Air pollution exceedances routinely occur at Thoroughbred racetracks in the contiguous United States.

Overview

• This study analyzed patterns of air pollution around Thoroughbred racetracks in the contiguous United States from 2011 to 2024, focusing on how often pollutant levels exceeded national safety standards and the implications for equine and human health.

Study Purpose

• To characterize spatial (location-based) and temporal (time-based) patterns of criteria air pollutants surrounding Thoroughbred racetracks across the US.
• To assess pollutant concentrations relative to the National Ambient Air Quality Standards (NAAQS).
• To identify how often and where these pollutants exceed safety thresholds and to understand potential risks to horses and people at these racetracks.

Data Collection and Methods

• All active Thoroughbred racetracks in the contiguous US were identified for the years 2011 through 2024 (totaling 56 racetracks).
• Pollutant data were obtained from the US Environmental Protection Agency (EPA) Air Quality System, which provides daily air quality measurements.
• For each racetrack, pollutant concentrations within a 50-kilometer bounding box around the location were gathered.
• Pollutants analyzed included ozone, fine particulate matter (PM2.5 and PM10), and lead, among others.
• Descriptive statistics summarized daily and annual pollutant levels, with trends assessed by month and year to reveal changes over time.
• Exceedances were defined as pollutant levels meeting or surpassing the NAAQS thresholds.
• Analysis across different EPA regions helped characterize spatial patterns in pollutant exceedances.

Key Findings

• All 56 racetracks experienced at least one exceedance of air pollutants.
• Exceedances were most frequently noted for ozone (in about 96% of racetracks) and for fine particulate matter (PM2.5 and PM10 in about 95%).
• Lead exhibited the greatest number of exceedances; however, lead levels showed a decline over the study period.
• Median pollutant concentrations generally remained below the NAAQS thresholds across EPA regions.
• An exception was annual PM2.5 levels exceeding the NAAQS thresholds in the Great Lakes and Southwest regions.
• Most pollutants declined over time, but notably, ozone, PM2.5, and PM10 increased after 2020.
• Approximately 25.2% of PM2.5 measurements were equal to or exceeded 11 µg/m3, a concentration linked with reduced performance in horses.

Implications and Recommendations

• Air pollution near racetracks routinely reaches levels that may impact the health and performance of racehorses, as well as pose risks to jockeys, racetrack staff, and spectators.
• Veterinarians and racetrack managers should stay informed about air quality conditions and understand the risks associated with exposure to these pollutants.
• Integrating continuous air quality monitoring at racetrack facilities is advised to enable timely action and mitigation strategies.
• Enhanced monitoring and protective measures can help safeguard the health and performance of horses and the safety of human participants and audiences.