Hazy skies as PSI in Singapore rises

The three-hour PSI reading from the National Environment Agency peaked at 92 at 2pm on Friday (Jul 10). A reading of 101 to 200 is considered “Unhealthy”.
Channel NewsAsia 10 Jul 15;

SINGAPORE: Parts of Singapore saw hazy skies on Friday afternoon (Jul 10), with the three-hour Pollutant Standards Index (PSI) reading crossing 90.

The three-hour PSI reading peaked at 92 at 2pm, according to the National Environment Agency (NEA), while the 24-hour PSI was 65-75. A reading of 51-100 is “Moderate”, while a reading of 101-200 is in the “Unhealthy” range.

"The hazy conditions are due to a change in the prevailing winds to blow from the southwest, and this could have brought in some haze from the fires in central Sumatra," explained a spokesperson from Meteorological Service Singapore, in response to media queries.

"The winds are forecast to blow from the south later today and an improvement in the conditions can be expected," the spokesperson added.

The last time the 24-hour PSI reading entered the "Unhealthy" range was on Nov 3, 2014, peaking at 120. The three-hour PSI reading on that day peaked at 116.

The Meteorological Service Singapore said last week that sporadic hotspot activities with smoke plumes were recently seen in Sumatra. This could affect Singapore, but would depend on factors like wind direction and rainfall, it said.

- CNA/cy

Hazy skies due to change in wind direction
Three-hour PSI peaks at 92 at 2pm, but conditions are expected to improve
LOUISA TANG Today Online 11 Jun 15;

SINGAPORE — The air quality around the island dipped yesterday, with the three-hour Pollutant Standards Index (PSI) hitting 92 in the early afternoon, but conditions are expected to improve.

The three-hour PSI climbed hourly from 52 at 9am, reaching 63 at 11am, 80 at noon, and 91 at 1pm.

It peaked at 92 at 2pm — with the 24-hour PSI between 65 and 75 — before improving steadily, falling to 76 at 4pm and 72 at 5pm. By 7pm, the three-hour PSI reading was 69, and the 24-hour PSI was between 69 and 73.

A PSI reading ranging from 51 to 100 is moderate, while anything from 101 and 200 is considered unhealthy.

In response to TODAY’s queries, the National Environment Agency (NEA) said there had been reports of a burning smell in some parts of Singapore.

“The hazy conditions are due to a change in the prevailing winds to blow from the south-west, and this could have brought in some haze from the fires in central Sumatra.”

It added that conditions would improve as winds were forecast to blow from the south later yesterday.

Last week, the NEA said slightly hazy conditions could be expected on a few days, particularly in the early morning, because of the accumulation of particulate matter under light wind conditions.

Two weeks ago, the Meteorological Service also noted that sporadic hot-spot activities with smoke plumes had been seen recently in Sumatra, which could affect Singapore, depending on factors such as wind direction and rainfall.

The previous time the 24-hour PSI reading entered the unhealthy range was on Nov 3 last year, when it peaked at 120. The three-hour PSI reading on that day peaked at 116.

In 2013, Singapore suffered one of its most serious haze episodes, when the three-hour PSI peaked at 401 on June 21.

Foggy skies as haze returns briefly here
Feng Zengkun and Joanna Seow, Straits Times AsiaOne 11 Jul 15;

The haze returned to Singapore briefly yesterday.

The pollution was worst in the early afternoon with the three-hour Pollutant Standards Index climbing from 63 at 11am to 92 at 2pm.

It then fell steadily for the rest of the day.

The index is published online hourly from 7am to 7pm and linked to the amount of air pollution in the previous three hours.

At no point did the air here become unhealthy, although there were complaints about the familiar acrid smell and foggy skies.

Public servant Puvana Devi, 25, who lives in Choa Chu Kang, was surprised by how thick the haze was when she left home in the morning. "It seemed like my area was being fumigated," she said.

Doctors have been put on alert by the Ministry of Health (MOH) to keep a closer eye on patients with asthma, in case they are affected by the haze.

Several general practitioners told The Straits Times that they were advised by the ministry late last month to take measures such as adjusting the dosage of asthma patients' medication if necessary.

They received similar advice last year.

A spokesman for MOH said it wanted to "remind all medical practitioners of the health advisory for the public during the haze season" and "the appropriate management of asthma patients during a haze period".

Earlier this month, the National Environment Agency warned that the Republic might have slight haze on a few days in the first two weeks of this month.

The Meteorological Service Singapore had also forecast that Singapore and the surrounding region can expect the months of June to early October to be drier and warmer than usual, partly due to the El Nino weather phenomenon.

This could increase the risk of haze in the region during this period, it said.

Meanwhile, forest fires in Sumatra, Indonesia - traditionally the source of haze in Singapore - have also been worsening in the past week.

On Thursday, The Straits Times reported that the Indonesian authorities were expanding cloud- seeding operations in Sumatra to artificially induce rain to put out the fires.

The cloud-seeding operations have been taking place over central Sumatra for more than two weeks.