What are the samples of earth and air important in the novel, Dust (Silo Saga)?

Samples of the air and earth from the world above are collected by Juliette for testing in Silo 18. These samples will determine whether or not the world is safe for human habitation. Juliette learns the samples all have a high amount of argon in them, which she believes is what is leading to the deaths of anyone who ventures outside. Keene later realizes the argon is how the nanobots – both good and bad – are transmitted by Silo 1.