Air Pollution Linked to Pneumonia in Seniors

(December 24, 2009) - Living near a highway or an industrial park may be one reason many seniors develop pneumonia. (Read about "Pneumonia") A new study claims to have has found the first evidence that prolonged exposure to higher levels of the pollutants found in car exhaust fumes and industrial air pollution can lead to hospitalization for pneumonia in adults aged 65 and older.

Infectious disease specialist Mark Loeb led a research team to assess the effect of long-term exposure to nitrogen dioxide and sulfur dioxide, both found in motor vehicle emissions, and fine particulate matter, found in industrial air pollution, on the risk of hospitalization for pneumonia in older adults.

"Our study found that among older individuals, long-term exposure to traffic pollution independently increased their risk of hospitalization for pneumonia," said Loeb. "We propose that exposure to air pollution may have increased the individuals' susceptibility to pneumonia by interfering with lung immune defenses (Read about "The Immune System") designed to protect the lung from pathogens."

The researchers found that exposure for more than 12 months to higher levels of nitrogen dioxide and fine particulate matter of less than 2.5 micrometers more than doubled the risk of hospitalization for pneumonia in adults aged 65 and older. Exposure to sulfur dioxide was not associated with an increased risk of hospitalization.

"The results of this study highlight the important health impact that long-term exposure to ambient air pollution can have on respiratory infections," Loeb said. "It also emphasizes the need to monitor emissions from vehicles, given that ground-level nitrogen dioxide is derived predominantly from traffic."