Does Haze Drive Pests Indoors? How Poor Air Quality May Affect Cockroaches, Mosquitoes & Rats in Malaysia
When haze starts to hit Malaysia, most of us think about the usual things — wearing a mask, staying indoors, checking the air quality and avoiding outdoor activities.
But there is another question that homeowners and businesses may not think about:
Does haze have anything to do with pests?
The short answer is: haze itself does not magically create cockroaches, mosquitoes or rats. However, the changes in our surroundings and daily habits during hazy weather can sometimes create conditions where pest problems become more noticeable.
Does Haze Kill Cockroaches, Mosquitoes or Rats?
One common misconception is that heavy haze will drive pests away or even kill them.
Unfortunately, it is not that simple.
Normal environmental haze is not a reliable pest-control method. Cockroaches can continue hiding in cracks, drains, cabinets and other sheltered areas. Rats can remain inside ceilings, storerooms, drains and rubbish areas. Mosquitoes may continue breeding wherever stagnant water is available.
In other words, if you already have a pest problem, waiting for the haze to disappear is unlikely to solve it.
Why Can Pest Problems Become More Noticeable During Hazy Weather?
When the air quality is poor, people naturally spend more time indoors. Businesses may also keep doors and windows closed for longer periods.
That means we may suddenly notice things we normally don't see.
A cockroach appearing in the kitchen at night, scratching sounds from the ceiling or mosquitoes inside the house may become much more obvious simply because everyone is spending more time indoors.
For restaurants, factories, offices and shopping malls, this can be even more important.
An existing pest problem that was previously hidden can quickly become a bigger concern when customers, employees or food-handling staff start noticing pest activity.
Cockroaches: Check Your Drains and Wet Areas
Cockroaches breathe through tiny openings along the sides of their bodies called spiracles. They don't breathe with lungs like humans, but they still need to exchange gases with the surrounding air.
During heavy haze, the air contains fine particles and other pollutants. While ordinary haze is unlikely to immediately kill a cockroach, poor air quality can create environmental stress, particularly for insects exposed to pollutants for prolonged periods.
This is one reason sheltered environments can become more attractive. Gaps under doors, drains, wall voids, cupboards and building cavities provide protection from outdoor conditions.
However, cockroaches aren't simply thinking, “The air is smoky, let's go inside.” Their movement is much more likely to be influenced by the combination of shelter, moisture, food and favourable temperature.
Don't Forget About Mosquito Breeding Sites
Mosquitoes also don't have lungs. They breathe through spiracles connected to a network of tubes called a tracheal system.
Airborne pollutants can potentially interfere with insect respiratory function, but the relationship between haze and mosquito populations is complicated. Haze should not be described as something that kills mosquitoes or automatically makes them move indoors.
What matters more for homeowners is that mosquitoes may seek shaded, sheltered and humid areas when outdoor environmental conditions become less favourable.
And there is an even bigger issue in Malaysia:
The breeding water is still there.
If stagnant water is left around your property, mosquitoes can continue their breeding cycle regardless of whether the sky is clear or hazy
Aedes mosquitoes can breed in surprisingly small amounts of stagnant water around homes and commercial premises.
Check places such as:
- Plant pots and saucers
- Blocked drains
- Roof gutters
- Discarded containers
- Buckets
- Outdoor equipment
- Construction materials
- Water-filled rubbish
Regular inspection is particularly important around factories, construction sites, schools, residential developments and commercial buildings.
What About Rats?
Rodents are another pest that businesses should keep an eye on.
A rat doesn't need an open door labelled “WELCOME.”
They can enter through surprisingly small gaps and make use of drains, service ducts, ceiling spaces, rubbish areas and structural openings.
If you notice:
Droppings + gnaw marks + scratching sounds + unusual smells
…it is worth investigating rather than assuming the problem will disappear on its own.
Rats are mammals, so unlike cockroaches and mosquitoes, they do have lungs.
Smoke and particulate pollution can irritate the respiratory system of mammals. During poor outdoor air-quality conditions, a sheltered environment with cleaner air can therefore be more favourable to rodents.
But again, we shouldn't oversimplify this as:
“Haze makes rats come indoors.”
Rats already prefer places that provide food, water, warmth, shelter and protection from predators.
Buildings, drains, rubbish rooms, warehouses, ceiling spaces and kitchens provide exactly that.If outdoor conditions become uncomfortable, these sheltered locations can become even more attractive.
For food businesses, warehouses and factories, rodent activity should be treated seriously because contamination can quickly become a food safety and hygiene issue.
Haze Is a Good Reminder to Look at Indoor Pest Risks
Perhaps the biggest connection between haze and pest control is simple:
When we spend more time indoors, we notice what is happening indoors.
This makes haze season a good reminder for homeowners and businesses to inspect areas that are often overlooked.
Look underneath sinks. Check drains. Inspect rubbish areas. Look for droppings. Check ceiling spaces. Look around loading bays and storage rooms.
You don't necessarily need to wait until you see a cockroach running across the floor.
Preventive pest management is usually much easier than dealing with a full-blown infestation.
What Should Businesses Do During Haze?
For restaurants, shopping malls, factories, hotels, offices and other commercial premises, pest control should continue as part of normal hygiene and facility management.
A good programme should include regular inspections, monitoring, sanitation recommendations and targeted treatments where necessary.
At Sincerae Services, our approach focuses on Integrated Pest Management (IPM) rather than simply spraying chemicals whenever a pest is spotted.
The objective is to identify the source of the problem, reduce food, water and harbourage opportunities, monitor pest activity and apply the appropriate treatment.
Don't Blame Everything on the Haze
Seeing more cockroaches or rats during a haze period doesn't necessarily mean the haze caused the infestation.
More often, it is a combination of weather, building conditions, sanitation, food sources, water availability and pest entry points.
The important thing is not to wait until the problem becomes obvious.
If you are noticing increasing pest activity at your home, restaurant, factory, office, warehouse or commercial property in Kuala Lumpur or Selangor, a proper inspection can help identify what is really happening.
Haze may change our behaviour, but good pest control starts with understanding the pest — not simply spraying whatever we can see.
18 Aug 2026
