Governments have a responsibility to address air pollution, a problem so ubiquitous that almost everyone (99% of the world’s population) is breathing unhealthy air.

Air pollution is the second leading risk factor and the greatest threat from outside of the human body that can cause death, cutting lives short by an average of 1.9 years across the globe.

Exposure to air pollution starts in the womb and can be linked to numerous poor health outcomes over a lifetime, as well as impacts on productivity and quality of life.

The burden is unequal, harming babies and young children in particular and residents of lower-income communities and countries where pollution tends to be higher.

Reliable and open data on air pollution are fundamental to understanding and taking corrective action to improve air quality.

These air pollution measurements are relevant not only to governments to improve and track their citizens’ health but also to anyone who breathes in the air. Those who can help solve the problem can use the data when conducting epidemiological studies, determining the sources of pollution, spreading awareness and building forecasting models.

Rather than attempt to solve air pollution in isolation, governments that embrace open data policies can leverage the expertise of others to build more innovative and durable approaches to solving the air pollution crisis.

OpenAQ – an NGO that hosts the world’s largest open-source, open-access database of real-time and historical outdoor air quality measurements – has analyzed different countries to determine which have government-level air quality monitoring programmes and whether and how those governments are opening their monitoring data to the public.

Just 64% of the countries examined conducted or sponsored continuous air quality monitoring at a national or subnational level in 2024, an increase of only 3% since the last report in 2022.

In other words, 36% of countries are not currently monitoring air pollution, one of the greatest global health risks. Major gaps in monitoring persist, with many of the most populated, polluted countries still lacking government-coordinated air quality monitoring programmes or conducting very limited monitoring, especially in the Global South.

In fact, nearly one billion people live across 71 countries where there is no evidence of government air quality monitoring. Nine out of 10 of them live in low-income or lower-middle-income countries, as classified by the World Bank.

Furthermore, for the most populated of countries whose national government is not monitoring air quality, air pollution is one of the top seven risk factors for death and disability in their country.

In the most populated countries without a national government air quality monitoring programme, air pollution is among the top seven risk factors for death and disability.

OpenAQ found that 55% of all countries surveyed share air quality data publicly; however, only 27% do so in a fully transparent way.

As one example, many countries share their data through an Air Quality Index (AQI), a first step toward transparency.

AQIs translate complex pollutant concentration data into a simple, understandable format that can alert the public about the immediate threat of polluted air. AQI providers often share actions that people can take to reduce exposure.

However, AQIs lack the detail necessary for most scientific inquiry and depending on the methodology used, they may even be misleading.

In short, barely over one-quarter of countries provide full and easy public access to maximally useful air quality data, with the requisite detail to inform scientific inquiry, policies to reduce air pollution, forecasts and other important use cases.

Compared to 2022, there is a slight increase in the number of countries that share their air quality data publicly (up by 2%) and a slight rise in countries making the data fully transparent and accessible (up by 4%).

Measuring and tracking air pollution levels is critical to understanding and developing solutions to poor air quality. Making air quality data open, easily accessible and freely available allows everyone across public, private and civil society to innovate, collaborate and apply effective solutions towards clean air.

To accelerate clean air progress, OpenAQ recommend:

Ensuring that air quality data is widely accessible and transparently shared is not just a technical necessity – it is a fundamental step toward safeguarding public health and achieving lasting solutions for cleaner air worldwide.