Other than death and taxes, the haze season in Singapore has got to be one of the certainties of life.
Also known as “that burning smell in the air” or “why the skyline so blur-blur one?”, haze has been a steadfast constant since as early as 1972. It’s just how bad it gets.
Perhaps one consolation of 2020 — despite it being a crappy year with COVID-19 and the resultant economic downturn — is that there wasn’t much haze.
However, before we start celebrating, experts say that 2021’s haze might be starting earlier, and some hotspots have already been detected. Climate change may have a part to play in this shift.
What is Haze?
Haze is like an airborne cocktail of pollutants that’s not good for the lungs. This is because the mixture includes nasties such as soot particles, carbon dioxide and other toxic gases.
How the severity of haze is measured is via the PSI or Pollutant Standards Index, a measure of air quality. PSI is calculated based on six pollutants: particulate matter (PM10), fine particulate matter (PM2.5), sulphur dioxide, carbon monoxide, ozone and nitrogen dioxide.
The main pollutant is PM2.5, named because the fine particles are less than 2.5 micrometres across and can remain suspended in the air for a longer period. Being so tiny (up to 100 times thinner than a human hair), these fine particles are able to penetrate deep into our lungs and even our blood stream should we inhale them — a health hazard.
As haze is so dependent on the presence of these PM2.5 particles, detecting a burning smell in the air does not always equate to worsening air quality and transboundary haze.
|0 to 50||Good|
|51 to 100||Moderate|
|Above 300||Unhealthy or hazardous|
According to a The Straits Times article, the National Environment Agency (NEA) said that “such smells could come from a variety of sources, including local and regional fires, and may be more pronounced during certain periods of the day due to weather conditions”.
Similarly, poor visibility may not be a key indicator of increasingly unhealthy PSI levels. Higher humidity means there is more water vapour in the air, which scatters light and reduces visibility.
The reverse is also true, as pollutants such as ozone are odourless but can contribute to an unhealthy PSI.
PSI values of 0 to 50 are good; 51 to 100 is moderate and anything above that is unhealthy or even hazardous (above 300).
Causes of Haze in Singapore
Why do we even have haze in Singapore? Where is all this smoke and brew of pollutants coming from? When and what is this “haze season”?
The causes of haze are typically slash-and-burn farming practices, as well as regional forest/peat fires caused by hotspots. It’s further exacerbated by periods of dry weather and low rainfall. Generally, haze in Southeast Asia is at its worst between July and September/October, during the southwest monsoon season where the winds carry the smoke over Singapore’s skies.
As a result, the resultant smoke blankets much of Southeast Asia, including Singapore. The haze area can cover an area that’s hundreds of kilometres across (much larger than the size of our Little Red Dot) and causes a significant deterioration of air quality (our PSI or pollutant standards index and PM2.5 readings) that can even force the closure of schools.
Singapore’s Worst Haze Ever
If you’re in your late teens or older, you might clearly remember Singapore’s worst haze ever, where 3-hour PSI readings reached a record-breaking 401 on 21 June 2013. We could barely see past the buildings nearest to us, and even the thick, choking smog leached into our homes through tightly-shut windows.
What’s being done: NEA has been working with Asean partners to manage the haze problem in the region via the monitoring and assessment of forest fires and transboundary smoke haze. Singapore has also been investigating forest fires in the region.
Areas Most Affected by Haze in Singapore
While the overall landmass of Singapore is small, some regions/towns could experience varying levels of haze based on factors such as wind direction, rainfall, and so on.
The NEA divides our sunny island into five regions — North, South, East, West and Central — which are based on town centres/areas. It’s similar to the listings on PropertyGuru, based on HDB estates/towns.
Haze in Singapore
Admiralty, Kranji, Woodlands, Sembawang, Yishun, Yio Chu Kang, Seletar, Punggol, Sengkang
Holland, Queenstown, Bukit Merah, Telok Blangah, Pasir Panjang, Sentosa, Bukit Timah, Newton, Orchard, City, Marina South
Serangoon, Hougang, Tampines, Pasir Ris, Loyang, Simei, Kallang, Katong, East Coast, Macpherson, Bedok, Pulau Ubin, Pulau Tekong
Lim Chu Kang, Choa Chu Kang, Bukit Panjang, Tuas, Jurong East, Jurong West, Jurong Industrial Estate, Bukit Batok, Hillview, West Coast, Clementi
Thomson, Marymount, Sin Ming, Ang Mo Kio, Bishan, Serangoon Gardens, MacRitchie, Toa Payoh
While there isn’t really any official chart showing how haze affects the different regions in Singapore (and which are the most affected), we’ll draw some data from past news reports and historical 24-hour PSI readings on the NEA’s haze website.
Although the data is far from conclusive, it can be seen that the southern region of Singapore tends to have the highest PSI readings. It’s then followed by west and east, with the central region being the least affected (but still affected, nonetheless).
Our guess would be that this is because the major hotspots in Sumatra lie to the south-west of Singapore, and other nearby hotspots are located in Malaysia (north of Singapore) and in Sarawak (further east) and Kalimantan (further east). Those living in the central region of Singapore may benefit from the dissipation of the particles over other buildings or vegetation.
For real-time updates of the haze situation and Singapore’s air quality, the NEA’s haze website is a good resource.
Haze in Singapore 2021
As you can see, we’ve had some brief encounters with moderate and borderline unhealthy haze levels earlier this year. These were due to hotspots in Johor and heightened levels of ozone, which can be influenced by ambient temperature, ultraviolet levels, wind speed, wind direction and rainfall.
Well, unless we walk around in a gigantic bubble with PM2.5 filters and a constant oxygen supply, there’s no sure-fire way to keep the haze at bay. The equivalent might be shutting ourselves indoors, windows sealed tight and the aircon turned on 24/7.
How to Protect Yourself from The Haze
In light of that, here are some quick tips to protect yourself this haze season:
- Monitor the PSI and PM2.5 readings
- Reduce/avoid prolonged strenuous outdoor physical exertion if needed
- Wear an N95 mask (not a surgical mask) when outdoors to reduce exposure, as that can filter out most of the harmful PM2.5 fine particulate matter
- Shut doors and windows when air quality worsens
- Invest in a portable air purifier if needed
- Don’t contribute to the worsening air quality by smoking indoors or deciding to dust your furniture/sweep the floor
- If your air conditioner unit draws in unfiltered air from outdoors, shut its outdoor air intake opening
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This article was written by Mary Wu, who hopes to share what she’s learnt from her home-buying and renovation journey with PropertyGuru readers. When she’s not writing, she’s usually baking up a storm or checking out a new cafe in town.