NEA to introduce new bands and descriptors for 1-hour PM2.5 readings

Linette Lim Channel NewsAsia 27 Jun 16;

SINGAPORE: Haze season is around the corner and the likely question on everyone's lips is: "Is it safe for me to go out now?"

To help Singaporeans answer that question, the National Environment Agency (NEA) is introducing bands and descriptors for the one-hour concentration readings for fine particulate matter (PM2.5), which it has been publishing hourly since 2014.

This was announced by Minister for the Environment and Water Resources Masagos Zulkifli on Monday (Jun 27), on the sidelines of a visit to the Meteorological Service Singapore’s (MSS) HQ at Changi Airport Terminal 2.

According to Mr Masagos, the new bands and descriptors will help the public better interpret the one-hour PM2.5 concentration readings and plan their activities.

During last year’s haze season, some Singaporeans turned to unofficial sources such as third-party apps and websites that purportedly gave one-hour readings of air quality. Several said NEA’s official three-hour and 24-hour Pollutant Standards Index (PSI) readings did not always square with what they observed outdoors in terms of haze visibility and smell. One example is volunteer group the People’s Movement to Stop Haze, which has been publishing one-hour PSI readings for five regions across the island since 2015.

For years, NEA resisted calls to publish one-hour PSI readings, stating that the practice of “converting raw pollutant concentration data into one-hour PSI readings is not supported by health studies”.

From Monday, it hopes the public will rely more on its official one-hour PM2.5 concentration readings, which it said is a "near real-time indicator of the current air quality”.

The PSI was developed by the United States Environmental Protection Agency. Its computation is based on the 24-hour average of PM10 concentration levels, among other pollutants. PM10 - the measure of particulate matter of 10 microns or smaller - is the dominant pollutant during haze episodes.

PM2.5 refers to particulate matter that is smaller than 2.5 microns, and is a subset of PM10.

Unlike the existing 24-hour PSI readings, which carry health advisories on what people should or should not do when readings are banded at certain levels, the four bands and descriptors for the one-hour PM2.5 readings - Normal (<55), Elevated (56-150), High (151-250) and Very High (>250) - will not carry corresponding health advisories. These will only be accompanied by a general guide on how haze particles affect health.

This is because existing studies “do not constitute a sufficient evidence-base” for the development of corresponding health advisories for the various bands, said NEA. The agency will phase out the three-hour PSI before the end of the year on the basis that it will no longer be relevant. It will also revise its microsite and its myENV app to reflect the new bands and descriptors.

- CNA/av

New PM2.5 bandings to help people plan activities better

SINGAPORE — One-hour readings of the fine particulate matter concentration (PM2.5) in the air now come with bands indicating if levels are normal, elevated, high or very high, to help the public to interpret one-hour PM2.5 better, and to plan their immediate activities.

Under the new banding, one-hour PM2.5 concentrations of 55 micrograms per cubic metre and below are “normal”; readings of 56 to 150 are “elevated”; readings of 151 to 250 are “high”; and anything above 250 is “very high”.

But the one-hour readings are not tied to health advisories, which apply only to 24-hour Pollutant Standards Index (PSI) readings because studies on sub-daily PM2.5 exposure still do not provide a sufficient evidence base, said the National Environment Agency (NEA), which introduced the banding on Monday (June 27).

The 24-hour PSI forecast will also continue to be used for major decisions such as the closure of schools.

Instead, the one-hour PM2.5 readings now come with a general guide noting that each person’s reaction to pollutants may vary. Hence, the level of physical activity should be according to one’s health status.

Although the PSI includes other pollutants like sulphur dioxide and carbon monoxide, PM2.5 is the air pollutant of concern during haze episodes, because their small size mean they can lodge deeply in the lungs.

The highest one-hour PM2.5 recorded in Singapore last year was 471 on Oct 19, when the region was affected by forest and plantation fires raging in Indonesia.

Last year, Singapore’s one-hour PM2.5 readings fell within the “normal” band 88.9 per cent of the time during both haze and non-haze periods. During the haze period, readings were still mostly within the “normal” range (49.6 per cent), followed by the “elevated” (41.6 per cent), “high” (7 per cent), and “very high” (1.8 per cent) bands.

With the introduction of bands for one-hour PM2.5, the NEA will do away with three-hour PSI readings as they will “no longer be relevant”, by the end of the year.

Speaking to reporters about the new banding during a visit to the Meteorological Service Singapore headquarters on Monday, Environment and Water Resources Minister Masagos Zulkifli said: “We want to position this more as an advisory band, rather than something which is medically impacting them.”

On how institutions, such as schools and military camps, should interpret the PM2.5 readings, Mr Masagos said they would still use the 24-hour PSI forecast, and whether they decide to continue with activities based on the one-hour PM2.5 readings would be left to their discretion.

The Ministry of Education said one-hour PM2.5 readings would be used as “an indicative measure to make the necessary adjustments” for more immediate activities. Activities for the next day would be planned using the NEA’s 24-hour PSI forecast and the corresponding MOH health advisory.

The Ministry of Defence (Mindef) said that apart from guidelines for the conduct of training in haze conditions, which use the 24-hour PSI, its commanders on the ground conduct a risk assessment before each outdoor or training activity, taking into account factors such as weather.

Commanders, Mindef said, could use the new PM2.5 bands as “one of the factors when making their risk assessments”.

The Ministry of Manpower (MOM) noted there is “insufficient evidence base” to develop workplace safety and health advisories for the one-hour PM2.5 readings. The readings, the MOM added, could also fluctuate over the course of a day.

Dr Madeleine Chew, a family physician at MW Medical Centre, said at the “elevated” band, patients with respiratory disorders, heart disease and lung cancer should avoid outdoor activities, while healthy adults should reduce their participation in such activities. The “high and “very high” bands should see only indoor activities, she said.

Killiney Family and Wellness Clinic’s Dr Clarence Yeo said the hourly readings would be “quite useful” as they provide more up-to-date information. But in advising patients, he would still use it “more as a guide (such as) whether you should go out and do a run.”

Meanwhile, a workplace safety and health coordinator in a construction firm, who wanted to be known only as Mr Khoo, said he was unlikely to refer to the bandings as they are only guidelines, adding the air quality here is generally good.

Associate Professor Matthias Roth, deputy head of the National University of Singapore’s geography department, noted that in cleaner cities, what would be considered “normal” here could be considered high elsewhere, such a city with less emissions from industries and vehicular traffic.

Also, readings in the “normal” range do not necessarily mean there are no health effects, he added.

Hourly PM2.5 haze readings now graded to indicate pollution level
NEA's enhanced PM2.5 readings will come with banding and descriptors.
Chen Jingwen AsiaOne 27 Jun 16;

The National Environment Agency is phasing out 3-hour PSI updates following the enhancement of its hourly PM2.5 readings with banding to reflect current levels of haze pollution.

Unsure of what PM2.5 readings in haze updates actually mean? Don't worry, now you would be better informed by the government's system monitoring harmful fine particles during a haze.

The National Environment Agency (NEA) has enhanced its hourly PM2.5 readings with four bands to indicate the current level of pollution by fine particles to accompany the figures, the agency said in a statement today.

This would serve as a guide for people who need to adjust their plan for an immediate activity, it said.

The four ranges, which come with band numbers and descriptors, are:

I Normal - 0 to 55 ug/m3 or micrograms per cubic metre
II Elevated - 56 to 150 ug/m3
III High - 151 to 250 ug/m3
IV Very High - 251 ug/m3 and above

With the enhancements, the updates now serve as a clearer indicator of the prevailing air quality and as a result, the 3-hour Pollutant Standards Index (PSI) will be phased out, said the agency.

In Singapore, the main air pollutant during a haze situation is fine particulate matter (PM2.5).

NEA started publishing PM2.5 figures in 2014 as they are said to be a better indicator of air quality.

They are based on near real-time readings whereas the 24-hour PSI and 3-hour PSI that the agency has been providing are rolling averages of readings taken during longer periods.

But still, many people did not understand what the PM2.5 numbers meant and how they should respond to them when overwhelmed by haze created largely by forest and peatland fires in Indonesia. The readings just provided numbers, with no classification or explanation.

Now, the updates will also be accompanied by a general health guide which Government agencies have issued to the public during periods of haze. (See below).

There will be no health advisory based on the one-hour updates because the results of recent studies on shorter-period PM2.5 exposure could not provide conclusive evidence to justify any medical advisory, said NEA. Also, one-hour readings can be volatile, tending to fluctuate throughout the day.

So the agency does not advise specifically what people should do when the haze moves into the 'Elevated' band, for instance. But common sense would tell those at risk to start taking precautions and refer to the health guide if the level persists for hours or jumps to the 'High' band.

Use 24-hour PSI when making plans for the next day

With the enhancement of PM2.5 updates, the 3-hour PSI will no longer be relevant. It will be phased out by the end of the year.

The 24-hour PSI daily forecast will continue to play its more important role as it helps in the formulation of health advisories and enables government agencies to make major decisions, such as the cancellation of school classes or outdoor events.

This integrated index incorporates PM2.5 as well as other key pollutants of concern - sulphur dioxide (SO2), coarser particulate matter (PM10), nitrogen dioxide (NO2), carbon monoxide (CO), and ozone (O3).

The public is advised to use the 24-hour forecast when making plans for the next day, like going to school or work.

Each reading will continue to be accompanied by its respective health advisory for the various classifications of people - healthy persons, elderly, children and pregnant women.

For instance, people from all age and health groups can continue with normal activities when the PSI is rated 'Good' or 'Moderate'. (See below for the full guide)

The changes in NEA's haze readings will be reflected on its Haze microsite ( and myENV app. The round-the-clock PSI Forecast will be featured prominently to encourage more people to use it.

The dreaded haze period is nearly here

The start of the dry season in Indonesia usually spells the start of hazy conditions in the region.

The period from June to October every year has seen unmanageable forest and peatland fires allegedly connected with palm oil, pulp and paper industries.

Last year's haze saw a bigger crisis as the fires raged on with intensity and length, exacerbated by the El Nino weather phenomenon.

Enveloping Indonesia and its neighbours like Singapore and Malaysia, the haze caused deaths, widespread illnesses, flights to be grounded and schools to be closed.

In Singapore, the one-hour PM2.5 reading hit an alarming high of 471 micrograms per cubic metre last October.

However, experts believe that any impending haze hitting Singapore this year might not be as severe as last year because of the subsiding El Nino phenomenon, which was believed to have ended recently. Quickly taking over is another weather system, La Nina, which has drenched the region with heavy rains in recent weeks.

Better haze, hotspot detection with new satellite
Chew Hui Yan Channel NewsAsia 27 Jun 16;

SINGAPORE: The Meteorological Service Singapore (MSS) is making use of a Japanese satellite which allows for more frequent monitoring and improved detection of weather systems and hotspots or haze in the region, the agency announced on Monday (Jun 27).

The satellite, Japan Meteorological Agency's Next Generation Himawari-8 geostationary meteorological satellite, replaced the MTSAT-2 that ceased direct transmission in December. The Himawari-8 was operationalised in July 2015, and MSS has been making use of its imagery since then.

The Himawari-8 has a 10min frequency of updates - compared to hourly updates for the MTSAT-2, allowing for enhanced monitoring of haze and weather systems, said MSS. The Japanese satellite also has more than three times the spectral bands - 16 compared to five - to improve the range of detection, as well as higher spatial resolution, resulting in more detail in the satellite image.

MSS said that it primarily makes use of data from polar-orbitting satellites operated by the US' National Oceanic and Atmospheric Administration and National Aeronautics and Space Administration to monitor hotspots and smoke haze in the region. These satellites normally make one day-time pass over the region each day.


To extend the observation network of real-time weather monitoring systems, the MSS has also installed an aerosol LIDAR – which stands for Light Detection and Ranging, a remote sensing method that uses light from a laser to measure ranges to Earth.

The detection system was installed on Jurong Island to measure the local distribution of particulate matter in the atmosphere, as well as a wind LIDAR.

This adds to the more than 60 automatic weather stations, a lightning detection system, weather radar and wind profiler in the network.

The aerosol LIDAR can measure the vertical extent of particulate matter to heights of about 12km, and provide an indication of upper level transboundary haze drifting into Singapore, MSS said. While it cannot differentiate particle size, it can also detect ash from volcanic eruptions in the region.

The wind LIDAR measures the vertical profile of wind speed and direction up to 12km above the ground level, and will complement MSS' existing wind profiler and enhance the real-time monitoring of upper-level winds, which affect the movement of weather systems and haze over Singapore.

"These new instruments can tell us not just the concentration of PM2.5 in the air but at different levels of the atmosphere and how they move according to wind conditions and atmospheric conditions," said Minister of Environment and Water Resources Masagos Zulkifli, who was briefed on the usage of the new technologies on Monday.

"We are still studying it but in the future I'm quite sure these can be used for even finer forecasts by the hour, making it more predictable for the public," he added.

- CNA/av

Rainier weather this year may help ease haze episodes: Masagos
Linette Lim Channel NewsAsia 27 Jun 16;

SINGAPORE: More rain is expected around the last quarter of the year, and this means the forest fires that cause the annual transboundary haze are more likely to be put out, said Minister for the Environment and Water Resources Masagos Zulkifli on Monday (Jun 27).

"Therefore we hope that with more rain, there will be less haze episodes that come to us," said Mr Masagos, speaking on the sidelines of a visit to the Meteorological Service Singapore’s (MSS) HQ at Changi Airport Terminal 2.

However, he added: "But we cannot be sure – this is the weather, it is most unpredictable, and there can therefore be dry spells. Dry spells take its toll over a longer period, and forests continue to be burned, particularly peat and forests, then we will particularly be affected by this.”

According to the National Environment Agency (NEA), weather conditions this year are "expected to be less conducive for hotspot activities as compared to 2015".

Responding to queries from Channel NewsAsia, NEA explained that based on assessments of model outlooks from international climate centres, there is a possibility of La Nina developing in the third quarter of 2016.

"Rainfall is expected to be normal to above normal from June to September," it said.

"However, as there could still be extended periods of drier weather, escalation of hotspot activities can occur which may lead to transboundary haze, and Singapore could be affected if the winds blow the haze towards Singapore."

NEA added that the region is currently seeing neutral conditions - neither El Nino nor La Nina - after a strong El Nino event which resulted in prolonged periods of dry weather in the second half of the year.

- CNA/av

Haze less likely as more rain seen in Q4, says Masagos
KENNETH CHENG Today Online 28 Jun 16;

SINGAPORE — With more rain forecast for the latter part of 2016, the risk of haze blanketing the Republic could be lower this year, as forest fires will likely be put out faster, Environment and Water Resources Minister Masagos Zulkifli said on Monday (June 27).

Speaking to reporters during a visit to the Meteorological Service Singapore’s (MSS) headquarters at Changi Airport Terminal 2, Mr Masagos said more rain was predicted towards the last quarter of the year. “Therefore, we hope that with more rain, there will be less haze episodes that come to us,” Mr Masagos said.

But he stressed that the Government could not be sure of this, given the unpredictable nature of the weather. There is the possibility of dry spells taking its toll over extended periods, and forests, particularly peatland, being set on fire. This may result in the Republic being besieged by haze.

Responding to TODAY’s queries, the National Environment Agency (NEA) said the strong El Nino event that triggered a protracted dry spell in the second half of last year has ended. The El Nino phenomenon is the warm phase of a temperature cycle in the tropical central and eastern Pacific Ocean.

While neutral conditions are prevailing over the region now, the NEA said the La Nina, which causes higher-than-normal rainfall, could develop in the third quarter of the year, based on model outlooks from international climate centres.

And with rainfall expected to be “normal to above normal” from June to September, weather conditions are forecast to be less conducive to hot spot activities than they were last year.

“However, as there could still be extended periods of drier weather, escalation of hot spot activities can occur, which may lead to transboundary haze, and Singapore could be affected if the winds blow the haze towards Singapore,” the NEA said.

Earlier in the day, Mr Masagos was briefed on the MSS’ new capabilities and technologies that support the national weather forecaster’s monitoring of the weather and haze.

Among them is imagery from the Himawari-8 geostationary meteorological satellite. The satellite provides more frequent updates, higher spatial resolution and more spectral bands than its predecessor, the MTSAT-2 satellite.

The Himawari-8, operated by the Japan Meteorological Agency, provides updates every 10 minutes, compared with hourly updates by the MTSAT-2, which stopped direct transmission last December. Its higher spatial resolution also means improved visible bands of between 0.5km and 1km compared with the MTSAT-2’s 1km, which means sharper details in satellite images.

In May, the MSS also installed an aerosol Light Detection and Ranging (Lidar) system on Jurong Island and a wind Lidar system in the south of Singapore.

Depending on atmospheric conditions, the aerosol Lidar can, among other things, measure the vertical extent of particulate matter to heights of about 12km. It can also offer an indication of upper-level transboundary haze wafting into the Republic.

The wind Lidar, which can measure the vertical profile of wind speed and direction up to about 12km above ground level, will complement the MSS’ existing wind profiler. This will improve the real-time tracking of upper-level winds, which affect the movement of weather systems and haze over Singapore.

The authorities are still studying the new capabilities, Mr Masagos said. “But for the future, I’m quite sure these can be used to give even finer forecasts for the hour … (which will be) more useful and predictable for the public.” ADDITIONAL REPORTING BY NEO CHAI CHIN