because someone has fitted a powerful extractor hood directly into the shared duct — air from one flat comes into the neighbouring flat's grille. That is the most common reason for smelling a neighbour's cooking or cigarettes.

What we can and cannot reach

We treat the grilles and the accessible part of the duct. Cleaning a full riser throughout a building is work on a different scale, organised by the property manager — we say so honestly if that is where the problem lies. Ozone treatment in such a case will remove the smell that has already soaked into your flat, but it does not stop the transfer; how long the result lasts depends on how strong the flow is.

When it is needed

• There is a persistent smell in the room with no visible source.
• A smell is coming from neighbouring flats through the ventilation.
• In offices and institutions after an outbreak of illness among staff.
• After flooding or a long period of damp in the premises.
• On properties where air quality is part of the requirements — medical facilities, nurseries, food businesses.
• After premises have stood unused for a long time and the system has been static.

Properties where it comes up regularly

In offices and institutions air quality usually becomes a topic after an outbreak of illness among staff, but the real problem often turns out to be a different one: there are too many people in the space for the available air exchange. Treatment in that case gives an improvement for a while, but the solution lies in how the ventilation is set up.

In nurseries, schools and care facilities the combination with contact surface treatment matters too — air treatment alone is only half the job there. In food and catering businesses the critical point is almost always the extraction system with its grease build-up, and that requires a separate scope of work.

What you can check yourself

Before ordering anything it is worth establishing whether the ventilation works at all. That changes everything that follows.

• Hold a thin sheet of paper against the ventilation grille in the kitchen and bathroom with a window slightly open. If the sheet holds, the duct is drawing; if it falls away, the draw is weak or reversed.
• Take the grille off and look at whether a thick layer of dust and grease has built up behind it.
• Check whether the windows have a trickle vent setting or supply vents — without a supply, the extract does not work.
• Check whether the smell is stronger right at the grille or elsewhere in the room — that points to two different problems.
• Note whether condensation forms regularly on the window glass in winter — that is a sign of poor air exchange.

Prices

Ozone treatment €1.20/m², minimum €60. Treatment of ventilation grilles and the accessible part of the duct is included in the overall scope of work — we confirm it after the inspection.