Atmosphere still has self-cleansing capacity

WASHINGTON - There’s cheering news on the environmental front — the atmosphere still has its self-cleansing capacity.

Some studies had suggested that such self-cleansing power is fragile and sensitive to environmental changes. But a latest international study shows the air’s self-cleansing capacity is rather stable, the journal Science reports.

New analysis shows that global levels of the hydroxyl radical - a critical player in atmospheric chemistry - do not vary much from year to year, according to a statement by US-based National Oceanic and Atmospheric Administration (NOAA), which led the study.

Levels of hydroxyl, which help clear many hazardous air pollutants and some important greenhouse gases, excluding carbon dioxide, dip and rise by only a few percent every year — not by up to 25 percent as once estimated.

“The new hydroxyl measurements give researchers a broad view of the ‘oxidising’ or self-cleansing capacity of the atmosphere,” said Stephen Montzka, the study’s lead author and research chemist at NOAA lab.

“Now we know that the atmosphere’s ability to rid itself of many pollutants is generally well buffered or stable,” Montzka said.

Hydroxyl is central to the chemistry of the atmosphere. It is involved in the formation and breakdown of surface-level ozone, a lung-damaging and crop-damaging pollutant.

It also reacts with and destroys the powerful greenhouse gas methane and air pollutants, including hydrocarbons, carbon monoxide and sulphur dioxide.