Battlefield and terrorist explosions pose new health risks

Mar 27, 2007

High concentrations of nitrogen dioxide gas — inhaled for even very brief periods following fires, explosions of military munitions or detonations of terrorist devices — could cause serious lung damage, scientists reported today at the 233rd national meeting of the American Chemical Society.

Dr. Zengfa Gu, M.D., Ph.D., and colleagues at the Walter Reed Army Institute of Research, Silver Spring, Md., reached that conclusion based on experiments with laboratory rats that were exposed to the toxic gas. Gu explained that previous research showed that chronic exposure to low and moderate levels of nitrogen dioxide could damage the lungs. However, there was no clear information on the health risks of brief, high-level exposures lasting only a few minutes.

Nitrogen dioxide, a reddish-brown gas with a sharp, biting odor, is most familiar as an air pollutant. Released to the air from the exhaust pipes of automobiles and the burning of coal and other fossil fuels, it is an ingredient in photochemical smog. Nitrogen dioxide also is a common indoor air pollutant that is released from gas ranges and other indoor combustion sources. It can cause nose, eye and more serious health problems. Government industrial health regulations limit workplace exposures to 5 parts per million (ppm).

The gas, however, also forms when the heat from fires and explosives makes nitrogen and oxygen in the air combine to form nitrogen dioxide.

Gu said information about such brief exposures to nitrogen dioxide is important for the military because in battlefield situations, personnel easily can be exposed to high concentrations of nitrogen dioxide. Civilians also could be exposed as a result of terrorist bombings. Similar exposure could occur among civilians trapped in fires for several minutes before being rescued.

“This research is very important,” Gu said. “The results tell us that if [one encounters] an environment with high concentrations of inorganic fire gases, serious lung injury may be induced rapidly. So this research provides the scientific background for prevention of inhalation trauma and the treatment of inhalation injury.”

In their experiments, scientists exposed laboratory rats to varying concentrations of nitrogen dioxide — 100 ppm, 500 ppm, 1,000 ppm and 2,000 ppm — for 5 minutes. They monitored effects of nitrogen dioxide during the exposure and examined the lungs afterward for signs of damage.

“The experimental data showed that after exposure to high concentrations of nitrogen dioxide for only five minutes, the respiratory function was extremely changed,” Gu said. “Breathing rate and depth were sharply inhibited; lung edema was rapidly induced, [and] acute and delayed lung damage occurred.”

Gu said that the research represents the first real-time measurements of breathing changes due to the inhalation of nitrogen dioxide gas. No other laboratories have conducted the same research due to technical challenges, which involved designing a special exposure chamber and computer software to make accurate measurements on living animals.

Source: American Chemical Society

Explore further: New material makes water and oil roll off

add to favorites email to friend print save as pdf

Related Stories

Reviving algae from the (almost) dead

Nov 03, 2014

Tucked away in darkness and almost dead, algae can emerge from a frigid and foggy environment to live again—and perhaps even become the seeds for a new beginning that can provide biofuel for a clean energy ...

Coming up for air

Oct 29, 2014

Sometimes you've got to hit bottom to battle your way back up. In 1992, the United Nations cited Mexico City as having the worst air quality in the world, with so much pollution that birds sometimes dropped ...

Recommended for you

New material makes water and oil roll off

25 minutes ago

Car finish, to which no dirt particles adhere, house fronts, from which graffiti paints roll off, and shoes that remain clean on muddy paths – the material "fluoropore" might make all this possible. Both ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.