What does PSI stand for in haze?
Computation of the Pollutant Standards Index (PSI) Page 1. 1. Computation of the Pollutant Standards Index (PSI) The PSI is based on six pollutants particulate matter (PM10), fine particulate matter (PM2.
When was the worst haze in Singapore?
The 2013 Southeast Asian haze was notable for causing record high levels of pollution in Singapore and several parts of Malaysia. The 3-hour Pollution Standards Index in Singapore reached a record high of 401 on 21 June 2013, surpassing the previous record of 226 set during the 1997 Southeast Asian Haze.
What PSI value indicates that at least one pollutant just reached its ambient air quality standard on that day?
A PSI value of 100 corresponds to the NAAQS established under the Clean Air Act. A PSI value greater than 100 (yellow) indicates that at least one criteria pollutant (with the exception of NO2) exceeded the level of the NAAQS, therefore designating air quality to be in the unhealthful range on that day.
What is PSI and AQI?
In essence, the AQI and PSI are the same thing except for these 2 differences: A) AQI uses the USA Environmental Protection Agency’s system. PSI uses the local NEA system. AQI uses the latest particulate matter data, PSI uses the 24-hour average.
What should be AQI?
AQI values at or below 100 are generally thought of as satisfactory. When AQI values are above 100, air quality is unhealthy: at first for certain sensitive groups of people, then for everyone as AQI values get higher.
What is the PSI level?
PSI stands for ‘Pollutant Standards Index’. It is an index to provide accurate and easily understandable information about daily levels of air quality….
| 24-hr PSI Value | PSI Descriptor |
|---|---|
| 0 – 50 | Good |
| 51 – 100 | Moderate |
| 101 – 200 | Unhealthy |
| 201 – 300 | Very unhealthy |
What is PSI Singapore?
PSI stands for ‘Pollutant Standards Index’. It is an index to provide accurate and easily understandable information about daily levels of air quality. PSI is computed based on 24-hour average of PM 2.5 concentration levels, among other pollutants. PM 2.5 is the dominant pollutant during haze episodes.
When was the first haze in Singapore?
One of the worst haze outbreaks in Singapore occurred in 1972. Visibility was as low as 1 to 2 km across parts of the island due to the thickness and persistence of the haze during the first two weeks of October that year.
What is good AQI level?
Air Quality Index Scale and Color Legend
| AQI | Air Pollution Level |
|---|---|
| 0 – 50 | Good |
| 51 -100 | Moderate |
| 101-150 | Unhealthy for Sensitive Groups |
| 151-200 | Unhealthy |
How is 24 hour PSI calculated?
In calculating Singapore’s 24-hour PSI, the NEA uses data from a network of air-monitoring sensors islandwide. These measure concentration levels of the six pollutant particles that Singapore uses to calculate its PSI. These are ozone, particle pollution, carbon monoxide, sulphur dioxide and nitrogen dioxide.
What does an AQI of 100 mean?
satisfactory
AQI values at and below 100 are generally considered to be satisfactory. When AQI values are above 100, air quality is considered to be unhealthy, at first for members of populations at greatest risk of a health effect, then for the entire population as AQI values get higher (greater than 150).