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

Malaysia Malaysia ( ; ) is a country in Southeast Asia. The federation, federal constitutional monarchy consists of States and federal territories of Malaysia, thirteen states and three federal territories, separated by the South China Sea into two r ...

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

mainland China "Mainland China" is a geopolitical term defined as the territory governed by the People's Republic of China (including islands like Hainan or Chongming), excluding dependent territories of the PRC, and other territories within Greater China. ...

and

Hong Kong Hong Kong ( (US) or (UK); , ), officially the Hong Kong Special Administrative Region of the People's Republic of China (abbr. Hong Kong SAR or HKSAR), is a city and special administrative region of China on the eastern Pearl River Delta i ...

. In mainland China the API was replaced by an updated air quality index 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 colorless, poisonous, odorless, tasteless, flammable gas that is slightly less dense than air. Carbon monoxide consists of one carbon atom and one oxygen atom connected by a triple bond. It is the simple ...

ozone Ozone (), or trioxygen, is an 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 , breaking down in the lo ...

nitrogen dioxide Nitrogen dioxide is a chemical compound with the formula . It is one of several nitrogen oxides. is an intermediate in the industrial synthesis of nitric acid, millions of tons of which are produced each year for use primarily in the productio ...

and sulfur dioxide) are reported in ppmv but PM_2.5 particulate matter 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 Environmental Protection Department (EPD) is a department of Hong Kong Government concerning the issues of environmental protection in Hong Kong.The EPD is responsible for developing policies covering environmental protection, nature conser ...

(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 with the symbol Pb (from the Latin ) and atomic number 82. It is a heavy metal that is denser than most common materials. Lead is soft and malleable, and also has a relatively low melting point. When freshly cu ...

(Pb), measured at all the monitoring stations throughout the territory.Pollution index based on index set 20 years ago, p5, South China Morning Post, 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 Eastern may refer to: Transportation *China Eastern Airlines, a current Chinese airline based in Shanghai *Eastern Air, former name of Zambia Skyways *Eastern Air Lines, a defunct American airline that operated from 1926 to 1991 *Eastern Air Li ...

Kwai Chung Kwai Chung is an urban area within Tsuen Wan New Town in the New Territories of Hong Kong. Together with Tsing Yi Island, it is part of the Kwai Tsing District District of Hong Kong. It is also part of Tsuen Wan New Town. In 2000, it had a popula ...

, Kwun Tong,

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 ...

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 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 Market") on the north of Lam Tsu ...

Tap Mun Grass Island or Tap Mun is an island in Hong Kong, located in the northeastern part of the territory. Its area is . Administratively, it is part of the Tai Po District. There are about 100 people living on the island, and feral cattle are know ...

Tsuen Wan Tsuen Wan (formerly also spelled Tsun Wan) is a town built on a bay in the western New Territories of Hong Kong, opposite of Tsing Yi Island across Rambler Channel. The market town of Tsuen Wan emerged from the surrounding villages and flee ...

Tung Chung Tung Chung, meaning " eastern stream", is an area on the northwestern coast of Lantau Island, Hong Kong. One of the most recent new towns, it was formerly a rural fishing village beside Tung Chung Bay, and along the delta and lower courses of ...

, 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 N ...

; the latter

Causeway Bay Causeway Bay is an area and a bay on Hong Kong Island, Hong Kong, straddling the border of the Eastern and the Wan Chai districts. It is a major shopping, leisure and cultural centre in Hong Kong, with a number of major shopping centres. Th ...

, Central, and

Mong Kok Mong Kok (also spelled Mongkok, often abbreviated as MK) is an area in Kowloon, Hong Kong. The Prince Edward subarea occupies the northern part of Mong Kok. Mong Kok is one of the major shopping areas in Hong Kong. The area is characterised ...

. 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/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, p5, South China Morning Post, 30 September 2007 The

World Health Organization The World Health Organization (WHO) is a specialized agency of the United Nations responsible for international public health. The WHO Constitution states its main objective as "the attainment by all peoples of the highest possible level of ...

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

External links