Angela's like a breath of fresh air when she comes to stay.(CIDI)
After all the criticism, his positive comments came as a breath of fresh air.(CIDI)
Angela's so cheerful and lively - she's like a breath of fresh air when she visits.(CALD)
We`re throughly enjoying having Betsy staying with us. She`s so lively and interesting - a real breath of fresh air for my parents, who never go out or see a new face. (English Idioms, Oxford)