Parliament Q&A

Written reply by Mr Masagos Zulkifli, Minister for the Environment and Water Resources, to Parliamentary Question on Air Quality and Emissions Inventory, on 6 Mar 2020

Ms Anthea Ong: To ask the Minister for the Environment and Water Resources (a) with respect to Singapore's 2020 air quality targets, how did we perform in 2019 for PM2.5, sulphur dioxide, ozone and nitrogen dioxide emissions; and (b) whether the Government will consider building and publishing emissions inventories for all pollutant types for better identification of the different sources of air pollutants and air quality management.

Written Reply by Minister Masagos:

1.                 The Ministry of the Environment and Water Resources (MEWR) and the National Environment Agency (NEA) benchmark Singapore’s air quality against the World Health Organization (WHO) Air Quality Guidelines (AQG). Singapore has adopted as its 2020 air quality targets the WHO AQG for particulate matter (PM10), nitrogen dioxide (NO2), carbon monoxide (CO), and ozone, and the WHO AQG’s Interim Targets for PM2.5 and sulphur dioxide (SO2). 

2.                 Comparing Singapore’s 2019 performance with the 2020 air quality targets, we met the 2020 target for NO2 and CO. For SO2, while the annual target (annual mean) was met in 2019, the maximum 24-hour mean level exceeded the limit in one day of the year (recorded at 57 µg/m3). We did not meet the 2020 targets for particulate matter (PM10 and PM2.5) and ozone in 2019. A summary of Singapore’s 2019 air quality performance in 2019 against the Singapore target by 2020 and the long term targets is shown in the table below.


Singapore target by 2020

Long Term Targets

2019 Performance

Sulphur Dioxide (SO2)

24-hour mean1: 50 µg/m3 (WHO Interim Target)

Annual mean: 15 µg/m3 (Sustainable Singapore Blueprint target)

24-hour mean1: 20 µg/m3 (WHO Final)


24-hour mean1: 57 µg/m3

Annual mean: 8 µg/m3

Fine Particulate Matter (PM2.5)

Annual mean: 12 µg/m3 (Sustainable Singapore Blueprint target)

24-hour mean2: 37.5 µg/m3 (WHO Interim)

Annual mean: 10 µg/m3

24-hour mean2: 25 µg/m3 (WHO Final)

Annual mean: 16 µg/m3

24-hour mean2: 62 µg/m3  

Particulate Matter (PM10)

Annual mean: 20 µg/m3

24-hour mean2: 50 µg/m3 (WHO Final)

Annual mean: 30 µg/m3

24-hour mean2: 90 µg/m3


8-hour mean1: 100 µg/m3 (WHO Final)

8-hour mean1: 125 µg/m3

Nitrogen Dioxide (NO2)

Annual mean: 40 µg/m3

1-hour mean1: 200 µg/m3 (WHO Final)

Annual mean: 23 µg/m3

1-hour mean1: 156 µg/m3

Carbon Monoxide (CO)

8-hour mean1: 10 mg/m3

1-hour mean1: 30 mg/m3 (WHO Final)

8-hour mean1: 1.7 mg/m3

1-hour mean1: 2.3 mg/m3

1Highest; 2 99th Percentile

3.       We have implemented a suite of measures to reduce the emission of pollutants. We are tightening industrial emission standards for new and existing plants from 2015 to 2023. We have also introduced measures to manage emissions from vehicles. These include stricter standards for fuel quality and tighter emissions standards for new vehicles, as well as incentive schemes to turn over older, more pollutive vehicles and encourage the purchase of new and cleaner vehicles. We will continue to review these measures.

4.       NEA conducts emissions inventory and source apportionment modelling studies to identify key sources of air pollutants in Singapore and develop air quality management strategies. These internal studies help us fine-tune and improve our air quality management strategies.  

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