For many people, it is hard to imagine what it is like to lose their sense of smell. Known as “anosmia”, loss of smell can have a substantial effect on our overall wellbeing and quality of life. But while a sudden respiratory infection (呼吸道感染) might lead to a temporary loss of this important sense, your sense of smell may well have been gradually eroding away for years due to something else- air pollution.

Exposure to PM2. 5 has previously been linked with smell loss, but typically only in occupational or industrial settings. But new research is now starting to reveal the true scale and the potential damage caused by the pollution we breathe in every day. On the underside of our brains lies the olfactory bulb (嗅球). This sensitive bit of tissue is essential for the enormously varied picture of the world we get from our sense of smell. It’s also our first line of defense against viruses and pollutants entering the brain. But, with repeated exposure to PM2. 5, these defenses slowly get worn down.

“Our data show there’s a 1.6 to 1.7-fold increased risk of developing anosmia with sustained particulate pollution (粒状物污染),” says Murugappan Ramanathan, a rhinologist. One Mexican study in 2006, which used strong coffee and orange odors showed that residents of Mexico City which often struggles with air pollution — tended to have a poorer sense of smell on average than people living in rural areas of the country.

So, should we care that air pollution to which we are all exposed -is damaging our sense of smell and causing anosmia? Clearly, the answer is yes. Ramanathan says, “Air quality matters. I think we need tight regulations and control. Many people may not even realize the pollution they are exposed to. But even the everyday, low level air pollution we are exposed to should be taken more seriously.”

【小题1】What do the underlined words “eroding away” mean in paragraph 1?

A．Evolving.	B．Becoming weak.
C．Becoming sharp.	D．Appearing.

【小题2】What can we infer from paragraph 2?

A．Exposure to PM2. 5 has nothing to do with smell loss.

B．The pollution we breathe in on a daily basis may cause harm.

C．Our nose stops viruses and pollutants from entering the brain.

D．Our defenses will disappear quickly with air pollution exposure.

【小题3】What does the study reveal about people in Mexico City?

A．They have developed anosmia with air pollution.

B．Their sense of smell is poorer than rural people’s.

C．They often consume strong coffee.

D．They tend to have a good sense of smell.

【小题4】What will the author probably talk about next?

A．How we should react to air pollution.

B．What we should do to protect the environment.

C．What steps we can take to recover from anosmia.

D．How we can improve our life quality.