The hazy conditions in Singapore is normally carried by the winds from neighbouring countries especially from forest fires. The September 2015 haze results from fires on plantations and peatlands in Sumatra and Kalimantan that were illegally cleared by burning blown in by the prevailing southerly winds.




The Pollutant Standards Index (PSI) measures air quality and translates the information into an index. Since April 2014, the PSI has included a sixth pollutant - fine particulate matter (PM2.5). PM2.5 are small, toxic particles that are associated with vehicle emissions and the haze from forest fires. Click the below image to read more from the National Environment Agency - The 1-2-3 of PSI.



Air Quality Based on PSI Value


PSI Air Quality Remarks
0 - 50 Good


Normal activities.


51 - 100 Moderate


Normal activities.


101 - 200 Unhealthy

Prolonged or strenuous outdoor physical exertion - Reduce for healthy persons; Minimise for elderly, pregnant women, children; Avoid for persons with chronic lung disease, heart disease.

201 - 300 Very unhealthy

Avoid prolonged or strenuous outdoor physical exertion. Minimise outdoor activity for elderly, pregnant women, children. Avoid outdoor activity for persons with chronic lung disease, heart disease.

Above 300 Hazardous

Minimise outdoor activity for healthy persons and avoid outdoor activity for the rest.


Visit NEA's Haze Microsite for the latest air quality readings, click on the NEA logo below.





The key air pollutants of concern include particulate matter (PM), sulphur dioxide, ozone, nitrogen dioxide and carbon monoxide. For healthy individuals, short-term exposure (i.e. over a few days) to haze will generally not cause any major health issues, other than irritation of the eyes, nose, and throat. In most cases, it is still safe to carry on with outdoor activities. However, you should drink plenty of water to stay hydrated. While the health advisory provides general precautionary advice, each individual's reaction to pollutants may vary.


The amount of physical activity or exertion that can be performed also differs according to an individual's health status or capacity. Persons who are feeling unwell, especially the elderly and children, and those with chronic heart or lung conditions, are advised to seek medical care. Drink lots of water to flush out the inhaled toxins, and take a healthy balanced diet rich in anti-oxidants.


(Source: https://www.moh.gov.sg/content/moh_web/home/









Experts say that people should not draw conclusions on air quality based on just visibility levels, or how bad the haze smells. The haze could be more visible because there is more water vapour in the air, according to the Ministry of the Environment and Water Resources. And the smell may be caused by other compounds generated when vegetation and peat are burned.


Instead, one of the best ways to determine how unhealthy the air is in real time is to look at the one-hour PM2.5 levels published by the National Environment Agency (NEA), say experts. Typically, two types of particles make up the haze.


There are the coarser ones, which the human body is mostly equipped to filter out. These particles are large enough to be trapped by the nasal passages or end up being passed directly through the body.


The bigger worry is the PM2.5 pollutants - so called because they are no larger than 2.5 microns, or a thirtieth the diameter of a human hair. These can become trapped deep in the lungs and are tiny enough to pass through linings into the bloodstream. Long-term exposure to these particles on a regular basis has been linked to increased risk of death from heart and lung complications such as lung cancer or heart disease.


On a regular, non-hazy day, the maximum concentration of PM2.5 is usually between 20 and 35 micrograms (mcg) per cubic m, said Dr Velasco. They start becoming a serious problem when the numbers hit 100, and dangerous when they exceed 200.


To put things in perspective,on a day when PM2.5 levels hit 100mcg per cubic m, a person will take in around 1,100mcg of these pollutants if he or she stays outdoors throughout the day. For comparison, a smoker will inhale between 10,000mcg and 40,000mcg of PM2.5 pollutants for every cigarette consumed.


To view PSI and determine how unhealthy the air is in real time is to look at the one-hour PM2.5 levels published by the National Environment Agency (NEA), click on the NEA logo below.



(Source: Extract from http://www.straitstimes.com/opinion/





There are different brands of N95 masks in the market which have the same functionality. They come in different colours, shapes and sizes.


EN-149 is one of the European Standard for masks while N95 masks are certified by the US National Institute for Occupational Safety and Health (NIOSH). Both types of masks are designed to reduce wearer’s respiratory exposure to airborne contaminants such as particles, gases or vapours.


The EN-149 masks are classified in three classes depending on the ability to separate air-borne particles:


Class Separation ability at 95L/min airflow
FFP1 Filter separates 80% of airborne particles
FFP2 Filter separates 94% of airborne particles
FFP3 Filter separates 80% of airborne particles


FFP2 masks that meet the EN-149 standard are the closet to N95 masks in the ability to filter particles.


(Source: http://www.nea.gov.sg/anti-pollution-radiation-protection/air-pollution-control/psi/faqs-on-psi)