When the Air Changes: Understanding Haze and What You Can Do

The sky looks different. The air feels heavier. And suddenly, something as ordinary as stepping outside requires a little more thought.

Haze doesn't always arrive with a warning. Sometimes, it's a faint smell of smoke. Sometimes, it's a distant skyline disappearing behind a grey curtain. Other times, it's the irritation in your eyes or throat that tells you something has changed.

Across Southeast Asia and other parts of the world, haze can affect communities far beyond the places where fires begin.

Understanding what's happening, knowing how to respond, and making a few practical adjustments can help protect your wellbeing and the people around you.

Here are five important questions worth understanding.

1. What Is Haze, and Why Does It Happen?

Haze occurs when tiny particles and other pollutants accumulate in the atmosphere, reducing visibility and affecting air quality.

While haze can have several causes, forest and peatland fires are major contributors to seasonal smoke haze in parts of Southeast Asia.

In Indonesia, forest and land fires are commonly referred to as Karhutla (Kebakaran Hutan dan Lahan)

Forest fires near a state campus in Palangka Raya, Central Kalimantan, Indonesia, 18 August 2026.
Photo: MWul / Wikimedia Commons · CC BY 4.0

During dry periods, fires can spread through forests, plantations and peatlands. Peat fires are particularly challenging because they can smoulder underground and continue releasing smoke for extended periods.

Wind can carry this smoke hundreds of kilometres, sometimes affecting neighbouring countries such as Singapore and Malaysia.

What is PM2.5?

One of the biggest concerns during haze episodes is PM2.5, which refers to fine airborne particles measuring 2.5 micrometres or smaller.

These particles are small enough to travel deep into the lungs. Some may also enter the bloodstream, contributing to wider health effects.

Unlike visible dust, PM2.5 cannot be reliably judged by sight alone.

A relatively clear-looking sky doesn't necessarily mean the air is clean.

What you can do: Check official air-quality readings rather than relying only on visibility, smell or how the sky looks.

2. Why Do Our Eyes, Throat and Lungs React to Haze?

Have you ever stepped outside during a hazy day and noticed your throat becoming dry, your eyes stinging or your breathing feeling uncomfortable?

These reactions can happen because smoke contains fine particles and irritating gases.

Common symptoms include:

• Eye irritation, redness or watering

• A dry or scratchy throat

• Coughing and nasal irritation

• Headaches or unusual discomfort

• Wheezing or difficulty breathing, particularly in sensitive individuals

Not everyone responds to haze in the same way.

Children, older adults, pregnant women and people with existing heart or respiratory conditions may be more vulnerable to its effects.

For someone with asthma, for example, exposure to smoke may trigger coughing, wheezing or an asthma attack.

What if you feel short of breath?

First, move away from the smoky environment and into a cleaner indoor space.

Reduce physical exertion and allow yourself to rest. If you have a prescribed reliever inhaler or other respiratory medication, follow your healthcare professional's instructions.

Seek medical advice if symptoms persist, worsen or feel unusual.

Severe breathing difficulty, chest pain, confusion or blue lips are medical emergencies. Seek emergency assistance immediately.

Remember, feeling uncomfortable isn't something you need to push through. Sometimes, the most practical response is to stop and adjust.

3. Do All Face Masks Protect You From Haze?

Not all masks are designed for the same purpose.

A mask that works well for one situation may provide limited protection in another.

During haze episodes, the main concern is reducing exposure to fine airborne particles, particularly PM2.5.

Understanding the differences

Why fit matters

Even a high-quality respirator can provide reduced protection if air leaks around the edges.

For better protection:

• Choose a certified respirator from a reliable manufacturer.

• Make sure it covers your nose, mouth and chin.

• Check that it fits securely without noticeable gaps.

• Follow the manufacturer's instructions for putting it on and checking the seal.

• Replace disposable respirators when damaged, dirty or difficult to breathe through.

A respirator filters particles, but it does not protect against every gas present in smoke.

Should everyone wear an N95 during haze?

Not necessarily.

The need for a respirator depends on air quality, exposure duration, activity level and individual health conditions.

For example, Singapore's Ministry of Health generally does not recommend N95 masks for brief commutes or ordinary indoor environments. During severe haze, a properly fitted respirator may help people who must spend extended periods outdoors.

People with certain heart or lung conditions, and some pregnant or elderly individuals, should consult a healthcare professional if respirator use causes breathing difficulty.

The most effective first step is often to reduce exposure, rather than simply wearing a mask and continuing outdoor activities as usual.

4. What Should You Do When Air Quality Gets Worse?

When haze develops, preparedness doesn't have to mean dramatic changes.

Often, small adjustments make the biggest difference.

At home

Keep polluted outdoor air from entering unnecessarily.

Close windows and doors when outdoor air quality is poor. If you use air-conditioning or mechanical ventilation, check whether the system draws in outside air and follow appropriate operating guidance.

Improve indoor air filtration.

A properly sized portable air purifier with an effective particle filter, such as HEPA, can help reduce indoor fine-particle levels.

Choose a unit suitable for your room size and maintain its filters according to the manufacturer's instructions.

Avoid adding more indoor pollution.

During haze episodes, minimise activities that generate additional particles, such as smoking, burning candles or incense, and unnecessary frying or grilling.

When going outside

Check air quality before making plans.

Air-quality reporting systems differ between countries. Some use an Air Quality Index (AQI), while Singapore uses the Pollutant Standards Index (PSI) and hourly PM2.5 readings.

Check the local authority's guidance, especially before exercising or spending several hours outdoors.

Adjust physical activity.

Running, cycling and other strenuous activities increase breathing rates and can increase the amount of pollution inhaled.

When air quality is poor, consider moving workouts indoors, reducing their intensity or postponing them.

Plan for vulnerable family members.

Children, older adults and people with respiratory conditions may need additional precautions.

Keep prescribed medication accessible, review school or outdoor activity advisories, and identify a cleaner indoor space where family members can spend time if conditions deteriorate.

A Simple Haze Preparedness Checklist

✓ Check official local air-quality updates

✓ Reduce unnecessary outdoor exposure when advised

✓ Keep windows and doors closed during poor air quality

✓ Check and maintain indoor air filters

✓ Keep prescribed respiratory medication accessible

✓ Have suitable respirators available if needed

✓ Adjust outdoor exercise and family activities

✓ Seek medical attention for concerning symptoms

You don't need to prepare for every possible scenario at once. Start with the steps most relevant to your household.

5. How Can You Protect Your Emotional Wellbeing During Haze?

Haze affects more than the air we breathe.

It can change everyday routines, cancel outdoor plans and make familiar surroundings feel unfamiliar.

For parents, it may bring concerns about children travelling to school.

For outdoor enthusiasts, it can interrupt training and recreation.

For people living closer to affected areas, the impact may be far more serious, including displacement, uncertainty and concern for loved ones.

Feeling frustrated, unsettled or anxious during an environmental event is understandable.

Focus on what you can control

You may not be able to change the direction of the wind or stop a distant fire.

But you can make informed decisions about your immediate environment.

Check reliable updates, adjust your activities and take practical precautions.

Avoid constant exposure to alarming information

Staying informed is useful. Repeatedly checking distressing images, speculation and unverified social media reports may increase anxiety without helping you make better decisions.

Choose trusted sources and check them at sensible intervals.

Maintain familiar routines where possible

If outdoor exercise isn't advisable, consider an indoor alternative.

If children cannot play outside, create simple activities at home.

Small routines can help restore a sense of normality when circumstances feel uncertain.

Look out for one another

Check in on elderly neighbours, family members with respiratory conditions and people who may need assistance.

For communities directly affected by fires, support credible humanitarian and environmental organisations where possible.

Preparedness is not only about protecting ourselves. It is also about recognising when others may need help.

When the Air Changes, We Adapt

We cannot control every environmental event.

A distant fire, shifting winds or a sudden deterioration in air quality can change an ordinary day.

But understanding the risks gives us more choices.

We can recognise the warning signs, protect our health, adjust our routines and look after those around us.

Preparedness doesn't mean expecting the worst.

It means knowing what to do when circumstances change.

Because when the air changes, the way we respond matters.

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Trusted Resources and Further Reading

For current conditions and health recommendations, always refer to your local authorities.

• Singapore National Environment Agency (NEA): https://www.nea.gov.sg

• Singapore Haze Information: https://www.haze.gov.sg

• Singapore Ministry of Health — Haze: https://www.moh.gov.sg/others/haze/

• ASEAN Specialised Meteorological Centre: https://asmc.asean.org

• US Environmental Protection Agency — AirNow: https://www.airnow.gov

• US Centers for Disease Control and Prevention: https://www.cdc.gov

Disclaimer: This article provides general educational information and is not a substitute for professional medical advice. Follow official local advisories and consult a healthcare professional for individual health concerns.