While air quality in North America and Europe has improved over the past decade thanks to stricter environmental regulations, extreme weather and record wildfires have raised new concerns about air pollution.

Smoke from wildfires in Quebec and Ontario drifted across the northeastern US this week, with an orange haze falling overhead New York City and unhealthy levels of air quality persisting in the region.

As a result, more and more people are turning to mobile apps to understand when air quality is improving or deteriorating wherever they are.

The Airnow mobile app was ranked sixth as of Thursday most downloaded a free app on the App Store for iPhone that beats TikTok, WhatsApp and Instagram.

Usage of these apps and new installations are often driven by regional events.

In general, air quality monitoring applications use a mix of data from government satellites, weather, fire and ambient air quality stations, as well as sensors and systems operated by private sector entities to monitor smoke and pollution levels. Some applications run on data obtained from relatively affordable air quality sensors sold by companies such as PurpleAir and IQAir.

• AirNow, created by the US Environmental Protection Agency, allows users to search for air quality levels by zip code or view country-wide Fire and SmokeMaps with some available fire and smoke data that may impact the US from Mexico and Canada. Like most air pollution trackers, it uses a color-coded visual system to indicate whether air pollution levels are good to dangerous, or if there is insufficient data to issue a rating.

• AirNow also has online maps that provide the public with actionable information about air pollution in any US zip code. These include a Map of fire and smoke, which provides information on fire locations, smoke plumes and air quality and AirNow interactive map shows ozone and particulate matter from air quality monitors across the country. While particulate matter (also called “PM 2.5” or “particulate pollution”) is the key pollutant in smoke, ozone can also be increased in fires.

• AirCare, made by developers in North Macedonia, it is available for iOS and Android mobile devices, including iPhones, iPads, Apple Watch and Huawei smartphones and many more. Tiers include an ad-supported free version and a pro version that costs $39.99 per year. The app includes kid-friendly air pollution information, charts and maps that show pollutant levels derived from government-run sensors and stations, along with PurpleAir volunteers and other sensors in the US, Europe and Australia. In some major metro areas, the app also tracks UV and pollen levels.

• AirVisual, made by Swiss air quality company IQAir, monitors air pollution in more than 10,000 cities and 80 countries using data from tens of thousands of sensors, some of which are located in US embassies overseas. The company’s free mobile apps are also ad-free and available for iOS and Android devices. In addition to real-time maps showing levels of six different types of major pollutants, AirVisual and the IQAir mobile website provide seven-day air pollution and weather forecasts, along with air pollution reports and health information. Apps can be paired with the company’s own sensors, including wearable ones AirVisual Pro sold for $299.

The researchers wrote in an email to CNBC in 2021 that: “Americans living in areas with poor air quality they tend to be people of color or low-income communities. We are finally starting to pay more attention to these issues, which will hopefully lead to change. The immission composition is also changing.”

In one example, greenhouse gas emissions from transportation refused in New York from 2014 to 2017, while commercial cooking emissions increased.

With wildfires increasing, the researchers wrote, “The sources and composition of the air pollution mix we experience could have different impacts on our health, so we need to better understand source-specific effects, especially for these newly important sources.”

While outdoor air quality is important, society doesn’t talk or do enough about it indoor air qualitysaid Richard Corsi of the University of California, Davis, incoming dean of the College of Engineering, currently a professor and dean at Portland State University.

Based on pre-pandemic numbers, Corsi explained that the average American will spend nearly 70 of their 79 years in buildings. “Because we spend so much time indoors, even our exposure to outdoor pollutants is controlled by what we breathe out there, especially in our homes,” he said.

Pollutants of outdoor origin, such as combustion engine vehicles, photochemical smog, refineries, and fires, can enter homes and buildings when doors and windows are opened, heating and air conditioning systems are used, or through other cracks in the building envelope.

Consumer apps and devices today do not provide users with absolute and accurate measurements down to micrograms per cubic meter of a given pollutant, Corsi noted. But they are very valuable for tracking trends and relative changes in air quality.

In addition, indoor sensors can work well to check whether protective measures are working to improve the air inside a home, school or other building.

Especially during wildfire season, Corsi said, some other simple actions that can protect or improve indoor air quality include: wet mopping floors and wiping surfaces to keep pollutants from accumulating, using HEPA or high-efficiency particulate air filters and increasing MERV . or the minimum reported efficiency value of the filters in the central air systems in the house.