Dataset Title: Data from: Yellow Air Day Advisory Study

Name and contact information of PI:
a. Name:  Arthur J. Caplan	
b. Institution:  Utah State University
c. Address:  Dept. of Applied Econ., 4835 Old Main Hill, Logan, Utah 84322
d. Email:  arthur.caplan@usu.edu

Funding source: Utah Agricultural Experiment Station, UTAO-1334

Abstract: Using a dataset consisting of daily vehicle trips, PM2.5 concentrations, along with a host of climactic control variables, we test the hypothesis that “yellow air day” advisories provided by the Utah Division of Air Quality resulted in subsequent reductions in vehicle trips taken during northern Utah’s winter-inversion seasons in the early 2000s. Winter inversions occur in northern Utah when climactic conditions are such that PM2.5 concentrations (derived mainly from vehicle emissions) become trapped in the lower atmosphere, leading to unhealthy air quality (concentrations of at least 35 µg/m3) over a span of what are called “red air days”. When concentrations rise to between 15 and 25 µg/m3 on their way to the 35 µg/m3 threshold, the region’s residents are informed via several different media sources and road signage that the region is experiencing a yellow air day, and urged to reduce their vehicle usage during the day. Our results suggest that yellow air day advisories have been at best weak, at worst perverse, measures for reducing vehicle usage on yellow air days and ultimately for mitigating the occurrence of red air day episodes during northern Utah’s winter inversion season.

Brief description of collection and processing of data: Data is secondary, compiled in comma-separated values (CSV) format. The data sources are the US Environmental Protection Agency, the Utah Division of Air Quality, the Utah Department of Transportation, and the Weather Underground.

Description of files: A single .csv file containing all the data for all regression analyses reported in paper.

Definition of acronyms, codes, and abbreviations: Variable abbreviations are as indicated in the paper and dataset.

Descriptions of parameters/variables:
a. Temporal (beginning and end dates of data collection): Data was collected from November 25, 2019 to January 3, 2020.
b. Instruments used and units of measurements: N/A
c. Column headings of data files (for tabular data): These are included in the dataset.
d. Location/GIS Coverage (if applicable to data): Cache County, Utah.
e. Symbol used for missing data: Blank spaces

Special software required to use data: Any software that can read or convert CSV format.

Publications that cite or use this data: N/A

This data is derived from orginal data sources from the US Environmental Protection Agency, the Utah Division of Air Quality, the Utah Department of Transportation, and the Weather Underground.