We asked doctors and researchers for their top face masks that balance comfort and safety

To pick the right face mask, doctors often recommend a simple trick: Try blowing out a candle while wearing it. A good mask should prevent you from extinguishing the flame.But it can be difficult to know whether a mask will pass the candle test just by looking at it.

So Business Insider asked four doctors and one mask researcher about the face coverings they wear outside work and those that meet their safety criteria. Some recommended DIY options, while others suggested multi-layer masks that have undergone independent filtration tests.

The best mask is the one that fits and that you're actually wearing," Dr. Alice Sato, an epidemiologist at Children's Hospital & Medical Center in Omaha.The ideal mask blocks both large respiratory droplets from coughs or sneezes, along with smaller airborne particles called aerosols, which are produced when people talk or exhale.

It should be sealed around the nose and mouth, since any gaps, holes, or vents could allow droplets to leak out and infect others. Sato said plenty of non-medical masks meet that criteria.

"We've actually not seen a very large difference at all between well-fitted ear loop masks or surgical masks compared to N95 respirators for this disease [COVID-19]," she said. "Really that fit is almost more important than that slight difference in the filtration."