Home   FAQ

Frequently Asked Questions (FAQs) On Haze

  1. Using the PSI and 1-hour PM2.5 Concentration Readings
  2. Impact of Haze on Health
  3. Practical Tips for Households
  4. Common Concerns & Misconceptions
  5. Use and Availability of Masks
  6. Impact of Haze on Workplace
  7. Annex

A. Using the PSI and 1-hour PM2.5 Concentration Readings

1.  What is PSI? How is the index measured? What is the meaning of the index?

PSI stands for 'Pollutant Standards Index'. It is an index to provide accurate and easily understandable information about daily levels of air quality. PSI is computed based on 24-hour average of PM2.5 concentration levels, among other pollutants. PM2.5 is the dominant pollutant during haze episodes. The ambient air in Singapore is monitored through a network of air monitoring stations located in different parts of Singapore.The monitoring stations measure concentration levels of particulate matter (PM10), fine particulate matter (PM2.5), sulphur dioxide (SO2), nitrogen dioxide (NO2), ozone (O3), and carbon monoxide (CO). These six pollutant parameters determine the PSI. The PSI value gives an indication of the air quality as shown:

PSI Value Air Quality Descriptor
0 - 50 Good
51 - 100 Moderate
101 - 200 Unhealthy
201 - 300 Very unhealthy
Above 300 Hazardous

Technical details on how the PSI is calculated can be found here: Computation of PSI

2. Which index are the health advisories based on?

The health impact of air pollution is related to concentration levels of pollutants, the duration of exposure, as well as the health status and level of activity of the individual. The health advisory is based on the 24-hour PSI (which incorporates the 24-hour PM2.5 concentration levels) as scientific and epidemiological studies on the health effects of particulate matter have been based on this duration of exposure. The 1-hour PM2.5 concentration readings are only an indicative measure of the current air quality. There are currently few studies on the health effects of short-term exposure to PM concentration levels.

24-hour PSI

Good

0-50

Moderate

51-100

Unhealthy

101-200

Very Unhealthy

201-300

Hazardous

>300

HEALTHY

PERSONS

Normal activities

Normal activities

Reduce prolonged

or strenuous outdoor

physical exertion

Avoid prolonged

or strenuous outdoor

physical exertion

Minimise outdoor activity

ELDERLY,

PREGNANT

WOMEN, CHILDREN

Normal activities

Normal activities

Minimise prolonged

or strenuous outdoor

physical exertion

Minimise outdoor activity

Avoid outdoor activity

PERSONS

WITH CHRONIC

LUNG DISEASE, HEART DISEASE

Normal activities

Normal activities

Avoid prolonged

or strenuous outdoor

physical exertion

Avoid outdoor activity

Avoid outdoor activity

3.  The PSI readings only show historical data. How can I plan for the days ahead or for my immediate activities?

During haze episodes, NEA will provide an air quality forecast for the next 24 hours. NEA will look at all relevant factors, including weather conditions, in determining this forward projection. In addition, the 1-hour PM2.5 concentration readings, which are a good indicator of the current air quality, can be used to plan one's immediate activities.

4.  How are the five regions (North, South, East, West and Central) for PSI / 1-hour PM2.5 determined and which regions' PSI / 1-hour PM2.5 should I note?

You should first note your location as the five regions are based on town centres/areas. A general guide of the town centres/ areas within each of the five regions is listed below. If your location is not listed, please use the region closest to you. NEA also provides haze situation updates and advisories during a haze period. The advisories are posted at www.haze.gov.sg. You may use the advisories to plan your activities.


Regions for Air Quality Reporting

Region Town Centres /Areas
North Admirality, Kranji, Woodlands, Sembawang, Yishun, Yio Chu Kang, Seletar, Sengkang
South Holland, Queenstown, Bukit Merah, Telok Blangah, Pasir Panjang, Sentosa, Bukit Timah, Newton, Orchard, City, Marina South
East Serangoon, Punggol, Hougang, Tampines, Pasir Ris, Loyang, Simei, Kallang, Katong, East Coast, Macpherson, Bedok, Pulau Ubin, Pulau Tekong
West Lim Chu Kang, Choa Chu Kang, Bukit Panjang, Tuas, Jurong East, Jurong West, Jurong Industrial Estate, Bukit Batok, Hillview, West Coast, Clementi
Central Thomson, Marymount, Sin Ming, Ang Mo Kio, Bishan, Serangoon Gardens, MacRitchie, Toa Payoh


5.  What would the public use the 1-hour PM2.5 concentrations for?

The 1-hour PM2.5 concentrations reflect the PM2.5 levels averaged over one hour, and can give you an indication of the current air quality. However, the 1-hour PM2.5 concentration levels can be volatile and tend to fluctuate over the day especially during periods of transboundary haze. Short-term fluctuations will also be very heavily influenced by weather conditions. For example, there could be a short period of transiently high PM2.5, only to improve rapidly in the next one to two hours. Therefore, if you wish to use the 1-hour PM2.5 concentration, it is best used as a guide to adjust your immediate activities. During haze episodes, health advice will be based on the 24-hour PSI. It is a better reflection of the total exposure of an individual to PM2.5 levels, and scientific and epidemiological studies on the health effects of particulate matter have been based on the 24-hour duration of exposure.

6.  Why give us the 1-hour PM2.5 readings but not a 1-hour PSI – both are just as volatile and are not accompanied by health advisories?

During episodes of transboundary haze, PM2.5 (particulate matter that are less than or equal to 2.5 micrometres in diameter), is the predominant air pollutant. The breakpoints to convert the PM2.5 concentrations into PSI readings have been derived based on health studies for a 24-hour exposure. Therefore PM2.5 concentrations averaged over a 24-hour period has to be used to convert the PM2.5 concentration to a PSI reading.  While a 1-hour PSI, an index for the PM2.5 over a 1-hour period, can be mathematically calculated, the resultant figures are not corroborated with any studies nor supported by health findings.

To date, the vast majority of studies on the health effects of short-term exposure to PM have used the 24-hour measurements. These studies do indeed demonstrate good correlation of health effects with 24-hour PM averages. In view of this, the health advisory in Singapore takes reference from the 24-hour PSI. Although there have been recent studies on sub-daily or shorter PM2.5 exposure, the evidence of these studies do not constitute a sufficient evidence-base for development of health advisories.

7.    How can I interpret the 1-hour PM2.5 concentration readings and use them to plan my activities?

The 1-hour PM2.5 concentration readings can be volatile and tend to fluctuate over the day especially during periods of transboundary haze. Short-term fluctuations will also be heavily influenced by weather conditions. For example, there could be a short period of transiently high PM2.5, followed by a rapid reduction of PM2.5 over the next few hours. Therefore, if the public wishes to use the 1-hour PM2.5 concentration reading, it is best used as a guide to adjust immediate activities, such as deciding if one should go outdoors for a jog now or delay that till later. The bands and descriptors for 1-hour PM2.5 concentration readings are given below:

Bands

Descriptors

Range of 1-hour PM2.5 (µg/m3)

General Guide (with MOH’s inputs)

I

Normal

≤ 55

Among healthy individuals, exposure to high levels of haze particles may cause irritation of the eyes, nose, and throat in healthy individuals. Such irritation resolves on its own in most cases.

Haze particles can affect the heart and lungs, especially in people who already have chronic heart or lung disease e.g. asthma, chronic obstructive pulmonary disease (COPD), or heart failure. Individuals with existing chronic heart and lung conditions should ensure that your medications are on hand and readily available.

Each individual’s reaction to pollutants may vary, and the amount of physical activity or exertion that can be performed differs according to your health status or physical capacity. Should you encounter symptoms or discomfort, please take additional measures to prevent further exposure. Persons who are not feeling well, especially the elderly and children, and those with chronic heart or lung conditions, should seek medical attention promptly.

II

Elevated

56 – 150

III

High

151 – 250

IV

Very High

> 250

 
8.    How did NEA arrive at the 1-hour PM2.5 concentration reading bands?

NEA is providing the bands and descriptors to serve as a gauge of the current air quality level based on the 1-hour PM2.5 concentration readings.

If the 1-hour PM2.5 concentration levels are maintained at the “Normal” band for 24 hours, the 24-hour PSI will be in the "Good to Moderate" level (1 - 100).

If the 1-hour PM2.5 concentration levels are maintained at the “Elevated” band for 24 hours, the 24-hour PSI will be in the "Unhealthy" level (101 - 200).

If the 1-hour PM2.5 concentration levels are maintained at the “High” band for 24 hours, the 24-hour PSI will be in the "Very Unhealthy" level (201 - 300).

If the 1-hour PM2.5 concentration levels are maintained at the “Very High” band for 24 hours, the 24-hour PSI will be in the "Hazardous" level (>300).

It should be noted that the 1-hour PM2.5 concentration readings can be volatile and tend to fluctuate over the day during haze episodes, as can be seen in the trend graphs below for the 1-hour PM2.5 concentrations and 24-hour PSI readings recorded for the South region of Singapore from 23 Sep 2015 to 27 Sep 2015, when Singapore was affected by transboundary haze.



9.    How should the public interpret the various air quality information (i.e. 24-hour PSI, 24-hour PSI forecast during haze period & 1-hour PM2.5 concentration) provided by NEA?

During times of haze, PM2.5 is the predominant pollutant in the PSI. The 24-hour PSI daily forecast, which is published during the haze period, is the forecast of the 24-hour PSI over the next 24 hours. It is based on NEA’s expectations about air quality and informs the corresponding health advisory, which is and will continue to be used to advise major decisions, e.g. school closure.

The 24-hour PSI is an interpretation of the historical 24-hour average of PM2.5 concentrations, translated to the PSI using breakpoints which have been derived from health studies. The 24-hour PSI has an accompanying health advisory based on medical studies and long-term exposure.

The 1-hour PM2.5 concentration readings are meant to guide immediate personal activities.

10.    Why has NEA decided to phase out the 3-hour PSI?

The 1-hour PM2.5 concentration readings (µg/m3 or micrograms per cubic metre) is a better near real-time gauge of current air quality than the 3-hour PSI which is based on readings taken over the past 3 hours. NEA has been providing 1-hour PM2.5 concentration readings for the five regions of Singapore since 2014.  NEA has enhanced the ease of use of the 1-hour PM2.5 concentration readings by introducing bands and descriptors to the 1-hour PM2.5 concentration readings. The NEA will phase out the 3-hour PSI after the 2016 haze season.

11.    Why was the 3-hour PSI introduced in the first place?

The ‘3-hour PSI’, which was based on the past 3-hour averages of PM10 concentration readings, was introduced in 1997 to provide additional information on the air quality which would be more reflective of the haze situation observed on the ground.

Since Apr 2014, the 3-hour PSI is calculated based on PM2.5 concentration averaged across 3 hours.

12.    There are claims that the National Environment Agency’s 1-hour PM2.5 breakpoints are not as rigorous as some other countries. Why is this so?

NEA has introduced the 1-hour PM2.5 bands with descriptors and a general guide to enable the public to better interpret 1-hour PM2.5 concentrations and use the information as a guide to decide on their immediate activities during haze periods. The 1-hour PM2.5 bands have been established based on an analysis of 1-hour PM2.5 concentration readings experienced during haze and non-haze periods in Singapore.

As there are no international guidelines on the computation of an air quality index, countries in the world adopt different index systems with different descriptors and breakpoints. It would therefore not be appropriate to compare the bands and descriptors that NEA has introduced for 1-hour PM2.5 concentrations with the longer duration PM2.5 breakpoints and descriptors used for the air quality index in Singapore or in other countries.

From NEA’s analysis of its records, outside the haze period, the 1-hour PM2.5 concentrations are less than 55ug/m3 about 99% of the time, with most of the readings being in the less than 30ug/m3 range. NEA has described 1-hour PM2.5 concentrations of 55 ug/m3 and below as ‘Normal’. During haze periods, 1-hour PM2.5 concentrations tend to be volatile. In periods of significant haze, the 1-hour PM2.5 concentrations are in the ‘Normal’ band about half the time, and in the ‘Elevated’ band of 55 ug/m3 to 150 ug/m3 about 40% of the time; the remaining 10% of the time would be in the ‘ High’ or even ‘Very High’ band.

The 1-hour PM2.5 bands and their descriptors are intended to give information on short-term fluctuations in PM2.5 concentrations through the day during haze periods, based on our local circumstances. Besides the 1-hour PM2.5 bands, NEA also provides the 24-hour PSI, which is an air quality index based on the level of pollutants over a 24 hour period.

During the haze period, NEA publishes the 24-hour PSI daily forecast, which is the forecast of the 24-hour PSI over the next 24 hours, with an accompanying health advisory. The public is advised to take reference from the health advisory based on the 24-hour PSI in the planning of their daily activities, and the general guide for the 1-hour PM2.5 concentration readings in the planning of their immediate personal activities. To date, the vast majority of studies on the health effects of short-term exposure to Particulate Matter (PM) have used the 24-hour measurements. These studies demonstrate good correlation of health effects with 24-hour PM averages.


B. Impact of Haze on Health

Source: Ministry of Health FAQs accessible here.

13.  What are the key air pollutants of concern?

The key air pollutants of concern include particulate matter (PM), sulphur dioxide, ozone, nitrogen dioxide and carbon monoxide. Short term exposure (i.e. continuous exposure to unhealthy daily average PSI levels over a period of a few days) to these air pollutants can cause respiratory symptoms and aggravate existing heart or lung disease. Exposure to particulate matter and sulphur dioxide may also cause irritation of the eyes, nose and throat in healthy individuals. In Singapore, the main air pollutant in the event of haze is particulate matter (PM).


14.  What is the short term effect of the haze on my health?

Haze particles can affect the heart and lungs, especially in people who already have chronic heart or lung disease e.g. asthma, chronic obstructive pulmonary disease (COPD), or heart failure. There may be up to 1-3 days of time between exposure to haze and health effects/ symptoms. Among healthy individuals, short term exposure (i.e. continuous exposure to unhealthy daily average PSI levels over a period of a few days) to high levels of haze particles may cause irritation of the eyes, nose, and throat in healthy individuals. Such irritation resolves on its own in most cases.

15.  What are the long term effects of the haze?

Singapore is not affected by the haze throughout the year. Any exposure is short-term in nature (i.e. continuous exposure to unhealthy daily average PSI levels over a period of a few days) and such exposure may vary from year to year. As international studies are based on long term exposure to air pollution, there is little robust data on the longer-term effects of short-term exposure to haze like the pattern seen in Singapore. Studies have shown that persons living overseas with continuous exposure over several years to high ambient pollution from fine particles (i.e. particulate matter 2.5 (PM2.5); particles smaller than 2.5 micrometers), may have a higher risk of (i) cardiovascular effects, such as heart attacks, (ii) reduced lung development, as well as (iii) the development of chronic respiratory diseases, such as asthma, in children.


16.  Which groups of people are more sensitive to haze?

In general, children, elderly, and people with chronic lung disease, heart disease are more sensitive to the health effects of haze, and should adopt the preventive measures in the MOH health advisory when air quality is poor. Individuals are advised to consult their doctor should they develop breathing difficulties. In addition, it is advised that pregnant women reduce exposure to haze for the health of their unborn baby.


17.  What is MOH’s advice to the public?

The public is recommended to adhere to the MOH haze health advisory. In most cases, it is still safe to carry on with outdoor activities. However, do drink plenty of water to stay well hydrated. Individuals with existing chronic heart and lung conditions should ensure that your medications are on hand and readily available. Nonetheless, please note that each individual’s reaction to pollutants may vary, and the amount of physical activity or exertion that can be performed differs according to an individual’s health status or physical capacity. Should you encounter symptoms or discomfort, please take additional measures to prevent further exposure.Although the general advice to the public when the air quality is good or moderate (PSI≤100) is to maintain normal activities, vulnerable persons, especially those with chronic heart and lung conditions, who develop symptoms or feel unwell should seek medical attention promptly.



C. Practical Tips for Households



18.  What are some practical tips for households to reduce exposure to haze particles at home?

During haze episodes, the air pollutant of concern is mainly haze particles. Some practical tips to reduce indoor exposure to haze particles at home include:

  • When the outdoor air quality appears to be worsening, close doors and windows. This will help to reduce the rate of haze particles entering the home.
  • Stay indoors and reduce physical activities.
  • Re-open the windows and doors in the home when the outdoor air quality improves.
  • Wet-cleaning methods (e.g. mopping or wiping) generally do not produce dust (unlike dry-dusting or vacuuming) and can be performed to remove settled dust.
  • Fans or air-conditioners may be used for air circulation and cooling. If the air-conditioner draws in unfiltered air from outside (e.g. window units), close the outdoor air intake opening.
  • Portable air purifiers can be used to further reduce the indoor particle level.

Advisory:

  • Minimize activities that can produce indoor air pollutants in enclosed spaces, e.g. smoking.

How to choose an air purifier:

  • Suitable cleaning technology: For removing fine particles, highly efficient filters, such as High Efficiency Particulate Air (HEPA) filters, are preferred.
  • Appropriate Size: For effective cleaning, the unit should be sized appropriately for the intended room. The effective floor area and flow rate of the air purifier are factors to consider for this purpose. Some air purifiers are labelled with a Clean Air Delivery Rate (CADR), which has three CADR numbers - one each for smoke, dust, and pollen. The smoke CADR is the most appropriate for haze pollutants. An appropriate air purifier should have a smoke CADR number that is at least 3 times the volume of the room in cubic metre, or 1/12 of the volume of room in cubic feet. A larger CADR number means faster cleaning in an enclosed room. There are many effective air purifiers without CADR rating in the market. Users should obtain from the manufacturer information that backs any claim on efficiency of removal of fine particles. http://www.haze.gov.sg/haze-updates/list-of-portable-air-cleaners-and-suppliers provides a list of portable air purifiers and suppliers for reference. For Practical Tips for Managing Particulate Matter Levels in Naturally Ventilated and Split-Unit Air-Conditioned Indoor Spaces During Haze, please click here.


D. Common Concerns & Misconceptions



19.  Can we conduct cloud seeding in Singapore to disperse the smoke haze?

Cloud seeding attempts to artificially induce rain by implanting clouds with suitable particles. The seeding particles serve as condensation or ice nuclei to induce formation of more water droplets or ice crystals in the cloud. However, there are no reliable means to validate the effectiveness of cloud seeding in Singapore. Cloud seeding requires existing clouds as it cannot generate rain out of thin and dry air. During dry seasons, cloud seeding is less effective due to the lack of suitable clouds for seeding. The small size of Singapore and the variability of winds also mean that the induced rain, if any, may not fall directly over our island. Rain may also provide only temporary relief as the smoke haze would continue to be blown toward Singapore by the prevailing winds, should the fires in the region continue to persist


20.  Why is there a burning smell during the haze period? Why is there sometimes a strong smell even though the PSI is low?

Transboundary haze affecting Singapore mainly arises from forest and peat fires in the region. Besides generating smoke particles, vegetation and peat land fires also generate a complex mixture of gases which cause an acrid burning smell. The smell is usually, but not always, accompanied by an increase in the PSI/ PM2.5 readings. The occurrence of some fires in your vicinity, may also contribute to the burning smell, which was the case on a number of occasions during the recent prolonged dry spell.


21. Why is NEA's air quality data different from the real-time data provided by other websites, such as aqicn.org? Is NEA’s data inaccurate?

The ambient air in Singapore is monitored through a comprehensive network of air monitoring stations located in different parts of Singapore. These monitoring stations measure concentration levels of particulate matter (PM10), fine particulate matter (PM2.5), sulphur dioxide (SO2), nitrogen dioxide (NO2), ozone (O3), and carbon monoxide (CO). These six pollutant parameters determine the PSI. Singapore uses the Pollutant Standards Index or PSI as the official national reporting system for air quality. PSI is computed based on a 24-hour average of the concentration levels of the abovementioned pollutants. PM2.5 is the dominant pollutant during transboundary haze episodes. The website aqicn.org in fact relies on the 24-hour average PM2.5 concentration data that is posted every hour by NEA. However, aqicn.org does not follow Singapore’s system of computing PSI. Instead, it computes an air quality index using the US Environmental Protection Agency‘s (USEPA) Air Quality Index (AQI) reporting system. There are no international guidelines on how air quality indices should be computed. Countries adopt different index systems based on their local needs and circumstances. While Singapore’s PSI is modelled after the USEPA AQI national reporting system, it is not identical to the USEPA AQI. The only country that adopts the USEPA AQI is the US. It is therefore incorrect to compare the PSI with other air quality indices which are calculated using different methodologies.


22. Are hailstones caused by acid rain or cloud seeding?

There has been some speculation that the hail (or “raining ice”) observed over the western part of Singapore between 1pm and 4:30pm on 25 June 2013 could be caused by acid rain or cloud seeding in Indonesia. This is false.

Meteorological Service Singapore (MSS) has explained that hailstones are basically balls or lumps of ice that form within intense thunderstorm clouds, and they are different from acid rain, which is rain that contains higher than normal amounts of nitric and sulphuric acids. In fact, hailstones are quite rare in the tropics because they usually melt as they fall from the clouds, before reaching the ground. On average, public sightings of hailstones in Singapore occur every one to two years. More information on hail can be found on NEA’s website at http://www.nea.gov.sg/training-knowledge/weather-climate/hail

MSS has confirmed that the hail experienced in Singapore on 25 June 2013 was not caused by the cloud seeding in Indonesia. Rain clouds formed by such seeding cannot travel such long distances to reach Singapore.


E. Use and Availability of Masks


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 is 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 very unhealthy (PSI > 200). If they have to be outdoors for several hours , they may reduce exposure by wearing a N95 mask.You should take a break from using a N95 mask if you feel 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 trimesters of pregnancy may already have reduced lung volumes or breathing issues. They should stop using a N95 mask if they feel uncomfortable.


23.  Is the N95 mask an adequate protection against haze? Does it protect against PM2.5?

N95 masks work only if there is a good fit with the face of the wearer. This way, most of the air that the wearer breathes in has to go through the filter and not through the gaps between the mask and the wearer’s face. Haze can contain fine particles that are 2.5 microns or smaller (PM2.5), and studies have shown that N95 masks do provide good protection against particle pollutants as they are at least 95% efficient against fine particles that are about 0.1 – 0.3 microns.


24.  What are the effects of wearing a N95 mask?

The use of N95 masks increases effort in breathing. For some people, the use of N95 mask may cause discomfort in breathing, tiredness or headache. This may be due to the mask causing increased resistance to breathing, and a reduction in the volume of air breathed. For most people this is not serious.However, some elderly people, people with lung or heart conditions, and women in the later stages of pregnancy may already have reduced lung volumes or breathing issues. You should take a break from using a N95 mask if you feel 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 trimesters of pregnancy may already have reduced lung volumes or breathing issues. They should stop using a N95 mask if they feel uncomfortable.


25.  How do I get a mask?

Masks are available at major pharmacies and supermarkets, such as Unity, Watsons, Guardian, Cold Storage, Giant and Fairprice. The national stockpile of N95 masks may be released to the major pharmacies and supermarkets if more are needed. Employers of workers who are required to work outdoors for prolonged period are encouraged to maintain a seven-day stock for immediate response. Procurement of additional masks can be made through the major pharmacies and supermarkets.


26.  Are there different types of N95 masks in the market?

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


28.  What are EN-149: 2001 masks? Are they equivalent to the N95 masks?

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 99% of airborne particles

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


29.  How would members of public know if the N95 or other types of masks meet safety and quality standards?

A NIOSH-approved mask is certified by the US National Institute for Occupational Safety and Health (NIOSH) to have 95% filter efficiency. A NIOSH-approved respirator has the following information printed on its packaging:

  • NIOSH
  • the type of approval (e.g.N95)
  • the manufacturer’s name

A list of NIOSH certified N95 masks is available on NIOSH’s website: http://www.cdc.gov/niosh/npptl/topics/respirators/disp_part/n95list1.html Please also see Annex B for some examples. EN149 is the European Standard for respiratory mask designed to reduce wearer’s respiratory exposure to airborne contaminants such as particles, gases or vapours.

Masks are classified in 3 three classes depending on the ability to separate air-borne particles according to the FFP (Filtering Face Pieces). An European standard certified mask will have the following text printed on it:

  • the CE mark
  • EN 149:2001; the classification of the mask (e.g.FFP2)
  • the manufacturer’s name.

30.  How does a consumer choose which mask to purchase?

Both the NIOSH-certified N95 masks or the EN-149 masks are designed to reduce wearer’s respiratory exposure to airborne contaminants such as particles, gases or vapours. Consumers should perform a fit check to ensure a good fit.


31.  How do I learn to fit my N95 mask?

For best effect, N95 masks need to be fitted properly for each user. To check for proper fit, please check that the available mask is appropriately sized and covers the nose and mouth comfortably without leak. The HPB website has a step by step guide on how to wear it N95 masks properly. See http://hpb.gov.sg/HOPPortal/health-article/HPB051226#ANNEXD The use of N95 masks to filter out pollutants in the air is not identical to the use of N95 masks for infection control in a healthcare institution during a disease pandemic situation. For use during a haze incident, even if the mask is not perfectly fitted, it can still be useful in filtering out pollutants for those who need to wear it.


32.  How do I wear a mask?

To learn how to put on a mask properly, the HPB has an info graphic on how to wear a mask on their website http://hpb.gov.sg/HOPPortal/health-article/HPB051226#ANNEXD. Please see also Annex C.


33.  Can I reuse my N95 mask?

You can reuse your N95 mask. It should be changed when it gets soiled or distorted in shape. It should not be shared.


34.  Are surgical masks useful?

Normal surgical masks can protect the wearer’s nose and mouth from irritants in the air but are not effective in filtering fine particles. Individuals with acute respiratory infections may wish to wear a surgical mask to prevent spread of infection. Individuals may feel more comfortable having a surgical mask for short periods of time for unavoidable outdoor exposure e.g. commuting from home to MRT station, and waiting for public transportation.

35.  Why are masks recommended for outdoor workers at lower PSI than for the general public?

The threshold for usage of N95 masks or equivalent for protection of outdoor workers is suggested at lower PSI than for the general public as work commitments may require prolonged outdoor exposure or strenuous work on a regular basis. Employers should refer to the MOM guidelines for more details on situations where suitable masks or respirators have to be used. In general, work arrangements to reduce outdoor work such as frequent breaks and job rotation should be made to reduce prolonged or strenuous outdoor work. Use of mechanical aids such as trolleys, lifts or hoists instead of manual lifting and carrying could also reduce the strenuous nature of these activities. Where outdoor work is unavoidable, employers should provide suitable masks (based on the MOM’s guidelines) to protect workers. If N95 masks are used, employers and employees should note that these increase the effort of breathing. For some employees, this may cause discomfort in breathing, tiredness or headache. This may be due to their masks causing increased resistance to breathing, and a reduction in the volume of air breathed. Employers should consider instituting regular breaks and encourage hydration of employees using masks. Risk assessment, taking into account the usage of the respirators, individual employee’s heath conditions and nature of outdoor work must be conducted.


36.  How will the haze impact patients in nursing homes and subsidised wards with natural ventilation?

These patients are indoors and sedentary. The healthcare institutions, such as hospitals and nursing homes, will monitor patients closely, and ensure ample circulation of clean air indoors.



F. Impact of Haze on Workplace

Source: Ministry of Manpower FAQs accessible here.

37.  Which haze index should employers monitor so as to decide what measures to take to protect their workers?

Employers should refer to the 24-hour PSI forecast on the NEA website, as well as the updated health advisories on the NEA website (www.nea.gov.sg) or the Haze website (www.haze.gov.sg). The impact on one’s health is dependent on the quality of air, duration of exposure, and one’s health conditions. Employers can take reference from MOM’s guideline to employers, available on MOM’s website (www.mom.gov.sg/haze) and the Haze website (www.haze.gov.sg) for general measures to minimise or mitigate the effects of haze on their employees. Additional measures specific to the work requirements and health conditions of the employees would have to be instituted based on the risk as assessed by the employers.


38.  What other workplace measures can companies consider or do to mitigate the impact of the haze on workers?

All employers should carry out proper risk assessments of their various work activities and implement appropriate measures, to ensure that the risks identified are minimised or mitigated. Depending on the air quality, employers should first find ways to reduce or avoid prolonged or strenuous outdoor work. Risk assessments, taking into account the impact of the haze, individual employee’s health, work demands and fatigue, etc, must be conducted and risk mitigating measures adopted.

Examples of such measures include:

  1. Use mechanical aids (e.g. trolleys, hoists) to transport or carry heavy objects instead of manual lifting or carrying.
  2. Adjust work assignments or rotate jobs to shorten the time spent in outdoor work.
  3. Schedule sufficient indoor rest breaks for workers performing outdoor work.
  4. Ensure adequate hydration for workers.
  5. Monitor employees’ health by encouraging feedback on any symptoms that may occur.
  6. Defer non-essential work.

If prolonged or strenuous outdoor work is unavoidable, an employer who requires an employee to do so due to extenuating circumstances, is strongly urged to provide masks. Employees who need to wear masks / respirators should be fit-tested to ensure good fit. Employers should ensure sufficient stock of masks / respirators for these employees, and conduct training and supervision to ensure correct usage. Masks should be changed when soiled/physically damaged or when the wearer finds it hard to breathe. Elderly and pregnant employees as well as those with chronic heart/lung disease should consult their treating doctors on the usage of masks. Reference should be made to the Singapore Standard SS 548:2009: Code of Practice for Selection, use and maintenance of respiratory protective devices. Employers are strongly encouraged to adopt a flexible and enlightened approach in implementing flexible work arrangements for all staff, especially susceptible employees, such as the elderly, pregnant and those with chronic heart or lung illnesses. Examples of flexible work arrangements include telecommuting. If their employees feel unwell and wish to rest at home, employers are encouraged to be flexible in allowing them to take their leave. For employees who have used up their annual leave/sick leave entitlements, employers could consider granting them advance leave or other leave arrangements. In such situations, the employees’ wages should not be deducted.


39.  MOM’s guidelines advise employers to institute regular rest breaks during the haze. How long would be a sufficient time for each break?

MOM’s guidelines provide general measures that employers can take to mitigate the risks their employees face in a haze situation, and is not meant to be prescriptive. Employers should carry out a proper risk assessment of their various work activities and implement appropriate measures (such as identifying appropriate rest periods) so as to ensure that the risks identified are minimised or mitigated.


40.  What should an outdoor worker do if an employer does not heed the advisory on the haze situation?

Workers should first raise their concerns to their supervisor, HR department and union representatives. If no action has been taken, workers can call the MOM Contact Centre at 6438 5122 or visit http://www.mom.gov.sg for general adviceIf there are significant safety concerns on outdoor work during the haze situation, workers can call the MOM Occupational Safety and Health Hotline at 6317 1111 or email MOM_OSHD@mom.gov.sg


41.  Who can workers turn to if there are employer and employee disputes regarding the haze risk assessment?

Workers should first raise their concerns to their supervisor, HR department and union representatives. If no action has been taken, workers can call the MOM Contact Centre at 6438 5122 or visit http://www.mom.gov.sg for general advice. If there are significant safety concerns on outdoor work during the haze situation, workers can call the MOM Occupational Safety and Health Hotline at 6317 1111 or email MOM_OSHD@mom.gov.sg


42.  What penalties can MOM impose if employers do not follow MOM's guidelines?

Under the Workplace Safety & Health Act (WSH Act), employers have a duty to protect their employees’ safety and health at work. In situations where haze poses risk to the safety and health of workers and measures have not been taken to mitigate those risks, either by adopting measures suggested in the advisory or other alternative mitigation measures, MOM may order the affected work to stop. If any person (individual or corporate bodies) subsequently fails to comply with a stop work order, under the WSH Act he shall be liable on conviction to a fine not exceeding $500,000 or to imprisonment for a term not exceeding 12 months or to both. Our inspectors will be looking out for employers who disregard the safety and health of their workers, especially those performing strenuous and prolonged outdoor work.


43.  If an employee suffers injury or illness while working in hazy conditions, will the worker be eligible for work injury compensation?

Under the Work Injury Compensation Act (WICA), an employee who sustains an illness/injury arising out of and in the course of employment is eligible to claim work injury compensation from his employer. Employers should notify MOM (through the iReport tool on the MOM website) if any employee has sustained an illness/injury due to working outdoors during the haze. For cases where the employee is able to recover over time and resume work without permanent ill effects, employers should pay any medical leave wages and medical expenses due directly to the employee.


44.  For employees who need to take leave arising from the haze, but have run out of their leave entitlements, what can they do?

Some employees may be unable to report for work because they are unwell or need to take care of their family members, e.g. family members are unwell because of the haze, or require alternative childcare arrangements as school / childcare facilities are closed.

They are encouraged to:

  • Discuss with their employers on the feasibility of adopting flexible work arrangements (FWAs) to meet organisational and personal needs.
  • Where FWAs are not feasible, employees may wish to seek approval from their employers to take time-off, use advance leave or other leave arrangements.

45. If employers decide that work should be stopped in view of the haze situation, can the employees’ salaries or annual leave be deducted on that day?

Employers who wish to suspend business operations should take note of the following:

  • If the suspension is on a short-term and ad-hoc basis, employers should bear the costs of doing so and not deduct from the pay or leave entitlements of their affected employees.
  • If the suspension of business operations is for longer periods, employers should discuss with their union and employees on the appropriate flexible work, leave and salary arrangements to be put in place.

46.  Can employers ask employees to take annual leave if the company closes or operations have stopped due to the haze situation?

If the suspension is on a short-term and ad-hoc basis, employers should bear the costs of doing so and not deduct from the pay or leave entitlements of their affected employees. If the suspension of business operations is for longer periods, employers should discuss with their union and employees on the appropriate flexible work, leave and salary arrangements to be put in place.


47.  Who can employees turn to if there are employer and employee disputes regarding leave and salaries?

Employers are strongly encouraged to put in place in advance internal company grievance handling procedures to manage any haze-related employment disputes. Employees should first approach their employers to resolve the matter amicably. If there are disagreements, the issue should be raised to the management via union representatives or your HR. If the dispute cannot be resolved amicably, you can make an online enquiry via www.mom.gov.sg/feedback or call the MOM Contact Centre at 6438 5122, for further assistance.



ANNEX A

EXAMPLES OF N95 MASKS

examples of niosh approved masks

 

 

ANNEX B

EXAMPLES OF NIOSH-APPROVED MASKS

examples of niosh approved masks

ANNEX C

HOW TO WEAR A MASK

how to wear n95 mask