How to Protect Yourself Against the Haze

Impact On Your Health

What are the short-term effects of haze on my health?

• The health impact of haze is dependent on one’s health status (e.g. whether one has pre-existing chronic heart or lung disease), the air quality (PSI level, PM 2.5 level) and the duration and intensity of outdoor activity.
• 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.
• 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. Such individuals may experience worsening of their symptoms when exposed to poorer air quality.
• There may be up to 1-3 days of time lag between exposure to haze and the onset of health effects or symptoms.
• As individuals may respond differently to haze, those who develop symptoms or feel unwell should seek medical attention, particularly vulnerable persons such as the elderly, pregnant women, children and those with chronic heart or
  lung conditions.

What are the long-term effects of the haze?

• Singapore is not affected by the haze throughout the year. Exposure is usually short-term in nature (over a period of hours to days) and such exposure may vary from year to year.
• Studies have shown that persons living overseas with continuous exposure over years to ambient pollution from fine particles such as PM2.5 may have a higher risk of (i) cardiovascular effects, such as heart attacks, (ii) lung cancer, as well as (iii) the development of respiratory diseases such as asthma in children. That said, evidence on long-term health effects from short-term or episodic haze exposure, such as those experienced in Singapore, remains limited. This is partly because it can be difficult to distinguish the longer-term effects of individual haze episodes from those associated with underlying daily exposure to ambient air pollution.

Protect Yourself by Understanding PSI

Which reading should I look at the plan my activities?

1-hour PM2.5 and personal guide: For immediate outdoor activities

• In 2020, MSE and MOH jointly developed a personal guide to help individuals decide on their immediate outdoor activities based on the current 1-hour PM2.5 concentration reading. This 1-hour PM2.5 personal guide serves as one of the guiding factors that the public can consider when deciding whether or not to continue with physical activities.
• The 1-hour PM2.5 levels can be volatile and tend to fluctuate over the day due to weather conditions, especially during periods of transboundary haze.
• Individuals may refer to the latest 1-hour PM2.5 reading to plan for immediate outdoor activities. This includes deciding on mask-wearing if they need to be outdoors for several hours when 1-hour PM2.5 levels are high or very high.

For immediate outdoor activities, use the 1-hour PM2.5 reading and personal guide^:

^This guide is not intended to be prescriptive. For the general population, symptoms that may arise from short-term exposure such as throat or eye irritations are expected to resolve after withdrawing from the exposure.

PSI forecast and health advisory: For next day outdoor activities 

• To plan next day outdoor activities or events that typically take place over many hours, individuals may refer to the PSI forecast, which indicates the likely PSI range over the next 24 hours, and the accompanying health advisory. This forecast is less volatile, making it suitable for forward planning.
• The health advisory is a guide for individuals to take precautions for prolonged outdoor activities.
• While the health advisory provides general precautionary advice, each individual’s reaction to air pollutants may vary.
• The amount of physical activity or exertion that can be performed outdoors during haze periods also differs according to an individual’s health status or capacity. Persons who are not feeling well, especially the elderly, children, and those with chronic heart or lung conditions should seek medical advice.

Note: Prolonged - continuous exposure for several hours; Strenuous - involving a lot of energy or effort; Reduce - do less; Minimise - do as little as possible; Avoid - do not do

• During periods of transboundary haze, the 1-hour PM2.5 and PSI forecast readings will be available on NEA’s website (www.nea.gov.sg), the haze microsite (www.haze.gov.sg), NEA’s Facebook page (www.facebook.com/NEASingapore), NEA Twitter (@NEAsg), and the myENV app.

What is MOH’s Advice to the Public?

• Reducing outdoor activities and physical exertion can help limit the ill effects from haze exposure.
• The public is recommended to adhere to the personal guide and MOH health advisory for general precautionary advice, though each individual’s reaction to the haze may vary depending on his or her health status, the amount of physical exertion and the duration of exposure.
• Persons who are not feeling well, especially the elderly, pregnant women, children, and persons with chronic heart or lung conditions, should seek medical attention.

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:

• Close doors and windows, when the outdoor air quality appears to be worsening. This will help to reduce the rate of haze particles entering the home.

• Stay indoors and reduce physical activities.

• Reduce other sources of indoor air pollution, e.g. cigarettes, candles.

• Re-open the windows and doors in the home when the outdoor air quality improves.

• Wet-cleaning methods (e.g. mopping or wiping) can be used to remove settled dust in the home as unlike dry-dusting or vacuuming, they generally do not stir up dust particles.

• 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: When choosing a portable air cleaner, select a unit that is appropriately sized for the space. The minimum smoke CADR (in m³/h or cmh) effected by air filters that a unit should provide for a particular room size can be estimated as follows: Smoke CADR (cmh) effected by air filters ≥ room size (m³) × 5
  
  In spaces where ventilation cannot be easily improved (e.g. no operable windows), and/or in spaces with high-risk activities, and/or if portable air cleaners contain electronic air-cleaning technologies, the sizing of portable air cleaners is recommended as follows: Overall smoke CADR (cmh) ≥ room size (m³) × 7
  
  For a typical bedroom (10–12 m²) in a 4-room HDB flat, air purifiers should have a smoke CADR of approximately 130–156 m³/h or higher, depending on room size. For a typical living room (20–25 m²) in a 4-room HDB flat, air purifiers should have a smoke CADR of approximately 260–325 m³/h or higher, depending on room size.

• For a list of portable air cleaners suitable for use in household and/or commercial settings for reducing airborne particulates, please click here.

Protect Yourself Outdoors

• 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. Unless the 1-hour PM2.5 reading is in Band 4 (Very High) or PSI forecast is hazardous, it is generally safe for healthy individuals to carry on with outdoor activities in most cases, at reduced intensity and/ or duration. However, you should drink plenty of water to stay hydrated. N95 masks (or equivalent) are not needed for commuting from home to school or work. N95 masks (or equivalent) are also not needed in an indoor environment.
• Individuals with existing chronic heart and lung conditions should ensure that medications are on hand and readily available.
• When the 1-hour PM2.5 reading is in Band 4 (Very High), healthy individuals should try to minimise all outdoor activity. However, persons who need to be outdoors for immediate activities may reduce exposure by wearing an N95 mask (or equivalent) with a good fit.
• When the 1-hour PM2.5 reading is in Band 3 (High), vulnerable persons such as the elderly, pregnant women and individuals with chronic heart or lung disease should avoid outdoor activity. If they need to be outdoors for immediate activities, they may wear an N95 mask (or equivalent) to reduce exposure. However, the elderly, pregnant women and those with severe lung or heart problems who have difficulty breathing at rest or on exertion should consult their doctor before using an N95 mask (or equivalent).
• Women in the 2nd and 3rd trimesters of pregnancy may already have reduced lung volumes or breathing issues, and should not use an N95 mask (or equivalent) for long duration.
• Any person who feels discomfort when using an N95 mask (or equivalent) should take a break from using the mask. N95 masks (or equivalent) must be fitted properly to the face of the wearer for it to effectively protect the user. The mask must be appropriately sized, and cover the nose and mouth comfortably without leaks. 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.
• N95 masks (or equivalent) can be reused but should not be shared. It should be changed when it gets soiled or distorted in shape.

Resources and Useful Links

You can get live updates on PSI readings on:

• NEA’s myENV app (available for download for iPhone and Android)
• NEA’s Twitter page
• NEA’s Facebook page
• NEA’s corporate website
• Haze Microsite
   

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• Haze Subsidy Scheme