A decadelong study, also the first major research into air pollution and disease has shown that living near a main road increases the risk of dementia (痴呆). The study of 6.6 million people found that one in ten dementia deaths in people living within 50 metres of a busy road was due to waste gas and noise.
Air pollution is already known to contribute to the deaths of around 40,000 people in Britain each year by worsening breathing and heart conditions, while previous research showed emissions (排放物) can cause brain shrinkage. But the new study by Canadian public health scientists is the first to find a link between living close to heavy traffic and the increasing of dementia, a discovery described as “believable” and “impressive” by British experts.
Dr Hong Chen said, “Our study suggests that busy roads could be a source of environmental stressors that could give rise to the onset of dementia. Population growth and urbanization have placed many people close to heavy traffic, and with widespread exposure to heavy traffic and growing rates of dementia, even a modest effect from nearroad exposure could cause a large public health burden. More research to understanding this link is needed, particularly into the effects of different aspects of traffic, such as air pollutants and noise.”
In the new study, the team tracked all adults aged between 20 and 85 living in Ontario for more than a decade from 2001 to 2012. They used postcodes to determine how close people lived to a main road and analysed medical records to see if they went on to develop dementia, Parkinson's disease or multiple sclerosis (多发性硬化)．
While there was no correlation between living near a road and Parkinson's disease or multiple sclerosis, dementia risk reduced as people lived further from a main road, with a seven per cent higher risk in developing dementia among those living within 50 metres; a four per cent higher risk at 50 — 100 metres and a two per cent higher risk at 101 — 200 metres. After 200 metres there was no increase. Researchers believe that noise of traffic may also play a role in the raised risk as well as other urban pollution, which is often present near busy roads.
本文是一篇说明文。研究表明：居住在主道路附近的居民由于受空气污染和噪声影响患痴呆的风险较高。
1．What can we know about Canadian's new study?
A．British experts think highly of it.
B．It brings benefits to dementia patients.
C．It shows that air pollution is very serious.
D．It shows that air pollution can cause brain shrinkage.
答案：A
解析：推理判断题。根据第二段“But the new study by Canadian public health...described as ‘believable’ and ‘impressive’ by British experts.”可知，英国专家很看重这项研究。故选A项。
2．What Dr Hong Chen said showed that ________.
A．people are diagnosed with dementia mainly due to air pollution
B．widespread exposure to traffic will reduce the risk of having dementia
C．the link between living near roads and having dementia was not obvious
D．busy roads could be a source of environmental stressors that caused dementia to increase
答案：D
解析：推理判断题。根据第三段“Dr Hong Chen said, ‘Our study suggests that busy roads could be a source of environmental stressors that could give rise to the onset of dementia.’”可知，Dr Hong Chen认为繁忙的道路是一种环境压力源，会使患痴呆症的风险升高。故选D项。
3．What does the underlined word “correlation” mean?
A．Change. B．Improvement.
C．Association. D．Secret.
答案：C
解析：词义猜测题。虽然生活在道路附近与帕金森病或多发性硬化症之间没有相关性，但随着人们远离主干道，患痴呆症的风险降低了。correlation与association同义，意为“相关，关联”。故选C项。
