Traffic, Air Quality, and Environmental Justice in the South Coast Air Basin During California’s COVID-19 Shutdown
The goal of this project was to find correlations between air quality levels (CO and NOx) and the reduction of traffic caused by the COVID-19 lockdowns. If strong correlations were observed, case studies were conducted in the areas in question to pinpoint reasons as to why they experienced such change. The study focused on the Southern California region, specifically Los Angeles, Ventura, Orange, San Bernardino, and Riverside counties.
Dwaraknath was responsible for processing traffic data, conduction GIS analysis relating traffic to the Southern California region, and creating plots for traffic flow, speed, air quality, and other variables that affected the study. He also conducted research on the physical characteristics of the observed areas that may have created a unique correlation between air quality and traffic flow.
Throughout this project Dwaraknath acquired the traffic flow and average speed data from the CalTrans website. Using R programming. Filters were applied to include data only on Tuesday-Thursday from 3:00-7:00 pm. This data was collected from stations that were fully responsive during the period of January 2020 to September 2020. This allowed the research team to see the dip and gradual recovery of traffic during the pandemic induced lockdowns. After applying these filters, the researchers were left with almost 3000 traffic stations that spread throughout Southern California.
Dwaraknath used R to calculate the weekly average of traffic flow and speed recorded by each station. With these weekly averages, he created scatter plots and heat maps that show the pattern of traffic data during the COVID-19 pandemic. Plots were also made relating NOx and CO to changes in traffic flow. CES scores were used as an indication of lower income areas and were related to air quality and traffic data. Regression lines were added to the heatmaps to see the trend of the plotted data. A video was created with the weekly heatmaps to show the change of traffic data relating to the CES score, as well as the change in the plotted regression line, from January 2020 to September 2020.
Using the traffic data weekly averages, Dwaraknath conducted GIS spatial analysis using ArcMap. Initially ArcMap was used to see where the traffic stations in California were located, and then averaged the station's data in the same census tracts so that we could better see the change in traffic flow and speed. The maps made were dipped together to create a video that shows how the region traffic data changes week by week.
Currently, Dwaraknath is observing the air quality sites to see if any physical traits of that site provide a unique relationship with traffic flow. The project completion is set for end of 2021.