What is personification? Personification is the act of giving human characteristics to non-human things, such as animals or inanimate objects. 

How does Auden use personification in his poem "September 1, 1939"?

Let's list some examples and dissect the personification therein: 

1. "As the clever hopes expire" -
   Here, hope is made into a person who can expire, or die. 
   
   
2. "The unmentionable odour of death / Offends the September night" -
   Here, the September night is made into a person who is offended by the smell of death. 
   
   
3. "Into this neutral air / Where blind skyscrapers use / Their full height to proclaim / The strength of Collective Man" - 
   Here, skyscrapers are made into people in two ways. Firstly, they are described as blind, which could naturally sightless or willfully sightless. Secondly, they are given voices with which to present to the world the powers that have made them possible. 
   
   
4. "All I have is a voice / To undo the folded lie, / The romantic lie in the brain / Of the sensual man-in-the-street / And the lie of Authority / Whose buildings grope the sky" -- 
   Here, Authority is made into a person who both owns the skyscrapers previously mentioned but also is convincing an entire population of a lie, against which the poet is battling. 
   
   
5. "Hunger allows no choice / To the citizen or the police" -- 
   Here, Hunger is made into a person that is overwhelmingly powerful and controls all people, from the average citizen to the powerful authority figures of the society.