[求助]GWD的一条题目,请指点,谢谢

4月7号

Houses built during the last ten years have been found to contain indoor air pollution at levels that are, on average, much higher than the levels found in older houses. The reason air-pollution levels are higher in the newer houses is that many such houses are built near the sites of old waste dumps or where automobile emissions are heavy.

Which of the following, if true, calls into question the explanation above?

Answer: Pressboard, an inexpensive new plywood substitute now often used in the construction of houses, emit the pollutant formaldehyde into the house.

Doubt: “Many new houses are built with air-filtration systems that remove from the house pollutants that are generated indoor.”，这是我选择的答案，新房子有了过滤设备，所以不应该将题干中的空气污染归咎于“many such houses are built near the sites of old waste dumps or where automobile emissions are heavy”，因此我选的这个选项应该也是削弱呀。能解释下吗？

Many new houses are built with air-filtration systems that remove from the house pollutants that are generated indoor.

这句话是说房子装了一种能把房内产生的污染排出的设备，这并不能反驳“房子被建在了污染严重的地区”，甚至从某种程度上还能加强它，因为房内的污染既然都被排出了，为什么污染指数还这么高？是不是从房屋外部传来的污染过于严重？

用便宜的放射污染物质的材料建造房屋也能使房屋污染指数上升，可以质疑原文的reason

你的选项我看来是无关选项，题目说这种十年前造的房子造成比比它更早造的房子更多污染，所以得出结论，这种房子是因为外界的污染而造成的。

而选项是从它的造成污染的原因来推翻这个结论的，如果造成污染源是内部不是外部，自然就推翻了结论，一般这种题目都是看最后作者的结论是最重要的，搞清逻辑，如果SUPPORT，就进一步加强，我没有看问题的时候，就在想，如果加强，那选项里应该出现，什么数据调查，确实发现周围环境差不好之类有结论提到的东西，如果削弱，从推翻的论点，不可能说靠近污染点的房子没有污染，故此只有从污染源这个上面去驳斥！