A local nurse in Texas has designed a mask, using commonly-available materials, that has been rated higher than the N-95 masks being used to protect against coronavirus.

University Health System chief executive nurse, Tommye Austin, has begun developing an emergency stockpile of the masks in anticipation for a Covid-19 surge in San Antonio, Texas, in May, according to a report on KSAT 12 News.

Ms Austin said the masks have a filtration efficiency of up to 99.5 per cent based on materials purchased at a local Lowe's store.

"Once we learned that the [Centers for Disease Control and Prevention] had given us the ability to create masks, rather than using a bandana or a handkerchief, we decided to look at creating our own N-95," she said.

"We had this AC filter material we purchased from Houston, Texas. The mask has a filtration rate of 99.5% with one material and has a 97.8% filtration efficiency with another material we are using," she explained.

"We have been working with the Southwest Research Institute in making sure that we just not develop something we think is a good product but something that we know is a good product by using science."

"It doesn't have what we call carbon dioxide buildup, which could make you dizzy or [give you] a headache. It is comfortable, and you can wear it for long periods of time," Ms Austin added.

The Southwest Research Institute would not confirm the results of the tests due to non-disclosure agreements.

So far Ms Austin and her team have made 600 masks and hope to produce 6,500 more. They will also be sharing the design with other facilities to anyone who needs an additional supply.

"Hearing the stories from the nurses in New York and other hot spots, it was just heartbreaking," she said. "As a nurse, we are to be advocates for people, so my primary goal was not to make money off this mask or anything. The main purpose of this mask was to keep people safe," Ms Austin said.