Defence Minister and Chairman of the Haze Inter-Ministerial Committee Ng Eng Hen on Friday urged the public to refer to the 24-hour Pollutant Standards Index (PSI) reading rather than the three-hour reading. He said that most studies on the exposure to pollutants are based on 24-hour measurements, and explained that was why the government’s guidelines are also based on 24-hour measurements.
This is dangerous nonsense. Does one whose house is burning around him make a decision whether to leave the premises based on 24-hour average temperature? Just as that person would be burned to death in minutes if he decided to stay in a burning building, similarly, serious lung damage could be sustained by one breathing in high PSI air for short durations like 15 minutes.
Has the relatively recent smoke grenade fatality involving a young NSF not taught us that fine particulate matter in air can be harmful in short intense exposure? Or has the poor young man been forgotten? Granted, that tragic case is not identical, but there are important similarities.
(The PAP Government should be reminded of the basic fact that if a 3-hour average PSI reading is, for instance, 300, then there must have been 10/20-minute average PSI readings in the relevant 3-hour time span above 300. Possibly significantly above 300.)
It is certainly true that the health impacts of air pollutants are determined both by the concentration and also the duration of exposure. But what the PAP Government is saying is truly incredible, and incredible claims have to be backed up by evidence.
If the government can put forth credible evidence that exposures of 10 to 20 minutes, common for simple necessary actions like walking to the bus stop and waiting for the bus, to PSI levels of over 200 has negligible ill-effects. We should take note and relax a little. But in the absence of such credible evidence, it is only safe and reasonable to assume that such exposure should be actively avoided because such exposures may cause complications; Complications that may be much more severe in some than others.
The PAP Government should not misinform Singaporeans about the haze threat. It is dangerous and does Singaporeans a huge disservice.
Jeremy Chen
* Jeremy is currently a PhD student at the Department of Decision Sciences at NUS Business School. Jeremy believes in the possibility of a beautiful synthesis of “social justice” and “the free market”. He also hopes for less politicking and more policy discussion in the political arena. He blogs at http://jeremy-chen.org.