Yellow or greenish chest mucus is generally a symptom of infection and is often a sign that you should go to your doctor. Chest mucus that contains blood is often a symptom of a more serious infection such as pneumonia or TB, and large amounts of blood in the chest mucus should be seen as a medical emergency.
In California, your residency depends on how long you live in California, what ties you have to the state and local government and whether you are financially self-sufficient. You must be physically present in California for 366 days to become a state resident, except for brief absences such as vacations.
A person who s tax home is, say Germany, and temporarily assigned to a U.S. company for less than 183 days is considered a non resident for U.S. tax purposes (absent the provisions of the substantial presence test).