Everything You Need to Know about the NEW 1-hour PM 2.5 PSI Measurement Because the Haze is Back

Last Updated on 2016-08-29 , 6:54 pm

Instead of waking up to the aroma of eggs, bacon, and hashbrowns, many wake up to a familiar burning smell that is similar to the 7th Lunar Month. Eh… wait a minute. Is someone burning offerings? Nope. The annual dreaded haze is back. Again.

What exactly is the PSI?

PSI is the Pollution Standards Index that provides accurate and comprehensible daily information on air quality. It is calculated based on a 24-hour average of the PM_2.5 concentration levels, pollutants (sulphur dioxide (SO₂), nitrogen dioxide (NO₂), ozone (O₃), and carbon monoxide (CO)), and particulates (PM₁₀ and PM_2.5) in the atmosphere, monitored by a system of monitoring stations located in different parts of Singapore.

24-hour PSI	Good 0-50	Moderate 51-100	Unhealthy 101-200	Very Unhealthy 201-300	Hazardous >300
HEALTHY PERSONS	Normal activities	Normal activities	Reduceprolonged or strenuous outdoor physical exertion	Avoid prolonged or strenuous outdoor physical exertion	Minimise outdoor activity
ELDERLY, PREGNANT WOMEN, CHILDREN	Normal activities	Normal activities	Minimiseprolonged Advertisements   or strenuous outdoor physical exertion	Minimise outdoor activity	Avoid outdoor activity
PERSONS WITH CHRONIC LUNG DISEASE, HEART DISEASE	Normal activities	Normal activities	Avoid prolonged or strenuous outdoor Advertisements   physical exertion	Avoid outdoor activity	Avoid outdoor activity

Source: www.nea.gov.sg

1-hour PM2.5 Readings

According to Channel NewsAsia (CNA), the National Environment Agency (NEA) resisted publishing the 1-hour PSI reading as such practice is not supported by health studies.

Nevertheless, CNA announced that the NEA is introducing bands and descriptors for the one-hour concentration readings for fine particulate matter (PM2.5), which it has been publishing hourly since 2014.

The new parameters are:
Normal (<55), Elevated (56-150), High (151-250), and Very High (>250).

Although no health advisories accompanied the readings, this is a general guide on how the haze particles affect health is provided.

The difference between the 24-hour and 1-hour readings is that the former is used to guide major decisions such as the closure of schools while the latter is to inform immediate personal activities.

Why the Shift?

During last year’s haze, many Singaporeans criticised the NEA’s official 3-hour and 24-hour PSI readings do not tally with their observations of outdoors visibility and smell.

CNA reported the NEA will be removing the 3-hour reading by the end of 2016 because of its irrelevance and the public should rely on the official hourly readings which are “more accurate”.

Is NEA’s Hourly PM_2.5 is Not as ‘Zai‘ as Other Countries’?

Presently, there aren’t any international guidelines for calculating the air quality index because different countries have different systems, descriptors, and breakpoints.

However, the NEA still appears to be advocating for the 24-hour PSI reading as it states the 24-hour measurement is employed by most respiratory health studies on exposure to Particulate Matter, which showed good correlated results.

For more comprehensive information on the PSI and PM_2.5, readers are advised to visit the NEA’s FAQ page.

This article was first published on goodyfeed.com