Health officials across Minnesota are distributing thousands of free, higher quality masks, especially to people in vulnerable groups who otherwise would lack access.

Gov. Tim Walz announced a plan in January to distribute 2.1 million masks from a state stockpile. Around 650,000 masks are being provided to local public health agencies, which in some instances are making limited supplies available to all residents. Schools are receiving 550,000 masks for staff and students.

The push, which includes both KN95 and N95 masks, comes as more Minnesotans are weighing their mask options. Experts in respiratory protection are highlighting everything from a type of mask popular in South Korea to N95 respirators that are available for free in retail pharmacies in the U.S.

"All of the masks fulfill the CDC and MDH recommendation that Minnesotans use N95 and KN95 masks to have stronger protection than cloth or surgical masks," said Devin Henry, a spokesman for the state's COVID-19 Response.

State data show about 1 million of the masks being distributed from the state stockpile are KN95 models, which are made according to international standards to provide more protection than surgical or cloth masks. These masks often feature a vertical fold in the middle and are held in place over the nose and mouth by ear loops.

Another 926,000 masks being distributed are N95 respirators, which are made according to U.S. standards for filtering out 95% of particles in the air. Rather than looping behind the ears, most U.S.-approved N95 masks have straps that extend to the back of the head. The straps create a tighter fit and allow N95 masks to provide more protection than KN95s, researchers say.

While masks being distributed by the state are primarily directed to certain community groups and schools, the federal government's separate program for free N95s is open to the general public.

At drug stores in Minnesota, supplies continue to be somewhat spotty. On Thursday, a Walmart in Brooklyn Center and a CVS Pharmacy in Maplewood had free masks, but three other stores in those communities had none.

Some people prefer KN95 masks, saying they're more comfortable than N95s. But it can be a challenge to know whether you're buying a well-made KN95. About 60% of KN95 respirators evaluated by the federal government in 2020 and 2021 did not measure up to standards.

In Minnesota, the state required mask manufacturers to send samples that were tested at the University of Minnesota, said Wayne Waslaski, project manager with the state's critical care supply team. The state also worked to find and manufacture quality masks with Bloomington-based Donaldson Co.

For the KN95s that the state is distributing, nearly 500,000 came through the Donaldson partnership while another 409,000 were manufactured by Maplewood-based 3M.

In some cases, counties are making limited supplies of KN95 masks available to the public, through vaccination events in Hennepin County and some libraries in Carver County. Ramsey County is providing masks to residents who complete an online form.

On Thursday, a Hennepin County clinic distributed masks — model 9501+ made by 3M — that provide 10-times better protection than average surgical masks, said Neil Carlson, an industrial hygienist at the U who did testing for the state.

Fit is key to making sure KN95 and N95 masks are providing the best possible protection, Carlson said. To guard against air gaps, users should check whether they're fogging up a pair of glasses while wearing their mask.

"You can have the best filtration material in the world," he said, "but if you've got an air gap where a bumblebee can fly through, what's the virus going to do?"

Carlson recommends buying KN95 masks in small quantities to minimize the investment in case there are problems.

"The likelihood of a person getting a good fit is very much dependent on the tension on the ear loop and then on the size of the face." Carlson said. "Very often — at least in my casual observation of people wearing KN95s — that fit is fairly loose.

"The ear loops may also be of poor quality and they'll detach. So when you get [KN95s], you need to pull back on them and you need to pull perpendicular to see if they're going to hold up. … Give it a little work out. Put it under some stress."

One trick for finding well-made KN95s online is to go a reputable manufacturer's website, said Aaron Collins, a self-described "mask nerd" who lives in Minneapolis and has developed a vast following on social media.

Manufacturers might not sell directly to consumers but often will link directly to third-party sellers like Amazon, so buyers know they're getting the real deal, Collins said.

Collins also suggests going through vetted suppliers: He recommends Bona Fide Masks and Project N95.

People who find KN95s more comfortable should consider a third higher-quality option — KF94 masks, Collins said.

Regulated by South Korea, KF94s have ear loops that often can be adjusted for a better fit. The masks come in various sizes for adults and children. As with KN95s, some find these "Korean Filter" masks easier to don and doff because they don't have the N95 head straps, which can frustrate people with long hair.

Not all KF94s sold online conform to South Korean standards, Collins said. He recommends buying masks imported directly from South Korea through suppliers such as Project N95, Be Healthy USA and Kollecte USA.

"I have no financial relationship with any mask manufacture or mask vendor," Collins said.

The state effort to distribute 2.1 million masks includes outreach to child care centers, clinics serving Medicaid enrollees, tribal nations and community groups that have worked with the Minnesota Department of Health to promote COVID-19 vaccines and testing in diverse communities.