Personal pollution sensors

With increasing population, inevitably also comes air pollution usually in the form of smog particles and oxides of nitrogen.  These have been linked in the past to respiratory and cardiac problems particularly amongst older people and those with chest diseases.  To find out more about who's at risk and why, a team based in London and Cambridge are working together to make personalised wearable sensors that can be given to people with breathing problems to see how pollution exposure affects their symptoms.  They're also hoping to use data from the sensors to help people to plot the least polluted routes to work.  Jenny Quint is a respiratory physician at the London School of Hygiene and Tropical Medicine, and she explained to Chris Smith

Jennifer -   Thanks, Chris.  So, for this particular piece of research, we've been interested in looking at the effect of environmental exposures - so temperature and certain pollutants - on people who have COPD which stands chronic obstructive pulmonary disease.  Now, this is an umbrella term that covers a spectrum of diseases from chronic bronchitis at one end where people tend to cough, bring up lots of phlegm to those that have emphysema at the other end of the spectrum and predominantly have symptoms of breathlessness.

Chris -   In the past people have shown that when the world is having a bad air day, there's a lot of pollution, that the rates of chest problems and also, cardiac problems and strokes shoot up, don't they?  So, don't we already know that bad air equals bad chest?

Jenny -   That's correct.  Work has been done at sort of higher ecological level.  In fact, we're just in the process of doing some work at London School of Hygiene and Tropical Medicine at the moment using the national network of monitors to look at temperature and pollution data and to link that with electronic health records.  So, hospital episode statistics and GP electronic health records to be able to plot specific patterns that we can see where there are increased hospital admissions or increased GP visits associated with symptoms of COPD at particular times of high air pollution or changes in temperature.  But of course, what we don't know is that what goes on at that high ecological level is always what's happening at individual level.  And that's the rationale behind taking this work one step further and doing this study and giving patients personal pollution monitors to carry around for 6 months.

Chris -   Tell us how this will work then.  You give the patient the sensor then what happens?

Jenny -   So, the idea is, we will recruit patients who have COPD to carry one of these pollution sensors with them for 6 months and we will ask them to have them with them 24 hours a day to take them when they go out and about.  And then in the evening, to set them up on a base station where we'll be able to upload the data that we're obtaining from the monitors.  The monitors will be able to record temperature as well as humidity and various pollutants, and particles.  And they'll also contain GPS so that we'll be able to look at patterns that people have taken when they've gone out and also a pedometer to be able to look again when they're in and out of the house.

Chris -   Can you monitor how active the people are?  Obviously, you can see that they're moving.  But can you also tell whether they're sitting on a bus and moving or actually, physically walking down the street because that might affect exposure too, might it?

Jenny -   Absolutely.  So, we know that exposure is affected by temperature, by humidity that changes in wind direction and even the height of buildings alongside the road.  So yes, we'll be able to get a little bit of an indication as to how active and out and about people are with these monitors.  

Chris -   And they're at the same time monitoring their own respiratory function so that you can marry up what the sensors are telling you they've encountered and when and what they were doing, with how bad they think their chest is.

Jenny -   Correct.  So, we'll do two things.  We will give patients say, peak flow monitor to ask them to measure their peak flow on a daily basis to see if we can see any objective change in their lung function.  We will also ask them to record symptoms on a diary card so that they can tell us if they're feeling more breathless for example or wheezy on a particular day.  On top of that, we will recruit patients through one of the large electronic health records databases, the Clinical Practice Research Data Link and we'll be able to link these patients' electronic health records with the pollution information that they're giving us.  So, we'll have two sources of information really - directly from the patient and also from their electronic health record to capture healthcare utilisation.

Chris -   What do you think that this is going to enable you to do with respect to our understanding of these sorts of chest diseases that we couldn't do before you were inventing these incredible sensors?

Jenny -   So, two things.  We know that COPD exacerbations cause an enormous health burden to patients as individuals and also to the healthcare system.  So, exacerbations of COPD are the second commonest cause of admission to hospital and the fifth commonest cause of re-admission.  So, if there's some way that we can warn patients to perhaps behave in a particularly different way to prevent them from developing symptoms and having an exacerbation, that will benefit them in terms of the natural history of their disease progression.  And also, it may allow us to alert hospitals or GPs that there's a particular period of time that's coming up that patients with COPD may be more likely to experience symptoms.

Chris -   If equally, a person goes about their daily business, they see that they have - without realising it - come into contact with a lot of pollution that day, could they then take proactive action?  They could take some drugs or something for their chest to prevent themselves having a flare up and therefore avoid hospital admission that would otherwise ensue?

Jenny -   There aren't any medications that we have that can avoid somebody developing an exacerbation of COPD.  But we certainly know that the sooner people start to initiate treatment when they develop symptoms of an exacerbation, the quicker they are to recover from that exacerbation and the less long term damage that has.  So, this may be helpful from that standpoint.

Chris -   How long before we're generating meaningful data from this because the project is just starting, isn't it?

Jenny -   That's right.  we're looking to recruit our first patient towards the end of this year, very beginning of next year.  I'd like to think we'd have some meaningful output within about 18 months.

Chris -   Given that our theme this week is looking at cities of the future, how will this sort of data also inform how people should plan cities and plan the way we live and plan traffic?

Jenny -   So, it may well play a role in terms of thinking about where people live relative to the way that they get to work for example or walk to the shops or the vicinity of parks, relative to where people are.  I think it'll just make people more aware of what they're exposing themselves to on a daily basis.

Chris -   Are you going to roll this out for the general public then?

Jenny -   So, once we've looked at this within people with COPD, I think it would be prudent to look within other respiratory diseases such as asthma for example.  And potentially yes, this is something that could be rolled out to the wider general public.