Haze Advisory to Organisers, update: Only hourly PM2.5 concentrations are suitable for a rapid response (and values > 55µg/m3 are unhealthy)

About half of the 70 organisations in the International Coastal Cleanup Singapore cancelled over the past week after the first haze advisory was issued. The remaining organisations, about half, are able to defer their decision to early tomorrow morning.

However, I had to improve the advisory. Since PSI indices are based on previously registered values, they cannot respond to rapid changes on the ground. So it is the 1-hr PM2.5(µg/m3) concentrations which NEA has published since 2014, which has been pointed to ICCS Organisers to keep an eye on.

Well, that and their eyes and noses!

———- Forwarded message ———-
From: International Coastal Cleanup Singapore
Date: Fri, Sep 18, 2015 at 10:03 PM

Dear International Coastal Cleanup Organisers in Singapore,

Some of you will decide if you can proceed with your coastal cleanup on the morning of the event itself. Here is our recommendation.

Check 1-hour PM2.5 values. PSI values are historical so will not help.

What is this value?

  • This value indicates the concentration of harmful fine particles less than 2.5 micrometers in diameter in the environment.
  • Yes it is a lower number than your PSI, because this value is a concentration, and not an index.
  • The concentration can be converted to an Air Quality Index (AQI) value.
  • The 3-hour and 24-hour indices report historical values so are not applicable to our situation.

You can rely on your eyes and nose too!

  • Conditions can change very rapidly with shifting winds and take up to an hour for readings to reflect this change.
  • Be observant and respond accordingly.

Why is the use of N95 masks for coastal cleanups not recommended?

  • Only N95 masks help prevent inhalation of fine particles. However they must used properly and in the right conditions.
  • Fit is of critical importance to prevent the entry of 2.5 micrometer-sized particles through gaps in the mask.
  • Each user needs to be fitted properly and the seal examined to ensure it is adequate, especially with people unfamiliar with use of the mask (most of us!)
  • Heavy breathing can disrupt the seal of a mask.
  • Wearing a mask and engaging in physical activity may require increased effort to breathe or create discomfort in breathing.

Why are we being so careful?
Isn’t the issue of marine pollution critical? Don’t we need the data?

  • ICCS is not such a critical exercise that it requires volunteers to take such risks.
  • Small and fine particles can pass through the throat and nose to enter the lungs and affect our heart and lungs.
  • This can cause serious short-term and long-term health effects.

Even though we have been working on the International Coastal Cleanup project since the start of the year, the health of all you precious volunteers is much more important.

All the best and let’s hope for clear skies!

Relevant Links



N. Sivasothi
Coordinator, International Coastal Cleanup Singapore
Lee Kong Chian Natural History Museum &
Department of Biological Sciences
National University of Singapore