The haze is an ongoing issue here in Singapore and authorities believe it may get worse this year due to the increasingly dry season. As such, MOH have release some guidelines to help doctors as well as the general public to minimise any negative effects.

Haze effects will be dependant on a variety of issues; health status, PSI, duration and intensity of outdoor activity among other. Those who feel unwell, are elderly or very young, or have other chronic health problems should seek medical attention.

Below is a table correlating PSI and recommended activity levels for different individuals:


How will the haze affect me?

Haze can be harmful to the heart and lungs, particularly those with pre-existing heart or lung problems (e.g asthma, COPD, heart failure). However, symptoms may not be immediate and there may be a period of 1-3 days before symptoms appear.

With healthy individuals, haze exposure over a few days may lead to irritation of the nose, mouth and throat but these usually subside once exposure to the haze is minimised. Individuals with pre-existing health problems should seek medical attention should they notice worsening of their symptoms.

Thankfully we do not experience the long term effects of the haze here in Singapore.

What does MOH recommend?

MOH firstly recommends that the general public stick to the boxed guidelines seen above. In most cases of haze here there should not be an issue of continuing outdoor activity but PSI numbers will change on a daily basis and public service announcements will be made if the haze reaches an unhealthy level.

Staying well hydrated is also important as this helps reduce symptoms such as dry cough and itchy throat.

Those with chronic conditions are advised to keep their medications available so that they can be taken if needed. For example, those with asthma are encouraged to have their inhalers on their person in case they need to use it.

Every individual will experience the haze differently but the key is to limit exposure to the haze should you be experiencing any symptoms or discomfort. Those with chronic conditions should lower their threshold for symptoms before seeking reprieve from the haze.

Should I be wearing a mask?

For short exposure such as short commutes to school or work then an N95 mask is not necessary. N95 masks are also not needed when indoors.

How to use an N95 Mask

A healthy person who may have to spend several hours outside when the PSI is in the hazardous range (>300PSI) may benefit from an N95 mask as this will reduce the exposure to haze.


N95 Mask

The best way for vulnerable people, which includes pregnant ladies, to protect themselves is to minimise outdoor activity when the air quality is unhealthy (>200 PSI). If they do need to be outdoors then an N95 mask is recommended. Those who have lung or breathing problems prior to using an N95 mask should seek medical attention first.

What is PM2.5 and will the N95 mask protect me?

PM2.5 stands for particle matter smaller than 2.5 micrometres. These particles are important because there has been reported an increased risk of symptoms and long term complications like heart and lung problems. With current measuring methods the Singapore 24 hour PSI takes the PM2.5 into account so this does not need to be stated separately.

The first note of mention is that the N95 mask will only work if the seal around the nose and mouth is secure. If there are any gaps then much bigger particles will still be able to bypass the mask rendering it less useful. However, if a good seal is formed and all the air is moving through the filter correctly then mask is 95% efficient. The mask can even filter out particles as small as 0.1 to 0.3 micrometres in size.

What effects may I experience if I wear the N95 mask?

The nature of air filtration means that the effort of breathing will be much greater. This is why those with pre-existing breathing problems should seek medical advice before using the mask. Even if you are generally healthy you may experience discomfort in breathing, tiredness, and headache after prolonged use.

If you are beginning to feel uncomfortable with the mask you should take a break by removing the mask when you are in an environment that is safe to do so.

So where can I get a mask?

Most major pharmacies and supermarkets will stock the N95 mask. Do not worry about stock shortage because MOH holds a large stockpile that is distributed to pharmacies in times of greatest need.

Are all masks the same?

There are many other masks similar to N95 which are also useful at reducing exposure to haze and if you are unsure then please ask your local healthcare professional. Please bear in mind that the regular surgical masks, which are becoming increasingly popular are not suitable for haze as the filter size is too large and they do not form a seal around the nose and mouth. Please see the image below for an example of a surgical mask;


Surgical face mask

So I have got an N95 mask. How do I check it is fitted properly?

Correct fitting will be different for every user. The size needs to be suitable and the nose and mouth need to be covered without any air leak. The Health Promotion Board (HPB) has a step-by-step guide on how to ensure good fitting:

Can I reuse the mask?

Yes, the mask is reusable. However, it should be changed once a good seal can no longer be formed or it has been visibly soiled. Please remember not to share your N95 mask – everyone should have their own mask.

For more information on haze please visit any of these sites:

  3. 013/haze.html


For more questions, please email them at to make an appointment today or visit them at