An Environmental Fitness Tracker

Personal fitness trackers are all the rage, and their ease of use enable people to keep an eye on not only their physical activity, but their general fitness and wellness. While fitness certainly plays a big part in determining human health, environmental stressors like air quality also play a role in overall health. Unlike fitness, air quality is less in your control and varies depending where you live. For example, smog resulting from air pollution results in poor air quality in large cities, while air quality can be much higher in areas with low population densities, away from air pollution sources.  However, air quality can still be impacted by your daily habits, such as choosing when and where to spend time outside and how often to change your home’s air filters. Exposure to poor air quality can be difficult to assess because of the need for continuous monitoring (people are exposed to air all the time). What if you could use the same convenient method as a Fitbit to measure a type of environmental fitness? That fitness measurement being Air Quality.

It used to be that sampling air quality required a large backpack full of expensive filters and pumps… not exactly ideal for everyday users to carry around. However, that’s changing due to a technique called passive air quality sampling. Passive air quality sampling avoids the need for a big pump or batteries to collect air samplers. This technology relies on a polymeric material (in many cases a silicone rubber-like material, but sometimes other plastics) that pulls pollutants out of the air. Some pollutants that we are worried about preferentially stick to the polymer over being distributed in the surrounding air. This ability to passively hold on to pollutants, makes the polymeric material a great alternative to air quality samplers that require backpacks with pumps.

Researchers at Yale University and the University of Massachusetts Amherst used this technology in a personal air quality monitoring wristband, Fresh Air Wristband, and tested its ability to measure common pollutants. Specifically, they measured exposure to volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs), and nitrogen dioxide (NO2). These different classes of pollutants are released from common sources such as cars, stoves, building materials, cleaning products, and heaters, and exposure to these pollutants has been associated with respiratory and cardiovascular disease.

Figure 1. The Fresh Air Wristband. Reprinted with permission from Lin et al. Copyright 2020 American Chemical Society.

The Fresh Air Wristband isn’t the first personal air quality monitor, and it isn’t even the first air-quality monitoring wristband, but it does possess significant improvements over some of its predecessors in its ease or portability and protection from contamination. For example, some previous models of air quality wristbands were susceptible to absorbing the compounds of interest from the wearer’s skin or from applied topical products, such as skin lotion. The Fresh Air Wristband, pictured below, houses the pollutant-absorbing pad and bar within a protective shell to avoid contamination issues. In this way, the Fresh Air wristband only measured pollutants that were in the surrounding air (causing exposure through inhalation) without measuring pollutants from other sources (that might cause exposure through skin). 

Figure 2. Asthma inhaler. Source

The research team, led by Elizabeth Lin at Yale, tested the wristband’s ability to measure the exposure of about 30 children, ages 12-13, over a duration of 4.3 days. The researchers evaluated the results with regard to differences in sex, asthma status, and home and transportation characteristics., It was unclear what was causing higher pollutant exposure, but the study team found that girls had higher exposures than boys and children with asthma also had higher exposures. Though not shown in this report, the development of asthma has been associated with increased exposure to air pollution. Lin and coworkers also observed that kids in homes with gas stoves generally had higher exposures to PAHs (a class of pollutants commonly associated with burning fuel) than those in homes with electric stoves, and that homes that used the stove vent had lower exposure. Finally, the team saw that exposures of certain pollutants were higher for kids that traveled home from school in a car compared to kids who walked or took the bus.

What is the value of air quality exposure measurements? Well, as indicated above, use of this technology could help people be aware of changes they could make to their daily routines to avoid exposure to poor air quality. For example, people could have their kids take the bus home from school, they could actively use the vent on their stoves, or they could replace their indoor air filters more regularly. Also, combining the data and habits from many people could be used by scientists and policy makers to better address air quality issues by targeting specific sources, practices, and policies.


Source Article: E. Z. Lin, S. Esenther, M. Mascelloni, F. Irfan, & K. J. G. Pollitt, Environ. Sci. Technol. Lett. 2020.

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Mary Davis

I earned my PhD in Chemical Engineering from Princeton University in 2018, where my research focused on nanoscale polymer systems and how their properties change with geometry. I am now applying my background in polymers to environmental systems. This involves studying the breakdown of plastics and plastic byproducts in the environment, as well as their interactions with other pollutants. When I’m not working in the lab, I enjoy crafting, cooking, and being outside.

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