A Story From the Field: The Boy Who Came Home and Needed His Inhaler Every Night

Aey (not her real name) teaches at a primary school in Song Phi Nong. Her two-storey home, concrete below and timber above, stands less than a hundred metres from the Tha Chin River. She lives there with her husband, her eight-year-old son Phum (also not his real name) and her mother, who is in her seventies. Phum has had asthma since he was four. His father has hay-fever-style allergies and sneezes whenever the house gets dusty.

When the river rose, water flowed into the ground floor to about mid-shin height and stayed there for almost ten days. The family moved upstairs and waited. As soon as the water drained away, Aey and her husband began shovelling out mud and hosing down the floors. They ran electric fans day and night to dry everything. From the outside, the house looked as if it was getting back to normal. But the musty smell would not go away. Green and black spots began to appear along the bottom of the concrete walls. The ceiling panels under the staircase developed a brown ring-shaped stain. And when they switched on the air-conditioner in the upstairs bedroom for the first time since the flood, a wave of damp, sour air blew out so strongly that they turned it off again straight away.

For three nights in a row, Phum woke in the small hours with a cough that would not stop. His breathing had a whistling sound, and he needed his reliever inhaler more often than he had in months. His father woke up every morning sneezing with a blocked nose, and Aey's mother complained of a scratchy throat. "We cleaned the whole house ourselves until we were exhausted," Aey said. "We even scrubbed the walls with bleach. But the more we scrubbed, the more my son coughed. In the end the doctor told us to remove as many triggers from the house as we could. That is when we realised we needed someone who actually knew how to deal with mold."

Aey's experience is a composite of what many families along the Tha Chin River, in Song Phi Nong, Bang Pla Ma and neighbouring districts, are going through. The water has gone down, but the problem in the air has not.

Why Mold Spores After a Flood Are Such a Problem for People With Allergies and Asthma

Mold grows remarkably fast on materials that stay wet for more than a day or two: plastered walls, timber, gypsum ceiling boards, carpets, curtains and mattresses. Once a colony is established, it releases spores, tiny reproductive particles far too small to see. They float on the slightest air current, travel from room to room on the breeze from fans and air-conditioners, and are small enough to be breathed deep into the lower airways.

A flooded house produces the perfect conditions for this to happen on a large scale. The humidity inside stays high for weeks. Organic material from the floodwater, such as silt, plant debris and sewage residue, coats surfaces and gives mold something to feed on. And because families are busy with the urgent work of clearing mud and salvaging belongings, the early growth often goes unnoticed until the smell becomes impossible to ignore.

The health effects

• Nasal and eye allergies. Mold spores are a common allergen. They can cause sneezing, a blocked or runny nose, and itchy, red, watery eyes.
• Asthma flare-ups. In people with asthma, exposure to mold and damp indoor air can bring on coughing, chest tightness and wheezing, and increase the need for reliever medication.
• Irritation even without allergies. People who have never had allergies can still develop a sore throat, cough or headache after spending time in heavily mold-affected rooms.
• Higher-risk groups. Young children, older adults and people with weakened immune systems should avoid mold exposure as much as possible.

Mold is not the only concern. Floodwater carries bacteria from drains and sewers, such as E. coli, into homes, which brings a risk of diarrhoeal illness and skin infections. Anyone with a cut or graze who touches mud or standing water is also at risk of leptospirosis. A home where someone already has a chronic respiratory condition therefore needs both problems dealt with at the same time: spores in the air and germs on surfaces.

The cost in money and time

When symptoms flare repeatedly, the costs add up quickly. There is more medication to buy, more trips to the clinic or hospital, and more days off. Children miss school. Adults miss work. Whoever stays up at night with a coughing child gets less sleep and has less energy for the long job of putting the house back together. The longer mold is allowed to stay in the house, the greater the damage to walls, furniture and the family's quality of life.

This article provides general information and is not medical advice. People with asthma should follow the treatment plan agreed with their own doctor. If someone is struggling to breathe, cannot finish a sentence, or is not improving after using their reliever inhaler, take them to hospital immediately.

Where Mold Spores Hide in a House After the Water Recedes

Most families clean the areas they can see. But a large share of the spores in a flooded home come from places that rarely get a second look. Work through this list room by room.

• Lower walls and behind furniture. Walls that were underwater wick moisture upwards, well above the visible tide line. Mold often grows behind wardrobes and sofas pushed against the wall, where air cannot circulate.
• Ceilings and the space under the stairs. Moisture evaporating from the floor rises and condenses inside ceiling cavities, leaving stains and hidden growth on the upper side of the boards.
• Under laminate and timber flooring. Water that seeps beneath floorboards dries extremely slowly, creating an ideal breeding ground.
• Air-conditioners. Filters, cooling coils and drip trays all collect moisture and dust. When the unit is switched on, it blows spores across the whole room.
• Curtains, rugs and mattresses. Fabrics absorb both moisture and odor, and bedding sits right next to your face for hours every night.
• Wardrobes and bookcases. Closed, unventilated spaces let mold grow on clothes, leather bags, shoes and books.
• Bathrooms and drains. Constant humidity, plus the chance of sewer smells backing up after a flood.

In a home with an asthma sufferer, the most important room of all is that person's bedroom. They spend many hours a day there, and asthma symptoms very often get worse at night. If you can only do one room thoroughly at first, make it this one.

Why Familiar Cleaning Habits Can Make Asthma Worse

Every family wants to fix the house as fast as possible, and it is natural to reach for whatever is in the cupboard. Unfortunately, some of the most common reactions to mold release more irritants into the air, exactly when the person with asthma is most vulnerable.

• Scrubbing dry mold with a brush. Brushing or wiping dry mold launches a cloud of spores into the air. If the person with asthma is in the house at the time, symptoms can flare almost immediately.
• Using strong bleach in a closed room. Chlorine fumes irritate the airways. Bleach must never be mixed with other cleaning products, especially acidic toilet cleaners or ammonia-based products, because dangerous gases can form.
• Pointing fans straight at moldy areas. Fans help walls dry, but they also blow spores from one room into every other room.
• Air fresheners, incense or scented candles. These add volatile chemicals and smoke to the air, which are asthma triggers in their own right, while the source of the smell stays in place.
• Painting over the walls straight away. If the wall is still damp inside, mold will grow back beneath the new paint within weeks, and the paint will blister and peel.
• Letting the person with asthma help clean. This is an unnecessary risk. People with asthma or severe allergies should stay away from the house during clean-up and during every stage of treatment.

None of this means that household cleaning is pointless. Washing away mud, airing the house and drying it out are essential first steps. The goal is simply to do them in a way that does not stir up more spores, and then to finish the job with methods that reach the air and the hidden corners as well as the visible surfaces.

The Solution: Disinfection Fogging and Ozone Treatment Designed for Homes With Vulnerable Occupants

WHD restores flood-affected homes with two complementary stages. The first is our disinfection service, which uses CHEMGENE HLD4H disinfectant delivered through ULV (ultra-low-volume) fogging equipment. The fine mist settles evenly on floors, walls, corners, the backs of cupboards and the undersides of furniture, dealing with germs on every surface the floodwater touched, without the scrubbing that sends spores into the air.

The second stage is our ozone treatment service. Ozone is a gas, so it spreads throughout a sealed room and reaches places that liquids and cloths cannot. It helps destroy mold spores floating in the air and clinging to curtains, rugs and upholstery, and it breaks down the molecules that cause musty odors at their source rather than masking them with fragrance.

How the process works

1. Site survey. The team inspects every room, checks moisture levels, looks for hidden mold, and asks whether anyone in the household has asthma or allergies so the plan can be adapted.
2. Preparation advice. We help you decide which materials should be removed, such as waterlogged gypsum ceiling boards, carpets that were submerged and mattresses that soaked in floodwater, and which can be cleaned and kept.
3. Wet cleaning and drying. We advise washing with water rather than dry-scrubbing mold, and drying the area as much as possible before treatment begins.
4. ULV disinfection fogging. Every area the water reached is fogged, including bathrooms, the kitchen and the bedroom of the person with asthma.
5. Ozone treatment. Rooms are sealed and treated with a controlled ozone dose matched to their size. Sensitive electronics, electric nebulisers, rubber items and artworks are covered or removed beforehand.
6. Thorough ventilation. Doors and windows are opened so the ozone breaks down back into oxygen. For homes with asthma sufferers, we recommend allowing extra ventilation time.
7. Re-check before vulnerable occupants return. Odor, humidity and mold are checked again, and you receive advice on keeping the home dry and healthy.

A Recovery Plan for Families Living With Asthma

Stage 1, before going back in. Arrange for the person with asthma to stay with relatives or in temporary accommodation. Anyone going in to clean should wear an N95 mask, rubber gloves and boots. Photograph the damage before you start, for insurance and for your own records.

Stage 2, clearing and washing. Take submerged mattresses, carpets and soft furnishings out of the house. Wash the mud away with water, open windows on opposite sides of the house for cross-ventilation, and run a dehumidifier if you have one.

Stage 3, professional treatment. The WHD team carries out disinfection fogging, ozone treatment and ventilation in sequence. Everyone stays out of the house throughout.

Stage 4, a gradual return. Family members without respiratory symptoms go back in first. Once there is no musty smell and no smell of ozone, the person with asthma can return. Watch their symptoms closely during the first week, and keep their reliever inhaler within easy reach.

Stage 5, ongoing care. Control humidity in the bedroom, clean the air-conditioner and replace its filter, check walls every week, and consider our dust mite removal service for mattresses and sofas. Dust mites are another major allergy trigger, and they multiply quickly in damp conditions.

Understanding Ozone: What Allergy and Asthma Households Should Know

Ozone is a form of oxygen made of three oxygen atoms instead of the usual two. That third atom makes it highly reactive. When ozone meets a mold spore, a bacterium or an odor molecule, it oxidises it, damaging the cell wall of the microorganism or breaking the odor compound into simpler, odorless substances. This is what makes ozone so useful after a flood: it can reach the air in every corner of a sealed room and the fibres of fabrics that cannot easily be washed.

The very same reactivity is the reason ozone must never be breathed at treatment concentrations. It can irritate the lining of the airways in anyone, and people with asthma are particularly sensitive. That is why the single most important rule in our process is that treatment only happens in an empty home, and why we are careful about ventilation afterwards.

The good news is that ozone does not linger. Once the generator is switched off and the windows are opened, it naturally breaks down back into ordinary oxygen, and good airflow speeds that process up. It does not leave behind a chemical film or perfume. For a household where fragrances and fumes are themselves triggers, this is an important advantage over sprays and scented products, provided the timing rules are followed.

It is equally important to understand what ozone cannot do. It does not dry out a wet wall, and it does not remove mold that is growing deep inside a waterlogged material. If the source of moisture is still there, mold will eventually return. That is why ozone treatment works best as part of a complete plan: remove what cannot be saved, dry the building, disinfect the surfaces, and then use ozone to clear the air and the odors.

Practical Tips for the Weeks After Treatment

The first month after a flood is when mold is most likely to make a comeback, because walls, floors and furniture can hold hidden moisture long after they feel dry. A few simple habits make a real difference for people with allergies and asthma.

• Keep humidity down. Open windows on dry days, keep internal doors open to encourage airflow, and use a dehumidifier in the bedroom if possible.
• Look after the air-conditioner. Clean the filter regularly and have the coils and drip tray cleaned professionally before relying on it every night.
• Wash bedding every week. Use the hottest wash the fabric allows, and dry it fully before putting it back on the bed.
• Use dust-mite-proof covers. Covers for mattresses and pillows reduce exposure to both mites and residual spores.
• Clean with damp cloths, not dusters. A damp cloth traps dust and spores instead of flicking them back into the air.
• Wipe high-touch surfaces. Door handles, light switches and tables can be wiped with CHEMGENE HLD4H spray, following the label, while the person with asthma is out of the room.
• Check hidden corners weekly. Look behind furniture, inside wardrobes and under the stairs. If new spots appear, deal with them early rather than waiting for them to spread.
• Delay repainting. Wait until walls have been dry for several weeks before painting, so you do not seal moisture in.

10 Reasons Allergy and Asthma Households in Song Phi Nong Choose WHD

1. Fewer airborne mold spores through ozone treatment that reaches every corner of the room.
2. Thorough surface disinfection with ULV fogging, without scrubbing that sends spores into the air.
3. A professional-grade disinfectant, CHEMGENE HLD4H, with no harsh chlorine smell left behind.
4. Odors removed at the source, with no need for perfumes or sprays that can trigger symptoms.
5. A plan built around vulnerable occupants, including room order, ventilation time and the order in which people return.
6. Controlled ozone dosing matched to room size, with sensitive electronics covered or removed first.
7. Help finding hidden mold in ceilings, behind cupboards and inside air-conditioners.
8. Dust mite removal for mattresses and sofas through our dust mite removal service.
9. Whole-home coverage. Learn more about residential ozone disinfection.
10. Fewer mosquitoes after the flood with our mosquito spraying service, helping protect the family from dengue.

Before and After

In the Client's Words

"What impressed me was that the team asked straight away whether anyone in the house had asthma. They told us clearly that nobody could be inside during the ozone treatment, that we had to air the house out properly, and that my son should be the last one to come back in. They also showed us mold hiding in the ceiling under the stairs and inside the air-conditioner, places we had never thought to check. The musty smell has gone, and my son is sleeping through the night much more often now."

— A mother in Song Phi Nong, Suphan Buri (a scenario based on real field situations)

Checklist Before the Person With Asthma Comes Home

• Walls, floors and ceilings are completely dry, with no new mold spots.
• There is no musty smell, mud smell or lingering ozone smell.
• The air-conditioner has been cleaned, including coils and drip tray, and the filter replaced.
• Submerged mattresses, carpets and waterlogged ceiling boards have been removed.
• The bedroom is well ventilated, with no piles of fabric or clutter collecting dust.
• Their medication is ready to use, and the family knows what to do if symptoms flare.
• There is no standing water around the house where mosquitoes can breed.

Frequently Asked Questions

Can someone with asthma stay in the house during ozone treatment?
No, never. The same applies to everyone else, as well as pets and plants. Everyone must leave the whole house and return only after it has been ventilated until no ozone smell remains.

How long after ozone treatment can the person with asthma come home?
It depends on the size of the house and how well it ventilates. Our team will give you the right timing. For homes with asthma sufferers, we recommend allowing extra time and having someone without symptoms check the air first.

Can I clean mold myself with bleach?
Diluted bleach can be used on some hard surfaces, following the label, with windows open and never mixed with other products. The person with asthma should not be in the house while it is used. Bleach also does nothing for spores floating in the air or odors trapped in fabric.

Once the house has been ozone-treated, will mold never come back?
Ozone is very effective at reducing spores and odors, but if the building is still damp, mold can return. Moisture has to be dealt with too, by removing waterlogged materials, ventilating and using a dehumidifier.

What should we do with electronics and an electric nebuliser?
Sensitive electronics, electric nebulisers, rubber items and artworks should be covered or removed before treatment. The person with asthma should take their own medication with them when they leave.

Should the air-conditioner be cleaned before or after ozone treatment?
We recommend cleaning the air-conditioner and replacing the filter before you use it for the first time after the flood, and keeping it switched off during treatment. Our team will advise on the best order for your home.

Does WHD serve Song Phi Nong?
Yes. WHD serves Suphan Buri, Phra Nakhon Si Ayutthaya, Nakhon Pathom, Bangkok and nearby areas. Call 065-556-6294 to book a site survey.

Help Everyone at Home Breathe Freely Again

The WHD team is ready to remove mold spores and musty odors after the flood, using a process that puts allergy and asthma sufferers first.

Book Ozone Treatment – Click Here

See Disinfection Service – Click Here

Call 065-556-6294 · LINE @whd268 · Email worldhealthdisinfection@gmail.com

Related Services and Reading

• Residential ozone disinfection
• Dust mite removal service
• Master Ozone Generator
• All WHD articles
• External sources: WHO Floods Fact Sheet and Thailand's Department of Disease Control