[ST, 14June2010] Haze 'is bad for your heart'

Haze 'is bad for your heart'
Victoria Vaughan Straits Times 14 Jun 10;
HAZE is bad for your heart, with evidence linking it to heart attacks and cardiovascular death having 'strengthened substantially', warned the American Heart Association (AHA) in a scientific statement on its website.
The culprit is particulate matter less than 2.5 micrograms in diameter, known as PM2.5, the main component of haze. The warning comes at a time when the haze season, caused by widespread burning of forests in Indonesia, is about to begin again in the region from next month.
Satellite pictures in April showed 3,166 hot spots in the region, much higher than the 2,427 detected in April last year, prompting fears that the haze will return even stronger in the traditional burning season from July to September.
In Singapore, air quality is calculated using the Pollutant Standards Index (PSI), which does not measure PM2.5 levels. Instead, it measures the amount of PM10, a larger particulate matter in haze.
Doctors say the very small PM2.5 particles may get into a human's blood circulation and cause direct harm to the person.
Singapore's National Environment Agency (NEA) said it monitors PM2.5 levels through its 11 air-monitoring stations islandwide, although this measurement is not made publicly available each day.
Instead, the agency lists the annual average reading in its annual report. The PM2.5 average here in the last two years were both above the 'safe' level recommended by the World Health Organisation (WHO) and the United States Environmental Protection Agency (EPA).
They were 16 micrograms (ug) per cubic m and 19 ug per cubic m respectively, which exceeds both the WHO standard of 10 ug per cubic m and the EPA standard of 15 ug per cubic m.
But the NEA said the levels clocked here were comparable to that in other major cities like London, New York, Los Angeles and Paris. The level was higher last year compared to the year before because of 'transboundary smoke haze', it added.
The PSI was a standard Singapore adopted from the EPA 19 years ago and daily PSI readings are made publicly available on NEA's website. The US agency no longer uses this index, having switched to the Air Quality Index (AQI) in 1999. This index measures PM2.5 levels in the air.
When asked if it would consider switching its method of calculating air quality, an NEA spokesman said there was 'no internationally-harmonised protocol' for reporting air quality indices.

'The PSI system that NEA has adopted has served us well in issuing appropriate public health advisories when Singapore's air quality was adversely affected by transboundary smoke haze in the past,' said the spokesman.
Other places such as Hong Kong, Malaysia, Brunei, Indonesia, Britain, France and Belgium also used indices which measured PM10 rather than PM2.5, the agency pointed out.
The NEA did not elaborate on why PM2.5 levels are not made available daily.
However, experts felt it was time for more regular updates on PM2.5 levels.
National University of Singapore climatologist, Associate Professor Matthias Roth, felt hourly values should be made available to the public.
'It's important for the public to know about the levels of PM2.5 in the air as these small particles have a strong association with most types of respiratory illness and even mortality,' he said. 'Reporting an annual average has limited use as it will have a low bias due to the numerous rainy days when concentration of air pollutants are minimal.'
When asked if the public should be concerned about PM2.5, Singapore's Health Ministry said: 'The PSI cut-offs are internationally accepted standards. People are advised to avoid vigorous outdoor activities at PSI more than 100 because air quality is unhealthy beyond this level. However, these are general public health guidelines and individuals may choose to avoid vigorous outdoor activities at PSI levels less than 100 if they are still concerned.'
According to the WHO, air pollution is estimated to cause about two million premature deaths worldwide each year.
But while AHA's warning seems pretty dire, heart doctors here say they have not seen increased incidents linked to haze.
Dr K. Gunasegaran, a senior consultant at the  Department of Cardiology in the National Heart Centre, noted the haze situation here is not particularly bad. 'Generally, it is not prevalent all year round,' he said.
But while the centre has not seen an upswing in cardiac failure during hazy periods, he said patients with underlying conditions such as lung disease could be at higher risk.
He suggested such individuals stay indoors during periods of haze and seek early medical attention if they feel unwell.

References:
- [XHN, China, 10May2010]: 'Air pollution associated with heart disease: AHA' : "Fine particulate matter, which is called PM2.5 by scientists because the particles have a diameter of 2.5 micrometers or less, is the type of air pollution most likely to cause cardiovascular disease.. "
- [ST 31May2010]: 'Please don't follow my example, says Khaw': "'I am making this confession so that hopefully it can be a life-saving reminder to others. Please do not follow my example,' Mr Khaw added."
- [ST, 14June2010]: 'Haze 'is bad for your heart'': "The PM2.5 average here in the last two years were both above the 'safe' level recommended by the World Health Organisation (WHO) and the United States Environmental Protection Agency (EPA).... "
- [ST, 19Jun2010]: 'Clear the air on pollutant levels', [alt site]: "The AHA concluded that short-term exposure of 'over a few hours to weeks' to PM2.5 can trigger fatal heart attacks, heart failure and heart rhythm problems. ... ... Better still, perhaps daily PM2.5 levels should be provided to the public."
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