Nasal hair has a biological purpose. According to the hair care website Keratin.com, hair fiber, hair follicles and the nerve networks around them offer protective functions for your body. The short hair you see protruding from your skin is a small portion, with the hair shaft extending through the epidermis, into the layers of the dermis and the hypodermis, and into the hair follicle.
Your nose hair, as well as other hair fibers on your body, create a tough yet flexible barrier. Keratin.com states that nasal hair protects the epidermal layer of your skin from small abrasions and sunlight. Nasal hair also has a more specialized function, creating a shield between your body's internal organs and the pollutants of the outside world. When you inhale, you can potentially take in small particles along with oxygen, but nose hairs filter away most debris.
Your nose hair contributes to your well-being in several ways. Nursing Times.net's article on the respiratory system states that airborne pathogens never reach your respiratory tract because of your nasal hairs. They are aided by your mucus, which traps particles and germs. If irritants do get by your nasal hairs and into your respiratory tract, you often sneeze to expel them.
Nasal hair fibers have ancillary purposes. The Hair Biology website attributes hair fiber with adding surface area to the skin, which aids in sweat evaporation. The network of nerves surrounding a nasal hair follicle provides information to your body about your environment.
An article about hair follicle structure on Regrowth.com warns that outside factors can influence hair growth, resulting in increased or decreased nasal hair. Certain medical treatments, chemicals and even cosmetics can destroy the hair follicle. In addition, health and genetic factors might change patterns of hair growth. Lack of nasal hair can increase your risk of getting ill.
While nasal hair serves key purposes, long nasal hair does not. You can safely trim longer hairs without affecting their filtering ability.