The Clean Air Catalyst Approach to Air Quality Monitoring

Blog by Chris Hagerbaumer, Executive Director, OpenAQ, August 28, 2023

OpenAQ is one of eight partners in the Clean Air Catalyst global partnership which is focused on building capacity for locally tailored solutions that curb air pollution, tackle climate change, and improve human health. Launched in 2020, it is supported by the U.S. Agency for International Development and led by World Resources Institute and Environmental Defense Fund, Inc. Other Catalyst partner organizations are Columbia Climate School Clean Air Toolbox for Cities, Climate and Clean Air Coalition, Internews, MAP-AQ and Vital Strategies. The Catalyst has projects on the ground in Indore, India; Jakarta, Indonesia; and Nairobi, Kenya.

Members of the Catalyst Indore team with one of the air quality monitoring stations installed in February 2023.

Clean Air Catalyst (Catalyst) operates under the theory that when people understand how pollution impacts them and their loved ones and what sources of pollution are affecting the air they breathe, they will have greater motivation to demand clean air and greater expertise to create solutions.

Expanding air quality monitoring and connecting it to the sources and impacts of air pollution is a key component of the Catalyst’s data-to-action approach for Indore, India, Jakarta, Indonesia and Nairobi, Kenya, as explained below: 

How is air quality monitored?

There are several different methods to measure the presence and concentrations of pollutants in the air, from fixed ground-level stations equipped with monitoring instruments to mobile monitoring using portable devices, to remote sensing techniques, such as satellites. Some are very accurate and precise, while others provide temporally and/or spatially coarser data, or estimates. Ground-based “reference-grade” or “research-grade” monitors are the gold standard, but because the operation of these monitors is complex, new ways to measure ground-level air quality have been developed in recent years. Many communities and even local governments are now supplementing reference-grade monitoring with monitoring using air sensors (often referred to as low-cost sensors) because their small size, portability and affordability allow for greater geographical coverage. In fact, in parts of the world where monitoring has never been possible because of its cost or complexity, air sensors are beginning to fill in data gaps. Satellite observations also fill in large gaps telling us generally which countries, regions and cities suffer the worst air pollution, but their precision depends on a number of variables and they are informed by ground-level measurements.

Reference-grade monitors retain their critical role in providing the most accurate data–often needed in regulatory situations–but the addition of satellite observations and air sensor measurements is helping communities and regions identify whether there is cause for concern.

Why is more monitoring needed?

By physically and chemically assessing the variations in air pollution levels and exposure in the airshed, monitoring can play a role in “source attribution” or identification of specific sources of pollution and their relative contribution to air pollution in a given area. Monitoring can also help capture differences in pollution levels within cities to identify pollution hotspots and communities that are most at risk of high levels of exposure. This level of detail is important to the Catalyst in order to better determine how air pollution impacts vulnerable populations, including women, children and low-income communities. The ultimate goal is to connect the dots between the lived experiences of people living, working and traveling in polluted sections of cities and actual air quality measurements.

What monitoring is the Clean Air Catalyst doing?

Because the cities where the Catalyst is working lack sufficient ground station monitoring, procurement of state-of-the-art continuous ambient air quality monitoring equipment has been prioritized. Continuous monitoring and reporting of real-time data is critical to identifying trends and patterns in air pollution levels. The teams chose reference-grade equipment to ensure the data collected is of the highest quality and can be used to support policy action.

In Indore, the Catalyst has partnered with the Indore Municipal Corporation (IMC) to install air monitoring equipment at three sites. Since February, the Indore Catalyst team has been operating the equipment, training local scientists and graduate students on its operation, and upon conclusion of the project, intends to hand the equipment off to IMC. In Jakarta, the Catalyst has facilitated a partnership between Jakarta Government Dinas Lingkungan Hidup (DHL) and WRI Indonesia and begun to install instruments at three new monitoring stations and upgrades to four existing ones. In Nairobi, site selection for two monitoring stations has been finalized and equipment has been ordered for an anticipated installation in 2024. To learn more about the monitoring equipment, see this document with frequently asked questions for Indore and Jakarta.

In Jakarta, the Catalyst is also participating in an innovative mobile monitoring project with Google Streetview to measure pollution on roadways. And it is collaborating with the low-cost monitoring company NAFAS to give sensors to women community leaders so they can experiment with tracking their pollution exposure. In Nairobi, the Catalyst is coordinating with Uganda-based AirQo to calibrate their network of low-cost sensors with the new ground monitoring stations when they are installed to provide more complete coverage of the city. And in Indore and the other cities, Catalyst partner MAP-AQ is using a combination of emissions inventories, modeling and ground-based measurements to provide deeper understanding of local and transboundary sources of pollution in the three Catalyst cities.

Who will have access to the monitoring data?

After robust quality assurance and quality control processes, the data will be provided to the public through the OpenAQ platform. OpenAQ works worldwide to make open air quality data freely available so that everyone can understand what’s in their air and can be part of the solution. Local government partners also have plans to incorporate the data into their public information platforms for researchers and public health officials to inform air quality alerts.

How is data quality ensured?

One of the principal concerns of governments, scientists, and organizations partnering with the Catalyst is to ensure that the data made public is quality assured, and quality controlled.

Air quality monitoring activities undertaken by the Clean Air Catalyst follow U.S. EPA guidance for quality assurance project plans (QAPPs) including EPA’s National Risk Management Research Laboratory QAPP Requirements for Measurement Projects, EPA Quality Assurance Handbook and Guidance Documents for Citizen Science Projects, and other best practices by members of the consortium and science team.

Quality assurance is hard work! Catalyst’s local science team and contractors carefully plan monitoring locations to ensure there are no interferences and that the pollutants measured correspond to the sources in that area. Teams visit sites weekly, ensure equipment is calibrated, analyze the data to identify and correct possible errors, and determine the causes of errors. Quality assurance planning allows gives the public confidence that Catalyst air quality data is validated and can be trusted.

There is great power in validated air quality data. When paired with reliable information about the sources of air pollution, it allows cities to design, implement, enforce and assess the effectiveness of their air pollution control policies. It can also be used to better understand how air pollution impacts human health, climate change, ecological health and economic well-being. The Catalyst’s investment in air quality monitoring is part of a comprehensive strategy to drive demand for actions that protect the atmosphere and our health.