Air and Coastal Water Quality Monitoring

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Benzene

Ambient Benzene Trends in Singapore

Benzene is a Volatile Organic Compound that occurs naturally in crude petroleum and is emitted through the processing and burning of petroleum products, with a wide range of sources like petrochemical industries, motor vehicle exhausts, and tobacco smoke.

The World Health Organization (WHO) provides risk-based guidelines for long-term benzene exposure, but does not set a single threshold. Jurisdictions such as the European Union (EU) have established an annual limit value of ~1.6 parts per billion (ppb) for ambient benzene concentrations.  Singapore’s annual benzene levels at our air monitoring stations in residential areas for the last five years are shown below, and have been consistently below the European Union limit of 1.6ppb.



A. Average Ambient Benzene Levels - All Stations Near Residential Areas

Unit: ppb

|

EU Benchmark: 1.6 ppb


B. Station-level Benzene Trends 

Unit: ppb

|

EU Benchmark: 1.6 ppb

 

C. Hourly Benzene Levels

Singapore's hourly benzene levels by station are shown below as a percentage of the US EPA 1-hour Acute Exposure Guideline Level-1 (AEGL-1) for benzene. This is the least severe of the three AEGL tiers and represents the airborne pollutant concentration threshold (i.e. 52,000 ppb) above which the general population, including susceptible individuals such as children, elderly persons, and those with respiratory conditions, could experience notable discomfort, irritation, or certain non-sensory effects. These effects are transient and reversible once exposure to the pollutant stops.

Update Period: Last 6 Hours

AEGL-1 Threshold: 52,000 ppb = 100%

Station Punggol Queenstown Changi-East Coast Jurong Hill Bishan-Ang Mo Kio
Date Hour % of AEGL-1 % of AEGL-1 % of AEGL-1 % of AEGL-1 % of AEGL-1
2026-08-12 10:00 AM <0.01% <0.01% <0.01% <0.01% <0.01%
2026-08-12 11:00 AM <0.01% <0.01% <0.01% <0.01% <0.01%
2026-08-12 12:00 PM <0.01% <0.01% <0.01% <0.01% <0.01%
2026-08-12 1:00 PM <0.01% <0.01% <0.01% <0.01% <0.01%
2026-08-12 2:00 PM <0.01% <0.01% <0.01% <0.01% <0.01%
2026-08-12 3:00 PM <0.01% <0.01% <0.01% <0.01% <0.01%
Station Sentosa Pulau Ubin Pulau Tekong Lower Seletar
Date Hour % of AEGL-1 % of AEGL-1 % of AEGL-1 % of AEGL-1
2026-08-12 10:00 AM <0.01% <0.01% <0.01% <0.01%
2026-08-12 11:00 AM <0.01% <0.01% <0.01% <0.01%
2026-08-12 12:00 PM <0.01% <0.01% <0.01% <0.01%
2026-08-12 1:00 PM <0.01% <0.01% <0.01% <0.01%
2026-08-12 2:00 PM <0.01% <0.01% <0.01% <0.01%
2026-08-12 3:00 PM <0.01% <0.01% <0.01% <0.01%

Note:
0.01% of AEGL-1 is equivalent to a concentration of 5.2 ppb; 0.1% is equivalent to a concentration of 52 ppb; 1% is equivalent to a concentration of 520 ppb. N/A indicates that data is temporarily unavailable due to maintenance.