LONDON -- LONDON (AP) — What many commuters choking on smog have long suspected has finally been scientifically validated: air pollution causes lung cancer.


The International Agency for Research on Cancer declared on Thursday that air pollution is a carcinogen, alongside known dangers such as asbestos, tobacco and ultraviolet radiation. The decision came after a consultation by an expert panel organized by IARC, the cancer agency of the World Health Organization, which is based in Lyon, France.


"We consider this to be the most important environmental carcinogen, more so than passive smoking," said Kurt Straif, head of the IARC department that evaluates cancer-causing substances.


IARC had previously deemed some of the components in air pollution such as diesel fumes to be carcinogens, but this is the first time it has classified air pollution in its entirety as cancer causing.


The risk to the individual is low, but Straif said the main sources of pollution are widespread, including transportation, power plants, and industrial and agricultural emissions.


Air pollution is a complex mixture that includes gases and particulate matter, and IARC said one of its primary risks is the fine particles that can be deposited deep in the lungs of people.


"These are difficult things for the individual to avoid," he said, observing the worrying dark clouds from nearby factories that he could see from his office window in Lyon. "When I walk on a street where there's heavy pollution from diesel exhaust, I try to go a bit further away," he said. "So that's something you can do."


The fact that nearly everyone on the planet is exposed to outdoor pollution could prompt governments and other agencies to adopt stricter controls on spewing fumes. Straif noted that WHO and the European Commission are reviewing their recommended limits on air pollution.


Previously, pollution had been found to boost the chances of heart and respiratory diseases.



The expert panel's classification was made after scientists analyzed more than 1,000 studies worldwide and concluded there was enough evidence that exposure to outdoor air pollution causes lung cancer.


In 2010, IARC said there were more than 220,000 lung cancer deaths worldwide connected to air pollution. The agency also noted a link with a slightly higher risk of bladder cancer.


Straif said there were dramatic differences in air quality between cities around the world and that the most polluted metropolises were in China and India, where people frequently don masks on streets to protect themselves.


"This is something governments and environmental agencies need to take care of," Straif said. "People can certainly contribute by doing things like not driving a big diesel car, but this needs much wider policies by national and international authorities."


Other experts emphasized the cancer risk from pollution for the average person was very low — but virtually unavoidable.


"You can choose not to drink or not to smoke, but you can't control whether or not you're exposed to air pollution," said Francesca Dominici, a professor of biostatics at Harvard University's School of Public Health. "You can't just decide not to breathe," she said. Dominici was not connected to the IARC expert panel.


A person's risk for cancer depends on numerous variables, including genetics, exposure to dangerous substances and lifestyle choices regarding issues such as drinking alcohol, smoking and exercising.


Dominici said scientists are still trying to figure out which bits of pollution are the most lethal and called for a more targeted approach.


"The level of ambient pollution in the U.S. is much, much lower than it used to be, but we still find evidence of cancer and birth defects," she said. "The question is: How are we going to clean the air even further?"


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Online:




http://www.iarc.fr/en/publications/books/sp161/index.php



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  • Coffee


    Coffee's a tricky one. Experts still aren't completely sure whether drinking coffee does more good than bad, as studies have shown it decreasing the risk of certain cancers but raising the risk of others.

    Research has shown that drinking <a href="http://jnci.oxfordjournals.org/content/early/2011/05/17/jnci.djr151" target="_hplink">six cups of coffee</a> every day can decrease the risk of prostate cancer, while drinking five or more cups of coffee a day lowers the risk of a certain kind of<a href="http://www.msnbc.msn.com/id/42991809/ns/health-cancer/t/coffee-habit-may-protect-against-breast-cancer/" target="_hplink"> breast cancer</a> by 57 percent. However additional research suggests drinking at least two cups a day could <a href="http://www.ncbi.nlm.nih.gov/pubmed/19362749" target="_hplink">increase the risk of lung cancer</a> by 14 percent.

    <strong>Classified: </strong>Possible carcinogen




  • Pickled Vegetables


    Eating pickled vegetables, as is common in Asian cultures, can raise the risk of certain kinds of cancer, including <a href="http://www.ncbi.nlm.nih.gov/pubmed/19862003" target="_hplink">esophageal cancer</a> and gastric cancer.

    One study that looked at the eating habits of Japanese and Korean people found a link between those who mainly ate pickled vegetables and <a href="http://www.ncbi.nlm.nih.gov/pubmed/19860848" target="_hplink">risk of gastric cancer</a> than people who said they mainly ate fresh vegetables.

    <strong>Classified: </strong>Possible carcinogen.




  • Alcoholic Beverages


    Alcohol may have low health risks when consumed in moderation (two drinks max per day for men and one for women, according to the Centers for Disease Control and Prevention), but that doesn't mean it's completely faultless.

    Alcohol is linked with <a href="http://www.huffingtonpost.com/2011/04/08/cancer-from-alcohol_n_846610.html" target="_hplink">10 percent of all cancers in men</a> and 3 percent of cancers in women, according to a recent study, and drinking too much raises the risk of breast, throat and liver cancer.

    <strong>Classified:</strong> Known carcinogen




  • Tanning beds


    A "healthy" tan may not be so healthy after all, as use of tanning beds is known to increase the risk of skin cancer. One study showed that the <a href="http://www.msnbc.msn.com/id/32187497/ns/health-cancer/t/study-tanning-beds-can-be-deadly-arsenic/" target="_hplink">risk of skin cancer</a> rockets up by 75 percent when people use tanning beds before they hit age 30. For years, the IARC had considered sun beds and sun lamps to be "probable carcinogens," but they were bumped up to "known carcinogens" in 2009.

    <strong>Classified:</strong> Known carcinogen




  • Talcum Powder


    Health experts aren't completely clear if talcum powder, used to keep skin dry and minimize rashes, is a definite cause of cancer.

    Talcum powder with asbestos, which is no longer used today, is a known carcinogen, but recent research suggests that use of talcum powder without asbestos (the kind that is used today) near the genital region can <a href="http://www.cancer.org/cancer/cancercauses/othercarcinogens/athome/talcum-powder-and-cancer" target="_hplink">increase the risk of ovarian cancer</a> by 30 percent. That's because the powder may be able to travel to the ovaries through the vagina, uterus or fallopian tubes.

    <strong>Classified:</strong> Possible carcinogen




  • Hormone Replacement Therapy


    Hormone replacement therapy -- taking estrogen or estrogen and progestin to relieve the symptoms of menopause, via a pill, patch or ring-- has also been linked with an increased risk of breast, ovarian, endometrial and uterine cancers. That's why doctors recommend taking <a href="http://www.cancer.org/cancer/cancercauses/othercarcinogens/medicaltreatments/menopausal-hormone-replacement-therapy-and-cancer-risk" target="_hplink">hormone replacement therapy</a> at the lowest dose and the shortest amount of time to relieve menopausal symptoms.

    <strong>Classified:</strong> Known carcinogen




  • Occupational Exposure


    Certain careers could up your cancer risk, according to the IARC. People who work in dry cleaning are exposed to chemical fumes and solvents shown to increase the risk of <a href="http://www.cancer.org/cancer/esophaguscancer/detailedguide/esophagus-cancer-risk-factors" target="_hplink">esophageal cancer</a>, while people who <a href="http://ije.oxfordjournals.org/content/38/6/1512.full.pdf" target="_hplink">work as hairdressers</a> or barbers could have an increased risk of lung and bladder cancer when exposed to certain toxins.

    <strong>Dry cleaning: </strong>Possible carcinogen
    <strong>Hairdresser or barber: </strong>Probable carcinogen




  • Ultraviolet Radiation


    Catching too many UV rays from the sun not only damages skin appearance, but it can also <a href="http://www.cancer.gov/melanomarisktool/melanoma-cancer-risk.html" target="_hplink">raise the risk of skin cancer</a>. Melanoma, the deadliest form of skin cancer, is more common in people who live in sun-kissed states, like California, than colder states, like Minnesota.

    <strong>Classified: </strong>Known carcinogen




  • Cadmium


    Cadmium made headlines last year when it was found at high levels in <a href="http://www.huffingtonpost.com/2010/05/19/mileys-cyrus-toxic-walmar_n_582020.html" target="_hplink">Miley Cyrus-branded necklaces and bracelets</a> from Wal-Mart. Even though cadmium is safe when simply worn, it can be dangerous and carcinogenic if it's ingested. Studies have shown that exposure to cadmium, through smoking or metalworking, increases the <a href="http://cebp.aacrjournals.org/content/9/2/139.full" target="_hplink">risk of pancreatic cancer</a>.

    <strong>Classified:</strong> Known carcinogen




  • Formaldehyde


    Formaldehyde is a flammable chemical that is released into the air through car exhaust, or from chemicals used in labs, factories and mortuaries. <a href="http://www.cancer.gov/cancertopics/factsheet/Risk/formaldehyde#r2" target="_hplink">Formaldehyde</a> is associated with nasal cancer in rats, as well as myeloid leukemia in funeral home workers and textile workers.

    <strong>Classified: </strong>Known carcinogen




  • Tamoxifen


    Tamoxifen, a drug commonly used to treat breast cancer, has in some cases been shown to <a href="http://www.cancer.gov/cancertopics/factsheet/Therapy/tamoxifen" target="_hplink">increase the risk of uterine cancer</a>. However, these risks are low compared to the benefit of taking tamoxifen to treat breast cancer, according to the American Cancer Society.

    <strong>Classified:</strong> Known carcinogen




  • Smokeless Tobacco


    Just because <a href="http://www.cancer.gov/cancertopics/factsheet/Tobacco/smokeless" target="_hplink">smokeless tobacco</a> isn't burned, doesn't make it benign. There are at least 28 chemicals in smokeless tobacco, which includes snuff and chewing tobacco, that are known to cause oral, esophageal and pancreatic cancer.

    <strong>Classified: </strong>Known carcinogen




  • Asbestos


    Asbestos, which is used as bundled fibers for insulation and strengthening cement, is known to cause cancer when asbestos fibers are released into the air and inhaled.

    <a href="http://www.cancer.gov/cancertopics/factsheet/Risk/asbestos" target="_hplink">Asbestos inhalation</a> is known to raise the risk of lung cancer and mesothelioma, a cancer of the membranes that line the abdomen and chest.

    <strong>Classified: </strong>Known carcinogen