Under the Air Pollution Control Ordinance (Cap 311), the Air Quality Objectives (AQOs) set out the targeted maximum levels of the numerous pollutants that affect air quality in Hong Kong. These pollutants are emitted from different sources and are thus regulated by various ordinances and government departments, not all of which incorporate the AQOs in their regulatory approach. In attempting to piece together the puzzle of air pollution regulation in Hong Kong, it becomes clear that new AQOs are only the first step towards cleaner air.

Introducing: the air we breathe

The main sources of air pollution in Hong Kong are from industry, transport and electricity generation (CLSA, ‘Boomtown to gloomtown: the implications of inaction’, September 2006).

Hong Kong’s air contains primary pollutants, emitted directly from identifiable sources, including: sulphur dioxide, a colourless gas with a sharp odour generated by combustion of fuel containing sulphur, which can aggravate existing respiratory and cardiovascular problems; nitrous oxides, the reddish-brown hue generated in the combustion of diesel fuels in power generation and vehicles, which irritates the lungs
and lowers resistance to respiratory infections such as the flu; lead, emitted in the use of leaded fuels, which accumulates in blood, bone and soft tissue; and carbon onoxide, generated by the use of petrol and diesel in transport, which interferes with the oxygen-carrying capacity of blood (CLSA, ‘The air we breathe’, April 2005).

Particulate matter may be a primary or secondary pollutant; the latter if it is created in the atmosphere through chemical reaction. Particulate matter is composed of various organic and inorganic substances and can absorb gaseous pollutants, delivering them directly into the lungs. Particulate matter can damage lung tissue and may also be carcinogenic. It is the most noticeable form of air pollution as it reduces visibility.

Ozone is the major secondary pollutant. It is formed by chemical reactions between different pollutants when exposed to sunlight.Ozone is a harmful gas and is the major component of smog. Shortterm exposure causes irritation of the eyes and lungs; long-term exposure can cause chronic health problems such as reduction of lung function.

Target amounts for seven air pollutants are set by the AQOs: sulphur dioxide, nitrogen dioxide, carbon monoxide, lead, ozone, total suspended particulates and respirable suspended particulates (particulate matter).

Air pollution and our health

Air pollution harms human health. The current evidence in Hong Kong is based only on studying short-term effects and may underestimate the impact of air pollution on the population, but there is a clear correlation between air pollution levels and rates of health care use and death: when air pollution rises, more people spend time in hospital, visit the doctor, or die. Based on this correlation, the Community Medicine Department at the University of Hong Kong estimated that the losses amount to 6.8 million doctor visits, over 60,000 hospital bed days and approximately 1600 deaths – translating into annual direct (health care) and indirect (lost productivity) costs of approximately HK$2 billion, plus a further HK$19 billion in intangible costs (‘The impact of air pollution on population health, health care and community costs’, November 2006).

The acute effects of air pollution are immediately felt. Air pollution irritates our eyes, noses, throats and lungs, reducing the flow of oxygen through our bodies. Local studies show that our continuous, longterm exposure to air pollution leads to the development of chronic respiratory and cardiovascular problems, and has also been linked with higher risk of asthma and lung cancer. Our children are worst affected; their higher breathing rates mean greater exposure to air pollution, which is permanently impairing the development of their lungs.

Of particular concern in winter is the effect air pollution has on our immune systems: there is a relationship between increased influenza infection rates and high levels of ozone.

A key question asked in the consultation is, therefore, ‘do you agree that protection of public health should be the key consideration in updating the AQOs?’ The effectiveness of air pollution regulation is indeed crucial for protecting health. Unfortunately, the laws that regulate air pollution are not necessarily geared towards the protection of health. The government’s controversial assertion that implementation of the proposals could extend average life expectancy by one month must be looked at critically in this light.

The traditional aims of air pollution regulation

Historically, air pollution was dealt with in Hong Kong under s 17(19) of the Public Health (Sanitation) Ordinance 1935 and the Air Navigation (Abatement of Smoke Nuisances) Ordinance 1955. In 1960, the Clean Air Ordinance repealed and replaced those laws, but smoke nuisances and safety of aircraft over the old airport remained the primary mischief at which the Ordinance was directed.

In 1983, the Clean Air Ordinance was replaced by the Air Pollution Control Ordinance (APCO), which remains the primary piece of legislation for regulation of air pollution. Whilst the APCO expanded upon and is more detailed than its predecessor, it adopts the same nuisance-based approach to air pollution, the complaintbased and subjective nature of which is not geared towards addressing the prevention of and protection from the incremental and long-term nature of damage to health.

It was not until 1993, when the APCO was amended, that ‘prejudice to health’ was introduced into the legislation. The old term ‘air pollutant nuisance’ was replaced by the current term, ‘air pollution’, defined as:

“an emission of air pollutant which either alone or with another emission of air pollutant – (a) is prejudicial to health; (b) is a nuisance; (c) imperils or is likely to imperil the safety of or otherwise interferes with the normal operation of aircraft; or (d) is determined to be air pollution under a technical memorandum” (emphasis added).

Thus, prejudice to health was grafted on to laws that previously were unconcerned with and did not provide for public health. Only by reading the long title of the APCO in this context can it be interpreted that the ordinance is intended to protect public health – 'to make provision for abating, prohibiting and controlling pollution of the atmosphere’ and reading ‘pollution of the atmosphere’ as equivalent to ‘air pollution’ as defined above.

The AQOs under the Air Pollution Control Ordinance

For the purposes of air pollution regulation, Hong Kong is divided into ‘air control zones’. Under the APCO, the AQOs are established by the Secretary for the Environment in respect of the air control zones. In accordance with s 7, the AQOs should ‘be the quality which, in the opinion of the Secretary, should be achieved and maintained in order to promote the conservation and best use of air in the zone in the public interest’.

The ‘best use of air’ is not defined. Protection of public health has not been explicitly integrated, though it is arguable that by necessary inference for the proper functioning of the ordinance, the setting of the AQOs must be linked to the protection of health. Unfortunately, even if the AQOs are intended to protect health, the AQOs currently in force were established in 1987 and have not been updated since. They are based on outdated medical science that no longer protects health.

Regulation of air pollution

The APCO provides the primary legislative framework, but it is not the only legislation relevant to air pollution. Both the Environmental Protection Department and the Legislative Council’s Subcommittee on Improving Air Quality have compiled lists of legislation relating to air quality, which include the Road Traffic Ordinance (Cap 374), the Shipping and Port Control Ordinance (Cap 313), the Merchant Shipping (Local Vessels) Ordinance (Cap 548), the Dutiable Commodities Ordinance (Cap 109), the Motor Vehicles (First Registration Tax) Ordinance (Cap 330), the Environmental Impact Assessment Ordinance (Cap 499) and the Public Health and Municipal Services Ordinance (Cap 132), as well as a number of regulations.

Ordinances such as these regulate air pollution emission sources, but as the following analysis will show, most are not concerned with the protection of health and do not refer to the AQOs at all in their regulatory approach.

Marine emissions

Marine emissions account for 5% of sulphur dioxide emissions, 9% of particulate matter emissions and some 18% of nitrous oxides emissions in Hong Kong. Marine emissions have been of particular concern following a recent study showing that the bunker fuel used by ocean-going vessels generates emissions of higher toxicity, and the concentration of such vessels in the Kwai Chung / Tsing Yi container terminal area is in close proximity to a densely populated area.

Generally, ships are regulated by the Shipping and Port Control Ordinance and the Merchant Shipping (Local Vessels) Ordinance, administered by the Director of Marine. Ferries are regulated by the Ferry Services Ordinance (Cap 104) and the Merchant Shipping (Safety) Ordinance (Cap 369), administered by the Secretary for Transport and Housing and the Commissioner for Transport.

Under s 43(1)(p) of the APCO and s 94(1) of the Merchant Shipping (Safety) Ordinance, the Secretary for Environment and the Secretary for Transport and Housing are respectively empowered to make regulations for marine fuel content. However, under rr 3 and 5 of the Merchant Shipping (Prevention of Air Pollution) Regulations, both local and non-local ships (vessels of any type whatsoever operating in the marine environment, under the Merchant Shipping (Prevention and Control of Pollution) Ordinance (Cap 413)) are not permitted to engage in voyages unless they are issued Hong Kong Air Pollution Prevention Certificates and International Air Pollution Prevention Certificates by the Director of Marine. These certificates implement the requirements of the International Convention for the Prevention of Pollution from Ships (Annex VI), which under rr 27, 28 and 29 respectively limits sulphur oxide, nitrogen oxide emissions, ozone depleting substances and caps the sulphur content of fuel oil at
4.5% m/m. Such certificates, however, are not issued with reference to the AQOs nor the possible health effects these emissions might cause.

Beyond certification, control of marine emissions is nuisancebased. Under s 50 of the Shipping and Port Control Ordinance, vessels in the waters of Hong Kong may not emit smoke in such quantity as to be a nuisance; similarly, it is an offence under s 51 of the Merchant Shipping (Local Vessels) Ordinance for any local vessel in the waters of Hong Kong to emit smoke in such quantity as to be a nuisance. Such offences may be dealt with by the Marine Department, public officers authorised by the Director of Marine or police officers ranked sergeant or above. Smoke emissions are not regulated with reference to the AQOs.

Furthermore, an authorised officer may, under s 52(2) of the Merchant Shipping (Local Vessels) Ordinance, seize and remove any local vessels from any part of Hong Kong waters if he has reason to suspect such vessels pose a hazard to the environment. Environmental hazards, however, are not defined in the ordinance, making this provision difficult to enforce. In particular, no reference is made to the AQOs or prejudice to health in order to determine what an environmental hazard is.

Roadside emissions

Roadside emissions currently account for 1% of sulphur dioxide emissions, 23% of nitrogen oxide emissions and 31% of particulate matter emissions in Hong Kong. Motor vehicles produce the emissions with the greatest health impacts.

Generally, road transport matters are regulated by the Road Traffic Ordinance, administered by the Secretary for Transport and Housing and the Commissioner for Transport, including the licensing of public service vehicles as well as private vehicles. Roadside emissions are controlled by regulating motor vehicle fuel and motor vehicles in Hong Kong.

In respect of motor vehicle fuel, s 43(1)(p) of the APCO empowers the Secretary for Environment to regulate the specification of the kinds of fuel or of any type of material that may evolve air pollutant. Furthermore, the prohibition on the sale of leaded fuel, the control of the supply of unleaded petrol for the purposes of air pollutant emissions control from motor vehicles, and regulatory powers under the ordinance are extended by the Air Pollution Control (Motor Vehicle Fuel) Regulations (Cap 311L) to motor vehicles and premises in which petrol is stored or offered for sale.

The regulation and licensing of motor vehicles under the Road Traffic Ordinance is administered by the Commissioner for Transport, who may require vehicles be tested under s 77B to determine if the vehicles comply with vehicle emission standards. The standards are set by the Secretary for Environment under the Air Pollution Control (Vehicle Design Standards) (Emission) Regulations (Cap 311J). Though the creation of these rules was unconnected with the AQOs specifically, they were created for ‘the purposes of this Ordinance’, and thus arguably intended to be connected to the protection of health.

Furthermore, under s 9(1)(b) of the Road Traffic Ordinance, the Transport and Housing Bureau is empowered to regulate the emission of smoke, fumes, vapour, sparks and grit from motor vehicles. Controlof these emissions is however unconnected with any prejudice to health they may cause, or to the AQOs.

Another regulation relevant to air pollution is r 31 of the Road Traffic (Construction and Maintenance of Vehicles) Regulations (Cap 374A), which provides that all motor vehicles must be constructed and maintained so excessive smoke or visible vapour is not emitted, though again, there is no link between those emissions and prejudice to health or the AQOs.

A legislative effort to reduce roadside emissions was made through the Dutiable Commodities Ordinance, whereby the duty for Euro V diesel is exempted and a lower duty is imposed on the import of ultralow sulphur diesel. And, in order to reduce roadside emissions, the Motor Vehicles (First Registration Tax) Ordinance was enacted so that first registration tax is not payable for motor vehicles which are propelled solely by electric power and do not emit any exhaust.

Emissions from electricity generation

Emissions from the generation of electricity account for 32% of particulate matter, 44% of nitrogen oxide and 89% of sulphur dioxide emissions in Hong Kong. Electricity works are regulated under Part IVB of the APCO as ‘specified licences’, for which there will be allocated a quantity of emission allowances under s 26G starting in 2010 for the purpose of attaining and maintaining (though not necessarily requiring compliance with) the AQOs. Breach of the allocated quantity leads to criminal liability and fines for excessive emissions, but adjustments can be made for emission allowances and
surplus can be carried forward for one year.

Ambient air quality controls

Under s 10 of the APCO, where the Environmental Protection Department is satisfied that air pollutants from a polluting process are contributing to existing or imminent air pollution, it may give an air pollution abatement notice which would require the emissions be ceased, reduced or other steps taken to abate the emission of air pollutants. The AQOs are not referred to for these purposes, but the advice of a medical practitioner may be taken into account. Similarly, under the Public Health and Municipal Services Ordinance, any dust, fumes or effluvia emitted in such a manner as to be a nuisance shall be regulated by a nuisance notice from the Food and Environmental Hygiene Department. These appear to be a form of emergency power against air pollution, but the effectiveness of such powers to deal with the incremental, long term health impacts caused by ambient air pollution is questionable.

Ambient air pollution controls may arguably be found in the Environmental Impact Assessment Ordinance, which provides for the assessment of the environmental impact of designated projects in the early planning stages, as well as alternatives or mitigation measures for the protection of the environment. Projects that must be assessed include roads, railways and depots; airports and port facilities; energy supply facilities; water extraction and water supply facilities; waterways and drainage works; industrial activities; storage, transfer and trans-shipment of fuel facilities; agriculture and fisheries activities; community facilities; tourist and recreational developments; and
residential and other developments.

Persons wishing to carry out such projects must first apply to the Environmental Protection Department for an environmental impact assessment study brief and prepare an environmental impact assessment report, which must then be approved before an environmental permit can be applied for.

Of particular relevance is that in deciding whether or not a permit will be granted, the Director of Environmental Protection shall have regard to (but not necessarily comply with) the AQOs and, more importantly, the likelihood of such a project causing prejudice to health. As the present AQOs are based on science that is 22 years out of date, impact assessment against the AQOs alone is insufficient for the protection of health; consideration of health effects beyond the AQOs is necessary for compliance.

An environmental permit may be suspended, varied or cancelled by the Chief Executive if the continuation of the project will likely be more prejudicial to health than was first expected, or by the Environmental Protection Department with the consent of the Environment Bureau if it is discovered that the applicant gave wrong or misleading information during the application, or that the applicant is no longer able to comply with the conditions of the environmental permit. A key weakness in the ordinance is the lack of requirementthat testing be done to ensure the projections of environmental impact
were accurate to begin with.

The imminence of new AQOs only makes projections more difficult, raising the issue of whether specified projects subject to impact assessment will be required to comply with the new standards. If not, structures in Hong Kong will fall under three categories: those that were not required to comply with impact assessment (completed before the Environmental Impact Assessment Ordinance came into force in 1998); those that comply with impact assessment based on the current AQOs; and those that will have to assess impact in accordance with the new AQOs after they are established. Such disparity is not conducive to effective air quality management.

Will the new AQOs lead to cleaner air in Hong Kong?

Given the constraints of space, it is impossible to canvass all legislative and regulatory provisions relevant to air pollution. However, from this overview, a number of conclusions may be drawn. First, the current AQOs are unable to protect health from the effects of air pollution. Second, the AQOs are not consistently or effectively integrated into the air pollution regulation system. Where the AQOs are integrated, as under the APCO and the Environmental Impact Assessment Ordinance, there is no mandatory compliance, only the need to have regard to them. Where the AQOs are not integrated,
there is a fragmentation of the regulatory system across many pieces of legislation, overseen by enforcement agencies that may not have control of or protection of health from air pollution as a priority. The effectiveness of updated AQOs in delivering clean air for Hong Kong is hampered by these issues.

Despite the scope of the Study to Review Hong Kong’s Air Quality Objectives, covering ‘the current state of air quality in Hong Kong ... as well as policies, programmes and legislation in place for controlling air pollution’ (emphasis added), no proposals have been put forward to address this underlying issue. The review of the AQOs can therefore only be seen as a first step towards clearing Hong Kong’s air, with legislative reform also required. 

Antonio M Da Roza
Barrister-at-Law
Research Fellow, Faculty of Law
The University of Hong Kong

Special thanks to researchers John Lee, Kelvin Tang (Laws III, HKU), Candy Au (Laws III, CUHK), Natalie Ip (Law and Business III, HKU) and Dicky Chen (Mathematics III, Oxford).

指標：清新空氣
香港的空氣質素指標公眾諮詢將持續至11月底，Antonio Da Roza闡釋了空氣質素指標與空氣污染法例之間的相互作用，並對最新的安全標準是否真正能夠使香港享有更清新的空氣提出疑問。

在《空氣污染管制條例》(第311章)下，空氣質素指標訂定了影響香港空氣質素的許多污染物可容許達到的最高水平。這些污染物的排放有著不同的來源，因而受不同的條例和政府部門所規管。然而，並非所有該等條例和部門都將空氣質素指標納入它們的規管架構內。在我們將規管香港空氣污染所面對的難題拼湊起來後，便可以清晰看到，新的空氣質素指標只是獲取更清新空氣的第一步。

我們所呼吸的空氣

香港空氣污染的主要來源是工業、交通運輸和發電(參見CLSA, ‘Boomtown to gloomtown: the implications of inaction’, September 2006)。

香港空氣中所含有的主要污染物，是從可直接識別的來源排放出來，包括：二氧化硫(一種帶有刺鼻氣味的無色氣體，由含硫燃料的燃燒所產生。它可以令現有的呼吸系統和心血管問題加劇)；氮氧化物(一種紅褐色的物質，於發電和車輛的柴油燃料燃燒時產生。它能刺激肺部，降低對呼吸道感染—例如流感—的抵抗力)；鉛(於使用含鉛燃料時被排放出來，並積聚於血液、骨骼與軟組織中)；一氧化碳 (在交通運輸工具使用汽油和柴油時產生，會對血液的攜氧能力構成妨礙)(參見CLSA, ‘The air we breathe’, April 2005)。

可吸入顆粒物可以屬於主要或次級污染物。假如是透過化學反應在大氣中產生，則屬於後者。可吸入顆粒物是由各種有機和無機物質組成，能吸收氣體污染物，將它們直接帶進肺部。可吸入顆粒物會破壞肺組織，並可能會致癌。它是一種最明顯的空氣污染形式，因為它會導致能見度的降低。

臭氧是主要的次級污染物，由不同污染物曝露在陽光下所產生的化學反應形成。臭氧是一種有害氣體，也是煙霧的主要組成部分。短期接觸可令致眼睛和肺部被刺激，長期接觸可引起慢性健康問題，例如降低肺功能。

空氣質素指標共對七種空氣污染物訂立了數量指標，計為：二氧化硫、二氧化氮、一氧化碳、鉛、臭氧、總懸浮粒子和可吸入懸浮粒子(可吸入顆粒物)。

空氣污染與健康

空氣污染危害人體健康。香港現時所掌握的證據，只是以研究短期影響為基礎，並且可能低估了空氣污染對人口的影響。但空氣污染水平，與醫療使用率和死亡率之間事實上存在一個明顯的相關性：當空氣污染情況加劇，便會有更多的人被送院和看醫生，或是死亡。基於這一相關性，香港大學社會醫學系估計，該等損失共包含680萬次就醫、超過60,000的醫院病床天數，大約1600人死亡—而每年的直接(醫療)和間接(生產力損失)耗費約為20億港元，再加上190億港元的無形成本(參見‘The impact of air pollution on population health, health care and community costs’, November 2006)。

空氣污染所產生的嚴重影響，可以令人立即感受得到。空氣污染會刺激我們的眼睛、鼻子、喉嚨、肺部，導致通過我們身體的氧氣減少。本地的研究證實，不斷和長期地曝露於空氣污染下，會導致我們產生慢性呼吸道疾病和心血管問題，而患上哮喘和肺癌的風險亦會增加。我們的兒童所受的影響最為嚴重，他們的較頻繁呼吸，顯示他們在相當程度上是曝露於空氣污染中，這對他們的肺部發展會造成永久性損害。

冬季特別令人關注的地方，是空氣污染對我們的免疫系統所產生的影響：流感病毒感染率的上升，與高臭氧水平存在一定關係 。

因此，在諮詢中提出的一個關鍵問題是：「你同意保障公眾健康，是更新空氣質素指標時的關鍵考慮因素嗎？」空氣污染的規管效能，對保障我們的健康確實非常重要。不幸的是，規管空氣污染的法例並非必然著眼於對人們健康的保障。政府所提出的，實施有關建議可使平均壽命延長一個月的具爭議說法，必須在此情況下認真地加以研究。

規管空氣污染的傳統目標

回顧過去，香港的空氣污染問題是根據《1935年公眾健康(衛生)條例》第17(19)條和《1955年空中航行(減除煙霧滋擾)條例》的規定來處理。1960年的《保持空氣清潔條例》廢除和取代了上述這些法例，但煙霧造成的滋擾，和對舊機場構成的飛行安全問題，仍然是該條例所主要針對的地方。

1983年，《保持空氣清潔條例》被《空氣污染管制條例》所取代，而後者目前仍然是規管空氣污染的主要法例。雖然《空氣污染管制條例》的適用範圍有所擴大，及比《保持空氣清潔條例》更為詳盡，但對於空氣污染問題它依然是採用相同的路向，以所構成的滋擾為基礎。它的以投訴為主的和主觀的性質，並未著眼於如何對健康所構成的嚴重、長期性損害作出預防和保障。

直到1993年當《空氣污染管制條例》進行了修訂後，「損害健康」的概念才告引入法例之中。舊有的用詞「空氣污染物的滋擾」被目前的「空氣污染」所取代，其定義為：

「指任何空氣污染物的排放，而它本身或連同另一空氣污染物的排放─(a)是損害健康的； (b)是造成滋擾的；(c)是危及或相當可能危及飛機的安全或在其他方面干擾其正常操作的； 或(d)是根據技術備忘錄被測定為空氣污染的」(加以強調)。

因此，損害健康的問題終被載入法例之中，而之前的法例對於公眾健康是漠視和未作任何規定的。我們只有通過閱讀《空氣污染管制條例》的詳題，才可以理解到該條例是旨在保障公眾健康—「本條例旨在就消減、禁止與管制大氣污染及相關事宜訂定條文」，並將「大氣污染」的意思，解釋為相當於以上所界定的「空氣污染」 的含義。

 《空氣污染管制條例》下的空氣質素指標

就空氣污染的防治目的而言，香港被劃分為數個「空氣質素管制區」。根據《空氣污染管制條例》的規定，空氣質素指標是由環境局局長就各個空氣質素管制區而制訂。根據條例第7條，空氣質素指標應「是局長認為為公眾利益而促進對該管制區內空氣的保護及最佳運用所應達致與保持的質素」。

條例對「空氣的最佳運用」 的意思並沒有作出界定。保障公眾健康的要求並沒有被明確載入，儘管通過對條例的適當運行而作的必要推斷，這是可以提出爭辯的。然而，空氣質素指標的設定必須與保障健康連繫於一起。

不幸的是，即使空氣質素指標的目的是要保障健康，但目前的空氣質素指標是於1987年訂立的，而自此之後一直沒有被更新。因此，該等指標是基於過時的醫療科學，不再能夠保障人們的健康。

規管空氣污染

《空氣污染管制條例》訂下了基本的法律框架，但它並不是唯一與空氣污染相關的法例。環境保護署及立法會改善空氣質素小組委員會已編制出與空氣質素法例有關的名單，當中包括《道路交通條例》(第374章)、《船舶及港口管制條例》(第313章)、《商船(本地船隻)條例》(第548章)、《應課稅品條例》(第109章)、汽車(首次登記稅)條例》(第330章)、《環境影響評估條例》(第499章)和《公眾衛生及市政條例》(第132章)，再加上若干規例。

這些條例對空氣污染的排放來源作出了規管，但正如下面的分析所顯示，當中大部分都不涉及對健康的保障，而在其所有規管途徑中，均沒有提述空氣質素指標。

船舶排放

船舶排放佔香港二氧化硫排放量的5%，可吸入顆粒物排放量的9%，以及氮氧化物排放量的約18%。最近的一項研究顯示，遠洋船隻所使用的船用燃料，會產生具較高毒性的排放物，因此船舶排放的廢氣乃受到特別關注，而這些船隻是集中在葵涌／青衣貨櫃碼頭區，與人口稠密的地區非常接近。

一般來說，船舶受《船舶及港口管制條例》和《商船(本地船隻)條例》所規管，並由海事處處長負責管理。渡輪是受《渡輪服務條例》(第104章)和《商船(安全)條例》(第369章) 所規管，並由運輸及房屋局局長和運輸署署長負責管理。

根據《空氣污染管制條例》第43(1)(p)條及《商船(安全)條例》第94(1)條，環境局局長和運輸及房屋局局長分別有權為船舶燃料的成份訂立規例。 然而根據《商船(防止空氣污染)規例》第3條和第5條，除非獲得海事處處長簽發「香港防止空氣污染證書」和「國際防止空氣污染證書」，否則本地和非本地船舶(根據《商船(防止及控制污染)條例》(第413章)的規定在海洋環境中操作的任何類型船隻)不得從事航行。該等證書實施《防止船舶污染國際公約》(附件六)的規定，當中的第27條、28條和29條分別限制硫氧化物、氮氧化物的排放量；消耗臭氧的物質；以及將燃油的含硫量上限訂於4.5% m/m。 然而，該等證書的發出並沒有參照空氣質素指標，以及考慮到這些排放可能對健康造成的影響。

除了發出證書以外，控制船舶的排放是以所造成的滋擾為基礎。《船舶及港口管制條例》第50條規定，在香港水域的船隻所噴出黑煙的數量，不得造成滋擾；同樣，根據《商船(本地船隻)條例》第51條，任何在香港水域內排放黑煙的本地船隻，其所排出的黑煙數量如造成滋擾，乃屬觸犯罪行。此種罪行可以由海事處、海事處處長授權的公職人員， 或是警長級或以上的警務人員處理。但黑煙排放量並沒有參照空氣質素指標來加以規範。

此外，根據《商船(本地船隻)條例》第52(2)條，獲授權人員可將任何本地船隻查封並將它從香港水域的任何部分移走，假如有理由懷疑這些船隻對環境構成危害的話。但是，條例並沒有界定對環境構成危害的意思，因而使這一規定難以執行。特別是，條例並沒有對空氣質素指標或損害健康作出提述，以確定對環境構成危害的含義是甚麼。

路邊的排放量

路邊的排放量目前約佔香港二氧化硫排放量的1%，氮氧化物排放量的23%，和可吸入顆粒物排放量的31%。汽車所產生的排放物對健康造成最大的影響。

一般而言，公路運輸事宜受《道路交通條例》規管，並由運輸及房屋局局長和運輸署署長負責管理，包括向公共服務車輛和私人車輛發牌。在香港，路邊排放是藉著對車輛燃料和機動車輛的規管來加以控制。

就汽車燃料而言，《空氣污染管制條例》第43(1)(p)條授權環境局局長監管各種燃料或是可能放出空氣污染物的任何類別材料的規格。此外，含鉛汽油的禁止銷售、為控制來自車輛的空氣污染物排放而對無鉛汽油供應作出管制，以及根據該條例而行使的監管權力，乃藉《空氣污染管制(汽車燃料)規例》(第311L章) 而伸延至汽車和供儲存汽油或供作出售汽油用途的處所。

在《道路交通條例》下對汽車的監管和發牌工作，是由運輸署署長負責。他有權要求車輛須根據第77B條的規定進行測試，以確定該車輛是否符合車輛廢氣排放標準。該標準是由環境局局長根據《空氣污染管制(車輛設計標準)(排放)規例》(第311J章)而制定。雖然這些規則的訂立並非具體地與空氣質素指標相關，但它們的制定是「為施行本條例的目的」，因此亦可以說是與保障健康的意圖相關。

此外，根據《道路交通條例》第9(1)(b)條，運輸及房屋局有權規管車輛所排放的黑煙、煙霧、氣體、火花和砂礫。然而，對這些排放量的控制，與它們對健康可能造成的損害，均沒有與空氣質素指標扯上任何關係。

另一項與規管空氣污染有關的規定為《道路交通(車輛構造及保養)規例》(第374A章) 第31條，當中規定所有機動車輛的建造和維修均必須達至一定的水平，使其不會排放過量的煙霧或可見氣體。但再一次，這些物質的排放均沒有被聯繫於空氣質素指標或是對健康可能造成的損害。

立法機關亦試圖藉《應課稅品條例》來減少路邊排放量，故歐盟五期柴油車獲得徵稅豁免，並對進口的超低硫柴油徵收較低的稅率。此外，為了減少路邊的排放量，立法會通過了《汽車(首次登記稅)條例》，使完全由電力推動而不排放任何廢氣的機動車輛無須支付首次登記稅。

發電的排放

發電排放佔香港可吸入顆粒物排放量的32%，氮氧化物排放量的44%，及二氧化硫排放量的89%。電力工程受《空氣污染管制條例》第IVB部的規管，作為「指明牌照」。為此，於2010年開始，政府將會根據第26G條的規定分配某一數量的排放限額，以達致和維持(雖然不一定需要遵守)空氣質素指標。假如不遵循所分配的限額，違規者將需要為過量的排放承擔刑事責任和被罰款，但排放限額可予以調整，而剩餘的限額可以結轉到下一年。

環境空氣質量控制

根據《空氣污染管制條例》第10條，如環境保護署認為來自某一污染工序的空氣污染物，正在導致現時的或即將出現的空氣污染，它可以發出空氣污染消減通知書，要求停止、減少排放量，或是採取其他措施來消減空氣污染物的排放。空氣質素指標並沒有在當中被提述，但醫生的意見可被列入考慮範圍內。同樣，根據《公眾衛生及市政條例》，任何灰塵、煙霧或臭氣的排放如構成滋擾，食物環境衛生署將會發出滋擾通知書以進行規管。這似乎是針對空氣污染的一種應急權力，但此一為應付環境空氣污染對健康所構成的嚴重、長期損害而行使的權力，其成效實令人懷疑。

對環境空氣污染的控制，大概可以在《環境影響評估條例》中找到，當中規定了須在早期規劃階段對指定工程項目進行環境影響評估，以及規定了保護環境的替代或緩解措施。必須進行評估的工程項目，包括公路、鐵路和倉庫；機場和港口設施；能源供應設施；取水和供水設施；水道和渠務工程；工業活動；燃料設施的儲存、轉移和轉運；農業和漁業活動；社區設施；旅遊及康樂發展；以及住宅和其他發展項目。

希望開展此類項目的人士，必須先向環境保護署提出申請，要求發給一份環境影響評估研究概要，並編寫環境影響評估報告，而該報告必須在提出環境許可證申請前獲得通過。

值得一提的是，環境保護署署長在決定是否簽發許可證前，必須先行考慮(但不一定需要遵循)空氣質素指標，而更重要的是，該項目會對健康造成損害的可能性。由於目前的空氣質素指標，是以22年前的已經過時的科學為依據，因此單是針對空氣質素指標而進行的影響評估，對於保障健康是起不了多大作用的。故我們必須從空氣質素指標以外的範圍來考慮對健康可能造成的影響。

假如工程項目的繼續施行，可能會比最初預期的情況更為損害健康，則行政長官有權暫停、更改或取消有關的環境許可證，而假如發現申請人在提出申請時，提供了錯誤或誤導性的資料，或是申請人再不能夠符合環境許可證所規定的條件，則在獲得環境局同意的情況下，環境保護署亦有權如此行事。條例中的一個主要弱點是沒有作出進行測試的規定，以確保在一開始的時候，對環境影響所作的預測便已經準確。

此等新訂立的空氣質素指標，只會使預測工作更加困難，並產生了須接受影響評估的指定項目，是否需要遵循新訂立的標準的問題。若否，則在香港的體系中，將包含三個不同類別：一個是不需要符合影響評估要求的類別(即是在《環境影響評估條例》於1998年生效前完成的)；一個是根據目前的空氣質素指標而符合影響評估的類別；而另一個是當新的空氣質素指標制定後，需要根據新的空氣質素指標來評估影響的類別。此等不一致情況的出現，實不利於有效的空氣質素管理。

新的空氣質素指標會否令香港享有更清新的空氣？

由於編幅的限制，在此實不可能詳細討論所有與空氣污染有關的法例和監管規定。不過，從這一個概述中我們亦可以得出若干結論。首先，目前的空氣質素指標並不能保障我們的健康免受空氣污染的影響。第二，空氣質素指標並沒有被一貫或有效地納入空氣污染的規管制度中。即使空氣質素指標被納入，例如是在《空氣污染管制條例》和《環境影響評估條例》中，但卻沒有任何強制遵循的規定，而是只需要考慮它們。假如空氣質素指標沒有被納入，那麼有的便只是一個分割的監管制度，形成許多不同的法例由不同的執法機構負責監督，而這些執法機構可能無法對空氣污染加以控制，或是無法以保障健康，使人們不受空氣污染損害作為其優先考慮事項。因此，旨在讓香港能夠享有清新空氣的新空氣質素指標，其有效性亦因該等問題而面對重重障礙。

儘管《檢討香港空氣質素指標的研究》之範圍，涵蓋了「香港當前的空氣質素狀況，⋯⋯以及已付諸實行的管制空氣污染政策、計劃和立法」(加以強調)，但並沒有任何解決這一根本性問題的方案被提出。因此，對空氣質素指標的檢討，只能夠看作是潔淨香港空氣的第一步，而立法改革必須同時並肩進行。

Antonio M Da Roza
Barrister-at-Law
Research Fellow, Faculty of Law
The University of Hong Kong

謹此向研究人員John Lee 、Kelvin Tang (Laws III, HKU) 、Candy Au (Laws III, CUHK) 、Natalie Ip (Law and Business III, HKU) 及Dicky Chen (Mathematics III, Oxford) 等致謝。