Haze is an air-pollution phenomenon that occurs when large amounts of tiny particles and pollutants become suspended in the air. These particles can reduce visibility and, more importantly, may enter the respiratory system when we breathe.
In Malaysia, haze can become particularly noticeable during periods of dry weather and widespread fires. However, haze is not simply a visibility problem—it can have significant effects on human health, especially when fine particulate matter such as PM2.5 reaches high levels.
WHAT IS HAZE?
Haze refers to a condition in which large quantities of tiny particles and pollutants are present in the atmosphere.
These pollutants can include:
- Fine particulate matter (PM2.5)
- Larger particulate matter (PM10)
- Smoke
- Dust
- Soot
- Carbon monoxide
- Sulfur dioxide
- Nitrogen dioxide
- Ozone
- Other combustion-related pollutants
PM2.5 is particularly concerning because these particles are extremely small and can travel deep into the lungs. Some particles can also enter the bloodstream and contribute to cardiovascular and respiratory health problems.
WHAT CAUSES HAZE?
Haze can have natural and human-related causes. In Malaysia, common sources include open burning, industrial emissions and vehicle exhaust.
1. OPEN BURNING
Open burning is one of the major contributors to haze.
Examples include:
- Burning leaves
- Burning household waste
- Burning agricultural waste
- Clearing land by fire
- Forest and peatland fires
- Uncontrolled vegetation fires
Smoke from these fires contains fine particles and various gases that can significantly deteriorate air quality.
2. FOREST AND LAND FIRES
Large-scale forest, peatland and agricultural fires can generate enormous amounts of smoke.
Under dry and windy conditions, smoke can travel considerable distances and affect areas far away from the original fire.
The resulting smoke can contain large amounts of PM2.5, which is considered one of the major health concerns associated with smoke exposure.
3. VEHICLE EXHAUST
Motor vehicles are another important source of air pollution.
Cars, motorcycles, buses and heavy vehicles can release pollutants through exhaust emissions.
Heavy traffic, particularly in densely populated urban areas, can contribute to poor air quality.
4. INDUSTRIAL EMISSIONS
Factories and industrial facilities may release pollutants into the atmosphere through combustion and industrial processes.
Depending on the industry and emission controls, pollutants can include particulate matter and various gases.
Industrial activities are recognised as an important source of outdoor air pollution.
5. CONSTRUCTION AND DUST
Construction activities can release large quantities of dust and particulate matter.
Examples include:
- Demolition
- Excavation
- Road construction
- Sand and soil movement
- Construction vehicles
Dust particles can contribute to poor air quality, particularly around heavily developed areas.
WHY IS HAZE DANGEROUS?
The biggest concern is what happens when polluted air is repeatedly inhaled.
Fine particles can penetrate deep into the respiratory system and may contribute to inflammation and other health problems. Long- and short-term exposure to particulate pollution has been associated with respiratory and cardiovascular disease.
COMMON HEALTH EFFECTS OF HAZE
1. EYE IRRITATION
Haze can irritate the eyes.
A person may experience:
- Red eyes
- Watery eyes
- Burning sensation
- Itchy eyes
- Eye discomfort
People who already have sensitive eyes may notice these symptoms more quickly.
2. NOSE AND THROAT IRRITATION
Polluted air can irritate the upper respiratory tract.
Possible symptoms include:
- Runny nose
- Stuffy nose
- Sneezing
- Dry throat
- Sore throat
- Throat irritation
3. COUGHING
Coughing is one of the common symptoms associated with exposure to smoke and polluted air.
The cough may be:
- Dry
- Persistent
- Worse outdoors
- Accompanied by throat irritation
- More noticeable during periods of heavy haze
Smoke exposure can also increase mucus and phlegm production.
4. WHEEZING
Some people may develop wheezing, which is a high-pitched or whistling sound during breathing.
This can be particularly concerning for people with asthma or other existing respiratory conditions.
Smoke exposure can aggravate asthma and other lung diseases.
5. SHORTNESS OF BREATH
Haze can make some people feel that they are struggling to breathe or cannot get enough air.
Shortness of breath may be more noticeable when:
- Walking outdoors
- Exercising
- Climbing stairs
- Spending extended periods outside
People with existing heart or lung conditions may be particularly vulnerable.
HAZE AND ASTHMA
People with asthma can be particularly sensitive to polluted air and smoke.
Haze may trigger or worsen:
- Coughing
- Wheezing
- Chest tightness
- Shortness of breath
- Asthma attacks
Anyone with asthma should follow their individual asthma management plan and reduce exposure to polluted air when haze levels are high.
EFFECTS ON THE HEART AND BLOOD VESSELS
Haze is not only a lung problem.
Fine particulate pollution can affect the cardiovascular system. Exposure to PM2.5 has been associated with cardiovascular effects including worsening of heart disease, heart attacks and stroke.
People with existing cardiovascular disease may therefore need to take extra precautions during severe pollution episodes.
LONG-TERM HEALTH RISKS
Repeated or prolonged exposure to air pollution can have more serious consequences.
Air pollution is associated with an increased risk of:
- Chronic respiratory disease
- Chronic obstructive pulmonary disease (COPD)
- Cardiovascular disease
- Stroke
- Lung cancer
- Respiratory infections
- Premature death
WHO identifies air pollution as a major environmental health risk and notes that PM2.5 can penetrate deep into the lungs and enter the bloodstream.
WHO IS MOST VULNERABLE TO HAZE?
Although everyone can be affected by polluted air, certain groups are at greater risk.
These include:
Children
Children's lungs are still developing, and they may spend significant time being physically active.
Older adults
Older people may be more vulnerable because of age-related changes and existing medical conditions.
Pregnant women
Pregnancy is one of the groups that requires additional attention during significant smoke and air-pollution events.
People with asthma
Haze can aggravate asthma symptoms and increase breathing difficulties.
People with heart disease
Pollution can worsen existing cardiovascular conditions.
People with chronic lung disease
Those with COPD and other chronic respiratory illnesses may experience worsening symptoms.
Outdoor workers
People who work outdoors may receive much greater exposure because they spend many hours in polluted air.
HOW TO PROTECT YOURSELF DURING HAZE
1. CHECK THE AIR QUALITY INDEX
Monitor the local air-quality readings and health advisories.
Avoid relying solely on how the sky looks because air pollution can contain microscopic particles that cannot be seen with the naked eye.
In Malaysia, the Air Pollutant Index (API) is used to communicate air-quality conditions and associated health concerns.
2. REDUCE OUTDOOR ACTIVITIES
When air quality deteriorates, reduce unnecessary outdoor activities.
This is particularly important during periods when haze is severe.
Avoid strenuous outdoor exercise because heavy breathing can increase the amount of polluted air entering the lungs.
3. KEEP WINDOWS AND DOORS CLOSED
When outdoor air is heavily polluted, keeping windows and doors closed can help reduce the amount of smoke entering the home.
Where appropriate, air conditioning can be used to maintain a more comfortable indoor environment.
EPA guidance similarly recommends staying indoors and keeping doors and windows closed during smoke events.
4. USE AN AIR PURIFIER
A properly selected air cleaner can help reduce indoor particulate pollution.
A portable air cleaner with an effective particle filter, such as a HEPA-filtered air cleaner, can be particularly useful during smoky conditions.
5. WEAR AN APPROPRIATE RESPIRATOR WHEN NECESSARY
If you must spend time outdoors during significant smoke exposure, a well-fitting respirator such as an N95 can reduce exposure to fine smoke particles when used correctly.
A loose-fitting ordinary mask may not provide the same level of protection against very fine particles.
People with heart or lung conditions who have difficulty breathing while wearing a respirator should seek medical advice regarding appropriate protection.
6. AVOID OUTDOOR EXERCISE DURING HEAVY HAZE
Running, cycling and other strenuous activities increase breathing rate.
This can increase the amount of polluted air inhaled.
Consider exercising indoors when air quality is poor.
7. DO NOT ADD MORE POLLUTION INDOORS
When haze is present, avoid activities that generate additional indoor pollution.
Examples include:
- Smoking
- Burning incense
- Burning candles unnecessarily
- Indoor burning
- Using poorly ventilated combustion appliances
EPA recommends avoiding activities that add to indoor air pollution during smoke events.
8. KEEP VULNERABLE PEOPLE AWAY FROM POLLUTED AIR
During significant haze episodes, take additional precautions with:
- Babies and young children
- Elderly family members
- Pregnant women
- People with asthma
- People with COPD
- People with heart disease
Reducing their exposure can help lower the risk of pollution-related health effects.
WHAT SHOULD YOU DO IF YOU DEVELOP SYMPTOMS?
If you develop mild symptoms such as coughing, throat irritation or eye irritation during haze:
- Move to an area with cleaner air.
- Reduce outdoor activities.
- Drink enough fluids.
- Monitor your symptoms.
- Check local air-quality information.
- Follow your doctor's instructions if you have an existing respiratory or heart condition.
If symptoms persist or become worse, seek medical advice.
WHEN SHOULD YOU SEEK URGENT MEDICAL ATTENTION?
Seek urgent medical attention if you develop significant:
- Difficulty breathing
- Severe shortness of breath
- Chest pain
- Severe wheezing
- Bluish lips or skin
- Confusion
- Fainting
- Severe weakness
- Rapid worsening of respiratory symptoms
People with asthma or chronic heart and lung disease should follow their personalised medical action plan and seek help if their symptoms are not responding to their prescribed treatment.
HOW CAN WE REDUCE HAZE AT ITS SOURCE?
Protecting ourselves from haze is important, but preventing haze is even more important.
1. STOP ILLEGAL OPEN BURNING
Avoid burning rubbish, leaves and agricultural waste unnecessarily.
Communities should report dangerous or illegal burning to the appropriate authorities.
2. PREVENT FOREST AND PEATLAND FIRES
Better land management, fire prevention and rapid firefighting responses can help reduce large-scale smoke events.
3. REDUCE VEHICLE EMISSIONS
Using public transportation, carpooling, walking or cycling when conditions are safe can help reduce vehicle-related emissions.
Regular vehicle maintenance can also help reduce unnecessary emissions.
4. IMPROVE INDUSTRIAL EMISSION CONTROL
Industries should comply with environmental regulations and use appropriate pollution-control technologies.
5. REDUCE WASTE BURNING
Proper waste collection, recycling and disposal can reduce the need for open burning.
HAZE IS MORE THAN JUST "BAD WEATHER"
Haze should not be viewed simply as an unpleasant period when the sky becomes grey.
The most important concern is the concentration of fine particles and other pollutants in the air we breathe. PM2.5 is particularly important because its small size allows it to penetrate deep into the lungs and potentially enter the bloodstream.
Even healthy people may experience temporary respiratory symptoms during heavy smoke exposure, while people with asthma, heart disease, chronic lung disease, children, older adults and pregnant women may face greater risks.
FINAL THOUGHTS
Haze is a serious environmental and public-health issue. Its major sources include open burning, forest and land fires, vehicle emissions, industrial activities and other combustion-related pollution.
The immediate effects can include eye irritation, coughing, throat irritation, wheezing and breathing difficulties. More serious exposure can aggravate respiratory and cardiovascular diseases, while long-term exposure to air pollution is associated with diseases such as COPD, heart disease, stroke and lung cancer.
The best protection is to reduce exposure when air quality is poor: monitor air-quality information, limit outdoor activities, avoid strenuous exercise outdoors, keep polluted air outside the home, improve indoor air filtration where possible, and use an appropriate well-fitting respirator when outdoor exposure cannot be avoided.
Disclaimer: This article is for general health education and does not replace professional medical advice. If you experience severe breathing difficulty, chest pain, confusion, bluish lips or rapidly worsening symptoms during a haze episode, seek urgent medical attention.
