NEA clears the air on pollution

Spokesman says air quality meets interim guidelines set by World Health Organisation
Grace Chua Straits Times 27 Nov 10;

SINGAPORE'S air is dirtier than is ideal - at least going by limits set by the World Health Organisation (WHO).

The level of particles hanging in the air called PM10 - meaning they are smaller than 10 micrometres or more than 10 times smaller than the width of a human hair - stands at 30 micrograms per cubic m here.

This level of pollution exceeds the WHO's guideline of 20 micrograms per cubic m averaged over a year, although it meets the limits of 50 micrograms per cubic m set by the National Environment Agency (NEA).

Singapore is not alone.

A United States-based air-pollution research body, the Health Effects Institute, has released a report showing that pollution in other major Asian cities also exceeds WHO standards.

Contributing to more than 500,000 premature deaths each year, air pollution puts people at risk of chronic lung conditions and cardiovascular disease; this can only worsen as populations age and Asia becomes more developed, said the report.

In Singapore, the PM10 level is of concern because the particles are fine enough to settle in the lungs and cause health problems, said respiratory disease specialist Philip Eng of Philip Eng Respiratory and Medical Clinic.

But still, the PM10 level here is the lowest among 20 Asian cities. Beijing, for example, has an annual average of 150 micrograms per cubic m; and Tokyo has nearly 40 micrograms per cubic m.

The report also looked at two other pollutants: nitrogen dioxide and sulphur dioxide. No Asian city has all three pollutants at levels within WHO's limits.

The report suggests that more data collection be done in Asia so the information can be used to shape public policy.

Responding to the findings, an NEA spokesman described the 2005 WHO air-quality guideline values for PM10 and the other air pollutants as 'very stringent'. She pointed out that Singapore's PM10 levels do, however, meet WHO's interim guidelines; these benchmarks can be used by countries to work towards meeting the international health body's final standards.

Dr Eng said long-term exposure to such particles raises one's risk of cardiovascular and respiratory diseases.

National University of Singapore climatologist Matthias Roth said that while recommended values represent an acceptable and achievable objective to minimise health effects, 'the aim should be to achieve the lowest concentrations possible in the local context'.

He warned that PM2.5, a pollutant 30 times smaller than the width of a human hair, also needs watching, as these particles are able to go deeper into the lungs and are even more toxic than PM10.

The level of PM2.5 here last year was 19 micrograms per cubic m, up from 16 the year before.

The NEA disclosed recently that it is reviewing the Pollutant Standards Index it now uses, which is based on US Environmental Protection Agency standards phased out in 1999.