美国南加州大学的研究人员发现，居住在空气污染严重地区的老年人大脑要比实际年龄“老三岁”，因其大脑认知功能受到空气质量影响衰退更快。这项针对超过1.4万50岁以上人群进行的研究发现，空气污染对大脑健康及其功能都有负面影响。研究人员发现，每立方米空气中的污染微颗粒增加10微克，大脑认知能力就会下降0.3。而人的年龄每增加一岁，大脑认知能力仅下降0.1。由于老年人在健康和身体功能方面均开始衰退，因此其大脑功能和身体状况更易受到空气污染的不良影响。此前已有研究显示，空气污染与日益增加心血管疾病和呼吸系统疾病有关。

　　Elderly people living in areas of high air pollution have brains that are 'three years older' as cognitive function is affected by air quality, a study has found for the first time.

　　Elderly people living in areas of high air pollution have brains that are 'three years older' as cognitive function is affected by air quality, a study has found for the first time.

　　Researchers found that elderly people did worse on thinking tests if they lived in areas with high levels of air pollution, compared to those in areas with relatively clean air.

　　The team from University of southern California presented their findings at the Gerontological Society of America's annual scientific meeting, in San Diego.

　　Postgraduate doctoral fellow Jennifer Ailshire conducted the analysis using data from the American Environmental Protection Agency and the Health and Retirement Study.

　　She said: "As a result of age-related declines in health and functioning, older adults are particularly vulnerable to the hazards of exposure to unhealthy air.

　　"Air pollution has been linked to increased cardiovascular and respiratory problems, and even premature death, in older populations, and there is emerging evidence that exposure to particulate air pollution may have adverse effects on brain health and functioning as well."

　　The study of 14,793 men and women aged over 50 matched their results on cognitive tests to maps of air pollution.

　　The association even remained after accounting for several factors, including age, race/ethnicity, education, smoking behavior, and respiratory and cardiovascular conditions.

　　Every ten micrograms of fine particle air pollution found per cubic meter was linked to a drop of a third of a point in cognitive scores.

　　Areas of low air pollution had 4.1 micrograms per cubic meter and areas with the worst had 20.7 micrograms.

　　The difference was the equivalent of ageing three years, Ms Ailshire said.

　　This was because one year increase in age was linked to a drop in cognitive scores of just over a tenth of a point.