Haze in Penang | Health Risks, API Explained and How to Stay Safe

Article by: Anonymous

27 August 2026

Haze in Penang: What the Air Is Doing to Your Body and How to Protect Yourself

Penang has been experiencing a period of poor air quality this week. On 25 August 2026, three of the state’s four monitoring stations recorded unhealthy Air Pollutant Index (API) readings, with Minden and Balik Pulau on the island reaching API 155 and 151, and Seberang Perai on the mainland logging 146. State health committee chairman Daniel Gooi advised the public to limit outdoor activities and wear face masks when heading out.

hazy skyline over Penang George Town

While a brief spell of rain on 26 August brought some relief, with all four stations dropping back to moderate levels, haze episodes in Malaysia tend to be recurring rather than one-off events, particularly during the Southwest Monsoon season, which runs from May to September. This is a good time to understand what haze actually does to the body, who is most at risk, and what you can do to reduce your exposure.

Understanding the Air Pollutant Index

Penang API air quality index scale chart

Penang API Air Quality Index Scale Chart - Department of Environment (DOE)

Malaysia uses the Air Pollutant Index (API), managed by the Department of Environment (DOE), to measure and report air quality across 68 monitoring stations nationwide. Readings are updated every hour.

1. What the API Numbers Mean

0 – 50 | Good – Normal outdoor activities are fine for everyone.
51 – 100 | Moderate – Generally safe for most people. Those who are sensitive may notice mild irritation.
101 – 200 | Unhealthy – Reduce prolonged or strenuous outdoor activities, especially if you are in a higher-risk group.
201 – 300 | Very Unhealthy – Avoid prolonged outdoor exposure. High-risk groups should remain indoors where possible.
Above 300 | Hazardous – All outdoor activity should be avoided. Follow emergency guidance from authorities.

Preventive and Health Control Measures That Must Be Followed During Hazard - Ministry Of Health Malaysia

2. What the API Is Actually Measuring

Malaysia’s API takes into account a few key pollutants: PM2.5, PM10, ozone, carbon monoxide, sulphur dioxide and nitrogen dioxide. During haze episodes in Malaysia, PM2.5 is typically the dominant concern.

PM2.5 refers to airborne particles smaller than 2.5 micrometres in diameter. To put that in perspective, a single human hair is roughly 70 micrometres wide. These particles are too small to be filtered by your nose or throat and can travel deep into the lungs and, in some cases, can trigger inflammation and cardiovascular effects.

One important note: the API’s particulate sub-index is based on a rolling 24-hour average. This means the reading you see right now may not fully reflect a sudden worsening in air quality over the past hour. If you want a more immediate picture, check a live PM2.5 reading alongside the API.

What Haze Does to Your Body

asian woman coughing covering mouth outdoors

Haze is not simply an inconvenience. The health effects of PM2.5 exposure are well documented and go beyond the respiratory system.

1. Respiratory Effects

When PM2.5 particles are inhaled, they penetrate deep into the airways and reach the alveoli (the tiny air sacs in the lungs where oxygen exchange takes place). Short-term exposure can cause:

Eye, nose, and throat irritation
Coughing and increased phlegm
Wheezing and shortness of breath
Chest tightness or discomfort
Worsening of existing respiratory conditions such as asthma and chronic obstructive pulmonary disease (COPD)

For people who already have respiratory conditions, even moderate API levels may worsen symptoms.

2. Cardiovascular Effects

This is the part most people do not expect. According to a Ministry of Health Malaysia advisory, the tiny particles found in haze can penetrate deep into the lungs and, once inhaled, may enter the bloodstream. They may then interact with compounds such as “bad” cholesterol and contribute to inflammation and other damaging effects. Prolonged exposure has been associated with:

Accelerated thickening of the arteries
Increased risk of heart attack and stroke
Higher cardiovascular mortality
Increased risk of diabetes

Research published in the National Institutes of Health database found that PM2.5 exposure is associated with increased emergency department visits for acute coronary syndrome, acute heart failure, and stroke. People with pre-existing heart disease are particularly vulnerable, even during short-term haze episodes.

3. Effects During Pregnancy

The MOH advisory also highlights that prolonged PM2.5 exposure during pregnancy has been linked to adverse outcomes including low birth weight and premature delivery. Pregnant women should take extra precaution during haze periods and consult their doctor if they have concerns.

Who Is Most at Risk?

elderly asian couple and young child at home indoors

While haze affects everyone, certain groups face greater health risks even at lower API levels. These include:

1. High-Risk Groups

Young children – their airways are still developing and they tend to breathe faster, taking in more particles per kilogram of body weight
Older adults – reduced lung capacity and more likelihood of underlying heart or respiratory conditions
Pregnant women – due to the risks outlined above for both mother and baby
People with existing respiratory conditions such as asthma, COPD, or bronchiectasis
People with existing cardiovascular conditions such as coronary artery disease or heart failure
People with diabetes – PM2.5 exposure may worsen glycaemic control

2. A Note on “Healthy” Adults

It is a common assumption that haze is only a problem for high-risk individuals. This is not entirely accurate. The Ministry of Health has noted that prolonged or high-level PM2.5 exposure can also affect otherwise healthy individuals. If you are spending extended time outdoors during a haze episode, the precautions in the next section apply to you too.

How to Protect Yourself During Haze

asian man wearing N95 mask outdoors during haze

1. Reduce Your Outdoor Exposure

Check the API on the DOE APIMS portal before heading out, and recheck it throughout the day as readings change hourly
Limit prolonged or strenuous outdoor activities when the API is above 100
Move exercise and outdoor activities indoors where possible
Keep doors and windows closed when outdoor air quality is poor
Switch your vehicle and home air conditioning to internal recirculation mode

2. Wear the Right Mask

This is one of the most misunderstood aspects of haze protection. According to the Ministry of Health Malaysia, haze particles can be as small as 2.5 micrometres. A standard surgical or cloth mask cannot filter particles this fine. Only a well-fitting N95 or equivalent respirator is effective at filtering PM2.5 when exposure cannot be avoided.

Important notes on N95 use:

The mask must fit snugly against the face to be effective. Facial hair can break the seal.
N95 respirators increase breathing resistance, which can cause discomfort, fatigue, or headaches. This is normal for most people, but take breaks if needed.
N95 masks are not recommended for young children or pregnant women. If you fall into either category, prioritise staying indoors instead.
People with chronic lung or heart conditions who feel uncomfortable in an N95 should stop using it and consult a doctor.

3. Manage Your Indoor Air Quality

Use an air purifier with a HEPA filter in your main living or sleeping area. Run it in a closed room rather than trying to purify the whole house.
Avoid smoking indoors, as this adds to indoor particulate levels on top of outdoor haze pollution.
Open windows only when outdoor air quality has improved to good or moderate levels.

4. Look After Your General Health

Stay well hydrated. Water helps the body manage the effects of airborne irritants
Wash your hands and face after returning indoors
Maintain a balanced diet with adequate fresh produce
If you take regular medication for heart or respiratory conditions, continue taking it as prescribed and follow your doctor’s specific advice during haze episodes

Warning Signs That Need Medical Attention

doctor checking patient with stethoscope

Some symptoms during a haze period are mild and temporary. Others are a sign that you need to see a doctor promptly.

1. Symptoms to Monitor

Eye, nose, or throat irritation that is mild and settles when you move indoors – this is common and usually resolves on its own
A dry cough or mild headache during outdoor exposure – monitor and reduce time outdoors

2. Symptoms That Warrant Medical Attention

Persistent or worsening cough
Wheezing or difficulty breathing
Chest tightness or chest pain
Shortness of breath that does not improve when you move indoors
Worsening of existing asthma, COPD, or heart symptoms
Any respiratory distress in young children or older adults

Do not wait for symptoms to become severe. Seek medical advice if symptoms persist, worsen, or concern you. You can reach our team at Sunway Medical Centre Penang for a consultation, or call us at 04-373 9191.

Key Takeaway

Haze is more than an inconvenience. The fine particles in polluted air can affect your lungs, your heart, and your long-term health, particularly if you are in a high-risk group or spending extended time outdoors.

The most practical thing you can do right now is check the latest API reading for your area, reduce unnecessary outdoor exposure when the reading is above 100, and consider using a well-fitting N95 or equivalent respirator when exposure cannot be avoided.

If you or a family member develop symptoms that concern you, please seek medical advice promptly.