THE haze returned with a vengeance last Thursday during Hari Raya Aidiladha. It had been gone for a week, but it has now blanketed many parts of the state, which caused the closure of schools and affected flights at the Senai International Airport in Johor.

However, a recent debate occurred on social media that the haze was not about the hot spots in Sumatra or Kalimantan or the blame game on who should be held responsible for the smog.

It was about Malaysia’s Air Pollutant Index or API reading, which is used by the Department of Environment (DoE) to measure air quality.

In Johor, many folk compared the API provided by the DoE with the system used to measure air quality by the Singaporean authorities.

There were stark differences in the readings between Johor and Singapore last week and this week.

While many people saw thick blankets of smog outside their windows in Johor, it was not reflected in the API readings, which were in the early range of the unhealthy band of between 101 and 200.

This newspaper reported on Monday that the Singapore National Environment Agency’s Pollutant Standards Index (PSI) hit the hazardous range (above 300) last Thursday evening and climbed to 341 at 5am on Friday.

In Johor Baru, the API readings during the same period were in the unhealthy band of between 139 and 192.

DoE director-general Datuk Halimah Hassan said the API readings were not watered down, but explained the different figures were due to Singapore’s inclusion of a sixth parameter in determining air quality.

Malaysia measures five parameters to determine API: carbon monoxide, ozone, nitrogen dioxide, sulphur dioxide and particulate matter (PM10).

Since April last year, Singapore has included a sixth parameter, known as fine particulate matter (PM2.5) in measuring its air quality under its PSI.

The PM2.5 refers to particles 2.5 micrometres in diameter or smaller, which can only be seen by electron microscope. Fine particles come from combustions, such as motor vehicles, forest fires or agriculture burning.

Experts and the layman had a lot to say about the story. Environmental Protection Society Malaysia vice-president Randolph Geremiah said he was all for having better API equipment if there was a need for it.

Johoreans were more brash in their comments.

“Our API system is a joke,” said a friend, who has been posting photographs of the haze in Johor Baru and API readings on Facebook.

One photograph was a view from one side of the Johor Straits, which saw the haze blanketing the view of Singapore from Johor.

A father of two from Taman Mount Austin, Johor Baru, Frankie Tan, was rather worried about the fine particulate matter or PM2.5 in the air, which is yet to be measured in the API.

“I think our health is important and I know that PM2.5 molecules are very harmful if it gets into your lungs,” said the senior manager at a property development company, who has now limited his family’s outdoor time.

The issue raises a lot of questions about the API readings and its technology, but it is something that can be improved with budgeting and the use of available technology.

Universiti Teknologi Malaysia (UTM) has been using its own calculations to measure fine particulate matter in the air.

UTM campus sustainability director Associate Professor Dr Mohd Fadzil Md Din said recent readings of air quality at its Skudai campus proved that its instrument showed almost similar readings as those shown in Woodlands, Singapore.

The instrument calculated a fine particulate matter (PM2.5) reading of 229 at noon on Tuesday. This was comparable with Singapore’s three hour PSI of 240.

“This shows the instrument used by UTM is at par with the one used by Singapore,” said Fadzil.

There is hope for our API system, but perhaps more effort must be made to unearth the research and development that has been done by Malaysian researchers on air pollutant calculations.

These systems are changing with the times and can produce accurate readings of air pollution.

And accuracy is very much needed when measuring the haze, which has an impact on health and workers’ productivity as well as affects sectors, such as education, tourism and sports.

The writer is NST’s Johor Bureau Chief