Air pollution in large cities four times the safe level – new data platform launched to aid fight for clean air

Brasilia view - by Messal Ciulla from Pexels
Brasilia view – by Messal Ciulla from Pexels
  • Global air pollution data from OpenAQ shows 33 of the largest cities in the world are exceeding WHO guidance for PM2.5 air pollution by 4 times on average.
  • 90% of the world suffers harmful pollution levels, yet only half has access to air quality data.
  • A new pilot platform hosted by the air quality data platform OpenAQ, in partnership with the Environmental Defense Fund, creates the largest open-source repository of low-cost sensor data.
  • Low-cost sensors help to fill key monitoring gaps and enable cities, governments, researchers, and citizens to participate in monitoring air quality and fighting air pollution in their communities.

Oxford, 01/02/2021. Some 90% of the world suffers from harmful levels of air pollution, believes a coalition of NGOs focusing on air quality. The problems are acute right now in urban areas in the global south, yet they are building in communities across the globe.

A recent investigation into the largest cities in the world showed that the average annual level of PM2.5 air pollution was 39 ug/m3, nearly 4 times higher than the World Health Organization guidelines (10 ug/m3). The worst affected cities were in Asia – Lahore (Pakistan), Delhi (India), Dhaka (Bangladesh), Ahmedabad (India) and Xi’an (China) having the highest levels measured, according to OpenAQ. The data illustrates the stark global inequalities of air pollution, For instance, the recorded PM2.5 levels in Delhi were 102 compared to just 7.7 in New York City.

Yet many of these problems could be addressed if better data became available through improved measurement and monitoring. Which is why OpenAQ, a global nonprofit NGO, today announced a new pilot platform integrating low-cost sensors that will enable citizens to track air quality and fight air pollution in their local communities.

OpenAQ aims to build the world’s largest repository of air quality data. Developed with the Environmental Defense Fund (EDF), a pilot project hosted on will provide a portal for research scientists, NGOs, and individuals, enabling them to access reference-grade air quality data across the world as well as newer, low-cost sensor data.

The platform brings together low-cost sensor air quality data from EDF’s Air Quality Data Commons as well as from organisations such as Purple Air, HabitatMap and Carnegie Mellon University. The OpenAQ platform already houses more than three quarter billion (750 million) data points from 11,000+ stations in 99 countries. It provides a dashboard for searching and understanding low-cost sensor data, as well as all the data previously available on OpenAQ’s website and platform via an API.

Kids and traffic don't mix - pic by Tear Cordez
Kids and traffic don’t mix – pic by Tear Cordez

The new platform will be a resource for cities, governments, and communities at a time when the effects of air pollution on public health, including the challenges they present in individuals diagnosed with COVID-19, have come into sharper focus. As nations around the world plan for a recovery from the pandemic that prioritizes climate change goals, tackling air pollution will become an important priority. OpenAQ’s data platform will give governments and communities an important aid to tracking these efforts and informing policies and programmes.

Low-cost sensors are a new air quality monitoring technology that complements more traditional and expensive reference grade monitors and helps address these data gaps. Low-cost sensor units can be installed by individual users, communities as well as governments to increase coverage and access to air quality data to a greater number of citizens, policymakers and NGOs. Given their smaller size, they can be either mobile or in one place (stationary).

Jeremy Taub, Executive Director of OpenAQ, said: “We want to encourage new, affordable solutions to monitor air quality, and bring that data to OpenAQ to increase funding and action for those communities who are most affected by air pollution. It will fill important data gaps allowing communities to develop solutions to air pollution.”

Beijing smog - by kentaroiemoto
Beijing smog – by kentaroiemoto

Millie Chu Baird, Associate Vice President at Environmental Defense Fund, said: “One of the keys to fighting air pollution inequity is data transparency—ensuring that as wide a range of people as possible have access to as much of it as possible. It’s foundational to the ability to take action.”

Michael Heimbinder, Executive Director of HabitatMap said: “HabitatMap makes technologies accessible so communities facing disproportionate environmental burdens can advocate for equity and improved quality of life. We’re excited to have the air quality data contributed to the open-source AirCasting platform made available via OpenAQ’s low-cost sensor pilot.”

Albert Presto, Associate Research Professor at Carnegie Mellon University, said: “Sensors bring air pollution data to the neighborhood level, but people need to be able to access the data from trusted sources using reliable tools. OpenAQ is one source that will allow us to further disseminate this valuable data.”

Case Study – Accra, Ghana

In Ghana, 17,000 premature deaths are attributed to poor air quality. Across West Africa, biomass burning, vehicle emissions, and industrial waste are identified as the main contributors to the air pollution problem. Clean Air One Atmosphere, an NGO in Accra, Ghana built Yakokoe, a mobile application using PurpleAir low-cost sensor data to engage, educate and empower citizens to use air quality data to make informed decisions about how to protect their health. The mobile application provides Ghanaian citizens with free air quality data in their region and its associated health risks by sharing an Air Quality Index (AQI) that has different thresholds based on risk levels. Having PurpleAir data now available on the integrated OpenAQ pilot platform opens new possibilities to scale impact, as it draws attention to air quality challenges in Ghana and West Africa at-large to the rest of the world.

Case Study – Los Angeles, United States

High volumes of traffic and pollution from diesel trucks, trains, and ships that service the Port of Los Angeles/Long Beach – the busiest port in the US – contribute to the LA metropolitan region’s ranking as one of most heavily polluted areas of the country. A Day in the Life at the University of Southern California allows young people, to tell the story of their own experiences with air pollution by combining low-cost sensor data with text, photos, and videos. After being trained to use the AirBeams + AirCasting platform which originates from HabitatMap one of the low-cost sensor data partners in the pilot, A Day in the Life participants collect data over a one to two week period with the goal of collecting at least eight to ten hours of data on a single day to illustrate their daily exposure to PM2.5. Started in 2017, participants have logged nearly 200 AirBeam sessions on the AirCasting mobile app resulting in over 520 hours of particulate matter exposure data collected.

Further information

[1] See p 10, OpenAQ report – Open Air Quality Data: The Global State of Play


[3] OpenAQ Impact Story. The Push for Open Air-Quality Data in West Africa

[4] More details: USC Environmental Health Centers (

Leave a Reply