California study links smog levels with hospitalizations
19 November 1997
Increases in daily levels of fine particle pollution in Southern California are closely associated with increases in the number of people admitted to hospitals for respiratory problems, according to the preliminary results of a study by Kaiser Permanente.
“This is the first study of its kind conducted in the basin and shows that the region's air pollution continues to be a leading public health concern,” said Shankar Prasad, M.B.B.S., health effects officer for the South Coast Air Quality Management District. "Never before have researchers had access to such detailed air quality data at multiple sites and correlated it with hospital admissions."
In the $145,000 study funded by AQMD, Van Den Eeden correlated hospital admissions of more than 1.6 million Kaiser patients living in specific geographic grid zones with the levels of particulate and other pollutants measured in those areas. Preliminary results show hospital admissions were correlated with increases in the level of ozone and microscopic-sized particulate matter between 2.5 (PM2.5) and 10 microns (PM10) in diameter.
For each 10 microgram increase in the concentration of particulate in the air, admissions at Kaiser hospitals were found to increase by 7% for chronic respiratory disease patients, 3% for cardiovascular disease patients and 3.5% for acute respiratory illnesses. For each 10 parts per billion increase in ozone levels, hospitalizations were found to increase by 2.7%, 5.7% and 1.5%, respectively.
At the time the study was conducted, the federal air quality health standards were exceeded when ozone reached a concentration higher than 120 parts per billion averaged over one hour and fine particulate reached 150 micrograms per cubic meter of air averaged over 24 hours. The federal government has since tightened the standards for both pollutants due to studies showing these levels did not adequately protect public health.
“Kaiser's findings that particulate in the PM2.5 to PM10 range may cause increased hospital admissions is reinforced by another study of how particulate pollution can impact health in Coachella Valley,” said Prasad. That study, conducted by researchers at the California Environmental Protection Agency's Office of Environmental Health Hazard Assessment, found that a 10 microgram increase in the daily level of PM10 was associated with a 2.5% increase in emergency room visits for pneumonia and a 1% increase in deaths.
AQMD is the air pollution control agency for parts of Los Angeles, San Bernardino and Riverside counties and Orange County. Contact: Sam Atwood or Bill Kelly (909) 396-3456
Source: South Coast Air Quality Management District