Know Your Medicines
Haze Alert

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Why does haze matter for your health?

Haze is a sign of air pollution by fine particles (consisting of microscopic solid or liquid droplets). When these particles enter your lungs, they may pose severe health problems, for example:

• worsening of heart or lung disease

• heart attacks

• irregular heartbeat

• worsening of asthma

• symptoms, such as throat irritation, coughing or difficulty breathing


People with heart or lung diseases, children and older adults are more sensitive to the harmful effect of haze. Healthy individuals may not be spared and will experience temporary symptoms from exposure to haze.


How is the severity of haze situation measured?   

It is measured by PSI, which stands for 'Pollutant Standards Index'. This index is developed by the United States Environmental Protection Agency (USEPA).

Singapore’s National Environmental Agency (NEA) monitors PSI constantly via network of monitoring stations and the Ministry of Health (MOH) issues specific health advisory for various range of 24-hour PSI.

Poster from MOH Haze Microsite


What are some ailments caused by haze and how you can deal with them?


Actions to be taken

Tearing, stinging sensation of eyes

Apply eye drops or natural tear supplements to wash away any pollutant particles in your eyes and to provide symptom relief.

Runny nose, blocked nose, Sneezing

Ask your pharmacist to recommend relevant medication for symptoms. If you are already taking medicine for allergy, make sure it is taken regularly. Consult your doctor if symptoms persist.

Coughing; dry, irritated throat

Ask your pharmacist for the relevant symptom reliever. Maintain good fluid intake by drinking about 10 to 12 glasses of water a day, unless otherwise advised by your doctor. See your doctor if cough persists for longer than 7 days or when signs of worsening are observed (e.g. thick phlegm,high fever)

Difficulty in breathing; chest tightness

Please see your doctor immediately.

Patients with asthma should always carry their reliever inhaler wherever they go. Those with asthma or airway/ lung disease should take any prescribed medicine as instructed by your doctor and monitor your condition closely. Consult your doctor again if your condition does not improve.

Should you wear face masks? What should you look out for?

According to the MOH Health Advisory for the General Public (20 Mar 2015), N95 masks are not needed for short exposure, like commuting from home to school or work, travel from bus-stop to shopping mall. N95 masks are also not needed in an indoor environment.

A healthy person who has to be outdoors for several hours when the air quality us in the hazardous  range (PSI>300) may reduce exposure by wearing a N95 mask.

People with chronic lung or heart disease, elderly and pregnant women should avoid or minimize outdoor activity when the air quality is unhealthy (PSI>200). If they have to be outdoors for several hours, they may reduce exposure by wearing a N95 mask.

Respiratory masks, such as N95 masks, protect the wearers from breathing in the smoke haze particles. Haze particles are predominantly made up of fine partlcles that are 2.5 microns or smaller (PM2.5). Studies have shown that N95 masks do provide good protection against the haze as they are at least 95% efficient against fine particles that are about 0.1 to 0.3 microns. It is even more efficient (99.5%efficient) against particles that are 0.75 microns and larger. These masks should be changed when they become distorted in shape or get soiled and they should not be shared.

N95 masks are designed to seal to the wearer's face and have to achieve a proper fit. This way, most of the air that is breathed in go through the filter and not through the gaps in between the mask and the wearer's face. Hence, N95 masks are not designed for use on children or people with facial hair (e.g beard). Children should minimize outdoor activities when the PSI levels are above 100 and avoid all outdoor activities if PSI levels reach higher than 300.

One should take a break from using N95 mask if one feels uncomfortable. Elderly, pregnant women and people with severe lung or heart problems who have difficulty breathing at rest or on exertion should consult their doctor as to whether they should use the N95 mask.

Women in the 2nd and 3rd trimester of pregnancy may already have reduced lung volumes or breathing issues. They should stop using a N95 mask if they feel uncomfortable.

Surgical masks and paper masks do not offer the required protection. Their main purpose is to prevent the spread of body fluids and do not filter out haze particles.

Poster from Health Promotion Board and Ministry of Health Singapore 


Respiratory masks are available in community and hospital retail pharmacies. Ask your pharmacist on the appropriate selection and use of respiratory mask.


Other tips

Avoid exercising in the open. Aerobic activities make you inhale deeply, hence you breathe in pollutants deep into your lungs. Avoid smoking. Smoking makes your lungs more sensitive to effects of haze particles.


References and for further updates on haze, you may wish to access the following sites:

MOH Haze Microsite

National Environment Agency

Health Promotion Board


A public education initiative brought to you by the PSS Community Chapter