短语讲解：

1.The WHO estimates that air pollution is responsible for about 6.5 million premature -- or early -- deaths every year.

be responsible for 为…负责，形成…的原因; 主管
例句：You'll be responsible for anything wrong.
出了事唯你是问。

2.Peltier and other air pollution and health experts agree on one important thing: No matter how much you pay for a mask, they only work if they fit snugly on your face.

no matter 不管; 不论; 不介意
例句：No matter what he is, he must obey the law.
不论他是什么人，他必须遵守法律。

3.Wearing a face mask – an inexpensive, non-working face mask made out of cloth – does give a false sense of security because it makes you feel like you’re being protected when in fact you’re not.

in fact 事实上; 实际上，其实
例句：You have to admit that you are, in fact, in difficulties
你不得不承认，你事实上是陷入了困境。