The disposable face mask can filter large droplets produced by someone coughing or talking loudly near you, and has a moisture repellent outer layer, but it is less able to filter the tiny aerosol particles that also potentially carry the virus, as it doesn't fit tightly to the face. However, like reusable face coverings, they do help to capture droplets exhaled by you when coughing, sneezing or talking, helping to limit the spread of viral particles. Surgical or medical face masks are single-use disposable products, usually sold in boxes of 50 or more, but they can also be found in smaller packs these days in high street stores and pharmacies. They tend to be blue, rectangular and pleated, with elastic ear straps and a nose wire.

http://www.hiknowmedical.com/disposable-face-mask/