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Air Pollution


Air Quality Targets for Singapore

Singapore today enjoys an air quality better than many cities in Asia and comparable with US and European cities. We have also been faring well with the PSI in the ‘Good’ range 96% of the time in 2011.


Like many other major cities, air emissions from the industries and motor vehicles are the two key sources of air pollution domestically.  Transboundary smoke haze from the land and forest fires in the region is also a problem which affects Singapore’s air quality intermittently during the South West Monsoon period from August to October.


Integrated urban and industrial planning, as well as development control have enabled the government to put in place preventive air pollution control measures during the planning stage. In addition, legislation, strict enforcement programme and air quality monitoring have helped to ensure that air quality remains good despite our dense urban development and large industrial base.


As international air quality benchmarks like the World Health Organisation Air Quality Guidelines are being periodically reviewed and enhanced based on latest findings on health, an Advisory Committee on Ambient Air Quality was formed by NEA in July 2010 to advise on a set of air quality targets for Singapore to safeguard public health.


The committee was chaired by the NEA with representatives from Ministry of Health, Ministry of Trade and Industry, Economic Development Board, Energy Market Authority, Ministry of Manpower, Ministry of Community Development, Youth and Sports, Singapore Environment Council, Singapore Tourism Board, National University of Singapore, Nanyang Technological University, National Health Group and the Singapore Health Services.


The committee completed its work in July 2011 and its recommendations were based on the assessment that the WHO AQGs are internationally recognised and rigorous as they are backed by scientific findings and health studies. The committee also advised that NEA should work towards achieving the WHO AQGs for all air pollutants in the long term. The executive summary of the recommendations of the Advisory Committee on Ambient Air Quality is attached.

Executive summary

MEWR, together with NEA, reviewed the recommendations of the Advisory Committee and the Sustainable Singapore Blueprint (SSB) commitments launched in 2009 to achieve an annual mean of 15µg/m3 of SO2 and 12µg/m3 of PM2.5 by 2020 and has worked with relevant government agencies and various stakeholders to arrive at a set of revised national air quality targets pegged to the WHO AQGs. The targets are in Annex I.

To work towards attaining the air quality targets by 2020, NEA has put together a roadmap with a set of abatement measures to achieve sustainable growth and development while maintaining public health and economic competitiveness.  The abatement measures are summarised in Annex II.

Annex 1: Singapore Ambient Air Quality Targets


Singapore Targets by 2020

Long Term Targets

Sulphur Dioxide


24-hour mean: 50µg/m3         

(WHO Interim Target)


Annual mean: 15 µg/m3

(Sustainable Singapore Blueprint target)

24-hour mean: 20µg/m3       

(WHO Final)

Particulate Matter


Annual mean: 12µg/m3

(Sustainable Singapore Blueprint target)[1]


24-hour mean: 37.5µg/m3

(WHO Interim Target)

Annual mean: 10µg/m3




24-hour mean: 25µg/m3

(WHO Final)

Particulate Matter


Annual mean: 20 µg/m3

24-hour mean: 50 µg/m3

(WHO Final)


8-hour mean: 100µg/m3

(WHO Final)

Nitrogen Dioxide


Annual mean: 40µg/m3

1-hour mean: 200µg/m3

(WHO Final)

Carbon Monoxide


8-hour mean: 10mg/m3

1-hour mean: 30mg/m3

(WHO Final)

[1] Sustainable Singapore Blueprint annual target for PM2.5 of 12µg/m3 will be retained and aligned with WHO Interim Target of 37.5 µg/m3 for 24-hour mean


Annex II: Summary of Abatement Measures



Sulphur Dioxide


From July 2013, NEA will mandate the supply of Near Sulphur-Free Diesel (NSFD) with a sulphur content of 0.001% to pave the way for Euro V emission standards for diesel vehicles and further reduce SO2 emissions from diesel vehicles and industries.

By 1 October 2013, NEA will mandate cleaner petrol for motor vehicles with sulphur content lower than 0.005% to pave the way for the Euro IV emission standards. This will also reduce HC and NOx which will give rise to ozone.

NEA, together with EDB, will work with refineries to improve their processes and decrease their SO2 emissions. Power stations are also working towards using cleaner fuels for their energy needs in order to lower their SO2 emissions. As the power stations and industries switch to the use of cleaner fuels to reduce SO2, there will also be a simultaneous reduction in other pollutants including PM2.5.  [In progress]

Particulate Matter

(PM2.5 + PM10)

From July 2013, NSFD with sulphur content less than 0.001% sulphur will be mandatory for motor vehicles and industries.

By 1 January 2014, the Euro IV emissions standards will give way to the stricter Euro V emission standards for all new diesel vehicles registered. The particulate emissions of Euro V diesel passenger cars are significantly lower than that of Euro IV diesel cars.


From 1 April 2014, new petrol vehicles will have to comply with Euro IV emission standards.

[2] Ozone is not directly emitted but is formed through complex chemical reactions involving hydrocarbons (HC) and nitric oxide & nitrogen dioxide (NOx) in the presence of sunlight. HC and NOx emitted from motor vehicles, industries, power stations and refineries are the precursors for ozone formation.

Sulphur Dioxide (SO2) Emission Inventory

One of the major pollutants in Singapore is sulphur dioxide (SO2). The sources of SO2 emissions in Singapore include refineries, power stations, other industries and other minor sources such as vehicles, airport and construction activities.

The 2012 SO2 emission inventory is summarized as shown in the table below.



SO2 Emissions (tonnes)

Contribution of SO2 Emissions






Singapore Refining Company




Power Stations

Tuas Power




Power Seraya




Senoko Power



Other Industries


Sembcorp Utilities and Terminals








ExxonMobil Petrochemical


Linde Syngas


Mitsui Phenol


Petrochemical Corporation of Singapore




Other Fuel Oil Users


Diesel Users


Motor Vehicles

Petrol Vehicles



Diesel Vehicles






Industrial Emissions

The NEA’s Source Emission Test Scheme for industries requires industries to conduct source emission test on their own or engage accredited consultants to do so on their behalf. This helps industries to monitor their air emissions regularly and to take measures, to ensure compliance with the prescribed air emission standards.

Motor Vehicles

Motor vehicles are a major source of air pollution. To control the emissions generated by motor vehicles, NEA regulates the type and quality of fuel that can be used in Singapore, and also sets minimum exhaust emission standards for all vehicles.

NEA takes stringent enforcement actions against smoky vehicles on the roads. Regulation 19 of the Environmental Protection and Management (Vehicular Emissions) Regulations stipulates that it is an offence for any person to use or permit the use of any smoky vehicle on the road.

It is the responsibility of every owner of a vehicle to ensure that the vehicle is in good condition before using it on the road. Besides carrying out proper servicing and maintenance of the vehicle regularly, the driver must also not overload the vehicle or drag the engine of the vehicle while driving. For 2-stroke motorcycles, the cause of white smoke emissions is usually due to addition of lubricating oil in excess of the amount specified in the vehicle manufacturer’s manual.

For further details on the regulations governing motor vehicle operation, importation and licensing, click here.

Off-Road Diesel Engines (revised on 30 Apr 2013)

Off-road diesel engines (ORDE) are any equipment or machinery that is equipped with diesel engines as the main or auxiliary prime mover and are not registered with the Land Transport Authority (LTA) for use on public roads.  Examples of off-road diesel engines include construction equipment such as cranes, excavators, forklifts and power generators. Diesel engines used in ships, railways, locomotives and aircraft are excluded.



With effect from 1 Jul 2012, approval in writing from NEA must be obtained prior to the import of ORDEs for use in Singapore. The application form for approval to import and use off-road diesel engines can be downloaded from this hyperlink. The duly completed from shall be emailed to the NEA (Pollution Control Department) at the following email address: (tel. no. 67319341) and (tel. no. 6731 9351)



ORDEs, either imported (new or used ones) or locally-manufactured for use in Singapore, are required to comply with the EU Stage II, US Tier II or Japan Tier I  off-road diesel engine emission standards, as shown below.


 Standby generators imported for use in Singapore with engine power rating of 560kW or  nore are given a grace period up till 31 Dec 2013 to comply with the stipulated emission standards. During the grace period, these standby generators shall comply with the US Tier I emission standards.  Approval in writing from NEA is also required prior to the import of such standby generators for use in Singapore.


Net Power (kW)


(Mandatory Standard)


US Tier II

130 < P <560

US Tier II or EU Stage II or Japan Tier I

75 < P <130

US Tier II or EU Stage II or Japan Tier I

37 < P <75

US Tier II or EU Stage II or Japan Tier I

19 < P <37

US Tier II or EU Stage II or Japan Tier I

< 19

US Tier II or Japan Tier I

For new ORDEs imported for use in Singapore, NEA would accept a batch emissions test report for each make and model provided it conforms to any of the above-mentioned standards for exhaust emissions.  For used ORDEs imported for use in Singapore, an emissions test shall be conducted for each and every unit of ORDE. 


The ORDE can be tested at an overseas or Singapore accredited laboratory for an emissions test according to the ISO 8178 standards.  If necessary, NEA may also require the applicant to submit a test report from an examiner stating that the ORDE was examined by the examiner on a date not earlier than 3 months before the date of application and was found to conform to any of the stipulated standards. Under the Environmental Protection and Management (Off-Road Diesel Engine Emissions) Regulations, it is an offence for any person to use off-road diesel engines imported into Singapore on or after 1 July 2012 if they do not comply with the stipulated emission standards.



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