Racial/ethnic disparities in the association between fine particles and respiratory hospital admissions in San Diego county, CA

Abstract

Ambient air pollution exposure is associated with exacerbating respiratory illnesses. Race/ethnicity (R/E) have been shown to influence an individual’s vulnerability to environmental health risks such as fine particles (PM 2.5). This study aims to assess the R/E disparities in vulnerability to air pollution with regards to respiratory hospital admissions in San Diego County, California where most days fall below National Ambient Air Quality Standards (NAAQS) for daily PM 2.5 concentrations. Daily PM 2.5 levels were estimated at the zip code level using a spatial interpolation using inverse-distance weighting from monitor networks. The association between daily PM 2.5 levels and respiratory hospital admissions in San Diego County over a 15-year period from 1999 to 2013 was assessed with a time-series analysis using a multi-level Poisson regression model. Cochran Q tests were used to assess the effect modification of race/ethnicity on this association. Daily fine particle levels varied greatly from 1 μg/m³ to 75.86 μg/m³ (SD = 6.08 μg/m³) with the majority of days falling below 24-hour NAAQS for PM 2.5 of 35 μg/m³. For every 10 μg/m³ increase in PM 2.5 levels, Black and White individuals had higher rates (8.6% and 6.2%, respectively) of hospitalization for respiratory admissions than observed in the county as a whole (4.1%). Increases in PM 2.5 levels drive an overall increase in respiratory hospital admissions with a disparate burden of health effects by R/E group. These findings suggest an opportunity to design interventions that address the unequal burden of air pollution among vulnerable communities in San Diego County that exist even below NAAQS for daily PM 2.5 concentrations.

Keywords:

• Air pollution
• PM 2.5
• vulnerability
• social inequalities in health

Acknowledgments

The authors declare they have no actual or potential competing financial interests. The observational temperature dataset is freely and publicly available from the University of Washington (ftp://ftp.hydro.washington.edu/pub/blivneh/CONUS/). Air pollution data are available from California Air Resources Board (https://ww2.arb.ca.gov). Health data are distributed by the Office of Statewide Health Planning and Development (https://www.oshpd.ca.gov/HID/Patient-Discharge-Data.html).

Additional information

Funding

This work was funded by the UC Multicampus Research Programs and Initiatives (Climate and Health Interdisciplinary Research Program: MRP-17-446315).