What are the local fruits in calamba laguna? ​

how can calamansi air freshener affects the people who have asthma?

Yes, anyone can. But the validity of which depends on the thinking tool and process of introspection it used to test it. Anyone can create their own metaphysics or a vernacular belief, but as to who they want to believe them, meaning the scope of their audience, or the gravity of their claim, such theories need a careful method of study. If it's just themselves they want to please, then yes, they can create their own theories out of the patterns they see in the world.