世界衛生組織：空氣污染致癌
Fresh air polluted by exhaust fumes and industrial emissions causes lung cancer, a team of World Health Organisation experts has officially declared.
Outdoor air pollution was officially classified as carcinogenic to humans by the cancer arm of the WHO after a review of the latest scientific evidence from around the world.
The International Agency for Research on Cancer (IARC) also highlighted an apparent link between air pollution and an increased risk of bladder cancer, although the findings were less conclusive.
Levels of pollution vary widely between urban and rural areas, but the working group said their findings applied to all regions of the world, and sent a “strong signal” to governments to tackle the problem immediately.
Dr Kurt Straif, head of the IARC Monographs Section which identifies environmental causes of cancer, said: “The air we breathe has become polluted with a mixture of cancer-causing substances.
“We now know that outdoor air pollution is not only a major risk to health in general, but also a leading environmental cause of cancer deaths.”
The latest available data suggest that in 2010, air pollution was responsible for the deaths of 223,000 lung cancer patients around the world.
Scientists from the IARC studied more than 1,000 academic papers on polluted air and, separately, small particles found in polluted air.
They found that the risk of developing lung cancer rises in tandem with increasing levels of either, concluding for the first time that outdoor air pollution is a cause of cancer.
Prof David Phillips of King’s College London, a member of the working group, said there was no particular threshold at which pollution becomes dangerous. “The higher the pollution, the greater the cancer risk,” he explained. “It does not suddenly kick in at a particular level.”
The programme had previously classed a variety of individual chemicals and mixtures found in polluted air as carcinogens, such as diesel engine exhaust, solvents, metals, and dusts.
Dr Dana Loomis, deputy head of the IARC monographs section, explained: “Our task was to evaluate the air everyone breathes rather than focus on specific air pollutants.
“The results from the reviewed studies point in the same direction: the risk of developing lung cancer is significantly increased in people exposed to air pollution.”
Although the findings do not come as a surprise, they are likely to significantly increase the pressure on governments around the world to tackle pollution, which has risen rapidly around the world during industrialisation and was already known to raise the risk of conditions like heart and respiratory diseases.
Traffic, power stations, industrial and agricultural emissions, and cooking and heating in the home are the main causes of air pollution.
Dr Christopher Wild, director of the IARC, said: “Classifying outdoor air pollution as carcinogenic to humans is an important step. There are effective ways to reduce air pollution and, given the scale of the exposure affecting people worldwide, this report should send a strong signal to the international community to take action without further delay.”據英國《每日電訊報》報道，世界衛生組織的專家們正式宣佈，被汽車尾氣和工業廢氣污染的空氣會導致肺癌。
世界衛生組織回顧了來自世界各地的最新證據後，正式將戶外空氣污染定爲致癌物質。
國際癌症研究機構也強調了空氣污染和膀胱癌發病率增加的明顯關聯，雖然還未被確定。
都市和鄉村的污染程度有很大的不同，但是研究組人員稱他們的結果是來自全球所有區域的，並且極力要求各個政府儘快解決這個問題。
庫爾特•斯特萊夫博士是國際癌症研究機構專論部的領導者，這個部門專門識別導致癌症的環境因素。他說：“我們呼吸的空氣已被一種混合的致癌物質所污染。”
“現在我們知道戶外空氣污染不但是對健康不利的主要因素，而且是癌症死亡的主要環境因素。”
最新的數據表明，在2010年，空氣污染造成全世界22.3萬人死於肺癌。
國際癌症研究機構的科學家們研究了1000多份空氣污染的學術報告，分別在被污染的空氣中找到了小顆粒物。
他們發現患肺癌的風險與空氣污染的增加是有關的，首次證明戶外空氣污染是癌症的誘因。
倫敦國王學院的戴維•菲利普斯教授是工作組的成員之一。他說沒有特定的臨界值可以判定污染到達什麼水平纔算危險。“污染指數越高，患癌症的風險越大，”他解釋說。“它不會突然達到一個特定的水平。”
該計劃曾將一些單獨的化學物質和受污染空氣中的混合物歸類於致癌物質，如柴油機排氣，溶劑，金屬和灰塵。
國際癌症研究機構專論部副主任達納•盧米斯博士解釋說：“我們的任務是評估每個人呼吸的空氣而不是關注特定的空氣污染物。”
“從相同方向研究的結果表明：患肺癌的風險對於暴露於空氣污染中的人們來說正顯著增加。”
雖然研究結果並不讓人感到驚訝，但他們可能會對世界各國政府在解決污染的問題上施加壓力。這些污染在全球工業化期間迅速飆升，人們也已知它們會提高患心臟病和呼吸疾病的風險。
交通、電力站、工業和農業的排污，家庭做飯和供暖是空氣污染的主要原因。
克里斯托弗•懷爾德博士是IARC的主任，他說：“將室外空氣污染歸類爲致癌物對人類來說是一個重要的步驟。我們有許多有效的方法來減少空氣污染。考慮到空氣污染範圍影響着全球人民，這個報告應該向國際社會發出強烈信號，讓他們立即採取行動。”
