Air pollution is now clearly identified as a major threat to human health. A lot of effort is put on creating air quality maps with better spatial and temporal resolution to better understand the nature of the air we breathe.
This is good… but we are missing an important point : air quality maps are not the only (and not the best) tool to assess the impact of air quality on our health.
First simple fact, most of us spend more than 90% of our time indoors, where air quality is much different than what can be found outdoors and shown on air quality maps. Some exceptional events such as wildfires or intense pollution events remind us of the connection between outdoor and indoor air but most of the time the levels and even the nature of the pollutants are different.
If we look at the literature, research papers or even the industry, indoor and outdoor air quality are often treated as 2 separate disciplines. And this makes sense as the key pollutants are different, have different sources, dynamics…
However, when we breathe, no matter if it is inside or outside, we breathe.
And this is where the concept of personal exposure monitoring comes into play, seeking to measure air pollution in our direct surroundings, at all time and not only relying on air quality maps as the sole input, often using wearables and portable devices to gather information.
This approach diverges considerably from the one traditionally used in air quality monitoring.
Are you smoking in your car or grilling some ribs on your BBQ?
Air pollution data you would gather at that time should be removed if you are doing traditional air quality monitoring. However it is super relevant if you want to evaluate your personal exposure and subsequently adapt your behavior.
Examples of portable devices / wearables
And the good news is that you don’t need costly equipment to do that and actually the result you get from a 200 $ device is probably more relevant – we could even say more accurate – than the data you would get from the high end reference station across the street. Can we then just basically compare both technologies? No, because in the end, even if both measure air pollutants, the purpose is not the same.
This struck me during Covid where multiple studies showed how many lives were saved because of as traffic went down, NO2 went down and therefore mortality due to air pollution also supposedly went down https://www.theguardian.com/environment/2022/jan/26/improved-air-quality-first-lockdown-saved-800-lives-europe. These conclusions were drawn through the traditional air quality monitoring approach using reference stations and modeling.
As we all know indoor air pollution is 2 to 5 times higher than outdoor pollution https://www.epa.gov/report-environment/indoor-air-quality so coming to this conclusion seems if not false, at least questionable. This shows how we still struggle solving that type of issue through the traditional approach, and this is where wearables and personal exposure monitoring provide new insights.
And you would be as surprised as I was when I realized that almost 80% of my personal daily exposure to PM took place in my kitchen and not in the street.
My personal exposure to PM 2.5, based on 270 000 recordings
Considering health and economical impacts, personal exposure monitoring to air quality should be considered by every company as a top priority to meet their Environmental and Societal Governance goals. Providing effective and measurable impacts, it offers a strong lever to improve employees quality of life and help companies fulfill their commitments.
Do these devices have limits and flaws? Yes, tons. But used in a proper way they can provide life changing insights on your personal exposure, in your personal or professional space.
They can help you adapt your behavior at an affordable cost, even if they don’t fit in the traditional air quality monitoring workflow.
Maps with higher spatial and temporal resolution remain a central tool and we need more of them. Advanced modeling, satellite technology, dense sensor networks and the rise of the new generation of mobile sensors (car or bus mounted) are definitely strong assets to better understand our environment and assess the impact of air pollution on our health on a global scale.
In conclusion we should aim for complementarity : traditional air quality monitoring is the only way to collect homogeneous information on a large scale and to get forecast on a wide spectrum of pollutants. If we want to zoom in on a specific situation (person, activity, process) personal monitoring, with its own tools and process, is a powerful approach to better understand our close interactions with the air we breathe.