The study examined racial and ethnic disparities in hospital admissions and emergency room visits.
While Hispanic residents were exposed to the highest levels of air pollution, the study found that they seek air pollution-related hospital care only as often as whites. Asians and Pacific Islanders in California experienced the lowest levels of air pollution-related hospital care among all ethnic groups studied.
The findings are published in the journal Social Science & Medicine.
“We found significant disparities across racial and ethnics groups in California in the rates they seek hospital care for illnesses caused by excessive levels of air pollution,” said John Romley, an economist at the Leonard D. Schaeffer Center for Health Policy and Economics at USC and RAND Corp. “Many factors contribute to these disparities, and our work suggests that they might be good targets for environmental justice efforts.”
The study examined racial and ethnic disparities in hospital admissions and emergency room visits caused by exposure to ozone and fine particulate matter at levels in excess of federal health standards.
Researchers used records from air pollution agencies and hospitals to estimate how air pollution in excess of federal health standards affected hospital admissions for respiratory and cardiovascular causes, and emergency room visits for asthma throughout California from 2005-07.
The study found that Hispanics were exposed to the highest levels of ozone and particulate matter during the study period. Compared to whites, blacks were exposed to higher levels of particulate matter, but lower levels of ozone. On average, Asians/Pacific Islanders and whites were exposed to the lowest levels of the two pollutants.
On average, blacks were more likely than other groups to seek hospital care for illnesses triggered by excessive air pollution levels. These disparities were especially large in certain categories of care. For example, blacks experienced nearly six times the rate of asthma-related emergency room visits compared to whites.
Researchers investigated the sources of these disparities by calculating the extent to which air pollution amplifies underlying differences in other factors, including health status and access to care. Their findings show that the disparities in the rates of air pollution-related hospital care cannot be fully explained by exposure to different levels of pollution.
For example, blacks’ higher levels of pollution-related emergency room visits for asthma were due mainly to disparities in factors other than pollution, rather than to disparities in pollution exposure. For Asians, the low rate of air pollution-related hospital care may be influenced by low rates of obesity and smoking, which likely contribute to less frequent cardiovascular and respiratory hospital admissions. Hispanics may not seek hospital care because they are less likely to have health insurance coverage than other ethnic groups. Higher levels of pollution exposure did drive blacks’ more frequent pollution-related cardiovascular admissions.
“Pollution exposure itself is not the end all when it comes to reducing disparities that some ethnic and racial groups face regarding hospital care triggered by excessive levels of air pollution,” Romley said. “From a policy standpoint, targeting pollution levels alone may not be the most effective path to addressing the environmental justice issues raised by these findings.”
Eliminating the disparities highlighted by the study will need to include efforts to target some of the underlying health and economic problems that contribute to the problem, researchers said.
Other authors of the study were Dana Goldman, holder of the Norman Topping/National Medical Enterprises Chair in Medicine and Public Policy at USC and director of the Schaeffer Center at USC, and Andrew Hackbarth of the Pardee RAND Graduate School.
Support for the study was provided by the William and Flora Hewlett Foundation.