If you have recalled back in 2016, the air quality reached a "very unhealthy" level. With the haze coming back over the last few days, we have received many questions from worrying swimmers and we are here to explain the situation.
What is haze and why is it a big deal?
Let us first explain what is haze:
Haze is an air-borne mixture of pollutants that includes soot particles, carbon dioxide and other toxic gases.
-Schweithelm, J., & Glover, D. (1999)
Other than reducing the visibility, exposure to haze does have an effect on health. Short term effects include EMT (Eyes, Mouth and Nose) irritation, dizziness and decrease lung function. These symptoms are usually mild and will subside when exposure to haze is minimised. Individuals who have chronic illnesses, especially respiratory related condition, will be more likely to experience more severe effects.
What is worrying is the particles in the haze which are smaller than 2.5 micrometers in diameter. Due to their size, these particles are more likely to stay in the air longer and carried over long distance. These particle are also more likely to be inhaled in by animals and humans.
These particles, commonly known as PM2.5, are able to bypass our body defense mechanism due to their size and may potentially interact with our body to cause damage from within.
How do we monitor haze?
In Singapore, National Environment Agency (NEA) uses Pollutant Standards Index (PSI) to measure the air quality and this can be tracked on NEA website. On the website, you will be able to view a 24hr PSI and 1hr PM2.5 reading.
The 24hr PSI reading gives us a forecast of the air quality in the next 24hr so we can plan our activities accordingly and the 1hr PM2.5 reading gives a more immediate reading on the air quality over the last 1hr.