Atmosphere's self-cleaning capacity stable: study

Yahoo News 7 Jan 11;

WASHINGTON (AFP) – An international team of researchers has found that the atmosphere's ability to cleanse itself of pollutants and other greenhouse gases, except carbon dioxide, is generally stable.

The study, published in Friday's edition of the journal Science, comes amid a fierce debate over whether, as some experts believe, the atmosphere's self-cleaning ability was fragile and sensitive to environmental changes.

The research team, which was led by the National Oceanic and Atmospheric Administration (NOAA), measured levels in the atmosphere of hydroxyl radicals, which play a key role in atmospheric chemistry.

Levels of the agent only fluctuated a few percentage points from one year to the next, not 25 percent as some studies had estimated, the researchers found.

"The new hydroxyl measurements give researchers a broad view of the 'oxidizing' or self-cleaning capacity of the atmosphere," said Stephen Montzka, the study's lead author, a research chemist at the Global Monitoring Division of NOAA's Boulder, Colorado laboratory.

"Now we know that the atmosphere's ability to rid itself of many pollutants is generally well buffered or stable... This fundamental property of the atmosphere was one we hadn't been able to confirm before."

He said the finding boosted confidence in models that project future levels of pollutants in the atmosphere.

The hydroxyl radical, a compound consisting of an oxygen atom and a hydrogen atom, has such a brief lifespan in the atmosphere that it has been extremely difficult to measure on global scales.