For an introduction to the problem, and to anyone who hasn&#x27;t lived in a severely air polluted city, I highly recommend the documentary <i>Under the Dome</i>, released earlier this year and later banned in China: <a href="https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=T6X2uwlQGQM" rel="nofollow">https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=T6X2uwlQGQM</a>