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Haze numbers to note

A couple walk before the financial business district shrouded with haze in Singapore on September 14, 2015

 

The Pollutants Standards Index (PSI) reached the 300s on Thursday (24 September), entering the “hazardous” zone and prompting the Singapore government to close all primary and secondary schools on Friday.

Caused by the slash and burn tactics used to clear land in Sumatra, the smog has become an annual affair, and one that strains the relationship between Jakarta and neighbouring governments.

Late Thursday, Singapore’s Foreign Minister K. Shanmugam even issued a strongly-worded statement on his Facebook page, slamming  “shocking statements made, at senior levels, from Indonesia, with a complete disregard for our people, and their own”.

In his post, the minister also pointed out how the PSI in parts of Indonesia was close to 2,000 – mainly seen in regions in Central Kalimantan.

Here are some other notable figures concerning the haze situation:

401

The highest the PSI – at least the three-hour reading – has ever reached in Singapore was 401 at the height of the haze crisis on 21 July, 2013. Prior to that, the highest recorded PSI level was 226 in September 1997.

According to guidelines from the Ministry of Health, a 24-hour PSI above 300 is hazardous, and people with lung or heart disease, the elderly, pregnant women, and children should all avoid outdoor activities.

8

During the 2013 haze period, a shortage of N95 masks caused by panic buying resulted in what Ng Eng Hen, who led an interministerial committee to tackle the haze, called “supply chain bottlenecks”.

This “artificial shortage” of masks drove prices up to as high as $8 per N95 mask, which had cost around $20 a box in the weeks before.

Currently, a box of 20 N95 masks from 3M retails for $38 on the website of local retailer NTUC Fairprice.

11

In March this year, Indonesian Vice-President Jusuf Kalla criticised Indonesia’s neighbours for not being grateful for the clean air they enjoyed outside of the haze period.

“For 11 months, they enjoyed nice air from Indonesia and they never thanked us… They have suffered because of the haze for one month and they get upset,” Jakarta Globe had quoted him as saying.

2.5

Particulate Matter 2.5 (PM 2.5) refers to fine particles smaller than 2.5 micrometres (one micrometre = one millionth of a metre) found in the haze.

Studies show people who live in areas with continuous exposure to such particles may have a higher risk of heart attacks and chronic respiratory diseases, as well as reduced lung development.

Prior to 2014, the PSI did not include PM 2.5 in its reading, but a new revised system integrates this in addition to sulphur dioxide, PM 10, nitrogen dioxide, carbon monoxide, and ozone.

24

The health advisory issued in Singapore is based on the 24-hour PSI, which now incorporates the 24-hour PM 2.5 reading.

According to the Ministry of Health and the National Environment Agency, studies on the effects of particulate matter use these measurements, a fact brought up by Defence Minister Ng in 2013.

In 2013, Second Minister for Environment and Water Resources Grace Fu also said the 24-hour measurements were a “better reflection” of exposure after the three-hour PSI hit 401.