Kiera Jefferson
The Pollutant Standards Index (PSI) is a type of air quality index used in Singapore to indicate the level of pollutants in the air. It considers six air pollutants: sulphur dioxide (SO2), particulate matter (PM10), fine particulate matter (PM2.5), nitrogen dioxide (NO2), carbon monoxide (CO), and ozone (O3). The PSI is determined by calculating a sub-index value for each pollutant based on its ambient air concentration and then selecting the highest sub-index value. This value is reported on a scale of 0 to 500, allowing the public to assess air pollution levels as good, unhealthy, hazardous, or worse. While PSI is unique to Singapore, other countries use similar air quality indices with different names and calculations, such as the Air Quality Health Index and the Air Pollution Index.
| Characteristics | Values |
|---|---|
| Name | Pollutant Standards Index (PSI) |
| Usage | Used in Singapore to indicate the level of pollutants in the air |
| Pollutants considered | Six: sulphur dioxide (SO2), particulate matter (PM10), fine particulate matter (PM2.5), nitrogen dioxide (NO2), carbon monoxide (CO), and ozone (O3) |
| Calculation method | A sub-index value is computed for each pollutant based on its ambient air concentration. The highest sub-index value is then taken as the PSI value. |
| Scale | 0 to 500 |
| Interpretation | The PSI figures enable the public to determine whether the air pollution levels in a location are good, unhealthy, hazardous, or worse. |
| Health outcomes | Singapore's PSI has been correlated with all-cause mortality, sudden cardiac deaths, acute myocardial infarction, and acute ischemic stroke. |
| Replaced by | The PSI has been replaced by the Air Quality Index (AQI) in the US since 1999 to incorporate new PM2.5 and ozone standards. |
Explore related products
What You'll Learn
- Calculating PSI: sub-index values for each pollutant are computed, with the highest value becoming the PSI value
- PSI is based on six air pollutants: sulphur dioxide, PM10, PM2.5, nitrogen dioxide, carbon monoxide and ozone
- AQI is calculated by converting measured pollutant concentrations to a uniform index
- Health benchmarks for AQI are pollutant-specific and established by the EPA
- PSI and health: Singapore's PSI and NEA's PSI ranges correlate with health outcomes including all-cause mortality
Calculating PSI: sub-index values for each pollutant are computed, with the highest value becoming the PSI value
The Pollutant Standards Index (PSI) is a type of air quality index used in Singapore to indicate the level of pollutants in the air. It was initially based on five air pollutants, but since 2014, it has also included fine particulate matter (PM2.5). The PSI is calculated by determining a sub-index value for each pollutant, which is based on the concentration of that pollutant in the ambient air. These sub-index values are then compared, and the highest value becomes the PSI value for that particular location. In other words, the PSI is determined by the pollutant with the highest concentration.
To calculate the sub-index value for each pollutant, the concentration of the pollutant in the ambient air is measured. These measurements are taken via a network of air monitoring stations located around Singapore. The pollutant with the most significant concentration, indicated by the highest sub-index value, will then determine the overall PSI for that location.
The PSI is reported as a number on a scale of 0 to 500, allowing the public to assess the air pollution levels in their area. Singapore publishes the PSI derived by averaging data collected over 24 hours, as well as 1-hour PM2.5 concentrations. The PSI table, provided by Singapore's National Environment Agency (NEA), groups these index values with descriptors explaining the effects of the pollution levels. For example, a high PSI value may indicate unhealthy or hazardous air quality.
The PSI is unique to Singapore and was introduced in 1997 to provide detailed air quality information. The PSI considers six air pollutants: sulphur dioxide (SO2), particulate matter (PM10), fine particulate matter (PM2.5), nitrogen dioxide (NO2), carbon monoxide (CO), and ozone (O3). It is worth noting that the US EPA has replaced the PSI with the Air Quality Index (AQI) since 1999 to incorporate new PM2.5 and ozone standards.
The Dark Side of Plastic: Environmental Impact
You may want to see also
Explore related products
PSI is based on six air pollutants: sulphur dioxide, PM10, PM2.5, nitrogen dioxide, carbon monoxide and ozone
The Pollutant Standards Index (PSI) is a type of air quality index used in Singapore. It is a number that indicates the level of pollutants in the air. PSI is calculated by first computing a sub-index value for each pollutant based on its ambient air concentration. The highest sub-index value is then taken as the PSI value. This means that the PSI is determined by the pollutant with the most significant concentration.
Initially, PSI was based on five air pollutants, but since 2014 it has also included fine particulate matter (PM2.5). The six pollutants that make up the PSI are:
- Sulphur dioxide (SO2)
- Particulate matter (PM10)
- Fine particulate matter (PM2.5)
- Nitrogen dioxide (NO2)
- Carbon monoxide (CO)
- Ozone (O3)
The concentrations of these pollutants in the ambient air are measured via a network of air monitoring stations located around Singapore. The PSI is reported as a number on a scale of 0 to 500. This allows the public to determine whether the air pollution levels in a particular location are good, unhealthy, hazardous, or worse. For example, an AQI value of 50 or below represents good air quality, while an AQI value over 300 represents hazardous air quality.
Singapore's computation of PSI has been shown to correlate with a number of health outcomes, including all-cause mortality. For sudden cardiac deaths, every increment of 30 units in PSI correlated with an 8.15% increased risk of out-of-hospital cardiac arrest on the same day of exposure. This risk remained elevated for 1-5 days after exposure. Similar short-term associations were found for acute myocardial infarction and acute ischemic stroke.
The Dark Side of Electric Vehicles: Pollution in Manufacturing
You may want to see also
Explore related products
AQI is calculated by converting measured pollutant concentrations to a uniform index
The Air Quality Index (AQI) is a uniform way to report daily air quality conditions. It was developed by the U.S. Environmental Protection Agency (EPA) and is based on the health effects associated with a pollutant. The AQI is calculated by converting measured pollutant concentrations to a uniform index.
The EPA establishes an AQI for five major air pollutants regulated by the Clean Air Act. Each of these pollutants has a national air quality standard set by the EPA to protect public health. The health benchmarks used for calculating the AQI are pollutant-specific and are established by the EPA through the National Ambient Air Quality Standards. The Clean Air Act requires the EPA to review these standards every five years.
AQI values are divided into six categories, with an AQI value of 100 generally thought of as satisfactory. When AQI values are above 100, air quality is considered unhealthy for certain sensitive groups of people, and as the AQI value increases, the health risk to the general population increases. An air quality alert is issued when measured or forecasted air quality conditions exceed 101 on the index, indicating that current or forecasted conditions may be harmful to those sensitive to air pollution.
The Pollutant Standards Index (PSI) used in Singapore is similar to the AQI, but it considers six air pollutants: sulphur dioxide (SO2), particulate matter (PM10), fine particulate matter (PM2.5), nitrogen dioxide (NO2), carbon monoxide (CO), and ozone (O3). The PSI is determined by the pollutant with the most significant concentration, and it is reported as a number on a scale of 0 to 500.
Climate Change and Pollution: A Complex Relationship
You may want to see also
Explore related products
Health benchmarks for AQI are pollutant-specific and established by the EPA
The Air Quality Index (AQI) is a tool developed by the US Environmental Protection Agency (EPA) to communicate information about outdoor air quality and health. The AQI is calculated by converting measured pollutant concentrations to a uniform index based on the health effects associated with a particular pollutant.
The health benchmarks used for calculating the AQI are pollutant-specific and are established by the EPA through the National Ambient Air Quality Standards (NAAQS). The Clean Air Act requires the EPA to review these standards every five years to reflect evolving health effects information. The AQI is adjusted periodically to reflect these changes.
The AQI is based on the five "criteria" pollutants regulated under the Clean Air Act: ground-level ozone, particulate matter, carbon monoxide, sulfur dioxide, and nitrogen dioxide. The EPA has established NAAQS for each of these pollutants to protect public health. An AQI value of 100 generally corresponds to the level of the NAAQS for the pollutant.
The AQI includes six color-coded categories, each corresponding to a range of index values. The higher the AQI value, the greater the level of air pollution and the more serious the health concern. For example, an AQI value of 50 or below represents good air quality, while an AQI value over 300 represents hazardous air quality. When the AQI is high, governmental bodies generally advise people to reduce physical activity outdoors or even avoid going outside altogether.
Addressing Ozone Pollution: CAIR and CSAPR Strategies
You may want to see also
Explore related products
PSI and health: Singapore's PSI and NEA's PSI ranges correlate with health outcomes including all-cause mortality
The Pollutant Standards Index (PSI) is a type of air quality index used in Singapore, which is a number used to indicate the level of pollutants in the air. PSI is reported as a number on a scale of 0 to 500, with the index figures enabling the public to determine whether the air pollution levels in a particular location are good, unhealthy, hazardous, or worse. The National Environment Agency (NEA) in Singapore provides two air quality readings: the 24-hour PSI and the 1-hour PM2.5 readings. The 24-hour PSI is calculated using data from a network of air-monitoring sensors that measure the concentration levels of six pollutant particles: sulphur dioxide (SO2), particulate matter (PM10), fine particulate matter (PM2.5), nitrogen dioxide (NO2), carbon monoxide (CO), and ozone (O3). For each pollutant, a sub-index is calculated on a scale from 0 to 500 based on concentration levels, and the 24-hour PSI is the average of the highest sub-indexes in each of the past 24 hours.
Singapore's PSI readings are unique and different from those used elsewhere due to the country's geographical proximity to Indonesia, which has led to frequent smoke haze incidents from forest fires in nearby Sumatra, Indonesia. These forest fires have been attributed to the slash-and-burn method favored by some large plantation owners for land clearing. During haze episodes, PM2.5 is the dominant pollutant and has the most influence on the 24-hour PSI readings, making it a good indicator of current air quality.
The NEA's 24-hour PSI readings have been criticized for downplaying the severity of the haze during hazy episodes. For example, while the World Air Quality Index (AQI) reflected unhealthy levels, the NEA's 24-hour PSI showed only "moderate" air quality. Despite this, Singapore's PSI and NEA's PSI ranges have been shown to correlate with a number of health outcomes, including all-cause mortality. For instance, every increment of 30 units in PSI correlated with an 8.15% increased risk of out-of-hospital cardiac arrest on the same day of exposure, with the risk remaining elevated for 1-5 days post-exposure. Similar short-term associations were found for acute myocardial infarction and acute ischemic stroke in national registry analyses.
The PSI is based on a scale devised by the United States Environmental Protection Agency (EPA) and is used to report air quality in broadcasts and newspapers. However, since 1999, the US EPA has replaced PSI with the Air Quality Index (AQI) to incorporate new PM2.5 and ozone standards. Singapore continues to use PSI and publishes both the 24-hour PSI and 1-hour PM2.5 concentrations, providing valuable information for planning future activities and gauging immediate actions respectively.
Air Pollution and Upper Respiratory Infections: What's the Link?
You may want to see also
Frequently asked questions
The Pollutant Standards Index (PSI) is a type of air quality index used in Singapore to indicate the level of pollutants in the air.
The PSI considers six air pollutants: sulphur dioxide (SO2), particulate matter (PM10), fine particulate matter (PM2.5), nitrogen dioxide (NO2), carbon monoxide (CO), and ozone (O3).
A sub-index value is computed for each pollutant based on its ambient air concentration. The PSI value is then determined by the pollutant with the highest sub-index value, i.e., the pollutant with the most significant concentration.
The PSI is reported as a number on a scale of 0 to 500. The index figures enable people to determine whether the air pollution levels are good, unhealthy, hazardous, or worse.
The PSI has been replaced by the Air Quality Index (AQI) in the US since 1999. The AQI is calculated by converting measured pollutant concentrations to a uniform index based on health effects. The AQI was developed by the US Environmental Protection Agency (EPA) to provide a simple, uniform way to report daily air quality conditions.
