Air pollution is one of the most pressing environmental challenges globally. The World Health Organization (WHO) states that 99% of the entire global population breathes air that surpasses WHO guideline limits and contains elevated pollutant levels, with the highest exposures being experienced predominantly by low- and middle-income countries.1
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A report by the Max Planck Institute for Chemistry estimated that annual mortality rates could reach around 30 million people globally by the end of the 21st century. This is from both air pollution and increasingly projected extreme temperatures.2
Several air pollutants are present in urban areas, many of which result from combustion and vehicles, including nitrogen dioxide, sulfur dioxide, and ozone (produced by burning fossil fuels), particulates from solid and liquid matter (created during fuel combustion), and carbon monoxide.
Sensors for Air Pollution Monitoring
Air pollution sensors are a critical technological solution for combatting these toxic pollutants, with many types of sensors available on the market.
This article will explore air pollution sensors and their use in the modern world.
The Basics of Air Pollution Sensors
As the name suggests, air pollution sensors detect the presence and concentration of airborne contaminants. Various sensors have been developed over the years, providing critical data to help protect human health.
Several sensing methods are employed in air pollution sensors, such as non-dispersive infrared (NDIR,) light scattering, and electrochemistry.
Common pollutants detected by air pollution sensors include particulate matter and gases such as volatile organic compounds (VOCs,) CO2, carbon monoxide, and nitrogen dioxide (NO2.)
Where are Air Pollution Sensors Installed?
Installation location is critical for the effectiveness of air pollution sensors, both indoor and outdoor variants.
Sensors in industrial settings are typically placed near emission sources and where workers are likely to be exposed to harmful contaminants.
Residential gas sensors are usually placed in living spaces away from direct pollution sources to ensure accuracy.
Outdoor air pollution sensors are placed in strategic locations to monitor ambient air quality.3
Satellite-based sensors monitor large-scale areas for air pollution and air quality, providing crucial data on the impact of human activities on the natural world.
Algorithms in many sensors, both low-cost and small-scale and expensive large-scale variants, convert raw data into useful information. Other features of higher-quality technologies include controlling the air temperature within them to ensure long-term measurement consistency.4
Multiple sensor networks can be employed to track air pollution and improve measurement reliability. While this is a more useful approach to gathering critical information on air pollution across both local and global scales, the level of expertise needed to interpret results is increased, especially if multiple types of sensors are employed.
What are the Benefits of Air Pollution Monitoring?
Air pollution sensors provide several benefits to experts in environmental monitoring and public health. For example, they provide real-time air quality monitoring capabilities in urban and industrial areas. Expanded monitoring also provides critical data on pollution hotspots and trends.
One of the most important benefits of air pollution sensors is their use in supporting public health initiatives. Their real-time monitoring capabilities, especially if multiple types of sensors are utilized, help to reduce urban populations' and workers' exposure to harmful pollutants.
Lower-cost sensors also enhance community engagement by lowering barriers to data accessibility and monitoring results. Furthermore, they can play a crucial role in emerging citizen science efforts.4
Monitoring air quality
Video Credit: European Space Agency, ESA/YouTube.com
Applications and Success Stories of Air Pollution Sensors
Air pollution sensors can be employed in various environments and emerging applications. The smart city concept, for instance, which is based on Internet of Things (IoT) technologies, makes widespread use of smart sensors, such as air pollution sensors, to provide real-time data on numerous factors that impact the health of urban populations.
Carbon emissions sensors are integral to modern factories, power stations, and other heavy industry settings. By placing sensors near emission sources such as smokestacks, emissions data can be analyzed, and emissions levels can be reduced. This helps to improve air quality and reduce industrial operations' carbon footprint.
Several success stories have emerged in recent years alongside innovations in fields such as wearable tech. The city of Beijing, for example, has installed a network of over 1,000 citywide-distributed PM2.5 sensors. The network utilizes technologies such as laser radar and satellite-based high-resolution remote sensing.5 Along with other efforts, Beijing saw a 25% reduction in PM2.5 levels between 2013 and 2017.
Another case study that highlights the success of innovation in air quality monitoring and air pollution sensors is HabitatMap.6 This non-profit project provides low-income communities and stakeholders with low-cost, wearable air quality sensors. HabitatMap offers Airbeam, a palm-sized air quality sensor system.
HabitatMap’s efforts over the past few years has led to the non-profit now providing one of the largest open-source databases on air pollution and quality monitoring globally. It is helping to democratize access to air quality data for conventionally underserved communities disproportionately impacted by air pollution.6
What are the Disadvantages of an Air Pollution Monitoring System?
Disadvantages of air pollution sensors include the variable performance of low-cost and readily available sensors, which can lead to inconsistent measurements, particularly if sensors manufactured by different companies are utilized. There can also be issues with algorithm transparency.
Data management can also be an issue. As monitoring networks expand, large amounts of inconsistently formatted data require closer management and increased storage.
The complexity of real-time data generation requires analysts with the expertise to interpret information on air pollution and quality gathered by sensor networks.
In addition, current satellite-based and low-cost sensors do not adequately monitor some toxins, and low-income communities face barriers to deploying sensors. This is especially problematic as these communities are disproportionately impacted by poor air quality.4
The Future of Air Pollution Sensors
Innovation will continue to be a cornerstone of the air pollution sensor field. Artificial intelligence (AI) integration, wearable technology, and IoT technologies are some emerging technologies that will play a key role in the industry's evolution. Furthermore, emerging trends such as citizen science and crowdsourced, open-source data will likely play a central part in the field's future.
Air pollution and air quality sensors are essential for improving human health and helping the world transition to net zero. Real-time, high-quality data from both large-scale satellite networks and emerging localized, low-cost technologies is playing a key role in helping to reduce emissions and improve air quality.
Sensors are just one piece of the puzzle, however. Without robust public health and clean air initiatives, as well as a global transition to renewables and green technologies and practices, air pollution, environmental impacts, and effects on health will continue to be a critical problem. Therefore, a comprehensive approach to emissions reductions and air quality improvement is needed.
Sensors are among the most powerful tools available to governments, local action groups, policymakers, and multiple other stakeholders. Their continued contributions and technological progress are helping to improve the health of billions worldwide and mitigate the harmful impact of modern industrial activity on the natural world.
Read More: Real-Time Environmental Awareness: The Power of Pollution Monitoring
References and Further Reading
1. World Health Organization. (n.d.) Air pollution. [Online] Available at : https://www.who.int/health-topics/air-pollution (Accessed on 7 January 2025)
2. The Max Planck Society (2024) Climate change and air pollution could risk 30 million lives annually by 2100 [online] Phys.org. Available at: https://phys.org/news/2024-11-climate-air-pollution-million-annually.html (Accessed on 4 January 2025)
3. Anju Thangum Joy (2024) Understanding Air Quality Sensors and Their Importance [online] Tameson.com. Available at: https://tameson.com/pages/air-quality-sensor (Accessed on 4 January 2025)
4. U.S. Governmental Accountability Office (2020) Science & Tech Spotlight: Air Quality Sensors [online] gao.gov. Available at: https://www.gao.gov/products/gao-21-189sp (Accessed on 4 January 2025)
5. Alam, N (2023) Clearing the skies: How Beijing tackled air pollution & what lies ahead [online] Sustainable Mobility. Available at: https://sustainablemobility.iclei.org/air-pollution-beijing (Accessed on 4 January 2025)
6. Clean Air Fund (2023) Wearable air sensors enable communities to advocate for clean air [online] Available at: https://www.cleanairfund.org/case-study/wearable-air-sensors/ (Accessed on 4 January 2025)
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