The hottest new apocalypse-preparation choice for 2019 is not a bunker or a gun or a lifeboat.

It’s a small gadget that measures the air pollution around you.

As climate change reports become increasingly dire, and as wildfires tear across the American West, and as trust in the federal government’s air quality oversight fades, thousands of people around the country are taking air measurements into their own hands.

Installed on a porch, a console table or hooked to a backpack, these small, sleek and increasingly inexpensive devices measure hyperlocal air quality. They are marketed to the discerning and alarmed consumer. Some have begun to self-identify as “breathers.”

The Atmotube and PlumeLab’s Flow are small and meant to be carried around, testing the air as a person walks or bikes, helping people plan routes that avoid bad air. The Awair looks like an old-timey radio and sits on a counter to test indoor air. Aeroqual’s particulate monitor, one of the most advanced, looks like an enormous old-fashioned cellphone.

But the monitor most intriguing local government environmental protection agencies and civilians alike is PurpleAir. It hooks up outside, connects to Wi-Fi, feeds into a global network and creates something like a guerrilla air quality monitoring network.

Adrian Dybwad, 49, founder of PurpleAir, would watch the dust from a nearby gravel pit blow near his house in Draper, Utah, where he lives with his wife. When the miners working there tried to expand it even closer, he decided he had to do something. First he had to prove there was something wrong with the air.

Read more: How to take air-pollution testing into your own hands