1. When it comes to the haze, a PSI reading of 101 and above is considered unhealthy. PSI readings above 300 is considered hazardous.
2. People with heart or respiratory diseases, as well as young children and elderly, should minimise going outdoors whilst the haze lasts in Singapore.
3. N95 masks are generally recommended when PSI levels exceed 300 and prolonged outdoor exposure is unavoidable. For short periods outdoors when PSI levels are moderate, most healthy individuals may not need a mask.
However, people with chronic lung or heart diseases, elderly, and pregnant women may consider wearing an N95 mask when PSI levels exceed 200, if they need to be outdoors for longer periods.
Haze in Singapore is an annual occurrence that typically occurs during May to October, as a result of raging forest fires in neighbouring Sumatra, Indonesia.
People with heart or respiratory diseases, as well as young children and elderly, should avoid going outdoors whilst the haze lasts in Singapore, advise experts. Even if you don’t have a pre-existing health condition, you should reduce your outdoor physical activity when the air quality is hazy and unhealthy. For the latest air quality readings, visit the National Environment Agency (NEA) website at www.nea.gov.sg. |
The smoke haze is an annual occurrence in Singapore and typically occurs in the May to October period.
It is caused by winds bringing in tiny particles of ash from forest fires burning around the region due to farmers using slash-and-burn to clear land.
These particles are called PM2.5 (2.5 refers to the size in microns of the particulate matters).
Breathing in an excess of these particles can increase a person’s risk of developing viral and bacterial infections, as well as heart and lung diseases, cancer and stroke.
While the bigger air particles are filtered out by the respiratory tract, tiny particles are typically deposited in the lungs. These tiny particles can accumulate over time and harm the body.
“Existing health conditions such as eczema, asthma, chronic obstructive pulmonary disease (COPD) and eye diseases like conjunctivitis are made worse by air pollution,” says Associate Professor Loo Chian Min, Senior Consultant, Department of Respiratory and Critical Care Medicine, Singapore General Hospital (SGH), a member of the SingHealth group.
“Even healthy people can suffer from irritation in the eyes, nose and throat, coughing and sneezing, if they spend time outdoors during a smoke haze.”
What is a safe PSI reading for air quality?
Refer to this table to understand what PSI readings mean and what activities are safe to do based on the air quality.
| PSI Reading | Air Quality | What To Do |
| 0-50 | Good | For Healthy Persons: Normal activities For the Elderly, Pregnany Women & Children: Normal activities For Persons with Heart Diseases: Normal activities |
| 51-100 | Moderate | For Healthy Persons: Normal activities For the Elderly, Pregnany Women & Children: Normal activities For Persons with Heart Diseases: Normal activities |
| 101-200 | Unhealthy | For Healthy Persons: Reduce prolonged or strenuous outdoor physical exertion For the Elderly, Pregnany Women & Children: Minimise prolonged or strenuous outdoor physical exertion For Persons with Heart Diseases: Avoid prolonged or strenuous outdoor physical exertion |
| 201-300 | Very Unhealthy | For Healthy Persons: Avoid prolonged or strenuous outdoor physical exertion For the Elderly, Pregnany Women & Children: Minimise outdoor activity For Persons with Heart Diseases: Avoid outdoor activity |
| Above 300 | Hazardous | For Healthy Persons: Minimise outdoor activity For the Elderly, Pregnany Women & Children: Avoid outdoor activity For Persons with Heart Diseases: Avoid outdoor activity |
Definitions:
- Prolonged = Continuous exposure for several hours
- Strenuous = Involving plenty of energy or effort
- Reduce = To do less
- Minimise = Do as little as possible
- Avoid = To not do completely
Ways to protect yourself from the haze
Take the following steps to protect yourself from the haze in Singapore:
- Minimise or avoid prolonged or strenuous outdoor activities when PSI levels are above 100
- When indoors, close doors and windows when outdoor air quality appears to be worsening
- Roll up the windows of your car if you are driving
- Use an air-conditioner in your home to help remove pollutants
- Use an air ioniser or air purifier to catch very small particles
- Drink more water than usual – this helps the kidneys flush out any toxins absorbed through the skin and lungs
- Cut down on coffee and alcohol – these promote fluid loss and leach nutrients from the body
- Build up your immunity with foods rich in vitamin C (oranges, guava, strawberries), vitamin E (nuts and seeds) and omega-3 fatty acids (oily fish)
- Cover your nose and mouth when you go out for prolonged periods
Do note that N95 masks are not needed for short exposures outdoors and in an indoor environment.
Ref. S13
Related articles:
How to Protect Your Child from the Haze
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