The Centers for Disease Control and Prevention now recommends Americans wear masks when they go out in public during the COVID-19 pandemic to prevent or slow down the spread of the virus.

A recent study shows the virus can spread between people interacting in close proximity, through speaking, coughing or sneezing. Masks are an important line of defense against respiratory infections and could reduce the risk of novel coronavirus infection.

Generally, there are three types of masks. Homemade cloth face masks, surgical masks and N95 respirators.

According to the CDC official website, “Cloth face coverings fashioned from household items or made at home from common materials at low cost can be used as an additional, voluntary public health measure.”

Materials used are the key to make homemade masks. Wake Forest University’s scientists and doctors recommend the materials used for facial covers be something that doesn’t let a lot of light show through. Tea towels, cotton-polyester blends and flannel pajamas are suitable materials for homemade face masks. These masks can be reinforced with coffee filters or other filtration materials.

Homemade masks should cover the nose and chin and allow for breathing without restriction.

“Surgical apparel are devices that are intended to be worn by operating room personnel during surgical procedures to protect both the surgical patient and the operating room personnel from transfer of microorganisms, body fluids, and particulate material,” according to the U.S. Food and Drug Administration website.

A surgical mask is effective in blocking splashes and large-particle droplets. But it is not meant to be used more than once. If the mask is damaged, people should replace it with a new one.

N95 Respirators could block at least 95% of very small particles from the air. They fit very closely to the face and should not be shared or reused.

This kind of mask is mainly used for the protection of medical and laboratory personnel.