I've had this filter for about 3 weeks. It has a strange odor. I have been running it as much as possible (probably 60% of that time) to see if the smell would go away, but it hasn't yet. This filter is for the air purifier in my bedroom so the smell is really bothersome. This is the third filter I've tried for this purifier and they all have this odor. Not sure if I should just give up at this point.