From the study: "FFRs with an exhalation valve provide respiratory protection to the wearer and—according to the findings from this study—can also reduce particle emissions to levels similar to or better than those provided by surgical masks and unregulated barrier face coverings. This study shows that modifications to these respirators can further reduce particle emissions. The use of an ECG pad or surgical tape secured over the valve from the inside of the FFR can provide source control similar to that of an FFR with no exhalation valve."

And valved N95s are now around $2-3 each from established (not pandemic profiteering) online sources.