The West Coast is suffering from some of the worst air in the world — these apps show how bad it is

Key Points

• Wildfires have been shrouding much of the Western United States and Canada in thick smoke.
• Portland, Oregon suffered from the worst air quality in the world for days. It's currently second only to Vancouver, Canada, which is choking on smoke from the U.S. blazes.
• The city of Seattle ranks third, San Francisco seventh and Los Angeles ninth.
• Worried residents are turning to maps and apps like AirNow, PurpleAir, and IQAir to see how bad the air is outside and where they can go to escape.
• Air quality sensors, like those from PurpleAir and IQAir, are also seeing record sales. 

As record-breaking fires wreak havoc on the Western United States, they're also releasing massive amounts of smoke and ash into the atmosphere, adding to the region's health woes.  

Portland, Oregon suffered from the worst air quality in the world for days. It's currently second only to Vancouver, Canada, which is choking on smoke from the U.S. blazes. Seattle ranks third, San Francisco seventh and Los Angeles ninth, according to IQAir. 

To find out where and when it's safe to go outside again, residents are flocking to air quality apps and websites like AirNow and PurpleAir in addition IQAir. They're also snapping up air quality sensors made by these and other groups to monitor pollution levels on their own properties, along with air purifiers to keep their homes and offices breathable.

On September 9, 2020, as skies above Oakland and San Francisco turned an eerie dark orange from the smoke, about 600,000 people visited the PurpleAir air quality map in a single day, according to Google Analytics data the company shared with CNBC. The vast majority of those visitors were from California. Site visits from users in Oregon and Washington were picking up on the 9th and 10th, as well, as Oregon prepared to evacuate some 500,000 people from harm's way.

PurpleAir CEO Adrian Dybwad told CNBC, "We feel glad to be able to help people measure and understand where the smoke is, how far it is traveling and where they might go to get clean air. But it is a very strange feeling when your business does well in the middle of such tragedies."

PurpleAir sold 1,000 sensors in recent weeks

Founded in 2015, PurpleAir creates its map with data that streams in from the sensors that the company makes at its Draper, Utah, headquarters, which cost between $199 to $279 apiece.

The company employs just 12 full-time employees but is looking to double that this season, and has about 9,000 of its sensors installed around the world up currently, up from about 6,000 at this time last year, Dybwad said. About 1,000 sensors were sold in the past few weeks, as lightning storms sparked an early fire season in California. 

The map is free and has no ads, and offers a simple color-coded key that shows just how bad the air is outside. A green dot means it's mostly clean. Orange means that sensitive groups will likely be affected after 24 hours, while red means everyone may be affected. The worst color, a dark purple-maroon, warns "Health warnings of emergency conditions if they are exposed for more than 24 hours. The entire population is more likely to be affected." On the worst days of the 2020 fire season, like Sept. 11, most of the west coast is covered in purple-maroon dots.

Readings on the PurpleAir map can appear higher than the measurements on the AirNow site managed by federal agencies including the U.S. Environmental Protection Agency and NASA.

Dybwad explained why: "Our sensors, essentially, shine a laser beam and when particles float through or are sucked through that beam of light, they count and assess the reflections. The more, and brighter the reflections generally, the more particles. The density that the sensor assumes can be slightly off depending what it is measuring, like wood smoke versus gravel dust, for example."

Wood smoke particles generally have a density of 1.5 grams per cubic centimeter, and gravel dust particles are typically 2.8 grams per cubic centimeter in density, he noted. 

For now, PurpleAir aims to show people where the intensity of air pollution is generally worsening or improving every few minutes, and whether the air is risky or healthy.

"We don't need to be splitting hairs all the time — whether it is purple or very purple, we know the intensity of the pollution is bad," said Dybwad. "Other companies try to hide their data, so you have to pay to log in to see it. Our philosophy is openness."

Other air quality companies are working on more precise measurements of particulates we breathe.

Aclima, a startup funded by the Schmidt Family Foundation, Emerson Collective and other environment-minded investors, is working on sensors that can measure particles and greenhouse gases, like ozone, to generate hyperlocal air quality data that is purchased and used by regulators and scientists, primarily.  

The startup's CEO and founder, Davida Herzl, said her systems work with a mix of technologies, including laser-based and electrochemical sensors and machine learning software, all combined into a kind of lab in a box. The systems are portable enough to go in the back of a passenger vehicle, which can rove around any town that needs to be monitored closely in the face of a new environmental threat. They can even generate readings of how air quality varies from one end of a city block to another.

The start-up is selling its data and systems to regulatory agencies like the Bay Area Air Quality Management District in California. They use Aclima data for emission reduction planning, and enforcement against polluters. Herzl said the company is monitoring air quality in an area that covers about 10 million residents, mostly in California with some in New York. She expects to double that coverage in the next six months.

Swiss air quality company IQAir, which also operates the AirVisual app, sees spikes in website visits and sales of air filtration systems whenever there's a significant environmental event like the fires now raging in the Western states, or the Australian wildfires in 2019, which burned 72,000 square miles of land, killed 34 people, and drove billions of animals out of their habitat.

For example, IQAir's CEO for North America, Glory Dolphin Hammes, told CNBC the company gained over 1 million new visitors to its air quality maps from August 17 to September 10 as fires broke out across the state of California, burning a record amount of acreage. Over that same period, new visitors to air quality maps for cities in Oregon and Washington on IQAir.com increased by more than 18,000% and 38,000% respectively. 

The company has more than 80,000 sensors measuring air quality around the world, with a majority in North America today, and some positioned at U.S. embassies around the world. 

While it's obvious that people should avoid going outside when the sky turns dark and orange with smoke, air quality problems and associated health risks remain even when skies appear normal, Hammes noted.

"We take air quality for granted all too often. You'll see a blue sky and assume you can breathe clean air as well. Tragic events like wildfires can bring a discussion about air quality to the forefront. But we want to make air quality visible and a topic of discussion all year round," she said.

Because the company sells air purification systems, not just sensors, some of its focus has shifted in 2020 to helping measure air quality and improve ventilation in more schools, hospitals and industrial settings. 

The rise of free, online air quality maps marks a massive shift in consumer awareness of air pollution, according to environmental journalist Amy Westervelt, creator of the climate change podcast Drilled. Westervelt says coal, manufacturing and other industries lobbied hard for government to treat air emissions data like a trade secret. But given sophisticated enough sensors, and data coming from consumers and open-source groups, industry won't be able to hide its impact on the air we breathe forever. 

"I think this 'airpocalypse' could put an end to environmental disinformation," said Westervelt. "You can't message your way out of it when the sky is on fire and nobody can leave the house."

WATCH: West Coast wildfires continue with at least 15 people dead