NO face mask, only a full face respirator-type with adequate filters, is 100% sure to stop viruses. But better an N95 than nothing. People also need to be aware that microbes, including the Coronavirus, can enter the body by hand transmission through touching the mouth or eyes. A study showed that people touch their faces about 20 times per hour! So first stage is to wear a mask now if you feel better, keep your hands frequently washed and avoid potential areas of risk - like Chinese New Year parties. The final stage, if the virus becomes pandemic (infects the whole world) and has a high death rate (sometimes those that spread the fastest do not kill the most) is to self-isolate. This means to stay in your home! Avoid visitors,but if any do arrive then greet from a distance with a mask on, send them away asap and wash your hands. This is a very serious step to take but it may be the only way to reduce the risk from, perhaps, 50% to almost (and possibly) zero. The flu pandemic of 1919 affected 500 million people and killed 50 million (these are only estimates and could be higher) - and think how infrequently people travelled in those days and how much lower and less-crowded the world population was!