Coronavirus disease (COVID-19) advice for the public: When and how to use masks

When to use a mask Video
If you are healthy, you only need to wear a mask if you are taking care of a person with suspected 2019-nCoV infection.
Wear a mask if you are coughing or sneezing.
Masks are effective only when used in combination with frequent hand-cleaning with alcohol-based hand rub or soap and water.
If you wear a mask, then you must know how to use it and dispose of it properly.
How to put on, use, take off and dispose of a mask

more: world health organization