“Low-cost” sensors to measure the external exposome

John Cherrie

PDC Session: The exposome and exposure in the workplace

Let’s take a minute to think…

�  Work with the person next to you and try to produce a list of things you might like to measure to characterize the external exposome?

�  For example… �  Pesticides �  Noise

�  Make a list and think how you could measure them

Summary…

�  Gas and particulate sensors �  Linking with contextual data �  An attempt to measure the external

exposome �  Diffusive samplers

Gasses and aerosols…

�  Lower-cost air pollution sensors are available for several gases and particles �  Metal oxide (MOS) and electrochemical (EC)

sensors �  Possible interference from other pollutants

and air temperature and humidity

Inappropriate temperature correction…

Personal sampler for CO with temperature correction

Key developments…

�  New smaller instrument profiles �  Improved sensors, e.g. nanotubes �  Low power consumption �  Advanced computing, data storage and

transmission �  Low(er) cost

Snyder et al. (2013). The Changing Paradigm of Air Pollution Monitoring. Environmental Science and Technology, 47(20), 11369–11377.

Sensors…

Sensor packages… €155

A good sensor package…

�  NetAtmo �  Measures temperature,

humidity, noise and CO2

�  Cloud enabled, syncs with phone, tablet and computer

�  Cost €176 http://www.netatmo.com

PM sensors…

Citizen science…

�  Dylos DC 1700 �  Laser-based particle

counter �  1 min data logging

capability more than 6 days

�  Quiet �  Mains operated with

battery for 6 hours �  Low cost - £265 Semple S, Apsley A, MacCalman L. An inexpensive particle monitor for smoker behaviour modification in homes. Tob Control. 2013 Sep;22(5):295-8.

http://www.refreshproject.org.uk/

All sensors need calibration…

r2 =0.86 Sidepak PM2.5 = 0.65 + 4.16 x 10-5[Dylos particles] + 1.57x10-11[Dylos particles]2

(n=25,301)

microAeth…

microAeth…

�  Real-time analysis by measuring the rate of change in absorption of transmitted light

�  Continuous collection of aerosol deposit on filter

�  Measurement at 880 nm �  Interpreted as concentration of Black Carbon �  Wt 280g

Edinburgh to Cambridge

First stage

With Moves data

And station stops

Some problems…

3170g �  Mark Nieuwenhuijsen and colleagues carried

out a study using personal sensors to assess the exposome and acute health effects �  Weighed over 3kg �  Battery life mostly around 24h or more �  Some instruments are expensive �  Generates a large amount of data that needs further

cleaning and processing

Nieuwenhuijsen, et al (2014). Using Personal Sensors to Assess the Exposome and Acute Health Effects. International Journal of Environmental Research and Public Health, 11(8), 7805–7819.

Diffusive samplers… �  Silicone Wristbands

�  Need pre-cleaning �  good extraction

efficiency (>96%) �  In a trial they identified 49

compounds, including polycyclic aromatic hydrocarbons, consumer products, personal care products, pesticides, phthalates, and other industrial compounds

�  At the moment they don’t have sampling rates O’Connell, S. G., Kincl, L. D., & Anderson, K. A. (2014). Silicone Wristbands as Personal Passive Samplers. Environmental Science and Technology, 48(6), 3327–3335.

And for aerosols…

�  Plastic badge with polypropylene electret material to attract dust

�  Used for sampling asbestos amongst plumbers

�  Equivalent sampling rate around 150 ml/min

�  Can be worn for a prolonged period

Burdett, G., & Bard, D. (2007). Exposure of UK industrial plumbers to asbestos, Part I: Monitoring of exposure using personal passive samplers. The Annals of Occupational Hygiene, 51(2), 121–130.

Summary…

�  Sensors systems have become cheaper, easier to use and more data connected

�  There are many issues still that need to be resolved to make them a practical prospect for exposome studies

�  However, this is a very fast-moving area of science