Theo b\u00e0i n\u00e0y (\u0111\u1ea7u n\u0103m 2018) th\u00ec ng\u01b0\u1eddi ta c\u00f2n c\u1ea7n l\u00e0m c\u00e1c nghi\u00ean c\u1ee9u \u0111\u1ec3 \u0111\u00e1nh gi\u00e1 kh\u1ea3 n\u0103ng b\u1ea3o v\u1ec7 s\u1ee9c kh\u1ecfe khi \u0111eo c\u00e1c lo\u1ea1i kh\u1ea9u trang, t\u1ee9c l\u00e0 hi\u1ec3u bi\u1ebft c\u1ee7a th\u1ebf gi\u1edbi v\u1ec1 vi\u1ec7c d\u00f9ng kh\u1ea9u trang ch\u1ed1ng b\u1ee5i cho s\u1ee9c kh\u1ecfe c\u1ed9ng \u0111\u1ed3ng l\u00e0 c\u00f2n ch\u01b0a \u0111\u01b0\u1ee3c c\u1ee5 th\u1ec3 l\u1eafm.<\/p>\n
(Reuters Health) – Face masks available to consumers in China for protection against air pollution vary widely in their real-world performance, suggests a recent study.<\/p>\n
Although a mask may filter tiny particles as advertised, face size and shape as well as movement can lead to leakage as high as 68 percent, researchers report in Occupational & Environmental Medicine.<\/p>\n
\u201cEven if the filtration efficiency of the mask is high, and the mask fits the person initially, the mask may not continue to give a good fit as the person goes about their daily activities – walking, talking, and more,\u201d said senior study author Miranda Loh, an exposure and environmental scientist at the Institute of Occupational Medicine in Edinburgh, Scotland.<\/p>\n
\u201cIt is important for people to understand that not all masks are effective at reducing exposure to particles in air pollution,\u201d Loh said in an email. \u201cAnd none of these masks reduced the concentration of pollution gases such as nitrogen dioxide.\u201d<\/p>\n
Although masks sold for workplace use generally must meet rigorous standards, there are few controls on masks marketed to consumers and little information on which mask will offer the best protection, the study team writes.<\/p>\n
<\/div>\nTheir assessment of a sampling of masks in Beijing is part of a larger project funded by the Research Councils UK, examining air pollution in the Chinese capital and its health effects.<\/p>\n
Air pollution causes an estimated 1.6 million premature deaths in China each year, the study team notes.<\/p>\n
At consumer outlets in Beijing, Loh and colleagues purchased nine different mask types that claimed to protect against fine particle pollution known as PM2.5, which includes soot, droplets and other particles smaller than 2.5 microns in diameter.<\/p>\n
These tiny particles are components of vehicle exhaust and industrial emissions and can penetrate deep into the lungs, and from there, enter the bloodstream.<\/p>\n
Researchers first tested each mask\u2019s filtration efficiency by drawing airborne diesel exhaust through a section of the material for 30 minutes and measuring the particulate matter and black carbon concentrations on both sides. They also tested four masks on 10 volunteers who were exposed to diesel exhaust in a lab while performing tasks such as talking, sitting, standing, bending over and walking in place.<\/p>\n
<\/div>\nIn the filtration tests, the average particle and carbon penetration ranged from 0.26 percent to 29 percent, depending on the mask material. In the volunteers, the average leakage around mask edges ranged from 3 percent to 68 percent during sedentary tasks and 7 percent to 66 percent in active tasks. Only one mask had an average leakage below 10 percent in both active and sedentary tests.<\/p>\n
\u201cIf it\u2019s important for you to protect yourself or your family with masks, choose the best one you can and look for one marketed to workplaces,\u201d said lead author John Cherrie, of the Institute of Occupational Medicine.<\/p>\n
\u201cDon\u2019t choose the cheapest option,\u201d Cherrie said in a telephone interview. \u201cChoose the one that\u2019s most likely to do the best job.\u201d<\/p>\n
The researchers are now exploring whether people tend to wear face masks only on high pollution days. They also want to know if the proportion of particles removed by the mask is enough to provide health benefits, and how long people must wear a mask to see those benefits.<\/p>\n
\u201cAir pollution is a global problem that is important for not only Beijing, but also Boston and Barcelona. Breathing pollutants, especially particulate matter, is very harmful, causing millions of early deaths across the world,\u201d Richard Peltier of the University of Massachusetts Amherst, who wasn\u2019t involved in the study, told Reuters Health by email.<\/p>\n
Future studies should recruit more volunteers, Peltier said, and focus on the main reasons why masks seem to fail – whether the material itself is faulty, the masks don\u2019t fit different people well, or they don\u2019t seem to work well for daily living conditions.<\/p>\n
\n\n\n\n\n\n\n\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\nAs wildfires devour towns new toxic threats emerge<\/span><\/div>\n<\/div>\n\u201cAir pollution exposure is a universal burden that affects us all, and somehow we are the ones obligated to find ways to reduce our exposure with these insufficient tools,\u201d he said. \u201cA far better solution is to prevent pollution at its source.\u201d<\/p>\n
SOURCE:\u00a0bit.ly\/2qBhMgo<\/a>\u00a0Occupational & Environmental Medicine, online April 9, 2018.<\/p><\/blockquote>\n
Source: Face masks available to consumers may be ineffective against air pollution | Reuters<\/a><\/em><\/p>\n
https:\/\/www.ncbi.nlm.nih.gov\/pmc\/articles\/PMC5969371\/<\/a> == bit.ly\/2qBhMgo<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"
Theo b\u00e0i n\u00e0y (\u0111\u1ea7u n\u0103m 2018) th\u00ec ng\u01b0\u1eddi ta c\u00f2n c\u1ea7n l\u00e0m c\u00e1c nghi\u00ean c\u1ee9u \u0111\u1ec3 \u0111\u00e1nh gi\u00e1 kh\u1ea3 n\u0103ng b\u1ea3o v\u1ec7 s\u1ee9c kh\u1ecfe khi \u0111eo c\u00e1c lo\u1ea1i kh\u1ea9u trang, t\u1ee9c l\u00e0 hi\u1ec3u bi\u1ebft c\u1ee7a th\u1ebf gi\u1edbi v\u1ec1 vi\u1ec7c d\u00f9ng<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_mi_skip_tracking":false},"categories":[330],"tags":[1160,1159,1017],"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/p8jhJx-rI","_links":{"self":[{"href":"https:\/\/rosetta.vn\/short\/wp-json\/wp\/v2\/posts\/1718"}],"collection":[{"href":"https:\/\/rosetta.vn\/short\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/rosetta.vn\/short\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/rosetta.vn\/short\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/rosetta.vn\/short\/wp-json\/wp\/v2\/comments?post=1718"}],"version-history":[{"count":3,"href":"https:\/\/rosetta.vn\/short\/wp-json\/wp\/v2\/posts\/1718\/revisions"}],"predecessor-version":[{"id":1721,"href":"https:\/\/rosetta.vn\/short\/wp-json\/wp\/v2\/posts\/1718\/revisions\/1721"}],"wp:attachment":[{"href":"https:\/\/rosetta.vn\/short\/wp-json\/wp\/v2\/media?parent=1718"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/rosetta.vn\/short\/wp-json\/wp\/v2\/categories?post=1718"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/rosetta.vn\/short\/wp-json\/wp\/v2\/tags?post=1718"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}