Air pollution is one of the most pressing global health issues of our time. Fine particulate matter (PM2.5), nitrogen dioxide (NO₂), and ozone are just a few pollutants linked to respiratory illness, cardiovascular disease, developmental issues in children, and even reduced life expectancy. These impacts are not distributed equally: low-income and marginalized communities, often located near highways, factories, or lacking green space, tend to bear the heaviest burden.
While the atmosphere connects us all, our access to air quality data is far from equal. In many parts of the world, especially in low- and middle-income countries and environmental justice communities, the infrastructure to monitor air quality simply doesn’t exist. And where data does exist it’s often not made public or is difficult to find–it might be locked behind paywalls or published in formats that are difficult to work with.
This disparity isn’t just about data; it’s about power, agency, and environmental justice. How can communities fight for solutions if they can’t see the problem?
This blog explores how OpenAQ, a nonprofit organization, is working behind the scenes to close these gaps by democratizing access to global air quality data. Through technical infrastructure, open-source tools, and partnerships worldwide, OpenAQ enables action, accountability, and equity–helping build a future where everyone can breathe easier and fight back with facts. To learn more about how this mission comes to life, I had the opportunity to interview Chris Hagerbaumer, the Executive Director of OpenAQ, and gain firsthand insight into the organization’s goals, challenges, and impact.
What Is OpenAQ?
OpenAQ was founded with a powerful mission: to make global air quality data open and accessible to all. Co-founded by Dr. Christa Hasenkopf and supported by scientists, developers, and advocates, OpenAQ grew from the idea that centralized, harmonized air quality data could accelerate science, policy, and community action.
Rather than creating sensors or conducting direct air quality monitoring, OpenAQ serves as a data infrastructure hub.The organization aggregates and harmonizes data from many government monitors and community sensors worldwide. This enables scientists, journalists, policymakers, and activists to access high-quality, standardized air quality information without needing to collect it from dozens of fragmented sources.
Whether it’s NASA validating satellite-based air quality forecasts with ground-level data or community groups identifying gaps in monitoring to advocate for change, OpenAQ is the invisible backbone supporting efforts for clean air worldwide.
The Power of Open Data
What exactly is open air quality data, and why does it matter?
At its core, open data is about freedom: the freedom to access information, use it, share it, and build on it without restrictions. When it comes to air quality, that freedom has real-world consequences. Open air quality data empowers researchers to identify health risks, journalists to expose environmental injustices, and communities to organize around local pollution issues. Without open data, this critical information remains hidden in silos, unavailable to the very people who need it most.
To OpenAQ, open data isn’t just about availability—it’s about utility. Data must be usable, not just posted online. That’s why OpenAQ defines truly open air quality data by four essential criteria:
- Timely: The data should be regularly updated—ideally in real time or hourly—to reflect current conditions and enable quick response.
- Location-Based: Data points must have precise geographic coordinates, not just vague city labels.
- Programmatically Accessible: Data should be retrievable through APIs (machine-to-machine), making immediate, large-scale analysis feasible. PDFs on a website don’t allow for this.
- Raw Measurements: Instead of unitless AQI (Air Quality Index) values, data should include actual pollutant concentrations (e.g., PM2.5 in µg/m³).
Why emphasize raw data? While an AQI is helpful for public alerts, it’s a simplification. Researchers, health professionals, and advocates need the underlying pollutant values to uncover patterns, run models, and develop evidence-based policies. An AQI doesn’t tell you how much PM2.5 was in the air when asthma rates spiked in a neighborhood; it is the raw numbers that reveal those connections.
OpenAQ provides access to real-time and historical data, serving as a repository so that longer-term trends can be examined.
OpenAQ’s mission is to make this level of transparency the global standard, not the exception. By liberating high-quality air quality data from hard-to-access sources, they’re enabling evidence-based action worldwide.
Bridging Global Gaps
The disparities in global air quality monitoring are prominent. OpenAQ’s biennial global report, Open Air Quality Data: The Global Landscape, reveals most recently that
- 36% of countries don’t monitor air quality at all.
- Only just over 25% of countries provide maximally valid open data.
- Even in well-resourced countries like the U.S., significant monitoring gaps exist, especially in rural areas and environmental justice communities.
Chris emphasized how surprising some of these gaps can be. For instance, a recent U.S. county-level analysis revealed that rural counties across the Midwest–places not typically considered pollution hotspots–often have no monitoring infrastructure. This means that pollutants from agriculture, oil, and gas operations, or wildfire smoke, can go undetected, leaving entire populations without data to protect their health.
This “air inequality” has real consequences. Without data, problems go unmeasured and unaddressed. That’s why OpenAQ’s work is so important: making data visible makes the inequality hard to ignore.
How OpenAQ Harmonizes Disparate Data
One of OpenAQ’s most critical roles is data harmonization. This means making air quality data from thousands of sources interoperable and comparable. Chris offered a few behind-the-scenes examples:
- Timestamps: Some monitors report data at the beginning of the hour, others at the end. Without correction, comparing them would be misleading.
- Time Zones: Global datasets require consistent reporting of time, OpenAQ ensures local time is correctly reported so values are usable and match local timezones and offsets.
- Measurement Units: Pollutant concentrations may be reported in different units, such as micrograms per cubic meter or parts per billion, requiring conversion.
- Data Formats: Some datasets are clean and API-ready. Others come from messy spreadsheets or even PDFs.
OpenAQ does the complex, tedious work of cleaning and aligning these datasets so others don’t have to. This allows users to easily run models, visualize trends, and build tools across borders and time periods.
Challenges to Scaling Open Access
Despite their success, OpenAQ faces several challenges, many of which are systemic.
- Funding and Maintenance: Open infrastructure is vital, but often undervalued. As Chris noted, platforms like OpenAQ operate behind the scenes and don’t always attract the same flashy attention or funding as hardware-based or AI-driven projects.
- Government resistance: In some regions, governments are reluctant to share air quality data, viewing it as politically sensitive. This creates barriers to openness, transparency, and accountability.
- Data Quality Variability: Not all data sources are equal, and even the most sophisticated monitors can report erroneous values. The equipment used to monitor air quality ranges from relatively inexpensive air sensors to “gold standard” reference monitors. While the data quality may improve with more expensive instrumentation, air sensors are becoming more and more accurate. Moreover, because absolute precision is not necessary for most use cases, OpenAQ believes in sharing data from a wide range of data sources. OpenAQ shares the data “as is” so as not to break the chain of custody of the data and provides metadata (the data providing the context for individual data points) to help data practitioners understand whether corrections are needed.
Community and Collaboration
While OpenAQ provides the global infrastructure to unlock air quality data, actual progress comes from the ground up. Community organizations, researchers, and citizen scientists are critical to translating data into action and filling in the remaining gaps.
Chris emphasized the importance of hyperlocal partnerships in bridging the divide between data availability and lived experience. Organizations such as Brightline Defense in the Bay Area exemplify this model. As a frontline environmental justice nonprofit, Brightline works directly with communities most impacted by pollution, deploying low-cost sensors to engage community members in understanding and advocating for cleaner air.
Lower-cost sensors are playing a transformative role, dramatically expanding access to air quality data, especially in underserved regions. OpenAQ believes that community monitoring networks using lower-cost sensors are reliable and accurate enough for their main purposes: to identify potential issues and serve as awareness-raising tools.
These networks aren’t just tools; they are invitations. Chris pointed out that students, researchers, and grassroots advocates all have a role to play in identifying data deserts and pushing for greater transparency. For instance, scientists can analyze OpenAQ datasets to uncover environmental inequalities, while local activists can install sensors to monitor school zones, industrial sites, or wildfire-prone areas that official networks overlook.
Ultimately, community-driven collaboration transforms open data into open power. By working together—from open-source coders to neighborhood coalitions—we move closer to a world where everyone can see the air they breathe and fight for the air they deserve.
Conclusion: A Call to Open the Air
After my conversation with Chris, it became clear that open air quality data is more than numbers on a screen; it’s the catalyst for awareness, equity, and action. When communities can access clear, reliable, and timely information, they can organize for cleaner air, advocate for policy change, and protect their health. When researchers and journalists can analyze raw pollutant data, they can uncover hidden patterns and push for stronger environmental protections. And when policymakers rely on transparent data, they can make more informed decisions.
The vision OpenAQ is building toward is one where every breath is informed, no community is left in the dark, and data serves the people who need it most. And this future depends on all of us.