If you are indoors with the air conditioning on, you may not realise it is there, but as soon as you step out and the acrid smell hits your nostrils, you will know that the haze is back yet again. In recent days, the haze situation has been closely followed by various news outlets.
The “Hazy” is Back!
In a recent article published by Channel News Asia titled, “Singapore’s air quality may enter ‘unhealthy’ range in the next 24 hours: NEA”, the National Environment Agency (NEA) said it was “slightly hazy” in Singapore on Thursday (12th September), with the 24-hour Pollutant Standards Index (PSI) reading falling in the Moderate range of between 75 and 87 at 7 pm.
At the time of writing of this article on 13th September, the PSI was recorded at 97 in the southern parts of Singapore. A PSI reading between 101 to 200 falls in the Unhealthy range.
Yes, this frequent yet unwelcome visitor has arrived at our shores once again. The haze in Singapore is caused by smoke originating from hotspots in central and southern Sumatra being blown in by the prevailing winds. The fires are usually started during operations to clear land for palm oil and pulp plantations.
For up to date air quality readings in Singapore including PSI and PM2.5 please refer to the NEA website: https://www.nea.gov.sg/
The Impact of Haze on our Health
The haze spells trouble for all of us in general, but particularly for those with pre-existing respiratory conditions like Asthma and Bronchitis, as the poor air quality can easily trigger exacerbations to occur. Hospital Emergency Departments tend to see a rise in such cases during times of haze. Research has shown that even minor exposure to air pollution can have a negative impact on the lungs, heart and even the brain. Aside from PSI, air quality is also measured by PM2.5, which is a measure of the concentration of tiny particles less than 2.5 micrometres in diameter, or about one-thirtieth the diameter of a human hair. Airborne particles in the PM10 size range and below can be drawn into the body with every breath, and deposited in the mouth, throat, nose and lungs.
The NEA advises that when the air quality reaches the Unhealthy range:
- Healthy people should reduce prolonged or strenuous outdoor physical activities
- Elderly, pregnant women and children should minimise prolonged or strenuous outdoor physical exertion
- Persons with chronic lung or heart disease should avoid prolonged or strenuous outdoor physical activities
Choosing the Correct Face Mask
This is the time when the public will start stocking up on face masks to shield themselves from air pollution. It is important to note that some common face masks may not be sufficient against fine haze particles, and choosing the wrong one will only give the wearer a false sense of security instead of providing adequate protection.
Common surgical face masks are designed to catch the wearer’s own bodily fluids, such as saliva and nasal discharge, and prevent any infectious liquid droplets from spreading to others. According to the United States Food and Drug Administration (FDA), if worn properly, these can also help prevent large-particle droplets, splashes, sprays or splatter that may contain viruses and bacteria from reaching a wearer’s mouth and nose.
Usage of surgical face masks can help to reduce the discomfort caused by haze by providing a barrier between the wearer and larger irritant particles in the air. However, as they do not have an in-built filter mechanism, they are ineffective in filtering particles that are PM2.5 or smaller, and thus cannot provide adequate protection when worn in the haze.
Particulate respirators contain a filter mechanism and are designed to be sealed against the face of the wearer. This way, most of the air that the wearer breathes in goes through the filter and not through the gaps between the mask and the wearer’s face. They are designed to protect the wearer from inhaling harmful dust, fumes, vapours or gases. Examples of particulate respirators include the well known N95 mask, which is certified by the US National Institute for Occupational Safety and Health (NIOSH), and also the EN-149 mask, which is the European equivalent.
How to Use an ‘N95’ Mask
‘N95’ means that the mask is not oil-resistant, and is able to filter out at least 95% of particles that do not contain oil. Studies have shown that N95 masks are able to provide good protection against the haze as they are at least 95% efficient against fine particles that are about 0.1 to 0.3 micrometres, and 99.5% efficient against particles that are 0.75 micrometres and larger.
It is important to take note of the following with regards to N95 mask usage:
- The mask has to fit the wearer appropriately and provide a good seal. Choose an appropriate size, check for a proper fit and ensure that it covers the mouth and nose without a leak.
- The mask has to be worn correctly in order to provide adequate protection. This video by the Ministry of Health demonstrates the 6 steps to follow when wearing an N95 mask:
- Due to the tight seal and filter mechanism, the N95 mask takes some getting used to and may feel uncomfortable to use as it reduces air intake and requires increased breathing effort. For persons with chronic lung or heart conditions and may have pre-existing breathing issues, consult your doctor if you are unsure if you should use the N95 mask.
- The N95 mask is recommended for use when outdoors for long durations. It is not necessary to use an N95 mask in indoor environments and for short outdoor exposure. As a guide, the NEA recommends that healthy people should use an N95 mask when the PSI exceeds 300. Persons with chronic lung or heart conditions, elderly and pregnant women should use an N95 mask when the PSI exceeds 200.
- The N95 mask is a disposable respirator. It can be reused, but do not share it with others. If it gets soiled or dirty, change the mask.
- If you decide to get an EN-149 mask, be sure to choose the FFP2 class, which filters 94% of airborne particles and is the closest equivalent to the N95 mask.
Mask up, and stay safe in this hazy weather!
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