Can the body cleanse itself of small, toxic haze particles?

SINGAPORE - Three experts helped to answer Singaporeans' questions about the haze at a special online forum organised by The Straits Times.

The questions ranged from health concerns to more technical ones, such as how the haze is measured.

The experts who gave their insights were: respiratory medicine specialist Dr Ong Kian Chung; research scientist at the Singapore-MIT Alliance for Research and Technology, Dr Erik Velasco; and senior research scientist at the Centre for Remote Imaging, Sensing & Processing (CRISP) at the National University of Singapore, Dr Santo Salinas.

Here are some of the questions posed at the forum, and the experts' answers:

Why was the haze so bad this year?

Dr Salinas: In the Philippines and Taiwan, there were storms that pulled the moisture north and created an episode of dry-spell in our region. That was a unique event that happened that led to the burning becoming worse. It's not likely to be repeated in the next three, four months, but we are at the beginning of the dry season, so we are still likely to get smoke from biomass burning.

Why does Singapore use the Pollutant Standards Index (PSI) and not the Air Quality Index, which other countries like the United States use?

Dr Velasco: The PSI includes five criteria pollutants - ozone, PM10, nitrous oxide, sulphur dioxide and carbon monoxide. The standard index doesn't include fine aerosols. These were picked by the US in the late 70s and 80s. At the time, we didn't know much about fine aerosols and didn't have the instrumentation to monitor them.

Can the human body cleanse itself of small, toxic particles called PM2.5?

Dr Ong: Once those foreign bodies are in there, they will cause some kind of inflammation which would have taken place once those particles are in the body. Once they are in the bloodstream they can go anywhere in the body, and it will be very difficult for the body to cleanse them.

Are spot-readings of the pollution in the haze useful?

Dr Velasco: The National Environment Agency's data is very useful to make decisions about pollution in general; however for events like smoke haze, we need to act quickly, so we need hourly data. The 24-hour, 8-hour or 3-hour average data removes spikes which are also important in terms of health. In the international arena, the majority of monitoring networks report both hourly and 24-hourly data.

How can people protect themselves against the haze's pollution?

Dr Ong: Follow the Government's health advisory and wear face masks outdoors if the air is unhealthy. Having air purifiers indoors can also help. The NEA has a list of recommended air purifiers on its website.

The forum's full exchange is available at The Straits Times Facebook page.

Get a copy of The Straits Times or go to for more stories.