McElroy Says Nitrous Oxide Harms Ozone

Recent experimental evidence shows that man's technological processes are pumping increased amounts of ozone-destroying agents into the atmosphere, Michael B. McElroy, Rotch professor of Atmospheric Sciences, told a Science Center D audience last night.

"We're trying to explore how the global biological balance is affected by the atmosphere and how humans have an effect on the atmosphere," McElroy said.

The ozone layer acts as a shield for the earth, blocking harmful amounts of ultraviolet radiation. McElroy was among the first to postulate that man-made propellants, such as freon in aerosal sprays, are a primary danger to the ozone layer.

McElroy cited nitrous oxide as another ozone-destroying agent, saying "nitrous oxide and freon act exactly the same way."

The action of these ozone-reducing agents not only leads to increased cases of skin cancer but also intensifies the so-called "greenhouse effect," McElroy said.

Through the greenhouse effect nitrous oxide, acting in the same fashion as carbon dioxide, traps heat within the earth's atmosphere. A rise in the nitrous oxide level could inevitably make the earth warmer, McElroy said.

Aerial Garbage

"We humans, using 10 per cent of the land area of the earth, and fertilizing it, represent a very big influence," he added, citing the high amounts of nitrous oxide that fertilizer production releases into the air.

McElroy discussed his recent research on the Potomac River, where as much as 10 per cent of the nitrous oxide released by the Blue Plains sewage treatment plant escapes into the air.

A recent study of ocean currents and nitrous oxide levels in different areas of the Pacific Ocean indicates that aqueous nitrous oxide may be coming primarily from one side of the earth, McElroy said.

"We're learning a lot as we do this," he said adding, "We still have a great deal to learn."