What are the Hidden Contributors to Poor Air Quality?

by Gary Atkinson | Jun 09, 2017

smart city technology


Last week we talked about the why and how of air quality monitoring but we did not explore how air quality may be impacted by other vectors and that is the focus of this article.

Measuring Air Quality

Typically, air quality measurements taken by local authorities in the UK focus entirely on measuring nitrogen dioxide and/or nitric oxide (NO2 and NO) levels. Measuring ozone at the same time gives a much better view of air quality as it relates to health implications.  But there are other factors in play that could shed additional light on what actually impacts air quality - other than the emissions of vehicles.

The Impact of Topology

The lay of the land can significantly influence air quality as basins or building layout can encourage air to stagnate and the lack of air flow means that the air continues to deteriorate as time goes by. An example of this problem is the city of Cambridge. Despite being a place recognised for its encouragement of the use of bicycles and having the highest "miles travelled by bike per capita" of any city in the UK, on its worst days, the air quality in the centre of Cambridge is the same as Oxford Street in London. It is suspected that Cambridge's location in a 3 sided valley, protected from winds that would stir up the air, are the principle cause of the poor air quality given that traffic volumes are below the average for a city of that size.

Topographic map of Cambridge - contributors of poor air quality

What about the microclimate?

After having a cursory look at the connection between a location's air quality and its microclimate, there appears to be a lot of evidence for how poor air quality in a city can actually raise the local temperature but there is very little discussion on whether the reverse effect is true: Is air quality worse on a cold, humid day as compared to a dry and warm day. Without measuring both the gas levels and the local temperature, humidity and barometric pressure, at the same location with time-stamped data, there is no way to know. 

Surely traffic is the root problem?

Clearly, the emissions of cars, trucks and buses contribute heavily to the quality of the air in and around urban areas. However, what is not known is what mode of transport is worse, what is the impact on volume of one type of vehicle over another or how does average speed impact the air quality in real time. The only way to understand this is to colocate the measurement of the air quality with sensors that can not only count the number of vehicles and their average speed, but also differentiate between how many buses, trucks, vans or cars passed by on a minute-by-minute basis.

What about particulates?

The primary source of "bad" particulates is from vehicle exhausts, often referred to as carbon black, which makes up 60% of all particulates. Of the remaining 40%, over half is down to brake dust with the rest coming from clutch wear, tyres and road wear. These particlates vary in size but the most dangerous ones are so small that they can be absorbed into the human body through the cell walls of the lungs. Measuring these tiny particulates is hard and so is currently pretty expensive so we really need a lower cost solution for detecting PM 1 or smaller particles as well as PM 10 and PM 25 (e..g pollen) in order to get the complete picture of the air quality in our built environments.

Of course, it goes without saying that enLight is developing solutions to be able to measure all of these variables so that a city or county council can get the all the data they need to make better decisions on transport routes and road planning projects.

To learn more about enLight's Smart City solutions, please download our brochure using the image below:

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In order to understand how an enLight Smart City platform can turn your existing lighting infrastructure from a cost burden into a strategic asset that all local authority departments can benefit from, we are offering Smart City workshops to qualifying city, district or county councils to help you understand the potential. For more information, please download our Workshop PDF and enter into the draw to win a free workshop worth over £5000.

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