2017年02月27日 第十七句

Traffic is a major contributor to air pollution and there is growing concern about emissions from diesel vehicles, which contribute through the production of particulate matter and nitrogen oxides(NOx).

词汇突破：1.particulate matter颗粒物（PM2.5知道是什么了吧！）
2.contributor来源
3.emissions排放
4.diesel vehicles柴油车
5.nitrogen oxides（NOx)氮氧化物

主干识别：traffic is a major contributor to air pollution 并列句一
there is growing concern 并列句二

切分成分：which contribute through the production of particulate matter and nitrogen oxides(NOx).定语从句 which=diesel vehicles