Disinfection and ozonation in Almaty

Why mold and fungus come back after regular cleaning and how ozone destroys them

Regular cleaning removes visible film but does not touch the cause: mycelium in the pores and spores in the air. Let’s break down why mold comes back and what ozone does where a cloth is powerless.

Why mold appears again after wet cleaning

Mold comes back because surface cleaning removes the pigmented film but does not destroy the mycelium that has grown into the plaster, tile joints, silicone, and wood. The fungus hypha penetrates 2-5 mm deep into the porous surface, while household chlorine-based products only work in the top layer. After 5-10 days, at 60-70% humidity and a temperature of 20-25 degrees, the remaining spores produce a new colony in the same spot. In Almaty panel buildings from the 1970s-1990s, the number of floors and weak bathroom ventilation make the problem worse: condensation on cold walls does not dry out for days. Before treatment, check the wall humidity with a household hygrometer — if it is above 15%, first fix the leak or improve the exhaust, otherwise any treatment will give only a temporary effect.

How ozone destroys spores in hard-to-reach places

Ozone, as a gas, penetrates where neither a brush nor a sprayer can reach: into tile joints, ventilation ducts, behind baseboards, into concrete pores, and into fabric upholstery. The O3 molecule destroys the spore’s cell wall and oxidizes the protein structures of the mycelium — the fungus loses its ability to reproduce rather than simply becoming discolored. In our practice, after ozone treatment, reoccurrence in the same area is not recorded during the season in 9 out of 10 cases, if the moisture cause has been eliminated. At the same time, ozone leaves no film and does not require rinsing, unlike chlorine compounds that eat into the joints and leave an odor. An important nuance: the gas works only at sufficient concentration and exposure — a short 15-minute “airing” kills the odor but not the mycelium.

Mold or odor: where ozone works and where it does not

Ozonation covers two different tasks — destroying microorganisms and eliminating the volatile compounds they release. Ozone suppresses mold in its active growth phase, but dense colonies deeper than 5 mm in brickwork require mechanical opening and treatment with an antiseptic before ozonation. The smell of dampness, tobacco, burning, and animals is a secondary effect that is fully removed by ozone, because the molecules of odorous compounds are oxidized to neutral ones. But if the source of the odor is a fresh leak or wet laundry, ozone will only mask the problem for 2-3 weeks. In Almaty apartments with Soviet-design ventilation, we first check the draft with an anemometer: at a speed of less than 1 m/s in the bathroom, ozone goes into the living rooms instead of the exhaust, and the treatment loses its point.

Three mistakes that make treatment fail

• The moisture cause is not fixed: if a faucet, joint, or ventilation is leaking, spores will return within a month regardless of the ozone concentration.
• Treatment without preparation: dust and grease film on surfaces bind ozone, and only part of the active gas reaches the spores.
• Too short exposure: ozone needs time to penetrate the pores — a 15-minute treatment works only against odor, not against fungus.

What to do after treatment so mold does not come back

• Dry out the space: airing for 20-30 minutes a day for a week reduces residual moisture in walls by 10-15%.
• Check ventilation: draft in the bathroom and kitchen should be at least 1 m/s, otherwise condensation will return.
• Remove organic matter: cardboard, old books, fabric wallpaper, and carpets in damp corners are a breeding ground for spores.
• Control humidity: a household hygrometer keeps the reading at 40-55%; above 60% is a risk zone.

If mold reappears in the same spot within 2-3 weeks after treatment, it signals a hidden leak or a wall that freezes through — in that case, ozonation is repeated only after the cause is fixed. At profi-clean, we always request a photo of the problem area before the visit: the image shows whether mechanical scraping is needed before gas is applied, and this saves the client a repeat visit. Ordering disinfection and ozonation in Almaty makes sense when the moisture source has already been found and fixed; otherwise, the procedure becomes cosmetic and requires repeating every few months. The price of disinfection and ozonation depends on the area and the extent of contamination — from 15,000 ₸.

Ozonation, UV treatment, and quartz treatment: comparing effectiveness and safety

The choice of disinfection technology depends on the type of space, the surface materials, and access to them. We break down three methods by their effectiveness against mold, viruses, and odors, as well as by their limitations for residential and work spaces.

How each technology affects microorganisms

Ozone destroys the cell walls of bacteria, mold spores, and viruses through oxidation, penetrating the pores of concrete, tile grout, and textiles. A UV lamp with a wavelength of 254 nm damages the DNA of microorganisms, but it only works in the direct irradiation zone — shadows behind furniture and seams remain untreated. Quartz treatment is the same UV principle, but with a harsher spectrum: it produces a pronounced ozone smell and requires the complete absence of people. In our practice, ozone delivers results in hard-to-reach areas where a lamp physically cannot reach. That is why, for mold in a bathroom, we combine both methods rather than choosing one.

Where each method falls short: common mistakes

• UV without preliminary cleaning: dust and film shield the rays — disinfection does not reach spores under a layer of dirt, so surfaces need washing before treatment.
• Quartz treatment in a living room with people present: harsh UV irritates mucous membranes and skin, and the ozone released accumulates in the air — the space must be empty.
• Ozone without calculating concentration: a low dose does not kill mycelium deep inside, while an excessive one damages rubber seals, latex, and some polymers.
• Treatment without subsequent ventilation: residual ozone irritates the respiratory tract, especially in children and people with allergies.

Material limitations: what ozone and UV damage

• Rubber and latex: ozone accelerates aging — window seals, hoses, and elastomers lose elasticity with frequent treatments.
• Natural leather and furniture: prolonged exposure to ozone dries and changes the shade, so we cover leather sofas.
• Polymers and plastic: most ABS and PVC are resistant, but thin film and vinyl coatings may become cloudy.
• Electronics: UV is harmless, but ozone at high concentrations oxidizes contacts — we remove equipment or seal it.
• Plants and aquariums: living organisms are removed from the premises for the entire duration of treatment and exposure.

Which disinfection method to choose for an apartment, office, and commercial space

The method is selected based on three inputs: the type of facility, the surface materials, and what exactly needs to be eliminated — bacteria, viruses, mold, or odor. Below is the working selection logic that we apply on site visits in Almaty.

Method selection matrix by type of premises

Where methods are mistakenly swapped

• Ozone in occupied premises: the gas requires full evacuation and 40-60 minutes to dissipate — treatment with residents present is unacceptable.
• Quartz treatment instead of disinfection: the lamp disinfects the air and open surfaces, but does not penetrate the crevices of baseboards and tile joints.
• Chlorine in living rooms: the concentration sufficient for mold spores corrodes metal fittings and leaves a persistent odor for 2-3 days.
• Spraying onto dirty surfaces: without preliminary washing, the disinfectant lands on a grease film and works at half strength.
• A single pass over a large area: with ceilings above 3 meters, a second pass from a different nozzle height is needed.

How to choose between spraying and ozonation

• Spraying of disinfectant: needed when surface, wall, and furniture treatment matters — the contact effect lasts up to 24 hours.
• Ozonation: chosen to eliminate odors, mold in pores, and disinfect the air in enclosed volumes — the gas penetrates where a sprayer cannot reach.
• Combination of methods: used in premises after prolonged vacancy, flooding, or infection — first spraying, then ozone.
• Cold fog: suitable for textiles and mattresses where moisture is unacceptable.
• UV treatment: an additional barrier for water and air in ventilation systems, not a replacement for the main method.

What to clarify with the contractor before the visit

• Hazard class of the product: for residential premises, only classes III-IV are acceptable; for warehouses, classes II-III.
• Presence of HEPA filtration: without it, spraying lifts spores into the air and spreads them throughout the entire premises.
• Exposure and ventilation time: typically 30-120 minutes of treatment depending on room volume and the task, then 30-60 minutes for ozone decay and airing.
• Documents after the work: a treatment report and recommendations for wet cleaning after 3-4 hours.
• Guarantee: free redo if you tell us within 24 hours about a defect — and this is written into the contract.

Before signing the contract, ask the contractor for a test report for a specific strain — universal claims of “against all bacteria” without documentation are worth nothing.

Typical mistakes during DIY ozonation and disinfection

We break down the mistakes that most often lead to zero results or damage to property. All of them are gathered from our site visits after DIY attempts — across Almaty apartments, offices, and cafes.

Mistake 1: working without protective equipment and in the presence of people

The main mistake during DIY ozonation is turning on the generator while staying in the room or leaving children and pets there. Ozone at a concentration of 0.1 ppm and above irritates mucous membranes; at 5-10 ppm it causes pulmonary edema and headaches; the maximum permissible single concentration of ozone in the air of populated areas is 0.16 mg/m³, while an industrial generator produces 20-50 times more in an hour. During treatment, windows and doors are closed, ventilation is turned off, and the premises are completely vacated for the exposure period — along with animals, plants, and aquariums, which ozone damages irreversibly. After the cycle, a pause for gas decay and through ventilation for 30-60 minutes are mandatory. In our practice, there was a case in the Bostandyk district when a client started the ozone generator and stayed in the next room with the door closed — they got severe mucous membrane irritation and saw a doctor. If there is an asthmatic or allergic person in the home, treatment is scheduled for their absence and with extra ventilation time.

Mistake 2: confusing surface disinfection with air treatment

Disinfection and ozonation solve different tasks, and replacing one with the other gives a false sense of cleanliness. A solution based on quaternary ammonium compounds or hypochlorite works only where it physically reaches: a soaked cloth, a sprayer, a mop. Ozone fills the entire volume and penetrates cracks, ventilation ducts, behind baseboards, into fabric upholstery — but it does not wash away grease, film, or biofilm. If surfaces are not washed first, organic matter binds the active substance, and the concentration drops below the working level. The correct sequence is mechanical cleaning, then disinfection of contact surfaces, then ozonation of the volume. Only this order gives an effect that lasts rather than disappearing within a day.

Mistake 3: ignoring surface material and humidity

• Natural stone and marble: acidic disinfectants eat through the polish in 2-3 treatments — leaving dull spots that cannot be buffed out.
• Lacquered wood and veneer: excess moisture raises the grain and leaves white streaks along the edges.
• Fabric upholstery and carpet: insufficient drying after treatment creates a new mold hotspot within 5-7 days at humidity above 60%.
• Aluminum and chrome faucets: chlorine-based solutions cause pitting corrosion and darkening.
• Electronics and appliances: ozone accelerates the oxidation of rubber seals and contacts, so appliances should be covered or removed.

Mistake 4: skimping on dwell time and mixing products “by eye”

Insufficient dwell time is the most common reason everything comes back within a week. The disinfectant manufacturer specifies the contact time for a specific concentration: 30, 60, or 120 minutes. Cutting it in half means you don’t kill the mold spores — you only weaken the mycelium, which recovers within 3-5 days. The same goes for ozone: treatment time is calculated based on room volume and generator output, not “by eye.” Mixing concentrate without a measuring cup, using a bottle cap, gives a 2-3x variance — either surface burns or zero result. In Almaty, tap water is hard with high mineralization: it reduces the activity of many disinfectants, so solutions are prepared with distilled or filtered water. Our senior team lead Gulnara Abisheva always repeats during technician training: saving 15 minutes of dwell time costs a repeat visit and a damaged reputation.

Mistake 5: treating only visible areas and forgetting the source

Treating visible walls and floors doesn’t solve the problem if the source remains untouched. Mold spores live in tile grout, behind the refrigerator, in the sink siphon, in the washing machine seal, in the ventilation duct, and under the windowsill. Humidity in Almaty apartments on ground floors and in buildings without waterproofing stays at 65-75% year-round — an ideal environment for regrowth. Until the leak is fixed, the exhaust is working properly, and the structures are dried out, any disinfection gives only a temporary effect for 2-4 weeks. In one cafe on Abay, we found the source in the air conditioner drain tube: surface treatment of the hall didn’t help until the indoor unit was removed and disinfected.

Mistake 6: mixing products “to boost power” and storing ready-made solutions

Mixing a chlorine-based and an acid-based product in an enclosed space releases chlorine gas — that’s poisoning with damage to the respiratory tract. Chlorine with ammonia produces chloramines, which are 10-20 times more toxic than the original components. Ready-made solutions should not be stored: chlorine loses activity within 4-6 hours, peroxide breaks down within a day, and a diluted concentrate in a warm room becomes a breeding ground for bacteria. Fill the sprayer under an exhaust hood or on a balcony, wearing gloves and a respirator. If someone in the home has asthma or allergies, chlorine-based products are excluded entirely — at profi-clean we use hypoallergenic Kiehl and Sodasan chemicals for exactly this reason. And never mix two products in one container, even if both are “for mold”: the result is unpredictable, and the consequences are — lung burns.

Mistake 7: assuming ozone will “reach” closed cabinets and appliances

Ozone is a gas, but it does not pass through dense barriers and does not penetrate closed boxes, cabinets, appliances, or sealed containers. If cabinet doors are closed, the original microflora remains inside. Ozone treats fabric items, mattresses, pillows, and upholstered furniture only on exposed surfaces — deep inside the filling, the concentration drops to ineffective levels. That is why before ozonation all doors, drawers, and lids are opened, and items are laid out loosely, not in a stack. Appliances and electronics are covered or removed: ozone destroys rubber seals and accelerates oxidation on metal contacts. In our practice, after a DIY treatment without opening the cabinets, a client found the smell in the linens again 10 days later — we had to repeat the process with full disassembly.

What ultimately distinguishes a proper treatment from a DIY attempt

If more than a week has passed since a DIY treatment and the smell or film has returned, it means the source was missed or the exposure was incorrect. In such cases, it is cheaper to call in specialists with equipment and HEPA filtration than to repeat the cycle over and over again. You can order disinfection and ozonation with source diagnostics from us — our technician will first inspect the premises and identify the cause, rather than simply spraying product on the walls.

Specifics of disinfection in Almaty: humidity, seasonality, old ventilation systems

The Almaty microclimate dictates its own treatment conditions: here the challenge is not dryness but moisture, dust from the mountains, and seasonal swings. Let us break down how this changes the approach to sanitization.

Why Almaty’s humidity accelerates the growth of microorganisms

Average humidity in Almaty stays at 60-70% for most of the year, and in the foothill districts — Medeu, Butakovka, Kamenskoye Plateau — the figure reaches 80%. At such levels, mold spores germinate in 48-72 hours, not in a week as in a dry climate. In practice, this means a premises that could stand untreated for a month in a dry region requires attention here within just five days. Ground floors and basements are especially vulnerable — moisture rises there from the foundation and groundwater, and condensation settles on walls and furniture. Our senior crew leader Gulnara Abisheva always repeats during technician training: first find the source of moisture, then treat. If you simply spray product without removing the cause, the mycelium will return within two weeks.

Seasonality: when the risk of contamination is highest

The peak in requests to profi-clean falls on two periods — March-April and October-November. In spring, snow melts in the mountains, the groundwater level rises, and basements, ground floors, and storage rooms fill with dampness. In autumn, heating is turned on, windows are closed, air exchange drops threefold, and the temperature difference between outside and indoors creates condensation on glass and exterior walls. In summer, another factor is added — dust: in July-August, the concentration of suspended particles in the air increases 2-3 times, dust settles on surfaces and serves as a breeding ground for bacteria. In winter, the problem shifts to ventilation: cold air from outside meets warm air inside and leaves condensation in the shafts.

Old housing stock and ventilation systems of Soviet construction

Houses in Almaty built before the 1990s — and this is a significant part of the housing stock in the Almaly, Zhetysu, and Turksib districts — have natural-draft ventilation without forced exhaust. Over decades, the ducts in such buildings accumulate dust, grease film (if these are kitchen risers), mold, and even insect nests. The draft in them is weak: in summer heat it may be absent altogether, and the air in the apartment stagnates. Treating ventilation grilles by spraying gives only a visible effect — the duct itself remains a source of spores. When working in old housing stock, our cleaners always check the draft with an anemometer and, if it is absent, treat the duct through an inspection opening or recommend mechanical cleaning before disinfection.

Mountain air and dust: a hidden risk factor

Almaty dust differs from the dust of lowland cities: it has a high proportion of mineral particles from mountain rocks, which settle as a fine fraction and penetrate the narrowest cracks. This dust is abrasive — it scratches the lacquer coating of furniture, and bacteria accumulate in the micro-scratches, where an ordinary cloth cannot reach. In districts closer to the mountains — Bostandyk, Medeu — the concentration of such dust is higher due to winds from the foothills. During disinfection, we first remove dust with a HEPA vacuum, otherwise the disinfectant lands on the dust layer and does not contact the surface. This is not a formality: treatment without preliminary dust removal reduces effectiveness by 40-60%.

Utility specifics: water outages and voltage surges

Almaty high-rise buildings periodically face scheduled hot water outages — usually for two weeks in the summer, and in some districts even longer. During this time, residents more often use reserve containers and fill bathtubs with water, which increases humidity in bathrooms and creates a favorable environment for bacterial growth. Voltage surges in old buildings disable household humidifiers and recirculators, and people are left without their usual means of microclimate control. During such periods, demand for disinfection of bathrooms and kitchens rises by a third. We take this into account in our schedule: if the water has been shut off in a building, it is better to plan treatment after supply resumes, when humidity stabilizes.

When ozonation will not help: cases requiring repair or replacement of materials

Ozone destroys microorganisms and neutralizes volatile odor molecules, but it does not restore damaged materials. Let us break down situations where treatment gives a temporary effect and the cause returns after 2-6 weeks.

When the source of the problem is a porous organic base

Ozone only works where it can reach the source: in the pores of drywall, plaster, and particleboard, mold mycelium goes as deep as 3-4 cm, where the gas only partially penetrates. If the substrate humidity exceeds 20%, colonies recover within 2-3 weeks after treatment. In our practice, Almaty apartments on the first floors of old Soviet-era buildings are a typical case: capillary moisture rises through the brick, ozone removes the visible film, but a month later the fungus resurfaces. The solution is to open up the finish down to the concrete, dry it with a heat gun, and treat it with an antiseptic-fungicide before installing new layers. Ozonation here is the final stage, not a standalone measure.

Disinfection and ozonation with damaged ventilation

Disinfection and ozonation are effective in a sealed volume, but if the exhaust duct is clogged or has reverse draft, spores return from the riser into the apartment within a week. Almaty panel buildings of the 1-464 series and high-rises on Rozybakiev often have building-wide shafts without filters: air from neighboring apartments with mold is pulled back through a non-working valve. Before treatment, we check the flow velocity in the grille with an anemometer — if it is below 1 m/s, we recommend first calling a ventilation specialist and installing a check valve. Without this, ozone gives an effect for 10-14 days, and the musty smell returns along with the humidity from the mountains. In a building on Dostyk we had a case: three treatments in a row did not help until the client replaced a flexible air duct with a tear.

Odors embedded in materials: tobacco, burning, animal metabolites

Ozone oxidizes volatile molecules in the air, but nicotine resins absorbed into plaster and wallpaper continue to evaporate for months. In an apartment after several years of smoking, the resins sit in the layer of paint and wallpaper, and one ozonation cycle is enough for 3-6 weeks. The same goes for cat and dog urea: if the marks got into the concrete floor through the seams of the laminate, salt crystals sit in the capillaries and release ammonia when humidity rises. Ordering disinfection and ozonation in such a case only makes sense after removing the wallpaper, sanding the walls, and treating the substrate with an enzyme neutralizer. Otherwise you are paying for temporary relief, not for eliminating the cause.

Table: signs that you need repairs, not just treatment

Cases where ozone is dangerous for the material itself

Ozone is a strong oxidizer, and at concentrations above 10 ppm it destroys natural rubber, latex, some types of vinyl, and untreated copper. In apartments with expensive solid oak or walnut furniture, prolonged treatment leads to darkening of the lacquer and microcracks in the veneer. At profi-clean we have a rule: we calculate the price of disinfection and ozonation taking protective measures into account — covering natural wood, brass fittings, and antique items. If a space has an art collection or handmade leather furniture, we replace ozone with fine-droplet hydrogen peroxide spraying with HEPA filtration — the effect on bacteria is comparable, while the risk to materials is lower. Cleaners receive individual instructions for each site, because there is no universal protocol for antiques.

When damage already exists at a site, ozonation is pointless

If a space has swollen parquet, peeling wallpaper, black deposits on concrete basement walls, or signs of rot on wooden joists, disinfection and ozonation address only the hygiene aspect, not the structural one. In a residential building basement on Abay, we refused treatment until the apron was repaired: water was coming in through cracks in the foundation, and any disinfection lasted a week at most. The correct sequence is: eliminate the source of moisture, replace damaged structures, dry everything out, and only then carry out the final ozone treatment. Ordering disinfection and ozonation before repairs means paying for a procedure whose result will be washed away by the first rain.