6 months baby breathing noisily for about a month especialhen he is breast feeding and sleeping. should i worry?

Nasal breathing: Infants at 6m are dependent on their nose most of their air exchange. Within a few months their neck growth will permit mouth breathing as older kids can, but until then, any irritants in babies environment cause nasal mucous flow & nasal noise. Dust, fragrance, cleaning fumes, and the like all aggravate the process.Since babies nose is often compressed during feeding it can be make the noise louder.