Reacting to change

Visual beats observable

The software engineers amongst you may have picked up on the very subtle play on words in the title (we’re all about subtle titles). This does of course refer to React, a library that helps you write web-based user interfaces. For a while now, we have been building visualisations with ObservableHQ, like our Breathe London node visualisation that we featured a while ago. We have been finding that ObservableHQ is great for less complex visualisations, but as soon as things get fancy, you spend more time figuring out ObservableHQ and less time on the actual visualisations.

And so we decided to migrate from ObservableHQ to a native platform written using React and hosted on fly.io. It’s still work-in-progress and we hope to be launching soon, but here are some key features:

Your one stop visualisation shop

1. Search box returns points of interest as well as monitoring nodes, making it easy to find nodes near places as well as a particular node.

2. All London Low Traffic Networks as of November 2022 (along with the dates they were added (and removed, if applicable), making it easy to identify nodes inside and out of LTNs.

3. Comparisons between a primary node and comparator nodes. The comparator nodes can be selected individually, by all nodes in a borough, by all nodes of a certain type (eg, roadside, urban background, industrial) or across all nodes in London. This is useful for looking for the effects of an intervention that happened on a given date, compared to background levels.

4. Features can be turned on and off as required. We have LTNs and borough boundaries so far, but would love to hear if there are any other datasets that would help with analysis of air pollution and its effects. You can also view PM2.5 and NO2 data separately - this highlights the phenomenon of PM dispersing across the city while NO2 tends to stay close to emissions sources.

5. Data is visualised as circles proportional to the concentration of pollutants. We found this style of visualising the data made it easy to see areas where air quality is poor.

Once we have the app up and running with the above features, we’ll add in the visualisations from our original Breathe London visualisations. We would love to make our new app a one-stop shop for analysing and visualising air quality data. If there are other features that would be useful to you, please let us know!