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122-490: Different countries have their own air quality indices , corresponding to different national air quality standards. Some of these are Canada's Air Quality Health Index , Malaysia's Air Pollution Index , and Singapore's Pollutant Standards Index . Computation of the AQI requires an air pollutant concentration over a specified averaging period, obtained from an air monitor or model . Taken together, concentration and time represent

244-458: A proposed extradition amendment bill permitting the extradition of fugitives to mainland China. The protests are the largest in Hong Kong's history, with organisers claiming to have attracted more than three million Hong Kong residents. The Hong Kong regional government and Chinese central government responded to the protests with a number of administrative measures to quell dissent. In June 2020,

366-402: A 2021 thematic report by the Hong Kong government, after excluding foreign domestic helpers, the real number of non-Chinese ethnic minorities in the city was 301,344, or 4% of Hong Kong's population. About half the population have some form of British nationality , a legacy of colonial rule; 3.4 million residents have British National (Overseas) status, and 260,000 British citizens live in

488-432: A behavioral change to reduce the environmental footprint. This index pays particular attention to people who are sensitive to air pollution. It provides them with advice on how to protect their health during air quality levels associated with low , moderate , high and very high health risks. The AQHI provides a number from 1 to 10+ to indicate the level of health risk associated with local air quality. On occasion, when

610-520: A diverse ecosystem; over 3,000 species of vascular plants occur in the region (300 of which are native to Hong Kong), and thousands of insect, avian, and marine species. Hong Kong has a humid subtropical climate ( Köppen Cwa ), characteristic of southern China, despite being located south of the Tropic of Cancer , although closely bordering on a tropical climate . Summers are long, hot and humid, with occasional showers and thunderstorms and warm air from

732-840: A four-year term. Twenty are directly elected from geographical constituencies , thirty-five represent functional constituencies (FC), and forty are chosen by an election committee consisting of representatives appointed by the Chinese central government. Thirty FC councillors are selected from limited electorates representing sectors of the economy or special interest groups, and the remaining five members are nominated from sitting district council members and selected in region-wide double direct elections . All popularly elected members are chosen by proportional representation . The 30 limited electorate functional constituencies fill their seats using first-past-the-post or instant-runoff voting. Twenty-two political parties had representatives elected to

854-501: A higher risk because of the weakening of the heart, lungs and immune system and increased likelihood of health problems such as heart and lung disease. Exposure to air pollutants can cause a range of symptoms. People with lung or heart disease may experience increased frequency and/or severity of symptoms, and increased medication requirements. It is recommended that those susceptive should take greater precautions. Environment Canada recommends looking for outdoor air quality by checking

976-411: A local air quality current value as well as a local air quality maximums forecast for today, tonight and tomorrow and provides associated health advice. As it is now known that even low levels of air pollution can trigger discomfort for the sensitive population, the index has been developed as a continuum: The higher the number, the greater the health risk and need to take precautions. The index describes

1098-486: A neutral zone to safeguard its status as a free port. The colonial government prepared for a possible attack, evacuating all British women and children in 1940. The Imperial Japanese Army attacked Hong Kong on 8 December 1941 , the same morning as its attack on Pearl Harbor . Hong Kong was occupied by Japan for almost four years before the British resumed control on 30 August 1945. Its population rebounded quickly after

1220-583: A period of very poor air quality, such as an air pollution episode , when the AQI indicates that acute exposure may cause significant harm to the public health, agencies may invoke emergency plans that allow them to order major emitters (such as coal burning industries) to curtail emissions until the hazardous conditions abate. Most air contaminants do not have an associated AQI. Many countries monitor ground-level ozone , particulates , sulfur dioxide , carbon monoxide and nitrogen dioxide , and calculate air quality indices for these pollutants. The definition of

1342-492: A pilot project in the British Columbia Interior in 2005 followed by Nova Scotia in 2006 and Toronto in 2007, as of 2016 it was implemented in 122 locations across Canada. The Air Quality Health Index provides a number from 1 to 10+ to indicate the level of health risk associated with local air quality. Occasionally, when the amount of air pollution is abnormally high, the number may exceed 10. The AQHI provides

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1464-409: A second language. Slightly over half the population (58.7%) speaks English , the other official language; 4.6% are native speakers, and 54.1% speak English as a second language. Code-switching , mixing English and Cantonese in informal conversation, is common among the bilingual population. Post-handover governments have promoted Mandarin , which is currently about as prevalent as English; 54.2% of

1586-516: A series of protests in 2014 which became known as the Umbrella Revolution. Discrepancies in the electoral registry and disqualification of elected legislators after the 2016 Legislative Council elections and enforcement of national law in the West Kowloon high-speed railway station raised further concerns about the region's autonomy. In June 2019, mass protests erupted in response to

1708-432: A severe amount of income inequality, which has risen since the handover, as the region's ageing population has gradually added to the number of nonworking people. Although median household income steadily increased during the decade to 2021, the wage gap remained high; the 90th percentile of earners receive 41% of all income. The city has the most billionaires per capita, with one billionaire per 109,657 people, as well as

1830-498: A small inlet located between Aberdeen Island and the southern coast of Hong Kong Island. Aberdeen was an initial point of contact between British sailors and local fishermen. Although the source of the romanised name is unknown, it is generally believed to be an early phonetic rendering of the Cantonese (or Tanka Cantonese ) phrase hēung góng . The name translates as "fragrant harbour" or "incense harbour". "Fragrant" may refer to

1952-431: Is a special administrative region of China , with executive, legislative, and judicial powers devolved from the national government . The Sino-British Joint Declaration provided for economic and administrative continuity through the handover, resulting in an executive-led governing system largely inherited from the territory's history as a British colony. Under these terms and the "one country, two systems" principle,

2074-466: Is a number on a scale from 0 to 100, where a low value means good air quality and a high value means extremely poor air quality. The index is defined in both hourly and daily versions, and separately near roads (a "roadside" or "traffic" index) or away from roads (a "background" index). As of 2012, the CAQI had two mandatory components for the roadside index, NO 2 and PM 10 , and three mandatory components for

2196-696: Is adjusted periodically to reflect these changes. The air quality index is a piecewise linear function of the pollutant concentration. At the boundary between AQI categories, there is a discontinuous jump of one AQI unit. To convert from concentration to AQI this equation is used: I = I h i g h − I l o w C h i g h − C l o w ( C − C l o w ) + I l o w {\displaystyle I={\frac {I_{high}-I_{low}}{C_{high}-C_{low}}}(C-C_{low})+I_{low}} (If multiple pollutants are measured,

2318-626: Is aimed towards two populations: 1. The "general" population; and 2. The "at-risk" populations. The latter consists of children, the elderly and people with existing respiratory or cardiovascular conditions, such as those with asthma , and people suffering from diabetes , heart disease or lung disease . Children are more vulnerable to air pollution: they have less-developed respiratory and defense systems. Because of their size, they inhale more air per kilogram of body weight than adults. Their elevated metabolic rate and young defense systems make them more susceptible to air pollution. Seniors are also at

2440-402: Is also defined, in which different pollutant sub-indices are separately normalised to a value typically near unity. For example, the yearly averages of NO 2 , PM 10 and PM 2.5 are divided by 40 μg/m, 40 μg/m and 20 μg/m, respectively. The overall background or traffic YACAQI for a city is the arithmetic mean of a defined subset of these sub-indices. The National Air Quality Index (NAQI)

2562-462: Is an upwind forest fire or from a lack of dilution of air pollutants. Stagnant air , often caused by an anticyclone , temperature inversion , or low wind speeds lets air pollution remain in a local area, leading to high concentrations of pollutants, chemical reactions between air contaminants and hazy conditions. On a day when the AQI is predicted to be elevated due to fine particle pollution, an agency or public health organization might: During

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2684-457: Is based on a three-hour average. In order to meet these needs, the individual pollutant concentrations are compared to Alberta's Ambient Air Quality Objectives (AAQOs). The national AQHI is used most of the time; however, if hourly air pollutant concentrations are higher than Alberta's AAQOs, the AQHI value is replaced (overridden) with the appropriate "High" or "Very High" risk value. This can occur for

2806-408: Is based on three-hour average concentrations of ground-level ozone (O 3 ), nitrogen dioxide (NO 2 ), and fine particulate matter (PM2.5). O 3 and NO 2 are measured in parts per billion (ppb) while PM2.5 is measured in micrograms per cubic metre (μg/m ). The AQHI is calculated on a community basis (each community may have one or more monitoring stations). First, the average concentration of

2928-477: Is best to exercise or work outdoor. The best way for someone to use the AQHI is to regularly check the current index value, to pay attention to personal symptoms and self-calibrate to the reported current AQHI value. For example, if symptoms are experienced when the index is a 6, then precaution should be taken when the index is at a 6 or higher by following the corresponding health messages. Then, when an individual knows what number triggers health symptoms, to get in

3050-416: Is better. Sensitive groups: Remain indoors and keep activity levels low. Follow tips for keeping particle levels low indoors. The United States Environmental Protection Agency (EPA) has developed an Air Quality Index that is used to report air quality. This AQI is divided into six categories indicating increasing levels of health concern. The AQI is based on the five "criteria" pollutants regulated under

3172-410: Is governed by a hybrid regime that is not fully representative of the population. Legislative Council members elected by functional constituencies composed of professional and special interest groups are accountable to these narrow corporate electorates and not the general public. This electoral arrangement has guaranteed a pro-Beijing camp majority in the legislature since the handover. Similarly,

3294-501: Is measured on a scale of 1 to 10+ and considers four air pollutants: ozone; nitrogen dioxide; sulfur dioxide and particulate matter (including PM10 and PM2.5). For any given hour the AQHI is calculated from the sum of the percentage excess risk of daily hospital admissions attributable to the 3-hour moving average concentrations of these four pollutants. The AQHIs are grouped into five AQHI health risk categories with health advice provided: China's Ministry of Environmental Protection ( MEP )

3416-552: Is responsible for measuring the level of air pollution in China . As of January 1, 2013, MEP monitors daily pollution level in 163 of its major cities. The AQI level is based on the level of six atmospheric pollutants, namely sulfur dioxide (SO 2 ), nitrogen dioxide (NO 2 ), suspended particulates smaller than 10 μm in aerodynamic diameter (PM 10 ), suspended particulates smaller than 2.5 μm in aerodynamic diameter (PM 2.5 ), carbon monoxide (CO), and ozone (O 3 ) measured at

3538-430: Is the final AQI score. Thus an AQI of 300 does not mean twice the pollution of AQI at 150, nor does it mean the air is twice as harmful. The concentration of a pollutant when its IAQI is 100 does not equal twice its concentration when its IAQI is 50, nor does it mean the pollutant is 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

3660-466: Is then rounded to the nearest whole number. Alberta has modified AQHI reporting to better suit the needs of the Province. Because of Alberta's energy based economy other pollutants are also considered when reporting the AQHI. Alberta also has rapidly changing air quality conditions quite often (for example during wildfire season) so, Alberta's AQHI needs to be more responsive than the national AQHI, which

3782-537: The Basic Law of Hong Kong for 50 years after the handover. It does not specify how Hong Kong will be governed after 2047, and the central government's role in determining the territory's future system of government is the subject of political debate and speculation. Hong Kong's political and judicial systems may be integrated with China's at that time, or the territory may continue to be administered separately. However, in response to large-scale protests in 2019 and 2020 ,

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3904-578: The Basic Law of Hong Kong is the regional constitution. The regional government is composed of three branches: The chief executive is the head of government and serves for a maximum of two five-year terms. The State Council (led by the Premier of China ) appoints the chief executive after nomination by the Election Committee , which is composed of 1500 business, community, and government leaders. The Legislative Council has 90 members, each serving

4026-592: The Chinese People's Political Consultative Conference appointed by the central government. Chinese national law does not generally apply in the region, and Hong Kong is treated as a separate jurisdiction. Its judicial system is based on common law , continuing the legal tradition established during British rule. Local courts may refer to precedents set in English law and overseas jurisprudence. However, mainland criminal procedure law applies to cases investigated by

4148-553: The Chinese central government 's adherence to the "one country, two systems" principle. After reversal of the last colonial era Legislative Council democratic reforms following the handover, the regional government unsuccessfully attempted to enact national security legislation pursuant to Article 23 of the Basic Law . The central government decision to implement nominee pre-screening before allowing chief executive elections triggered

4270-681: The Clean Air Act : ground-level ozone, particulate matter, carbon monoxide, sulfur dioxide, and nitrogen dioxide. The EPA has established National Ambient Air Quality Standards (NAAQS) for each of these pollutants in order to protect public health. An AQI value of 100 generally corresponds to the level of the NAAQS for the pollutant. The Clean Air Act (USA) (1990) requires the EPA to review its National Ambient Air Quality Standards every five years to reflect evolving health effects information. The Air Quality Index

4392-642: The Committee on the Medical Effects of Air Pollutants (COMEAP). This index has ten points, which are further grouped into four bands: low, moderate, high and very high. Each of the bands comes with advice for at-risk groups and the general population. The index is based on the concentrations of five pollutants. The index is calculated from the concentrations of the following pollutants: ozone, nitrogen dioxide, sulfur ioxide, PM2.5 and PM10. The breakpoints between index values are defined for each pollutant separately and

4514-513: The European Air Quality Index (EAQI) and started encouraging its use on websites and for other ways of informing the public about air quality. As of 2012, the EU -supported project CiteairII argued that the CAQI had been evaluated on a "large set" of data, and described the CAQI's motivation and definition. CiteairII stated that having an air quality index that would be easy to present to

4636-643: The Former Marine Police Headquarters was redeveloped into a commercial and retail complex, and Béthanie (built in 1875 as a sanatorium ) houses the Hong Kong Academy for Performing Arts . The Tin Hau Temple , dedicated to the sea goddess Mazu (originally built in 1012 and rebuilt in 1266), is the territory's oldest existing structure. The Ping Shan Heritage Trail has architectural examples of several imperial Chinese dynasties, including

4758-461: The Hong Kong dollar , is the ninth most traded currency in the world. Home to the seventh-highest number of billionaires of any city in the world, Hong Kong has the largest number of ultra high-net-worth individuals . Although the city has one of the highest per capita incomes in the world, severe income inequality exists among the population. Despite being the city with the most skyscrapers in

4880-780: The Middle Neolithic period, about 6,000 years ago, the region had been widely occupied by humans. Neolithic to Bronze Age Hong Kong settlers were semi-coastal people. Early inhabitants are believed to be Austronesians in the Middle Neolithic period and later the Yue people. As hinted by the archaeological works in Sha Ha, Sai Kung, rice cultivation had been introduced since Late Neolithic period. Bronze Age Hong Kong featured coarse pottery, hard pottery, quartz and stone jewelry, as well as small bronze implements. The Qin dynasty incorporated

5002-708: The Office for Safeguarding National Security of the CPG in the HKSAR . Interpretative and amending power over the Basic Law and jurisdiction over acts of state lie with the central authority, making regional courts ultimately subordinate to the mainland's socialist civil law system. Decisions made by the Standing Committee of the National People's Congress override any territorial judicial process. Furthermore, in circumstances where

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5124-697: The People's Liberation Army is responsible for the region's defence. Although the Chairman of the Central Military Commission is supreme commander of the armed forces, the regional government may request assistance from the garrison. Hong Kong residents are not required to perform military service, and current law has no provision for local enlistment, so its defence is composed entirely of non-Hongkongers. The central government and Ministry of Foreign Affairs handle diplomatic matters, but Hong Kong retains

5246-670: The Pollutant Standards Index to report on its air quality, with details of the calculation similar but not identical to those used in Malaysia and Hong Kong. The PSI chart below is grouped by index values and descriptors, according to the National Environment Agency . The Ministry of Environment of South Korea uses the Comprehensive Air-quality Index (CAI) to describe the ambient air quality based on

5368-570: The Safeguarding National Security Ordinance was passed by the Legislative Council to grant officials "even more powers to crack down on opposition to Beijing and the Hong Kong government" and includes penalties such as life imprisonment for political crimes such as treason and insurrection . Critics state that this expansion "will strike a lasting blow to the partial autonomy the city had been promised by China [in

5490-701: The Shanghai Street shophouses in Mong Kok . Mass-produced public-housing estates , built since the 1960s, are mainly constructed in modernist style . The Census and Statistics Department estimated Hong Kong's population at 7,413,070 in 2021. The overwhelming majority (91.6%) is Han Chinese , most of whom are Taishanese , Teochew , Hakka , and other Cantonese peoples . The remaining 8.4% are non-ethnic Chinese minorities, primarily Filipinos , Indonesians , and South Asians . However, most Filipinos and Indonesians in Hong Kong are short-term workers. According to

5612-547: The Sino-British Joint Declaration ]." Hong Kong's administrative divisions are divided into three levels: Areas (區域), Districts (地區), and Sub-districts (分區). Hong Kong is administratively divided into three areas: Hong Kong Island , Kowloon , and the New Territories . They are further divided into 18 districts. The area of Hong Kong Island has four districts, the area of Kowloon has five districts, and

5734-453: The Standing Committee of the National People's Congress passed the controversial Hong Kong national security law . The law criminalises secession, subversion, terrorism and collusion with foreign elements and establishes the Office for Safeguarding National Security of the CPG in the HKSAR, an investigative office under Central People's Government authority immune from HKSAR jurisdiction. Some of

5856-595: The Tsui Sing Lau Pagoda (Hong Kong's only remaining pagoda). Tong lau , mixed-use tenement buildings constructed during the colonial era, blended southern Chinese architectural styles with European influences. These were especially prolific during the immediate post-war period, when many were rapidly built to house large numbers of Chinese migrants. Examples include Lui Seng Chun , the Blue House in Wan Chai , and

5978-657: The central government in Beijing in June 2020 resulted in the suspension of bilateral extradition treaties by the United Kingdom, Canada, Australia, New Zealand, Finland, and Ireland. The United States ended its preferential economic and trade treatment of Hong Kong in July 2020 because it was no longer able to distinguish Hong Kong as a separate entity from the People's Republic of China. In 2024,

6100-518: The dose of the air pollutant. Health effects corresponding to a given dose are established by epidemiological research. Air pollutants vary in potency, and the function used to convert from air pollutant concentration to AQI varies by pollutant. Its air quality index values are typically grouped into ranges. Each range is assigned a descriptor, a color code, and a standardized public health advisory. The AQI can increase due to an increase of air emissions. For example, during rush hour traffic or when there

6222-573: The environmental footprint . This index pays particular attention to people who are sensitive to air pollution. It provides them with advice on how to protect their health during air quality levels associated with low, moderate, high and very high health risks. Air quality in Canada has historically been reported by the US Air Quality Index in various provinces. Significantly, AQI values reflect air quality management objectives, which are based on

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6344-708: The tallest buildings in Hong Kong and are among the tallest in the Asia-Pacific region. Other distinctive buildings lining the Hong Kong Island skyline include the HSBC Main Building , the anemometer -topped triangular Central Plaza , the circular Hopewell Centre , and the sharp-edged Bank of China Tower . Demand for new construction has contributed to frequent demolition of older buildings, freeing space for modern high-rises. However, many examples of European and Lingnan architecture are still found throughout

6466-622: The 1279 Battle of Yamen by the Yuan Dynasty. By the end of the Yuan dynasty , seven large families had settled in the region and owned most of the land. Settlers from nearby provinces migrated to Kowloon throughout the Ming dynasty . The earliest European visitor was Portuguese explorer Jorge Álvares , who arrived in 1513. Portuguese merchants established a trading post called Tamão in Hong Kong waters and began regular trade with southern China. Although

6588-966: The 3 hour "community average" for each parameter is calculated from the 3 hour substance averages at the available stations. If no stations are available for a parameter, that parameter is set to "Not Available". This part of the process results in three community parameter averages. Third, if all three community parameter averages are available, a community AQHI is calculated. The formula is: A Q H I = ( 10 10.4 ) × 100 × [ ( e 0.000537 × O 3 − 1 ) + ( e 0.000871 × N O 2 − 1 ) + ( e 0.000487 × P M 2.5 − 1 ) ] {\displaystyle AQHI=({\frac {10}{10.4}})\times 100\times [(e^{0.000537\times O_{3}}-1)+(e^{0.000871\times NO_{2}}-1)+(e^{0.000487\times PM_{2.5}}-1)]} The result

6710-447: The AQHI before heading off to work or play as well as to use the forecasts to plan activities, whether over the next hour or the next day. Seniors, parents, those with asthma, and people suffering from diabetes, heart or lung disease, can use the AQHI to assess the immediate risk air pollution poses on their health and take steps to lessen that risk. The AQHI is also recommended for healthy, fit and active people to consult to decide when it

6832-437: The AQHI program would not be possible without the commitment and support of the provinces, municipalities and NGOs. From air quality monitoring to health risk communication and community engagement, local partners are responsible for the vast majority of work related to AQHI implementation. The AQHI has been rolled out across Canada and has replaced the AQI as the public face of air quality information. Originally launched as

6954-464: The AQHI, Health Canada's original analysis of health effects included five major air pollutants: airborne particulate matter, ozone, and nitrogen dioxide (NO 2 ), as well as sulphur dioxide (SO 2 ), and carbon monoxide (CO). The latter two pollutants provided little information in predicting health effects and were removed from the AQHI formulation. The AQHI does not measure the effects of odour, pollen , dust, heat or humidity. The national AQHI

7076-466: The AQI in a particular nation reflects the discourse surrounding the development of national air quality standards in that nation. A website allowing government agencies anywhere in the world to submit their real-time air monitoring data for display using a common definition of the air quality index has recently become available. Each of the states and territories of Australia is responsible for monitoring air quality and publishing data in accordance with

7198-633: The British Empire after the Qing dynasty ceded Hong Kong Island in 1841–1842 as a consequence of losing the First Opium War . The colony expanded to the Kowloon Peninsula in 1860 and was further extended when the United Kingdom obtained a 99-year lease of the New Territories in 1898. Hong Kong was occupied by Japan from 1941 to 1945 during World War II . The territory was handed over from

7320-753: The Hong Kong area into China for the first time in 214 BCE, after conquering the indigenous Baiyue . The region was consolidated under the Nanyue kingdom (a predecessor state of Vietnam ) after the Qin collapse and recaptured by China after the Han conquest . During the Mongol conquest of China in the 13th century, the Southern Song court was briefly located in modern-day Kowloon City (the Sung Wong Toi site) before its final defeat in

7442-581: The Hongkong and Shanghai Banking Corporation (HSBC). Earliest known human traces in what is now Hong Kong are dated by some to 35,000 and 39,000 years ago during the Paleolithic period. The claim is based on an archaeological investigation in Wong Tei Tung , Sai Kung in 2003. The archaeological works revealed knapped stone tools from deposits that were dated using optical luminescence dating . During

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7564-406: The Legislative Council and the requirement that all candidates be vetted and approved by a Beijing-appointed Candidate Eligibility Review Committee . In May 2023, the Legislative Council also introduced legislation to reduce the number of directly elected seats in the district councils, and a District Council Eligibility Review Committee was similarly established to vet candidates. Hong Kong

7686-541: The Legislative Council in the 2016 election . These parties have aligned themselves into three ideological groups: the pro-Beijing camp (the current government), the pro-democracy camp , and localist groups . The Chinese Communist Party does not have an official political presence in Hong Kong, and its members do not run in local elections. Hong Kong is represented in the National People's Congress by 36 deputies chosen through an electoral college and 203 delegates in

7808-547: The Legislative Council passed the National Anthem Ordinance , which criminalised "insults to the national anthem of China". The Chinese central government meanwhile enacted the Hong Kong national security law to help quell protests in the region. Nine months later, in March 2021, the Chinese central government introduced amendments to Hong Kong's electoral system , which included the reduction of directly elected seats in

7930-687: The NEPM. These maximum concentration standards are: The air quality index (AQI) for an individual location is simply the highest of the air quality index values for each pollutant being monitored at that location. There are six AQI bands, with health advice for each: Everyone: Cut back or reschedule strenuous outdoor activities Everyone: Significantly cut back on outdoor physical activities Air quality in Canada has been reported for many years with provincial air quality indices (AQIs). Significantly, AQI values reflect air quality management objectives, which are based on

8052-529: The National Environment Protection (Ambient Air Quality) Measure (NEPM) standards. Each state and territory publishes air quality data for individual monitoring locations, and most states and territories publish air quality indexes for each monitoring location. Across Australia, a consistent approach is taken with air quality indexes, using a simple linear scale where 100 represents the maximum concentration standard for each pollutant, as set by

8174-496: The New Territories. Much of this is built on reclaimed land ; 70 km (27 sq mi) (6% of the total land or about 25% of developed space in the territory) is reclaimed from the sea. Undeveloped terrain is hilly to mountainous, with very little flat land, and consists mostly of grassland, woodland, shrubland, or farmland. About 40% of the remaining land area is country parks and nature reserves. The territory has

8296-472: The Philippines and Indonesia, have little protection under regional law. Although they live and work in Hong Kong, these workers are not treated as ordinary residents and do not have the right of abode in the territory. Sex trafficking is also an issue, local, mainland Chinese, and foreign women have been trafficked for sex in brothels , homes, and businesses in the city. The Joint Declaration guarantees

8418-523: The Standing Committee declares a state of emergency in Hong Kong, the State Council may enforce national law in the region. The territory's jurisdictional independence is most apparent in its immigration and taxation policies. The Immigration Department issues passports for permanent residents which differ from those of the mainland or Macau, and the region maintains a regulated border with

8540-522: The United Kingdom to China in 1997. Hong Kong maintains separate governing and economic systems from that of mainland China under the principle of one country, two systems . Originally a sparsely populated area of farming and fishing villages, the territory is now one of the world's most significant financial centres and commercial ports. Hong Kong is the world's third-ranked global financial centre (behind New York City and London ), ninth-largest exporter, and eighth-largest importer. Its currency,

8662-704: The ability to maintain separate economic and cultural relations with foreign nations . The territory actively participates in the World Trade Organization , the Asia-Pacific Economic Cooperation forum, the International Olympic Committee , and many United Nations agencies. The regional government maintains trade offices in Greater China and other nations. The imposition of the Hong Kong national security law by

8784-567: The aforementioned acts were previously considered protected speech under Hong Kong law. The United Kingdom considers the law to be a serious violation of the Joint Declaration. In October 2020, the Hong Kong Police arrested seven pro- democracy politicians over tussles with pro-Beijing politicians in the Legislative Council in May. They were charged with contempt and interfering with members of

8906-620: The agreement. After more than a year of further hostilities, Hong Kong Island was formally ceded to the United Kingdom in the 1842 Treaty of Nanking . Administrative infrastructure was quickly built by early 1842, but piracy, disease, and hostile Qing policies initially prevented the government from attracting commerce. Conditions on the island improved during the Taiping Rebellion in the 1850s, when many Chinese refugees, including wealthy merchants, fled mainland turbulence and settled in

9028-645: The amount of air pollution is abnormally high, the number may exceed 10. The AQHI provides a local air quality current value as well as a local air quality maximums forecast for today, tonight, and tomorrow, and provides associated health advice. On December 30, 2013, Hong Kong replaced the Air Pollution Index with a new index called the Air Quality Health Index . This index, reported by the Environmental Protection Department ,

9150-399: The area of the New Territories has nine districts. Each district is represented by a district council . The district councils advise the government on local issues such as public facility provisioning, community programme maintenance, cultural promotion, and environmental policy. As of 2024, there are a total of 470 district council seats, 88 of which are directly elected. In May 2023,

9272-636: The background index, NO 2 , PM 10 and O 3 . It also included optional pollutants PM 2.5 , CO and SO 2 . A "sub-index" is calculated for each of the mandatory (and optional if available) components. The CAQI is defined as the sub-index that represents the worst quality among those components. Some of the key pollutant concentrations in μg/m for the hourly background index, the corresponding sub-indices, and five CAQI ranges and verbal descriptions are as follows. Frequently updated CAQI values and maps are shown on www.airqualitynow.eu and other websites. A separate Year Average Common Air Quality Index (YACAQI)

9394-632: The calculated AQI is the highest value calculated from the above equation applied for each pollutant.) where: The EPA's table of breakpoints is: 8-hr 1-hr Air Quality Health Index (Canada) The Air Quality Health Index ( AQHI ) is a scale designed in Canada to help understand the impact of air quality on health. It is a health protection tool used to make decisions to reduce short-term exposure to air pollution by adjusting activity levels during increased levels of air pollution. The Air Quality Health Index also provides advice on how to improve air quality by proposing behavioral change to reduce

9516-634: The categories as shown below. The N Seoul Tower on Namsan Mountain in central Seoul, South Korea , is illuminated in blue, from sunset to 23:00 and 22:00 in winter, on days where the air quality in Seoul is 45 or less. During the spring of 2012, the Tower was lit up for 52 days, which is four days more than in 2011. The most commonly used air quality index in the UK is the Daily Air Quality Index recommended by

9638-1152: The chief executive is selected by establishment politicians and corporate members of the Election Committee rather than directly elected. Despite universal suffrage being established as ultimate goals for the election of the chief executive and all members of the Legislative Council in Articles 45 and 68 of the basic law, the legislature is only partially directly elected, and the executive continues to be nominated by an unrepresentative body. The government has been repeatedly petitioned to introduce direct elections for these positions, but has not introduced these direct elections as of 2024. Ethnic minorities (except those of European ancestry) have marginal representation in government and often experience discrimination in housing, education, and employment. Employment vacancies and public service appointments frequently have language requirements which minority job seekers do not meet, and language education resources remain inadequate for Chinese learners. Foreign domestic helpers , mostly women from

9760-621: The colony. Further tensions between the British and Qing over the opium trade escalated into the Second Opium War . The Qing were again defeated and forced to give up Kowloon Peninsula and Stonecutters Island in the Convention of Peking . By the end of this war, Hong Kong had evolved from a transient colonial outpost into a major entrepôt . Rapid economic improvement during the 1850s attracted foreign investment, as potential stakeholders became more confident in Hong Kong's future. The colony

9882-433: The colour of soil over which a waterfall on the island flowed. The simplified name Hong Kong was frequently used by 1810. The name was also commonly written as the single word Hongkong until 1926, when the government officially adopted the two-word name. Some corporations founded during the early colonial era still keep this name, including Hongkong Land , Hongkong Electric Company , Hongkong and Shanghai Hotels and

10004-575: The council, while none of the pro-Beijing lawmakers were detained. Annual commemorations of the 1989 Tiananmen Square protests and massacre were also cancelled amidst fears of violating the national security law. In March 2021, the Chinese central government unilaterally changed Hong Kong's electoral system and established the Candidate Eligibility Review Committee , which would be tasked with screening and evaluating political candidates for their "patriotism", effectively crushing

10126-1006: The country having more than 342 monitoring stations. An Expert Group comprising medical professionals, air quality experts, academia, advocacy groups, and SPCBs was constituted and a technical study was awarded to IIT Kanpur . IIT Kanpur and the Expert Group recommended an AQI scheme in 2014. While the earlier measuring index was limited to three indicators, the new index measures eight parameters. The continuous monitoring systems that provide data on near real-time basis are installed in New Delhi, Mumbai , Pune , Kolkata and Ahmedabad . There are six NAQI categories, namely Good , Satisfactory , Moderate , Poor , Very Poor and Severe . The proposed NAQI will consider eight pollutants PM 10 , PM 2.5 , NO 2 , SO 2 , CO, O 3 , NH 3 , and Pb) for which short-term (up to 24-hourly averaging period) National Ambient Air Quality Standards are prescribed. Based on

10248-404: The end of the New Territories lease approached, and Governor Murray MacLehose raised the question of Hong Kong's status with Deng Xiaoping in 1979. Diplomatic negotiations with China resulted in the 1984 Sino-British Joint Declaration , in which the United Kingdom agreed to the handover of the colony in 1997 and China would guarantee Hong Kong's economic and political systems for 50 years after

10370-567: The following pollutants (when they exceed the noted concentrations): In Alberta, special community messaging is used when the level of specific pollutants is higher than specified odour or visibility thresholds but the AQHI is rated as "Low" or "Moderate" risk. This messaging is used for the following pollutants (when they exceed the noted concentrations): An example of this special odour/visibility messaging can be: "While you may detect an odour or change in visibility or clarity, enjoy your outdoor activities unless you experience symptoms." The AQHI

10492-633: The general public was a major motivation, leaving aside the more complex question of a health-based index, which would require, for example, effects of combined levels of different pollutants. The main aim of the CAQI was to have an index that would encourage wide comparison across the EU, without replacing local indices. CiteairII stated that the "main goal of the CAQI is not to warn people for possible adverse health effects of poor air quality but to attract their attention to urban air pollution and its main source (traffic) and help them decrease their exposure." The CAQI

10614-547: The government proposed reforms to the District Council electoral system which further cut the number of directly elected seats from 452 to 88, and total seats from 479 to 470. A requirement that district council candidates be vetted and approved by the District Council Eligibility Review Committee was also proposed. The Legislative Council approved the reforms in July 2023. Hong Kong

10736-400: The habit of checking the maximum forecast to plan activities ahead of time. Twitter Hong Kong Hong Kong is a special administrative region of China . With 7.4 million residents of various nationalities in a 1,104-square-kilometre (426 sq mi) territory, Hong Kong is the fourth most densely populated region in the world. Hong Kong was established as a colony of

10858-418: The handover. The impending handover triggered a wave of mass emigration as residents feared an erosion of civil rights, the rule of law, and quality of life. Over half a million people left the territory during the peak migration period, from 1987 to 1996. The Legislative Council became a fully elected legislature for the first time in 1995 and extensively expanded its functions and organisations throughout

10980-462: The health risks of air pollution. The index aims to help the public easily understand the air quality and protect people's health. The CAI is on a scale from 0 to 500, which is divided into six categories. The higher the CAI value, the greater the level of air pollution. Of values of the five air pollutants, the highest is the CAI value. The index also has associated health effects and a colour representation of

11102-612: The identified eight pollutants are as follows: According to Japan Weather Association , Japan uses a different scale to measure the air quality index. The air quality in Mexico City is reported in IMECAs. The IMECA is calculated using the measurements of average times of the chemicals ozone (O 3 ), sulfur dioxide (SO 2 ), nitrogen dioxide (NO 2 ), carbon monoxide (CO), particles smaller than 2.5 micrometers (PM 2.5 ), and particles smaller than 10 micrometers (PM 10 ). Singapore uses

11224-401: The last years of the colonial rule. The handover of Hong Kong to China was at midnight on 1 July 1997, after 156 years of British rule. Immediately after the handover, Hong Kong was severely affected by several crises. The Hong Kong government was forced to use substantial foreign exchange reserves to maintain the Hong Kong dollar's currency peg during the 1997 Asian financial crisis , and

11346-574: The level of health risk associated with this number as 'low', 'moderate', 'high' or 'very high', and suggests steps that can be taken to reduce exposure. The formulation of the national AQHI is based on the observed relationship of nitrogen dioxide (NO 2 ), ground-level ozone (O 3 ) and fine particulate matter (PM 2.5 ) with mortality from an analysis of several Canadian cities. Significantly, all three of these pollutants can pose health risks, even at low levels of exposure, especially among those with pre-existing health problems. When developing

11468-429: The lowest achievable emissions rate, and not exclusively concern for human health. The AQHI was created with a different goal - to report on the specific health risks posed by air pollution. As such, the AQHI represents a paradigm shift in communicating air quality information to the public. The Air Quality Health Index (AQHI) is a federal program jointly coordinated by Health Canada and Environment Canada . However,

11590-464: The lowest achievable emissions rate, rather than exclusive concern for human health. The Air Quality Health Index (AQHI) is a scale designed to help understand the impact of air quality on health. It is a health protection tool used to make decisions to reduce short-term exposure to air pollution by adjusting activity levels during increased levels of air pollution. The Air Quality Health Index also provides advice on how to improve air quality by proposing

11712-528: The maritime area is included) consists of Hong Kong Island , the Kowloon Peninsula , the New Territories , Lantau Island , and over 200 other islands. Of the total area, 1,073 km (414 sq mi) is land and 35 km (14 sq mi) is water. The territory's highest point is Tai Mo Shan , 957 metres (3,140 ft) above sea level. Urban development is concentrated on the Kowloon Peninsula, Hong Kong Island, and in new towns throughout

11834-463: The measured ambient concentrations, corresponding standards and likely health impact, a sub-index is calculated for each of these pollutants. The worst sub-index reflects overall NAQI. Likely health impacts for different NAQI categories and pollutants have also been suggested, with primary inputs from the medical experts in the group. The NAQI values and corresponding ambient concentrations (health breakpoints) as well as associated likely health impacts for

11956-463: The monitoring stations throughout each city. An individual score (Individual Air Quality Index, IAQI) is calculated using breakpoint concentrations below, and using same piecewise linear function to calculate intermediate values as the US AQI scale. and The final AQI value can be calculated either per hour or per 24 hours and is the max of these six scores. The score for each pollutant is non-linear, as

12078-726: The north and occasionally result in chilly weather. Autumn is the sunniest season, whilst spring is generally cloudy. Snowfall has been extremely rare in Hong Kong; the last reported instance was on Tai Mo Shan in 1975. Hong Kong averages 1,709 hours of sunshine per year. Historic temperature extremes at the Hong Kong Observatory are 36.6 °C (97.9 °F) on 22 August 2017 and 0.0 °C (32.0 °F) on 18 January 1893. The highest and lowest recorded temperatures in all of Hong Kong are 39.0 °C (102 °F) at Wetland Park on 22 August 2017, and −6.0 °C (21.2 °F) at Tai Mo Shan on 24 January 2016 . Hong Kong has

12200-426: The opium trade. The commissioner destroyed opium stockpiles and halted all foreign trade, triggering a British military response and the First Opium War . The Qing surrendered early in the war and ceded Hong Kong Island in the Convention of Chuenpi . British forces began controlling Hong Kong shortly after the signing of the convention, from 26 January 1841. However, both countries were dissatisfied and did not ratify

12322-412: The overall index is defined as the maximum value of the index. Different averaging periods are used for different pollutants. Everyone else: It's a good day to be active outside. Everyone else: Reduce prolonged or heavy exertion. Take more breaks during all outdoor activities. Everyone else: Avoid prolonged or heavy exertion. Consider moving activities indoors or rescheduling to a time when air quality

12444-550: The pollution is acceptable even if the benchmark of 100 is deemed safe. Because the benchmark is a 24-hour target, and the annual average must match the annual target, it is entirely possible to have safe air every day of the year but still fail the annual pollution benchmark. The Common Air Quality Index (CAQI) is an air quality index used in Europe since 2006. In November 2017, the European Environment Agency announced

12566-591: The population speak Mandarin, with 2.3% native speakers and 51.9% as a second language. Traditional Chinese characters are used in writing, rather than the simplified characters used in the mainland . Among the religious population, the traditional " three teachings " of China, Buddhism , Confucianism , and Taoism , have the most adherents (20%), followed by Christianity (12%) and Islam (4%). Followers of other religions, including Sikhism , Hinduism , and Judaism , generally originate from regions where their religion predominates. Life expectancy in Hong Kong

12688-440: The post-war decades to provide safer housing, integrity in the civil service, and more reliable transportation. Nevertheless, widespread public discontent resulted in multiple protests from the 1950s to 1980s, including pro- Republic of China and pro- Chinese Communist Party protests. In the 1967 Hong Kong riots , pro- PRC protestors clashed with the British colonial government. As many as 51 were killed and 802 were injured in

12810-473: The recovery from this was muted by an H5N1 avian-flu outbreak and a housing surplus. This was followed by the 2003 SARS epidemic , during which the territory experienced its most serious economic downturn. Chinese communists portrayed the return of Hong Kong as key moment in the PRC's rise to great power status. Political debates after the handover have centred around the region's democratic development and

12932-531: The region into a wasteland. The Kangxi Emperor lifted the maritime trade prohibition, allowing foreigners to enter Chinese ports in 1684. Qing authorities established the Canton System in 1757 to regulate trade more strictly, restricting non-Russian ships to the port of Canton . Although European demand for Chinese commodities like tea, silk, and porcelain was high, Chinese interest in European manufactured goods

13054-699: The remainder of the Pro-Democracy camp . Hong Kong is on China's southern coast, 60 km (37 mi) east of Macau, on the east side of the mouth of the Pearl River estuary . It is surrounded by the South China Sea on all sides except the north, which neighbours the Guangdong city of Shenzhen along the Sham Chun River . The territory's 1,110.18 km (428.64 sq mi) area (2,754.97 km if

13176-412: The rest of the country. All travellers between Hong Kong and China and Macau must pass through border controls, regardless of nationality. Mainland Chinese citizens do not have right of abode in Hong Kong and are subject to immigration controls. Public finances are handled separately from the national government; taxes levied in Hong Kong do not fund the central authority. The Hong Kong Garrison of

13298-481: The southwest. The humid nature of Hong Kong exacerbates the warmth of summer. Typhoons occur most often then, sometimes resulting in floods or landslides. Also rarely occurring are waterspouts and tornadoes , which occurred at Hong Kong International Airport on 26 September 2020 and at Victoria Harbour on 28 September 2024. Winters are short, mild and usually sunny at the beginning, becoming cloudy towards February. Frequent cold fronts bring strong, cooling winds from

13420-461: The sweet taste of the harbour's freshwater influx from the Pearl River or to the odour from incense factories lining the coast of northern Kowloon . The incense was stored near Aberdeen Harbour for export before Victoria Harbour was developed. Sir John Davis (the second colonial governor) offered an alternative origin; Davis said that the name derived from "Hoong-keang" ("red torrent"), reflecting

13542-460: The territory. The vast majority also hold Chinese nationality , automatically granted to all ethnic Chinese residents at the handover. Headline population density exceeds 7,060 people/km , and is the fourth-highest in the world. The predominant language is Cantonese , a variety of Chinese originating in Guangdong. It is spoken by 93.7% of the population, 88.2% as a first language and 5.5% as

13664-503: The territory. Older government buildings are examples of colonial architecture. The 1846 Flagstaff House , the former residence of the Commander of the British forces in Hong Kong , is the oldest Western-style building in Hong Kong. Some buildings, such as the Court of Final Appeal Building and the Hong Kong Observatory retain their original functions, and others have been adapted and reused ;

13786-410: The three substances (O 3 , NO 2 , PM2.5) is calculated at each station within a community for the 3 preceding hours. This is considered valid only if at least 2 out of 3 hours are available at the station. If more than 1 of the preceding 3 hours is missing the station average is set to "Not Available". This part of the process results in three "station parameter averages" for each station. Second,

13908-514: The traders were expelled after military clashes in the 1520s, Portuguese-Chinese trade relations were re-established by 1549 . Portugal acquired a permanent lease for Macau in 1887. After the Qing conquest , maritime trade was banned under the Haijin policies. From 1661 to 1683, the population of most of the area forming present day Hong Kong was cleared under the Great Clearance , turning

14030-475: The violence, including dozens killed by the Royal Hong Kong Police via beatings and shootings. Although the territory's competitiveness in manufacturing gradually declined because of rising labour and property costs, it transitioned to a service-based economy. By the early 1990s, Hong Kong had established itself as a global financial centre and shipping hub. The colony faced an uncertain future as

14152-730: The war, as skilled Chinese migrants fled from the Chinese Civil War and more refugees crossed the border when the Chinese Communist Party took control of mainland China in 1949. Hong Kong became the first of the Four Asian Tiger economies to industrialise during the 1950s. With a rapidly increasing population, the colonial government attempted reforms to improve infrastructure and public services. The public-housing estate programme , Independent Commission Against Corruption , and Mass Transit Railway were all established during

14274-508: The world , housing in Hong Kong is consistently in high demand . Hong Kong is a highly developed territory and has a Human Development Index (HDI) of 0.956, ranking fourth in the world and currently the only place in Asia to be in the top 5. The city has the highest life expectancy in the world , and a public transport usage exceeding 90 per cent. The name of the territory, first romanised as "He-Ong-Kong" in 1780, originally referred to

14396-494: The world's largest number of skyscrapers , with 554 towers taller than 150 metres (490 ft), and the third-largest number of high-rise buildings in the world. The lack of available space restricted development to high-density residential tenements and commercial complexes packed closely together on buildable land. Single-family detached homes are uncommon and generally only found in outlying areas. The International Commerce Centre and Two International Finance Centre are

14518-420: Was 81.3 years for males and 87.2 years for females in 2022, one of the highest in the world. Cancer , pneumonia , heart disease , cerebrovascular disease , and accidents are the territory's five leading causes of death. The universal public healthcare system is funded by general-tax revenue, and treatment is highly subsidised; on average, 95% of healthcare costs are covered by the government. The city has

14640-528: Was further expanded in 1898 when the United Kingdom obtained a 99-year lease of the New Territories. The University of Hong Kong was established in 1911 as the territory's first institution of higher education. Kai Tak Airport began operation in 1924, and the colony avoided a prolonged economic downturn after the 1925–26 Canton–Hong Kong strike . At the start of the Second Sino-Japanese War in 1937, Governor Geoffry Northcote declared Hong Kong

14762-519: Was insignificant, so that Chinese goods could only be bought with precious metals. To reduce the trade imbalance, the British sold large amounts of Indian opium to China. Faced with a drug crisis, Qing officials pursued ever more aggressive actions to halt the opium trade. In 1839, the Daoguang Emperor rejected proposals to legalise and tax opium and ordered imperial commissioner Lin Zexu to eradicate

14884-725: Was launched in New Delhi on September 17, 2014, under the Swachh Bharat Abhiyan . The highest AQI in India was recorded in New Delhi on 18th November 2024 with it being 1,081 and the concentration of PM2.5 - particulate matter measuring 2.5 microns or less in diameter that can be carried into lungs, causing deadly diseases and cardiac issues. Expected to soar even higher later or next year. The Central Pollution Control Board along with State Pollution Control Boards has been operating National Air Monitoring Program (NAMP) covering 240 cities of

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