Saturday, June 22, 2013

Haze Myth: PSI vs Visibility vs PM2.5

Rumours abound in times of trouble...and its' human nature to 'panic' and fear the unknown or unnatural. As a medical doctor and recent public health graduate, sometimes we see things differently through broader lenses. Rational, educated mind is a good defense against irrational feelings and emotions. Despite what our eyes tell us, let us focus on creating solutions and calming those around us, instead of creating more anger and fear. That's why I was quite impressed with what PM Lee said recently regarding this crisis - no megaphone diplomacy for this statesman.

Firstly, the PSI has been adopted in Singapore to give the public an up-to-date information on the air quality in this country, as opposed to the different indices used in US, Malaysia, etc. It's a composite of various substances in the air which may cause harm to the human body if we are exposed to it in significant concentration, depending on what is your health status. A normal healthy adult obviously could tolerate the pollutants a bit better than a sickly person, the young and the old. However, if you are exposed to it in significant amounts over a prolonged duration, there may be both short and long-term effects.



Secondly, I would say of all the pollutants being reported, the most insidious and hardest to clear from our body is the PM2.5 particulate which is lodged in our alveoli. These particulates are suspended in the air, but invisible to the naked eye and odourless. When its consistently high (as reported by various authorities), it can cause long-term lung damages, especially lung fibrosis in the future. Not now. What's happening now is the sequelae of direct irritants in the air, to our airway - sore throat, cough, asthma attacks, shortness of breath, conjunctivitis, headache etc. It's usually a brief episode unless the hazy condition persists.

Thirdly, staying indoors is a good advice, provided that you have air purifier or a good working air-conditioner with functional air filter. Indoor air quality can be worsened if u open the doors/windows intermittently and trap the haze within the closed compound. Especially for those susceptible to the effects of haze, please take precautions - wear a well-fitted N95 mask properly whenever u are exposed to hazy outdoor air but do not hoard. There are more than enough masks around - just be patient and resourceful. Visibility is not equivalent to high PSI. Check the official results regularly to be well-informed.

Lastly, public health problems require public health solutions...it has be long-term sustainable solutions, tackling the root causes and not just a one-off assistance. Short term measures like creating rain artificially or fighting the fire are temporary measures. We have to work together to tackle the root causes of why these fires are started at the first place. Eradicate poverty, improve on peat-fire surveillance, tighten legislations and change this burning practice. This is a man-made calamity, which means, we can work together to eradicate the cause and not point fingers. Empty vessels are of no help now. Human behaviour may be hard to change, but it's not impossible. The collaborative task-force should be sustained long-term and not hastily convened at the sight of trouble. Prevention is better than cure....

Meanwhile, continue to keep calm, drink lotsa water and pray on.

Caveat: This article is purely personal opinion and doesn't amount of professional medical advice. Please seek a doctor's consultation if you are suffering from the effects of haze. Thank u.

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