A decade ago, when the firefighter John Burke earned his master’s degree in health care emergency management, he wrote his thesis on pandemic planning. So when the coronavirus hit last spring, Mr. Burke, now the fire chief in Sandwich, Mass., was ready.

“I had my playbook ready to go,” Mr. Burke said.

Testing for the virus was a top priority, so he connected with a private laboratory to ensure that his firefighters, who were transporting coronavirus patients to hospitals, could be regularly tested.

And then he heard that Thermo Fisher Scientific, a Massachusetts company that makes laboratory equipment and materials, was beta testing an air sampler that could help him detect airborne coronavirus particles.

By December, he had installed one in a fire station hallway. The device, about the size of a toaster oven, sucked in ambient air and trapped airborne virus particles — if there were any to be found — in a specialized cartridge. Each afternoon, an employee would remove the cartridge and walk it to the UPS drop box across the street, sending it off for laboratory analysis.