Why does my guinea pig keep sneezing?

I just got a new guinea pig for Easter. She is wonderful in every way but for some reason she has been sneezing. Others has said bedding and others said freshner. But I though and thought and wondered could it be the smell of my turtle. I'm keeping a aquatic turtle for spring break or my teacher. Do you think that's it? I hope so because I will be giving her back Tuesday. Please give me a opinion. Thanks.