Sahara Fragile

Main Menu

  • Home
  • Sahara desert
  • Namib desert
  • Kalahari desert
  • Savanna desert
  • Fragile States

Sahara Fragile

Header Banner

Sahara Fragile

  • Home
  • Sahara desert
  • Namib desert
  • Kalahari desert
  • Savanna desert
  • Fragile States
Sahara desert
Home›Sahara desert›Iodine-laden desert dust eats away at ozone pollution

Iodine-laden desert dust eats away at ozone pollution

By Christopher J. Jones
February 28, 2022
0
0



While in Antofagasta, Chile, studying gases emitted by nutrient-rich waters flowing from Antarctica along the west coast of South America, Rainer Volkamer and his team discovered something something they did not expect.

“We found these surprisingly high levels of iodine oxide radicals” in layers of dust 1 to 5 kilometers above the surface, said Volkamer, professor of chemistry at the University of Colorado at Boulder. They were puzzled because the ocean provides most of the atmosphere’s iodine, and iodine levels are generally highest where the ocean meets the air.

The research team stumbled upon a potential answer to a question that has vexed atmospheric chemists for years: what eats away at ozone in dusty air?

In trying to reconcile this contradiction, the research team stumbled upon a potential answer to a question that has plagued atmospheric chemists for years: what eats away at ozone in dusty air?

In layers of dust floating off the Sahara and other deserts, scientists have seen ozone levels drop below those in less dusty air. Separately, some have also observed layers of iodine-rich dust. It is also well known that iodine is a powerful destroyer of ozone, a pollutant harmful to humans and crops. But until now, no one had found a likely mechanism that unites ozone, dust and iodine and explains the low levels of ozone in dust.

The riddle

Volkamer and his colleagues wanted to know what is going on inside the layers of dust. They flew between central Chile and southern Peru for 13 days between January and February 2012 and used high spectral resolution lidar to track dust layers in the free troposphere while spectroscopy instruments recorded dust levels. ozone and iodine monoxide.

After the flights, the team pored over weather records and traced the source of the dust-laden air masses back to the Atacama and Sechura deserts. Field measurements showed that the dust layers had 10 times the iodine oxide concentration of background air at the same altitudes. The researchers then modeled how these iodine concentrations might affect ozone levels in ambient air and found that ozone concentrations decreased by 35% locally (over an area of ​​approximately 57,000 square kilometers) and 9.4% at the regional level (an area of ​​approximately 5 million square kilometres). ).

“It was a conundrum in the community. … There were measurements of dust and weak ozone, but there were no simultaneous measurements of dust and ozone with iodine.”

Scientists are unsure of the precise mechanism, but have proposed that when the wind blows dust into the air, the dust, which is alkaline, can attract acids. These acids can activate dust particles to release iodine, resulting in photochemical reactions in which iodine destroys ozone.

“It was an enigma in the community,” Volkamer said. “There were measurements of dust and weak ozone, but there were no simultaneous measurements of dust and ozone with iodine.”

Further laboratory and field experiments are needed to verify these results, which have been published in Scientists progress. “We have a limited data set, and we haven’t measured iodine in dust. [directly],” noted Theodore Koenigpostdoctoral researcher at Peking University and lead author of the study.

But these findings give atmospheric chemists a framework to explain the degradation of ozone in dust. “It’s certainly credible evidence, but of course it’s not representative for the whole world,” said Jos Lelievelddirector of the Max Planck Institute for Chemistry, who was not involved in the study.

Fill gaps

Land-based sources of iodine are not as well known as marine sources, and they contribute a much smaller share of the element to the atmosphere. But without accounting for this source, atmospheric models could miss a small, but impactful, factor in ozone levels. “Iodine provides an explanation that fills in the gaps left by other techniques,” Volkamer said.

Additionally, air quality regulators might want to consider iodine when implementing pollution control measures. The iodine emitted from the dust is a sink for ozone, Volkamer explained, which reduces ozone pollution near the surface. But Lelieveld warned that more work is needed to understand how iodine chemistry affects air quality.

The findings also have implications for geoengineering proposals to inject dust into the air to cool the Earth. Injecting dust without a full understanding of its interactions with ozone could delay recovery of the protective ozone layer in the stratosphere. And although it destroys ozone, the chemistry of iodine increases the lifespan of other greenhouse gases in the air. “We’re careful before we try to solve one problem and make another worse, and iodine is something we need to have on the map,” Volkamer said.

—Jackie Rocheleau (@JackieRocheleau), science writer

Quote: Rocheleau, J. (2022), Iodine-laden desert dust eats away at ozone pollution, Eos, 103, https://doi.org/10.1029/2022EO220112. Posted February 28, 2022.
Text © 2022. The authors. CC BY-NC-ND 3.0
Unless otherwise stated, images are subject to copyright. Any reuse without the express permission of the copyright holder is prohibited.

Related

Related posts:

  1. North Africa: Adrar issues exposed as Sahara desert heats up
  2. Migrants rescued in remote Sahara desert
  3. Annual dust cloud from the Sahara Desert is en route to Mexico
  4. Paul Skipworth tackles seven-day Sahara Desert ultramarathon

CATEGORIES

  • Fragile States
  • Kalahari desert
  • Namib desert
  • Sahara desert
  • Savanna desert

RECENT POSTS

  • The expert opinion on Burnley’s finances and the questions raised by the club’s ‘worried’ accounts
  • Claim Online Payday Loans for Unemployed at Filld.com – CryptoMode
  • QuickQuid and Pounds to Pocket borrowers receive payment news
  • Michael T. Kildow Obituary – The Desert Sun
  • Rare black-legged kitten recovers from injury – NBC Los Angeles

ARCHIVES

  • May 2022
  • April 2022
  • March 2022
  • February 2022
  • January 2022
  • December 2021
  • November 2021
  • October 2021
  • September 2021
  • August 2021
  • July 2021
  • June 2021
  • May 2021
  • April 2021
  • March 2021
  • February 2021
  • January 2021
  • December 2020
  • November 2020
  • October 2020
  • September 2020
  • August 2020
  • July 2020
  • June 2020
  • May 2020
  • April 2020
  • March 2020
  • February 2020
  • January 2020
  • December 2019
  • November 2019
  • October 2019
  • September 2019
  • August 2019
  • July 2019
  • June 2019
  • May 2019
  • April 2019
  • February 2019
  • January 2019
  • October 2018
  • September 2018
  • August 2018
  • July 2018
  • June 2018
  • May 2018
  • April 2018
  • March 2018
  • February 2018
  • January 2018
  • December 2017
  • October 2017
  • September 2017
  • August 2017
  • June 2017
  • May 2017
  • March 2017
  • January 2017
  • November 2016
  • October 2016
  • September 2016
  • August 2016
  • June 2016
  • May 2016
  • April 2016
  • March 2016
  • January 2016
  • November 2015
  • May 2015
  • April 2015
  • January 2015
  • December 2014
  • October 2014
  • September 2014
  • June 2014
  • May 2014
  • January 2014
  • November 2013
  • October 2013
  • September 2013
  • April 2013
  • March 2013
  • November 2012
  • May 2012
  • October 2011
  • November 2010
  • April 2008
  • July 2006
  • November 2005
  • Privacy Policy
  • Terms and Conditions