We present the results of a study of circumstellar dust envelopes of 36 stars of early(O-B-A) types in the directions of the associations Cas OB1, Cas OB2, Per OB1, and Ori OB1. We determine the absorption at λ1640 A, the linear radius of the dust envelopes, the mean value of the coefficient kλ, and the masses of the envelopes. They differ significantly from one another.