Unless nations act air pollution deaths will double by 2050 study concludes

first_img Sign up for our daily newsletter Get more great content like this delivered right to you! Country Click to view the privacy policy. Required fields are indicated by an asterisk (*) To get a clearer picture, researchers led by Jos Lelieveld of the Germany-based Max Planck Institute decided to take a global look at outdoor air pollution, which the World Health Organization (WHO) estimates is responsible for almost 3.5 million premature deaths annually. (WHO estimates indoor air pollution accounts for an additional 3.5 million.)Using a computer model that fused air pollution and atmospheric chemistry data, they estimated what annual average levels of ozone (a key smog ingredient) and fine particulates smaller than 2.5 microns (PM2.5) were in 2010 within 100-km-by-100-km grid squares across the world. Then they forecast what the levels of both pollutants would be in 2050, assuming policymakers implemented no new controls.Next, the researchers estimated how many premature deaths the pollution caused in each square. To do that, they used a set of equations—recently updated based on the most recent epidemiological research—describing how exposure to air pollution affects a person’s risk of dying from various diseases. These “exposure response relationship” equations enabled the researchers to calculate how fine particles and smog would affect the risk of a range of diseases, including heart attacks, strokes, lung cancer, and pulmonary disorders.In a final step, they estimated the fraction of deaths in each square attributable to a specific pollution source, including automobiles, power plants, in-home energy generation, and farm activities such as burning crop residues.Overall, the researchers concluded that, in 2010, 3.3 million people died prematurely from outdoor PM2.5 and ozone pollution. That number echoes recent WHO estimates. But the more troubling finding, the researchers say, is that the annual death toll would rise to 6.6 million by 2050 without new controls.The deadliest outdoor pollution source—accounting for 31%, or about 1 million, of premature deaths in 2010—is residential energy use, such as furnaces. And the bulk of these deaths would occur in Asian countries such as India and China, the researchers concluded, where households often use soot-emitting stoves and furnaces powered by wood. These emissions could be tricky to clamp down on; for instance, persuading residents of India to adopt cleaner technologies has proven difficult, Lelieveld says, in no small part because of cultural and family traditions.The second deadliest source of pollution in 2010 was agriculture, accounting for about 20%, or more than 600,000, of the premature deaths in 2010, the researchers say.“I was surprised” by that result, Lelieveld said. “What you tend to think is that [air pollution comes from] mostly traffic, and maybe industry.” But agricultural activities such as animal husbandry and fertilizer use generate ammonia, which can be converted to fine particles in the air, he explained. Agriculture is the leading source of outdoor pollution–related premature mortality in the eastern United States, Europe, and in countries such as Russia, Japan, and Turkey, the researchers found.Other pollution sources, including the power sector, industry, biomass burning, and vehicle traffic, each made smaller contributions to the death total, the study concluded.Lelieveld cautions that the findings depend on a number of assumptions. One is that all forms of PM2.5 have the same toxicity. But the particles can differ in chemical composition, he notes, and thus could differ in toxicity, based on location or source type. For instance, a limited body of research suggests that carbon-rich particles from residential energy and biomass are more toxic than particles from agriculture and other sources, Lelieveld says. If that’s true—though Cohen argues that this is still an area of unsettled science—the fraction of outdoor pollution–related deaths from residential energy and biomass burning could be higher than the study found, whereas the fraction from the other sources would go down, the researchers say.The mortality numbers also depend to some degree on the accuracy of assumptions about how exposure to different levels of pollution affects disease risk. For example, in the case of deaths due to cardiovascular disease related to PM 2.5 exposure, research now suggests that adding even small amounts of pollution to relatively clean air boosts disease risks more than adding the same amount of pollution to relatively dirty air. The researchers incorporated that research in modeling how PM2.5 levels related to risk of death. That carries a big policy implication, Cohen says: It not only “makes both public health and economic sense to clean up dirty places,” but also means there could be significant health benefits from reducing air pollution even in areas that already have relatively tight controls.“Even in countries with good air quality such as Australia, there is still a health gain to be made by reducing fine particle pollution,” noted health researchers Christine Cowie and Bin Jalaludin the University of New South Wales, Kensington, in Australia, in a statement released by the Science Media Centre.Cohen notes a limitation to the study. The authors assumed that death rates from cardiovascular disease would be constant over time, he says, even though populations in countries like China and India are steadily aging—potentially boosting such death rates. To offset that demographic impact, China and India may have to make even deeper pollution cuts in order to cut death rates, Cohen and other researchers noted earlier this year in a study published in Environmental Science & Technology. Still, Cohen lauds the new work. “It’s important,” he says, “because actions taken to improve air quality, and to improve public health, have to focus on [controlling emissions from] major sources of air pollution.” Emailcenter_img The annual death toll from outdoor air pollution could double to 6.6 million globally by 2050 without new antipollution measures, a new study suggests. But policymakers seeking to reduce the death toll will need to clamp down on a wide array of potentially hard to control pollution sources—including household furnaces and agricultural activities—that are expected to play a growing role, researchers report today in Nature.The study marks a solid step toward clarifying exactly how major sources of air pollution contribute to premature death around the world, says Aaron Cohen, an epidemiologist at the Health Effects Institute, a nonprofit research organization in Boston, who wasn’t involved in the study. That information will prove useful to policymakers, he suggests.Existing estimates have been hampered by gaps in air pollution data, particularly in the developing world, and a lack of knowledge about how specific air pollution sources contribute to the risk of disease and death.  Country * Afghanistan Aland Islands Albania Algeria Andorra Angola Anguilla Antarctica Antigua and Barbuda Argentina Armenia Aruba Australia Austria Azerbaijan Bahamas Bahrain Bangladesh Barbados Belarus Belgium Belize Benin Bermuda Bhutan Bolivia, Plurinational State of Bonaire, Sint Eustatius and Saba Bosnia and Herzegovina Botswana Bouvet Island Brazil British Indian Ocean Territory Brunei Darussalam Bulgaria Burkina Faso Burundi Cambodia Cameroon Canada Cape Verde Cayman Islands Central African Republic Chad Chile China Christmas Island Cocos (Keeling) Islands Colombia Comoros Congo Congo, the Democratic Republic of the Cook Islands Costa Rica Cote d’Ivoire Croatia Cuba Curaçao Cyprus Czech Republic Denmark Djibouti Dominica Dominican Republic Ecuador Egypt El Salvador Equatorial Guinea Eritrea Estonia Ethiopia Falkland Islands (Malvinas) Faroe Islands Fiji Finland France French Guiana French Polynesia French Southern Territories Gabon Gambia Georgia Germany Ghana Gibraltar Greece Greenland Grenada Guadeloupe Guatemala Guernsey Guinea Guinea-Bissau Guyana Haiti Heard Island and McDonald Islands Holy See (Vatican City State) Honduras Hungary Iceland India Indonesia Iran, Islamic Republic of Iraq Ireland Isle of Man Israel Italy Jamaica Japan Jersey Jordan Kazakhstan Kenya Kiribati Korea, Democratic People’s Republic of Korea, Republic of Kuwait Kyrgyzstan Lao People’s Democratic Republic Latvia Lebanon Lesotho Liberia Libyan Arab Jamahiriya Liechtenstein Lithuania Luxembourg Macao Macedonia, the former Yugoslav Republic of Madagascar Malawi Malaysia Maldives Mali Malta Martinique Mauritania Mauritius Mayotte Mexico Moldova, Republic of Monaco Mongolia Montenegro Montserrat Morocco Mozambique Myanmar Namibia Nauru Nepal Netherlands New Caledonia New Zealand Nicaragua Niger Nigeria Niue Norfolk Island Norway Oman Pakistan Palestine Panama Papua New Guinea Paraguay Peru Philippines Pitcairn Poland Portugal Qatar Reunion Romania Russian Federation Rwanda Saint Barthélemy Saint Helena, Ascension and Tristan da Cunha Saint Kitts and Nevis Saint Lucia Saint Martin (French part) Saint Pierre and Miquelon Saint Vincent and the Grenadines Samoa San Marino Sao Tome and Principe Saudi Arabia Senegal Serbia Seychelles Sierra Leone Singapore Sint Maarten (Dutch part) Slovakia Slovenia Solomon Islands Somalia South Africa South Georgia and the South Sandwich Islands South Sudan Spain Sri Lanka Sudan Suriname Svalbard and Jan Mayen Swaziland Sweden Switzerland Syrian Arab Republic Taiwan Tajikistan Tanzania, United Republic of Thailand Timor-Leste Togo Tokelau Tonga Trinidad and Tobago Tunisia Turkey Turkmenistan Turks and Caicos Islands Tuvalu Uganda Ukraine United Arab Emirates United Kingdom United States Uruguay Uzbekistan Vanuatu Venezuela, Bolivarian Republic of Vietnam Virgin Islands, British Wallis and Futuna Western Sahara Yemen Zambia Zimbabwelast_img

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