KUALA LUMPUR, Sept 28, 2015:
While people continue to debate the overwhelming difference between Malaysia and Singapore’s readings of the Air Pollutants Index (API), the inclusion of a sixth parameter called fine particulate matter (PM2.5) by the city state has been identified as the key component behind the readings.
While in Malaysia the APO readings are based on five parameters — carbon monoxide, ozone, nitrogen dioxide, sulphur dioxide and particulate matter (PM10) — Singapore decided in April last year to include PM2.5 and the index is now called Pollutant Standards Index (PSI).
According to the United States Environment Protection Agency (EPA), particles smaller than 10 micrometres in diameter (PM10) pose a health concern because they can be inhaled and accumulate in the respiratory system.
“Particles smaller than 2.5 micrometres in diameter (PM2.5) are referred to as ‘fine’ particles and are believed to pose the greatest health risks.
“Because of their small size (approximately 1/30th the average width of a human hair), fine particles can lodge deeply into the lungs,” it said.
The EPA added that PM2.5 travels deeper into the lungs. Because PM2.5 is made up things that are more toxic (like heavy metals and cancer-causing organic compounds), PM2.5 can have worse health effects than the bigger PM10.
The EPA said children are most at risk because their bodies are still developing, adding that the elderly population is at risk. It pointed out that people of all ages, who were active outdoors, were at an increased risk because during physical activity, PM2.5 penetrates deeper into the parts of the lungs that are more vulnerable to injury.
The EPA said readings of 151 to 200 were considered unhealthy and people with respiratory disease, such as asthma, should avoid outdoor exertion. Everyone else, especially the elderly and children, should limit prolonged outdoor exertion.
The EPA went on to advise the public that once the reading went past the 201 level, it was considered very unhealthy and people with respiratory disease, such as asthma, should avoid any outdoor activity. Everyone else, especially the elderly and children, should limit outdoor exertion.
It also warned that once the reading passed the 301 level it was hazardous and everyone should avoid any outdoor exertion and people with respiratory disease, such as asthma, should remain indoors.