The Air Pollution Index (API; ) is a simple and generalized way to describe the air quality, which is used in

Malaysia Malaysia is a country in Southeast Asia. Featuring the Tanjung Piai, southernmost point of continental Eurasia, it is a federation, federal constitutional monarchy consisting of States and federal territories of Malaysia, 13 states and thre ...

. It is calculated from several sets of air pollution data and was formerly used in

mainland China "Mainland China", also referred to as "the Chinese mainland", is a Geopolitics, geopolitical term defined as the territory under direct administration of the People's Republic of China (PRC) in the aftermath of the Chinese Civil War. In addit ...

and

Hong Kong Hong Kong)., Legally Hong Kong, China in international treaties and organizations. is a special administrative region of China. With 7.5 million residents in a territory, Hong Kong is the fourth most densely populated region in the wor ...

. In mainland China the API was replaced by an updated

air quality index An air quality index (AQI) is an indicator developed by government agencies to communicate to the public how polluted the air currently is or how polluted it is forecast to become. As air pollution levels rise, so does the AQI, along with the a ...

in early 2012 and on 30 December 2013 Hong Kong moved to a health based index.

Malaysia

The air quality in Malaysia is reported as the API (Air Pollutant Index) or in Malay as IPU (Indeks Pencemaran Udara). Four of the index's pollutant components (i.e.,

carbon monoxide Carbon monoxide (chemical formula CO) is a poisonous, flammable gas that is colorless, odorless, tasteless, and slightly less dense than air. Carbon monoxide consists of one carbon atom and one oxygen atom connected by a triple bond. It is the si ...

ozone Ozone () (or trioxygen) is an Inorganic compound, inorganic molecule with the chemical formula . It is a pale blue gas with a distinctively pungent smell. It is an allotrope of oxygen that is much less stable than the diatomic allotrope , break ...

nitrogen dioxide Nitrogen dioxide is a chemical compound with the formula . One of several nitrogen oxides, nitrogen dioxide is a reddish-brown gas. It is a paramagnetic, bent molecule with C2v point group symmetry. Industrially, is an intermediate in the s ...

and

sulfur dioxide Sulfur dioxide (IUPAC-recommended spelling) or sulphur dioxide (traditional Commonwealth English) is the chemical compound with the formula . It is a colorless gas with a pungent smell that is responsible for the odor of burnt matches. It is r ...

) are reported in ppmv but PM_2.5

particulate matter Particulate matter (PM) or particulates are microscopic particles of solid or liquid matter suspended in the air. An ''aerosol'' is a mixture of particulates and air, as opposed to the particulate matter alone, though it is sometimes defin ...

is reported in μg/m³. This scale below shows the Health classifications used by the Malaysian government. If the API exceeds 500, a state of emergency is declared in the reporting area. Usually, this means that non-essential government services are suspended, and all ports in the affected area are closed. There may also be a prohibition on private sector commercial and industrial activities in the reporting area excluding the food sector.

Former indices

China

China's State Environment Protection Agency ( SEPA) is responsible for measuring the level of air pollution in China. As of 28 August 2008, SEPA monitored daily pollution level in 86 of its major cities. The AQI level was based on the level of five atmospheric pollutants, namely sulfur dioxide (SO₂), nitrogen dioxide (NO₂), suspended particulates (PM₁₀), carbon monoxide (CO), and ozone (O₃), measured at the monitoring stations throughout each city. AQI Mechanics
An individual score is assigned to the level of each pollutant and the final AQI is the highest of those five scores. The pollutants can be measured quite differently. SO₂, NO₂ and PM₁₀ concentration are measured as average per day. CO and O₃ are more harmful and are measured as average per hour. The final AQI value is calculated per day. The scale for each pollutant is non-linear, as is the final AQI score. Thus an AQI of 100 does not mean twice the pollution of AQI at 50, nor does it mean twice as harmful. While an AQI of 50 from day 1 to 182 and AQI of 100 from day 183 to 365 does provide an annual average of 75, it does ''not'' mean the pollution is acceptable even if the benchmark of 100 is deemed safe. This is because the benchmark is a 24-hour target. The annual average must match against the annual target. It is entirely possible to have safe air every day of the year but still fail the annual pollution benchmark. AQI and Health Implications (Daily Targets)

Hong Kong

The API was in use in Hong Kong from June 1995 to December 2013. It was measured and updated hourly by the Environmental Protection Department (EPD). Moreover, the EPD made forecasts of the API for the following day every day. The API was based on the level of six atmospheric pollutants, namely sulphur dioxide (SO₂), nitrogen dioxide (NO₂), respirable suspended particulates, carbon monoxide (CO), ozone (O₃), and

lead Lead () is a chemical element; it has Chemical symbol, symbol Pb (from Latin ) and atomic number 82. It is a Heavy metal (elements), heavy metal that is density, denser than most common materials. Lead is Mohs scale, soft and Ductility, malleabl ...

(Pb), measured at all the monitoring stations throughout the territory.Pollution index based on index set 20 years ago, p. 5, ''

South China Morning Post The ''South China Morning Post'' (''SCMP''), with its Sunday edition, the ''Sunday Morning Post'', is a Hong Kong-based English-language newspaper owned by Alibaba Group. Founded in 1903 by Tse Tsan-tai and Alfred Cunningham, it has remaine ...

'', 30 September 2007 It was replaced by the Air Quality Health Index on 30 December 2013. There are 11 General Stations and 3 Roadside Stations. The former includes Central / Western, Eastern, Kwai Chung,

Kwun Tong Kwun Tong is an area in the Kwun Tong District of Hong Kong, situated at the eastern part of the Kowloon Peninsula, and its boundary stretches from Lion Rock in the north to Lei Yue Mun in the south, and from the winding paths of Kowloon P ...

Sha Tin Sha Tin, also spelt Shatin, is a neighbourhood along Shing Mun River in the eastern New Territories, Hong Kong. Administratively, it is part of the Sha Tin District. Sha Tin is one of the neighbourhoods of the Sha Tin New Town project. The new ...

Sham Shui Po Sham Shui Po () is an area of Kowloon, Hong Kong, situated in the northwestern part of the Kowloon Peninsula, north of Tai Kok Tsui, east of Cheung Sha Wan and south of Shek Kip Mei (). It is located in and is the namesake of the Sham Shui ...

Tai Po Tai Po is an List of areas of Hong Kong, area in the New Territories of Hong Kong. It refers to the vicinity of the traditional market towns in the area presently known as Tai Po Old Market or Tai Po Kau Hui () (the original "Tai Po Mark ...

, Tap Mun,

Tsuen Wan Tsuen Wan (formerly also spelled Tsun Wan) is a New towns of Hong Kong, town built on a bay in the New Territories West (constituency), western New Territories of Hong Kong, opposite Tsing Yi, Tsing Yi Island across Rambler Channel. The market ...

, Tung Chung, and

Yuen Long Yuen Long is a town in the western New Territories, Hong Kong. To its west lie Hung Shui Kiu (), Tin Shui Wai, Lau Fau Shan and Ha Tsuen, to the south Shap Pat Heung and Tai Tong, to the east Au Tau and Kam Tin (), and to the north Nam Sang Wa ...

; the latter

Causeway Bay Causeway Bay is list of buildings, sites and areas in Hong Kong, an area and Victoria Park, Hong Kong, a bay on Hong Kong Island, Hong Kong, straddling the border of the Eastern District, Hong Kong, Eastern and the Wan Chai District, Wan Chai ...

, Central, and

Mong Kok Mong Kok (Chinese language, Chinese: 旺角), also spelled Mongkok, often abbreviated as MK, is an area in Kowloon, Hong Kong. The Prince Edward, Hong Kong, Prince Edward subarea occupies the northern part of Mong Kok. As one of the major sho ...

. In Hong Kong, there were two types of API: General API and Roadside API. The EPD reported the latest APIs hourly. The index and the air quality objectives were set in 1987; and pollutant levels are measured over varying periods, in

μg In the metric system, a microgram or microgramme is a Physical unit, unit of mass equal to one millionth () of a gram. The unit symbol is μg according to the International System of Units (SI); the recommended symbol in the United States and Uni ...

/m³. There are hourly, 24-hour and annual targets for sulfur dioxide and nitrogen dioxide, and 24-hour and annual targets for particulates. The table below shows the official Health Implications of the respective AQHI levels in Hong Kong. In 1998, the Education Bureau's recommended schools to curtail outdoor activities when the index reached 200, whereas leading healthcare advocates are urging that the level be revised to 100.Foul-air gauge for pupils too high, say critics, p. 5, ''South China Morning Post'', 30 September 2007 The

World Health Organization The World Health Organization (WHO) is a list of specialized agencies of the United Nations, specialized agency of the United Nations which coordinates responses to international public health issues and emergencies. It is headquartered in Gen ...

revised its air quality guideline levels of sulfur dioxide, nitrogen dioxide and ozone in 2006 in light of new scientific evidence. The WHO also introduced new measurement guidelines for very small particulates which are more dangerous to pulmonary function. At the '200' level, Hong Kong levels of SO₂ (800μg/m³) and NO₂ (1,130μg/m³) are 40 times and 5½ times WHO guidelines respectively; the equivalent for particulates (350μg/m³) is 7 times WHO guidelines.

References

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External links