I do wonder about that but I hate to think that my beloved garden harmed me! My doctors think I've had this for a long time. I've traveled a lot around the world and lived in Asia too which is where I first was diagnosed with asthma. The air quality is horrible and I did drink the water. No regrets though, it was an amazing experience to work there. I have never smoked, exercise and eat healthy food. I considered myself healthy until my recent diagnosis. One of my doctors said I easily could have picked it up right here at home from the water and another said I probably picked it up overseas. I know it doesn't matter but like you, I do wonder.