SINCE the haze is still the hottest topic around, Eye thought that perhaps we could shed a little light on what the numbers of the Air Pollutant Index (API) mean.
This too, came about when an old pakcik from a kampung near Kuching asked “Apa sebenarnya disukat sidak dalam API tok? Nya sukat ketebalan asap ya ka?” (What do they measure to get the API? The density of the smoke?)
Not surprisingly, many people do not really understand what makes up the API reading. Some still think that the readings are generally measurements of the density of smoke in the air – be it from burning, exhaust fumes or factories.
And to many, smoke is smoke – it is irritating, it stinks and it causes respiratory problems in those who are sensitive and with allergies.
Those who think that smoke does not get to them because they are not sensitive, are not very bothered by the haze and in fact continue to loiter around outside and puff on their cigarettes and vape gadgets.
Little do they know that they are contributing much of the toxic pollutants into the air around us. There are also those who still inconsiderately burn their garden waste – dead leaves, twigs, and cut grass – out in their backyards during the dry season.
Do they not realise how much harm they are causing to themselves and their own families?
But first, let us understand what the air quality index entails. In Malaysia, it is known as the API, while in Singapore it is called the Pollutants Standard Index (PSI). In China and Hong Kong, the term Air Quality Index (AQI) is used.
Generally, there are six levels of air quality – Good (0-50); Moderate (51-100); Unhealthy for Sensitive Groups (101-150); Unhealthy (151-200); Very Unhealthy (201-300) and Hazardous (readings greater than 300). The highest API level recorded in Malaysia was 839 on Sept 23, 1997 in Kuching during the infamous 1997 Southeast Asian Haze. However, there are those who argue that the readings back then were in fact much higher if new standards of measuring air pollutants had been applied.
When measuring air pollution, particles or particulate matter floating around in the air are analysed. Even when the skies are clear and when we seem to have clean air, there are still particulates hanging around in the air.
These particles come in many shapes and sizes. For the purpose of measuring pollutants in the air, experts have divided these particles into two groups – PM10 and PM2.5. It wasn’t too long after the 1997 haze incident that PM2.5 was included in measuring pollutants in the air.
So what exactly do PM10 and PM2.5 mean to us?
According to the many informative websites on air quality, PM10 refers to bigger particles between 2.5 and 10 micrometres. These particles are said to cause less severe health effects.
What is a micrometre? Well, just imagine this – PM10 refers to particles that are between 25 and 100 times thinner than a single strand of human hair.
PM2.5 refer to particles smaller than 2.5micrometres (100 times thinner than a single hair on your head).
PM10 usually refers to coarse particles such as dirt and dust from factories and roads, smoke, pollen and spores. Take for example, dirt in the air caused by quarrying and excavation of rocks and soil.
PM2.5, on the other hand, refers to particles that are toxic and originate from exhaust fumes, processing of metals and burning of plant materials in the case of bush fires, forest fires as well as burning of garden waste. PM2.5 or smaller particles stay in the air longer and travel further.
How does particulate matter affect our health then?
Obviously, finer particulates are able travel further into our lungs when we inhale. While both groups of particulates can cause health problems, these finer particulates are considered more dangerous as they are more toxic (chemicals and cancer-causing compounds).
Malaysia included PM2.5 into its API measurements in December 2012, which means that the API is now calculated based on five major air pollutants – sulphur dioxide, nitrogen dioxide, carbon monoxide, particulate matters (PM2.5 and PM10), and ozone.
And just by knowing these five major pollutants, we know the API tells us a lot more than just how hazy it is out there, and not merely how dense the haze it. The higher the API, the more likely we are exposed to more than just smoke.
Scientists agree that the burning of forests or plant materials does not only increase carbon into the air, but also releases organic toxins, which are especially harmful to children.
In other words, take note of the API this hazy season and think twice the next time you decide to burn your garden waste. This will decide how your health turns out in the long run.
The higher the API, the higher the risk of us damaging our bodies if we do not take precautionary measures such as wearing the right type of face masks (N95 particulate masks), not burning our garden waste, cutting down on running our vehicles and reducing time spent outdoors during the haze.
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