Engineers have been designing and marketing small, wearable/portable pollution sensors for several years now. The sensors are intended to inform the users about how pollution levels change as they change their location.
In fact, air pollution can differ drastically even from one neighbourhood to the next, said Michael Jerrett, chair of the department of environmental health sciences at the University of California at Los Angeles. “Depending on the type of pollution, you can see a lot of variability or change in the levels of pollution over very short distances,” he said. For example, a cyclist pedalling down a busy road might be exposed to five or even 10 times higher levels of ultrafine particles or carbon monoxide, thanks to traffic, than would a person in a neighbourhood just a few streets over.
Hence, there are practical choices that such sensors can help us make, such as where to go jogging or which parks to take children to play in. Wearable sensors could in theory be useful on a larger scientific scale as well, although the technology may require some improvements before it reaches that point. “I think that most people who work in environmental or spatial epidemiology would agree that the very best assessment you could get of someone’s exposure would be to have them carry a sensor on their person,” Jerrett said. “And to then know where they were and what they were doing, their activity level.”
Most studies of air pollution and premature mortality have tended to rely on models that take little information into account when it comes to the different neighbourhoods people go into on a day-to-day basis or their activity levels at the time. Researchers may be able to recruit large numbers of people to wear these types of sensors and take part in population-level studies, said Mark Nieuwenhuijsen, a research professor at the Centre for Research in Environmental Epidemiology in Spain. He has been involved with projects exploring the utility of personal sensors as part of the CITI-SENSE consortium, a collaboration involving several dozen European institutions aiming to develop community-based environmental monitoring projects. Nieuwenhuijsen said some personal sensors measure pollution concentrations “reasonably well,” and may be useful for the individual, but whether they would be suitable for larger-scale research projects is still unclear.
“Most of them have not reached a level of precision that we would consider valid for research purposes,” Jerrett noted. For instance, certain factors, such as changes in humidity, are suspected to affect the way some sensors report pollution levels, he said.
“I would say that the current state of the science is there are some sensors that are good enough to detect changes in microenvironments,” he said. “But they do not line up as well as we’d like with a reference instrument that would cost $10,000 and require a lot of labour.” As the technology plays catch-up, Nieuwenhuijsen pointed out that there are other issues to be aware of.
“What you have to be careful of is to put too much responsibility on the individual,” he said. Wearable pollution sensors might allow people to make more informed choices about their daily activities, but policymakers still need to look at pollution through a bigger lens and put measures in place to protect whole cities or regions. In other words, action should be “more on a community basis than an individual basis,” he said.
By designing a wearable pollution device that changes its colour based on the pollution level of the area you are walking in, the invisible is made visible to both individuals and environment-related policymakers. Hence, the burden of actions being taken belongs to both individuals (they decide which place to go based on the colour of their costumes) and institutions (as soon as a lot of red costumes are seen in an area, this is a clear indication that environmental measures should be taken within that area). Thus, such wearable devices not only affect people’s daily decisions, but can raise awareness among environmental policymakers as well.