(c) flickr & Alfonsina Blyde
空気中のオゾンへの短時間の曝露が，心臓病の危険性を示唆する生理学的変化を起こすことが分かった。オゾンは自動車，発電所，工場，生活用品などからの汚染物質が日光の下で反応すると生じる。健康な被験者23名を0.3 ppmのオゾンに2時間曝露したところ，その直後と翌朝の検査で，血管の炎症と血管を詰まらせる血餅を溶かす能力の低下を示唆する結果が得られ，自律神経による心拍の制御にも変化が見られた。この曝露は米環境保護庁の8時間基準，0.076 ppmへの8時間の曝露とほぼ同じとされる。オゾンへの暴露と死亡の関連性は以前報告されていたが，具体的な変化が確認されたのは初めてだという。（吉田素子）
New Evidence Links Ozone Exposure to Potential Heart Attacks
Young, healthy adult volunteers exposed for two hours to ozone developed physiological changes associated with cardiovascular ailments, according to a small study reported in Circulation, an American Heart Association journal.
Study participants showed evidence of vascular inflammation, a potential reduced ability to dissolve artery-blocking blood clots, and changes in the autonomic nervous system that controls the heart’s rhythm. The changes were temporary and reversible in these young, healthy participants.
Ground level ozone is created when pollutants from vehicles, power plants, industry, chemical solvents and consumer products react in the presence of sunlight. Recent epidemiology studies have reported associations between acute exposure to ozone and death but little is known about the underlying pathophysiological pathways responsible.
“This study provides a plausible explanation for the link between acute ozone exposure and death,” said Robert B. Devlin, Ph.D., the study’s lead author and senior scientist at the U.S. Environmental Protection Agency’s (EPA) National Health and Environmental Effects Research Laboratory in Research Triangle Park, N.C.
Devlin and colleagues focused on a single, short-term exposure and not the effects of years of exposure to ozone.
Researchers exposed 23 volunteers, ages 19 to 33, to 0.3 parts per million (ppm) of ozone. The dose was higher than the EPA’s eight hour ozone standard of 0.076 ppm.
However, a person breathing 0.3 ppm for two hours receives roughly the same amount of ozone as does a person breathing the lower 0.076 ppm for eight hours, Devlin noted.
［単語和訳］
Ozone：オゾン Exposure：曝露 Heart Attacks：心臓発作
physiological：生理学的な associated with：～と関連した cardiovascular：心血管の ailments：病気 according to：～によると Circulation：循環（Circulationは雑誌名） American Heart Association：米国心臓協会
participants：参加者 vascular inflammation：血管炎症 dissolve：～を溶解する artery-blocking：動脈を詰まらせる blood clots：血餅 autonomic nervous system：自律神経系 reversible：可逆的
Ground level：地表面の pollutants：汚染物質 power plants：発電所 chemical solvents：化学溶剤 consumer products：生活用品 in the presence of：～の存在下で epidemiology：疫学 acute：急性の underlying：根本的な pathophysiological pathways：病態生理学的経路
plausible：説得力のある Ph.D.：博士 lead author：筆頭著者 senior scientist：主席研究員（研究主幹） U.S. Environmental Protection Agency：米環境保護庁 National Health and Environmental Effects Research Laboratory：国立保健環境影響研究所 Research Triangle Park：リサーチ・トライアングル・パーク N.C.：ノースカロライナ州
colleagues：同僚（研究仲間） focused on：～に重点的に取り組んだ short-term：短期の
Researchers：研究者 parts per million：ppm（百万分率） dose：用量
