The National Environment Agency (NEA) will consider releasing more raw data on the haze but it also has to be mindful of not putting out information that might be "unnecessarily alarming", said Mr Choi Shing Kwok, permanent secretary for the Ministry of the Environment and Water Resources, on Thursday.
Addressing questions from reporters on why NEA gives the PSI reading as an average of three hours instead of an hourly reading, Mr Choi noted that the health effects of haze depend on both the level as well as the duration of exposure.
Already, Singapore is unique in giving the three-hour average as the convention in other countries is the 24-hour reading, said project director of NEA's Pollution Control Development Indrani Rajaram at the media briefing on Thursday.
NEA's health advisories are based on the 24-hour measurement, said Ms Indrani, adding that there are no studies done on the health effects of exposure to short-term spikes in the PSI level. International data on air pollution and health is also largely based on the 24-hour PSI reading.
However, NEA will start publishing hourly updates on the PSI level - based on the average of the past three hours - round the clock starting on Thursday. Currently, the updates are given from 6am to midnight.
It will also publish hourly updates on the 24-hour reading of PM2.5, which measures the amount of particles in the air smaller than 2.5 microns, compared to the PSI which measures particles smaller than 10 microns. The PM2.5 reading is currently updated three times a day.