Zooming out – NO2 Pollution

It hasn’t been a long time since one of the AQ monitors that I have, the uHoo, activated the NO2 sensor and helped me realize that the air quality isn’t so good regarding the levels of Nitrogen Oxide inside my house. I had to do some research and find out if the sensor was right and where this NO2 comes from.

Mainly, NO2 is produced by road traffic and energy production like power plants, with that in mind I began investigating. It wasn’t an easy possess, I had to consider many factors.

Firstly, I thought the source of this particular pollutant NO2 was the neighbors’ cars as early in the morning they will all go to work and some of them they will turn the engines on and they will wait till the engines are warmed up enough to set off. The buildings in my neighborhood create a U and cars are parked inside that U where the NO2 could be trapped temporally until it enters inside the houses, through the windows or escapes. Partly, I was right some spikes of NO2 were registered by the sensor at this time of the day. Source #1 was found but unfortunately the NO2 wasn’t high only at that time of the day, so I had to search further.

Screen Shot 2017-11-12 at 16.29.45
Buildings forming a U

Next, I analyzed the topography of my area. I had to find all the possible sources because I wanted to understand it as good as possible. A highway is very close to my neighborhood, about 650m but we are separated by a natural hill. I am not able to hear any road noise but I guess some pollution finds its way here depending the weather and wind conditions. Source #2


Screen Shot street no2
Highway A7

Then I had to see the greatest picture and with some further examination I was able to find all the factories / power plants in my region. There are quite many as you can see on the map below. My city Almeria doesn’t have as many factories as Sevilla for example but here is produced a enormous quantity of vegetables and fruit as a result the transportation is quite active. Source #3

Screen Shot 2017-11-12 at 12.04.16
Industries across Andalusia

Finally, the winds can bring a great amount of NO2 from as far as 300km away. As you can see from the animated GIF below, in Gibraltar were many boats enter into the Mediterranean sea a huge concentration of NO2 is created there. Source #4


no2 graph


By starting super locally inside my bedroom I was able to zoom out and see the whole picture of the air pollution and how it expands. It is amazing how the pollution can travel long distances and reach our lungs. This is the reason we have to raise awareness globally. Regarding the sensor, although the NO2 values that the sensor took weren’t very precise, due to the lack of calibration, the device was able to detect the fluctuations of the pollutant and alert me. This is a domestic or an office device and I think the results are expected because you can’t compare it with a laboratory instrument that cost thousands of dollars. The importance here is the value that the device will bring to the user, and it is substantial.


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