Project description:

We created some of the most detailed maps of cancer-causing air in seven parishes in southeast Louisiana, at a time when there’s an influx of new plants being constructed in the area. The project maps the toxic air down to the square kilometer level, and shows flaws in how industrial emissions are regulated in the area, and how much worse it could get when new facilities get built.

Impact reached:

This project was the first of its kind to show this sort of cancer-causing air toxicity, and to model the potential new pollutants from new industrial development in this area. We gave the people of south eastern Louisiana and the government the tools to evaluate the potential impact of cancer-causing chemicals on the community at a level never done before.

Techniques/technologies used:

We used the output of an obscure scientific model developed by the Environmental Protection Agency to map the toxic air and potential hazards to residents. We analyzed a billion-row database to show cumulative cancer effects of air pollution, and we processed that information into two parts. One, at the bottom of the piece, is a MapBox map and associated vector tiles that make up an exploratory lookup map that lets you see how toxic air near you compares to the rest of the seven parishes. The other is a set of data that we processed into a set of animated maps using canvas, d3 and vue.js to walk readers through different facets of the flaws in how industrial air emissions are regulated in southeast Louisiana. 

What was the hardest part of this project?

Understanding and processing the data was a real challenge. We went back and forth with sources for months to understand how to use this database. Before we even got there, we had to transcribe and assemble a database of emissions permits for new plants and work with a modeler to model expected emissions. Rendering an animated map of 810 square grid cells was also difficult, to put it mildly. In order to even show the mapped gradients showing cancer-causing air toxicity, we had to develop our own methodology for quantifying the extent of these problems.

What can others learn from this project?

Sometimes finding ways to visualize what would appear to be boring, wonky or scientifically dense data can be incredibly impactful. Also, the more granular you show information like this, the more illustrative and interesting it is. We could have shown this at the county level, but being able to see these plumes of toxic air wafting into the community from facilities gives a more visceral response. It literally shows the story.

Project links:

projects.propublica.org/louisiana-toxic-air/