Anyone who's ever used a public restroom appreciates regular and dependable air freshener.
Earth's atmosphere has just that, thankfully, and it's operating better than expected. A critical part of the self-cleaning system is hydroxl, and the chemical maintains a more stable level of activity than previously thought, according to research by the National Oceanic and Atmospheric Administration (NOAA). Considering that recent models indicate greenhouse gasses are going to be a long-term atmospheric issue to clean up after, this news comes as a bresh of fresh air.
“Now we know that the atmosphere’s ability to rid itself of many pollutants is generally well buffered or stable,” said lead author, Stephen Montzka of the National Oceanic and Atmospheric Administration (NOAA).
“This fundamental property of the atmosphere was one we hadn’t been able to confirm before,” said Montzka in a NOAA press release.
The amount of hydroxyl in the atmosphere rises and falls by only a few percentage points a year, according to the results published recently in Science. Earlier studies had suggested it might fluctuate by as much as 25 percent.
Hydroxyl helps break down pollutants like sulfur dioxide, carbon monoxide, hydrocarbons and even the powerful greenhouse gas, methane. Methane is over 20 times more effective than carbon dioxide at trapping heat. However hydroxyl has no effect on carbon dioxide.
“Say we wanted to know how much we’d need to reduce human-derived emissions of methane to cut its climate influence by half,” Montzka said. “That would require an understanding of hydroxyl and its variability. Since the new results suggest that large hydroxyl radical changes are unlikely, such projections become more reliable.”
Previous studies inferred the levels of hydroxyl being produced in the atmosphere by measuring the concentration of methyl chloroform, a long lived pollutant partly responsible for ripping a hole in the ozone layer. But the results varied widely, possibly because of inaccurate estimates of methyl chloroform released by human activities. The gas was banned by the Montreal Protocol, so now, no new methyl chloroform is fouling the data.
Now that the gas is no longer being produced, scientists can more accurately gauge the action of hydroxyl upon methyl chloroform's atmospheric concentration. They took measurements over time of methyl chloride concentrations. By measuring its decay, they could calculate the amount of hydroxyl acting upon it.
With a better understanding of the mechanisms that clean the atmosphere, scientists can better forecast the future.
by "environment clean generations"
Posted in: 
0 comentarii:
Post a Comment