Scientists found that larger noses inhale almost seven per cent fewer pollutants than smaller ones, and also act as a barrier to deflect germs away from the mouth.
Bigger noses could even reduce the effects of hay fever, which is on a rise among Britons.
Researchers found that more prominent facial features, such as noses and lips, reduce "aspiration efficiency" and therefore fewer dust particles and airborne bacteria enter the body.
The findings provide some comfort for those who worry about their features, including actress Lisa Kudrow, 46, who played Phoebe in 'Friends' and who had cosmetic surgery to change the shape of her nose when she was 16.
Gisele Bundchen, the 29-year-old Brazilian model, has referred to her own nose as "big" but insisted "that's fine".
For the study, researchers at the University of Iowa in the United States created two artificial noses, one 2.3 times bigger than the other.
Each nose was placed on an artificial head in turn and in variation with two sets of lips, also in different sizes.
The lips covered the end of a tube and drew in air containing a range of particles.
The results revealed 6.5 per cent fewer particles were taken in with the large nose in place.
The large lips also reduced the particle intake by 3.2 per cent.
"The nose sticks out and gives better protection to the mouth. A big nose might lower the risk of being infected. It may work for pollen too," the Telegraph quoted Dr Renee Anthony, assistant professor at the Department of Occupational and Environmental Health at the University of Iowa, who led the study, as saying.
The research was published in the journal Annals Of Occupational Hygiene.