How to Use a Thermal Fogging Machine Correctly: Before, During and After Fogging, a Field Guide for Local Government Staff

Even the best mosquito fogger will underperform if the team using it has no clear procedure. This article is a plain-language field guide for staff of subdistrict administrative organizations, municipalities, public health teams and village health volunteers who actually carry the machine into the community. We walk through preparation, safe fogging technique, shutdown, cleaning and record keeping, all built on one rule that matters more than any other: always follow the manufacturer's manual and the chemical product label.

1-Minute Summary

• Before fogging: read the machine manual and the chemical label, inspect the machine, prepare personal protective equipment (PPE), notify residents in advance, check the weather and plan the route.
• During fogging: fog in the early morning or evening when mosquitoes are active, walk at a steady pace, direct the fog under houses, into shrubs and dark corners, and keep clear of people, pets, food, water and open flames.
• After fogging: shut off the chemical and stop the engine in the order the manual specifies, let the machine cool, clean it, store chemicals properly, wash up and record the operation.
• A machine that makes the job easier: the AIROFOG AT35, a 100% stainless steel, lightweight thermal fogger that works with both water-based and oil-based chemicals and is certified in Germany and the UK.
• Next 3 steps: call or LINE for a quotation and specifications, request a demonstration and training, then set the budget and procure according to regulations.

A Story From a Village by the Rice Fields (illustrative scenario)

It is a Thursday evening at the start of the rainy season. Somsak, a public health officer at a subdistrict administrative organization in central Thailand, gets a call from the local health promoting hospital: a primary school pupil in Village 5 has been diagnosed with dengue. The team must fog around the patient's home as quickly as possible. Somsak grabs two new colleagues who have just transferred from the engineering division, loads the old fogging machine into the pickup and heads out.

At the site, problems pile up one after another. One colleague overfills the fuel tank while the machine is still warm from a test run at the office. The other mixes the chemical by eye because nobody can find the measuring cup. Many households were never told the team was coming, so laundry is still hanging out and dinner is laid out under the house. While they fog, the nozzle occasionally spits flame, startling everyone, and a cool breeze carries the fog out across the paddy fields instead of into the bushes around the homes.

That night someone posts in the village LINE group: "They just walked past, the smoke stinks, and our food is ruined." Two weeks later, a new case appears on the same lane. Looking back, Somsak realizes the problems came not from bad intentions but from a missing procedure. The rest of this article compiles practical steps any team can adapt into its own operating guide.

Why Using a Mosquito Fogger the Wrong Way Is a Big Deal

1. Residents stay at risk

The Aedes mosquito carries dengue, chikungunya and Zika. Dengue brings high fever, headache and muscle pain, and some patients go into shock as the fever falls. Children, older adults, pregnant women and people with chronic conditions are most vulnerable. If fog misses where mosquitoes rest, infected mosquitoes survive and keep biting.

2. Staff safety

A thermal fogging machine works with heat, and its combustion pipe and nozzle stay hot after shutdown. Refueling at the wrong moment, placing it near flammable material or skipping protective gear can cause fires, burns or needless chemical exposure. One injured sprayer can stall a whole subdistrict's disease control plan.

3. Wasted budget

Chemical mixed at the wrong rate, fogging in wind or rain, or fogging at midday when mosquitoes hide in shade all burn through insecticide and fuel for little result. A mosquito sprayer used incorrectly also breaks down sooner, wasting hard-won government equipment budget.

4. Image and public trust

Anyone can film and post a clip in seconds. Officers fogging into a food stall or near children at play raise questions about professionalism. A team that gives notice, wears full protective gear and fogs systematically earns trust.

5. Duplicate workload

When the first round fails, the team must go back, answer complaints, write reports and repair the machine. A clear procedure from the start reduces workload in the long run.

Why the Usual Approach Often Fails

• Old, unmaintained machines: soot in the combustion pipe, clogged nozzles and leaking gaskets make machines hard to start, cause them to stall mid-route or fog unevenly.
• Nobody reads the manual: many agencies receive a manual with the machine but file it away. Knowledge lives with one person, and when that person transfers, it leaves too.
• Mixing out of habit: estimating by eye or reusing an old recipe without reading the label of the new batch can make the mix too strong or too weak. Both are bad.
• Wrong timing: fogging in late morning or afternoon heat makes the fog rise and disperse quickly, while many Aedes mosquitoes are resting in dark, humid places.
• Unsuitable droplet size: a poorly adjusted machine or worn nozzle may produce large droplets that fall to the ground quickly instead of hanging in the air long enough to contact mosquitoes.
• Cheap, non-standard equipment: rusts easily, lacks spare parts and sits idle when it fails mid-outbreak.
• No after-sales support: nobody trains new staff, so the same mistakes repeat every year.

Stage 1: Before Fogging (preparation removes most of the risk)

Preparation is the most important stage, because most problems on site can be prevented back at the office. Here is a practical checklist your team should run every time.

1.1 Read the machine manual and the chemical label

Before every operation, the team leader should review the model's manual for starting, chemical supply and shutdown. Then read the label of the chemical product for that batch. The label states the mixing rate, the permitted carrier (water or oil), precautions, first aid and storage. Every number used in mixing must come from the label, never from memory or from what someone else did.

Jargon in one line: the label is the legal document supplied with a chemical that states how to use it safely and effectively; using a product outside its label is a risk the agency carries on its own.

1.2 Inspect the machine

• Check the fuel tank and chemical tank for leaks or cracks, and make sure caps close tightly and seals are in good condition.
• Check hoses, fittings and valves for splits, looseness or signs of seepage.
• Check the combustion pipe and nozzle for heavy soot build-up or blockage.
• Check the battery or cells for the ignition system (if the model uses them).
• Run a test start in an open area away from flammable materials, without opening the chemical supply, and listen for a steady running sound.

1.3 Prepare personal protective equipment

Minimum protection should follow what the chemical label and machine manual require. Typically this means a respirator with suitable cartridges for chemical vapors, goggles or a face shield, chemical-resistant gloves, long sleeves and trousers or coveralls, closed shoes and hearing protection, because thermal foggers are loud. Check that cartridges have not expired and that everyone's gear fits properly.

1.4 Mix the chemical correctly

• Mix in an open, ventilated place away from flames, houses, water sources and children.
• Use containers and measuring tools reserved only for chemical work; never use them for food or drinking water.
• Use the carrier stated on the label. If the label says water, use water; if it says oil, use the type of oil it specifies. Never substitute on your own.
• Mix only what you will use in that round to avoid leftover mixed chemical.
• Label the container with the product name and mixing date.

1.5 Refuel safely

Refuel only when the machine is fully off and cool. Use a funnel, do not overfill and wipe up spills immediately. No smoking or open flame nearby. Keep fuel containers and chemical containers clearly separated and labeled so nobody grabs the wrong one in a hurry.

1.6 Communicate with the community

Notify community leaders, village health volunteers and residents ahead of time via the village loudspeaker or LINE groups. Tell people the date, time and area, and ask them to cover water and food, bring in laundry, protect pets and fish tanks, and keep children, older adults, pregnant women and people with respiratory conditions away from the fogging area.

1.7 Check the weather and plan the route

As a general rule, fog when the air is fairly calm, the wind is light, it is not raining and mosquitoes are active, which means early morning or evening. Plan your route so that the breeze carries fog toward houses and vegetation, not back at the operator. Mark the start point, rest points, refill points and end point. When fogging around a patient's home, cover a radius of about 100 meters, in line with commonly used guidance, and coordinate with the health team on repeat rounds.

Stage 2: During Fogging (effective and safe at the same time)

2.1 Start the machine in the order the manual gives

Start in an open area away from flammable materials, and let the machine run smoothly and reach operating temperature before opening the chemical valve. This matters: opening the chemical before the combustion chamber is ready can produce large drops or cause flame to shoot from the nozzle. The exact sequence and timing depend on the model, so follow its manual.

2.2 Posture and walking speed

Hold the machine securely, nozzle pointing toward the target, never at yourself or teammates. Walk at a steady pace, neither rushing past corners nor lingering until one spot is overdosed. One person walks ahead to clear the path and inform residents while the other operates; rotate roles to reduce fatigue.

2.3 Aim at the right places

Aedes mosquitoes like to rest in dark, humid, still places: under raised houses, behind cupboards, under beds, in low shrubs, piles of old materials, discarded tires and bathroom corners. Let the fog drift into those spots and give it a moment to fill the space before moving on. For indoor use, follow the machine manual and chemical label strictly, because dense fog in a closed room carries higher fire and breathing risks than open areas. Many agencies therefore choose a ULV cold fogger for indoor work and use the thermal fogger outdoors.

2.4 Places to avoid

• Never fog directly at people, pets, food or drinking water.
• Avoid water bodies, fish ponds and beehives, as label precautions usually require.
• Never fog near open flames, charcoal stoves, fires or suspected gas leaks.
• Take extra care around schools, child development centers and health facilities, and schedule times when children or patients are not present.

2.5 Watch for warning signs

If the engine note stutters, the fog changes color, liquid drips from the nozzle, flames burst out abnormally or you smell burning, close the chemical valve first, then shut the machine down according to procedure. Put it somewhere safe to cool before inspecting it. Never open a tank cap or add anything while the machine is hot.

2.6 Look after yourself and your team

Take breaks away from the fog and wash hands before eating or drinking. If anyone feels dizzy, nauseous or short of breath, stop, move to fresh air, give first aid per the label and see a doctor with the label in hand.

Stage 3: After Fogging (close out properly so the machine lasts)

3.1 Shut down in the right order

In general, close the chemical valve first, let the machine run briefly to purge chemical from the line, then stop the engine. The right duration depends on the model, so follow the manual. Stopping the engine while chemical is still flowing can leave residue in the combustion chamber and cause flare-ups or abnormal smoke on the next start.

3.2 Let it cool

Set the machine on a non-flammable surface away from dry grass. Never load it hot, cover it or let children touch it.

3.3 Handle leftover chemicals

Deal with leftover mixed chemical as the label instructs. Never pour it into drains, canals or water bodies. Dispose of empty containers as the label specifies and never reuse them for water or food. Keep unopened products in a lockable, ventilated cabinet or room with warning signs, separate from food.

3.4 Clean the machine

Clean according to the manual: flush the chemical system as directed, wipe the exterior, check the nozzle and remove soot at the recommended intervals. A stainless body like the AT35's wipes down easily, but internal parts still need care.

3.5 Look after staff

Remove PPE in an order that limits contamination: rinse gloves before taking them off, wash hands and face, and shower and change as soon as possible. Wash work clothes separately from family laundry. Store respirators and cartridges in a sealed bag and replace them on the manufacturer's schedule.

3.6 Record and report

Record the date, area, households covered, product name, amount used, weather, problems and operators. This supports planning, reporting and value-for-money checks. Log machine running hours to plan maintenance.

3.7 Follow up with other measures

Fogging kills adult mosquitoes but does not remove larvae in water containers. After every round, work with village health volunteers and residents on the "3 Keeps" approach promoted by Thailand's Department of Disease Control: keep the house tidy, keep rubbish cleared and keep water covered, to prevent dengue, chikungunya and Zika. Fogging is one tool in a vector control plan, not the only answer.

Vehicle Checklist (print it and keep it in the truck)

The Solution: AIROFOG AT35, a Thermal Fogger Designed to Be Easy to Use and Maintain

A good procedure delivers its full value when paired with a machine you can trust. The AIROFOG AT35 thermal fogging machine is supplied and serviced in Thailand by World Health Disinfection Co., Ltd. (WHD). According to its product information, key features include:

• 100% stainless steel body: resists corrosion and is easy to wipe clean, ideal for field work in rain, humidity and chemical exposure.
• Lightweight: staff can carry it for longer, which helps them keep the steady walking pace the procedure requires.
• Works with water-based and oil-based chemicals: the agency can choose a registered product suited to the area and mix it according to the label.
• Certified in Germany and the UK: useful supporting information for procurement committees.
• Versatile: homes, communities, factories, hospitals and public areas, for mosquito control and for controlling other insects that the labeled chemical covers.

WHD also holds ISO and GMP, performs 100% quality control before delivery, provides full after-sales service with technicians and spare parts, and its products meet Thai government equipment standards.

Jargon in one line: a thermal fogger uses heat to turn chemical into a clearly visible fog that drifts into corners, while a ULV cold fogger uses air pressure to break chemical into very fine droplets without heat.

10 Reasons the AT35 Helps Local Teams Follow the Procedure

1. Faster pre-use inspection, because leaks and unusual residue are easy to spot on a stainless body.
2. Light weight lets operators keep a steady pace for longer instead of rushing to finish.
3. Broad chemical compatibility with water-based and oil-based products, so teams can follow the label that fits each site.
4. Corrosion resistance against chemicals and humidity reduces the rust that often causes leaks.
5. Easy after-use cleaning on stainless surfaces supports routine maintenance.
6. International certification from Germany and the UK can be cited when drafting specifications.
7. Technicians and spare parts from WHD mean less downtime when something seems wrong.
8. Training on request helps pass the before, during and after routine to new staff so knowledge is not stuck with one person. See the AT35 details.
9. 100% QC before delivery means you start with a checked machine from day one.
10. Meets government equipment standards, helping procurement and acceptance inspection run smoothly.

Before and After: When the Team Has a Clear Procedure

Procurement Tips: Buy the Procedure, Not Just the Machine

Build correct operation into the purchase from day one:

• Specifications (TOR): require the supplier to deliver an operation and maintenance manual in Thai, or a Thai summary alongside the original.
• Training: require an on-site demonstration and staff training covering starting, shutdown, safety and cleaning.
• After-sales service: a technician contact channel, the warranty period the supplier offers and availability of spare parts.
• Complete budgeting: besides the equipment budget line for the machine, plan materials budget for PPE, cartridges, registered chemicals and maintenance under the categories your agency already uses.
• Documents: keep copies of certifications for acceptance inspection.

Always follow your agency's procurement regulations and consult your procurement officer.

Example Field Perspective

"We used to fog out of habit, and whenever the team changed we started from zero. Once we taped a before, during and after checklist inside the truck and practiced on a real machine, complaints about smell and spoiled food almost disappeared. The machine starts more easily too, because we always close the chemical before stopping the engine."

(A composite example based on the typical work of local public health officers, not a quote from a real person.)

Frequently Asked Questions

1. What is the best time to fog?

Generally early morning or evening, when Aedes mosquitoes are active and the air is calm. Avoid rain and strong wind.

2. What mixing rate should we use?

Only the rate on the label of the product you are using, since products differ in concentration and carrier. Use only products properly registered for public health use.

3. Do we need to warn residents in advance?

Yes, whenever possible, so that people can cover food and water, bring in laundry, look after pets and keep vulnerable people away. Advance notice also cuts complaints significantly.

4. What if flames shoot from the nozzle?

Close the chemical valve first, then shut down according to the manual, let the machine cool somewhere safe and inspect it or call a technician. This can happen when chemical is opened before the machine is hot enough, or when the combustion system needs maintenance.

5. Can a thermal fogger be used indoors?

It depends on the manual and label; fire and breathing risks need extra care. Many agencies use a ULV cold fogger such as the AIROFOG U240 indoors and the thermal fogger outdoors.

6. Is one round of fogging enough?

Usually not. Fogging around a patient's home is normally done in rounds per public health guidance, alongside removing breeding sites. Coordinate with your local health office.

7. Can WHD help train our team?

Yes. Request a demonstration and training at 065-556-6294 or LINE @whd268.

Ready to Upgrade Your Fogging Team?

Request a quotation, specifications and a demonstration of the AT35 thermal fogging machine today.

See AT35 Product and Price, Click Here

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

Browse Government Mosquito Control Equipment

Related Links

• WHD government mosquito and insect control equipment hub
• AIROFOG U240 ULV cold fogger for indoor work
• SOLO PORT423 backpack ULV sprayer
• Department of Disease Control, Thailand
• WHO: Dengue and severe dengue

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