These are, in fact, blackheads. Blackheads are a type of acne
caused when the pores on the skin become distended and clogged open with dead skin debris, bacteria, and the skin's natural oily secretions. A chemical reaction between the air and this debris gives the blackhead its typical grey or black look. Blackheads are often more common on the nose than on other parts of the face because the skin's oil glands on the nose are very active.
Treatment of blackheads mostly involves attempts to reduce the amount of debris that can clog the pores. The first step, of course, is a good daily facial cleansing regimen to remove oil and dead skin. Gentle exfoliation is also quite helpful. If this alone is not sufficient, then the next step would be to add an over the counter acne preparation containing a comedonolytic such as benzoyl peroxide or salicylic acid. Comedonolytics work by 'stripping' the upper dead layer of skin. Numerous acne preparations are available that contain one of these products.
If these methods do not work, then it is time to see your primary care doctor
or a dermatologist
. They can provide you with stronger creams and other medications to get the acne under control.