Excel spreadsheet with the following columns of data: Date/Time (6/2016 to 10/2016) Total Gaseous Mercury Concentration (ng/m3) Sulfur dioxide concentration (ppb) Carbon monoxide concentration (ppm) Carbon dioxide concentration (ppm) Wind direction in degrees Wind speed in miles per hour Temperature in degrees celcius Percent relative humidity. This dataset is not publicly accessible because: The data used in this study were not generated or funded by the EPA. It can be accessed through the following means: The total-gaseous mercury (TGM) measurement data were collected by Dr. Lynne Gratz, Assistant Professor of Environmental Science, at Colorado College, 14 E. Cache La Poudre St. Colorado Springs, Colorado 80903 USA. This data is not available to EPA for public dissemination. Information on obtaining this data should be directed to Dr. Gratz at: lgratz@coloradocollege.edu or (719) 389-7465.

The CO, SO2, temperature, wind speed, wind direction, and relative humidity were collected at the Colorado Department of Public Health & Environment (CDPHE) air monitoring location at Highway 24 in Colorado Springs. This data is already available in the public domain.

Certified hourly data from this and other CDPHE air monitoring stations, including the Manitou Springs and Colorado College stations that were also mentioned in this manuscript, are available through the U.S. EPA Air Quality System (AQS) database (https://aqs.epa.gov/api) downloaded on September 1st 2017. Additional information can be obtained by emailing: cdphe.information@state.co.us303. Format: The data are in an Excel format. Citation information for this dataset can be found in the EDG's Metadata Reference Information section and Data.gov's References section.