Straits Times Forum 27 Jun 13;
THE haze problem has drawn attention to the Pollutant Standards Index (PSI) readings released by the National Environment Agency.
Previously, only PM10 readings were released (as part of the PSI), but people have become increasingly aware of PM2.5's impact on health as these smaller particles are more toxic.
The World Health Organisation sets down guidelines of a maximum PM2.5 level of 25 micrograms per cubic m over a 24-hour period, and 10 micrograms per cubic m averaged over a year.
Looking at the historical data starting from 2009, Singapore's average PM2.5 levels have been consistently above these levels, even without the haze.
Is the air quality in Singapore not as good as what we have believed it to be?
Has our growing population, with the resulting increase in vehicle numbers and reduced green spaces, been a factor? Perhaps we should look at the impact a growing population has on air quality.
Yeo Chee Kean
