Building a new instrument to measure the air we breathe

Jasmine Wareham-1550x2340

This is a blog post from Jasmine Wareham. Jasmine is currently in the second year of her PhD with the atmospheric chemistry group at the University of Leicester. This blog gives an introduction to her project.

Since this is my first (ever) blog, I thought it would be appropriate to start with an overview of what my PhD project is about. My project involves developing a new highly sensitive and selective instrument to measure nitrogen dioxide (NO2) in the air we breathe. NO2 is a major component of air pollution, which is mainly emitted into the atmosphere via road traffic vehicles. It’s likely that you will have come across a news article or two about air pollution in recent months, due to its growing concern across the world and whenever cars are involved, it’s also very likely that NO2 will be too (the VW scandal comes to mind here…). We care about NO2 because it’s bad for our health, mainly affecting the respiratory system and this can be particularly problematic for children, the elderly and for people with existing health conditions, such as asthma.

It’s vital that we monitor air pollution so that we can establish:

  1. Which areas are affected,
  2. Whether the pollutants are within their legislative limits, and
  3. To see if measures to improve air pollution and/or mitigate its effects have been effective

You may have seen/heard of air quality monitoring stations dotted about the country – we have one on campus, here at the University of Leicester (photo below). The network of monitoring stations is called the AURN (Automatic Urban and Rural Network). These stations typically house multiple air quality instruments, measuring a range of pollutants, such as NO2 and particulate matter (PM = really small bits of solids/liquids suspended in the air. These tiny particles can penetrate into our bodies and cause harm). The outside air is sucked in through a series of tubes which are located on the roof of the building. Weather data such as wind speed/direction and temperature are also recorded at some stations. If you’re interested, the data recorded at all AURN sites can be accessed online by anyone via this link: https://uk-air.defra.gov.uk/data/data_selector?=l&1=&s=&o=#mid

AURN-2133x1600

Once my instrument is more portable (it’s currently in its development stage, whereby all of the components are spread out and screwed down to an optical table in the lab), I’m hoping to test it in the above AURN monitoring station and that way, I can directly compare these data to the NO2 data which are already being gathered. You may now be asking that if there’s already an instrument (and in fact multiple instruments) which measure NO2, why on earth am I making another one?! Well, very valid question and the simple answer is that the existing instruments have weaknesses in ways such as how they go about detecting NO2 and how intensive they are to operate. Most commercial instruments make assumptions in their detecting method and assume that the signal they measure is solely due to NO2, but in reality, this is not case when measuring NO2 in this way and therefore false positives are recorded. The instrument I’m developing unambiguously identifies NO2 and does not have interferences in its measurement – i.e. I know that the concentration I get for NO2 is just due to NO2.

Once fully developed, it is hoped that the instrument will also be less labour intensive to operate than existing techniques, reducing the amount of specialist knowledge needed to run it, as well as eliminating the need for calibration gases. These factors will make the instrument much more attractive for use in air quality monitoring stations and in time, improving measurement methods will hopefully help clean up our dirty air!

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