Singapore’s air pollution levels are nearly twice as worse as the WHO’s guideline levels – and most of it doesn’t come from cars

Originally posted: May 23, 2017
Updated September 2018
Additional reports from major news outlets included
Exposure to idling vehicles – including bus stops – could be worse than haze particles – AsiaOne
Singapore is failing to meet its pollution targets – CNA
Traffic, industry are major causes of local pollution – ST

SINGAPORE – Here in Singapore, a ‘garden’ city, the air quality is decent, surely not as bad as some towns in developing countries, right?

Wrong. By some measures, Singapore’s air quality is terrible – twice the World Health Organisation’s (WHO) guideline limits, and worse than Manila’s, according to this report in the Guardian UK on global air pollution.

Air pollution has many components. Carbon dioxide, while tagged as a greenhouse gas culprit, isn’t super bad for us, but oxides of nitrogen, which come from diesel vehicles amongst others, are. Particulate matter of 10 microns in size (or PM10s) such as visible soot and smoke are considered bad, but not as bad as PM2.5s which are small enough to enter your bloodstream via the lungs.
PM2.5 is considered one of the major signs of bad air and is measured in two ways: annual and 24-hour, both using the mean (that is, the average).  The WHO’s guidelines for PM2.5, established in 2006, are a maximum of 10µg/m³ (microgrammes per cubic metre of air) annual mean, and 25µg/m³ for the 24-hour mean.

Singapore’s average annual mean from 2009 to 2015 is nearly double that, at 19.1µg/m³, while the average 24-hour mean is 79µg/m³ over the same period, or more than three times as much.  The haze caused PM2.5 to spike in 2013 and 2015, but even without the help from our neighbours, the averages were still 18µg/m³ and 64.4µg/m³ respectively.

To put this into perspective, the worst PM2.5 level to be found is 217µg/m³ annual mean at Zabol, Iran. But Singapore isn’t a developing country, so to compare the worst scores in Europe: Tetovo in Macedonia, has 81µg/m³, Tuzla in Bosnia, 65µg/m³, and the next eight worst cities average 40 to 45µg/m³.

The worst PM2.5 in the USA is Visalia-Porterville, in California, with a score of 18µg/m³. The highest PM2.5 ratings for Australia are Perth, Melbourne and Sydney (8µg/m³ each). These scores, taken from The Guardian’s report online, show Singapore’s annual mean is quoted as 18µg/m³, and while many Asian cities have much higher levels (Beijing 85µg/m³. Delhi 122µg/m³), it also means Manila (17µg/m³) has better air quality than us.

Why should you care about dirty air?
A report in The Guardian (‘Tipping Point’, February 13 2017, Guardian.com) showed that in 15 cities around the world, air pollution has become so bad that the downsides of half an hour of exposure, via cycling, outweigh the benefits of exercise.

These are particularly bad examples of course, such as in Allahabad, India, and Zabol, Iran. The developing world sees burning plant matter for fuel as a major contributor to air pollution, such as wood stoves, and much less environmental regulation.

Air pollution is estimated to cause one in eight premature deaths, or seven million deaths, according to a report from the World Health Organisation in 2012. It causes respiratory diseases (asthma, bronchitis, flu), lung disease (emphysema, chronic bronchitis), heart disease, lung cancer and strokes.

To be fair, levels of nitrogen/sulphur dioxide and carbon monoxide haven’t increased in significant levels on average in Singapore in those years, but at the same time PM2.5, PM10 and Ozone have all significantly increased over the same time frame.

So while Singapore isn’t facing imminent lung armageddon, the fact is we could probably do a lot better. Is anything being done to help this? Sure, the National Environment Agency (NEA) has taken concrete steps to improving the situation – there are too many to list here but its website gives a good idea of what’s being done.

The problem is that even in future, we’re settling for less. There is a plan in place called the ‘Sustainable Singapore Blueprint 2015 (which) ‘outlines our national vision and plans for a more liveable and sustainable Singapore, to support the diverse needs and growing aspirations of Singaporeans.’

The blueprint calls for a PM2.5 target of 12µg/m³ (annual) and 37.5µg/m³ (24-hour) by 2020, and as mentioned these do not gel with the WHO’s recommended, now decade-old targets, although the nebulous ‘long term’ targets are defined as identical to the WHO’s recommendations.

Can we help improve air quality by changing our driving habits? That’s for certain, since vehicles emit a lot of localised air pollution. Yet a much more fundamental change is needed to our legislation, not just to minimise vehicles that pollute more but to truly promote cleaner motoring. The CEVS system is due for an overhaul in the next few years, but we should also keep something else in mind, which I’ll leave here as a footnote.

There is no extensive breakdown of the contributors to air pollution for Singapore online, but the NEA lists the major contributors of sulphur dioxide here: 93.1 percent of it comes from three oil refineries. 5.1 percent from ‘other’ (chemical, petrochemical) industries, 1.7 percent of it comes from power generation, and 0.1 percent of it from motor vehicles.

*For more information on this check out:
– www.singstats.gov.sg ‘Yearbook of Statistics, Singapore, 2016’, for historical air pollution data.
–  www.mewr.gov.sg/ssb/ ‘Sustainable Singapore Report 2015’,
– www.theguardian.com/cities/series/the-air-we-breathe ‘The Air We Breathe’
– www.nea.gov.sg/anti-pollution-radiation-protection/air-pollution-control ‘Air Quality and Targets’