Dataset Information

Observed suppression of ozone formation at extremely high temperatures due to chemical and biophysical feedbacks.

ABSTRACT: Ground level ozone concentrations ([O(3)]) typically show a direct linear relationship with surface air temperature. Three decades of California measurements provide evidence of a statistically significant change in the ozone-temperature slope (?m(O3-T)) under extremely high temperatures (> 312 K). This ?m(O3-T) leads to a plateau or decrease in [O(3)], reflecting the diminished role of nitrogen oxide sequestration by peroxyacetyl nitrates and reduced biogenic isoprene emissions at high temperatures. Despite inclusion of these processes in global and regional chemistry-climate models, a statistically significant change in ?m(O3-T) has not been noted in prior studies. Future climate projections suggest a more frequent and spatially widespread occurrence of this ?m(O3-T) response, confounding predictions of extreme ozone events based on the historically observed linear relationship.

SUBMITTER: Steiner AL

PROVIDER: S-EPMC2993403 | biostudies-literature | 2010 Nov

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Observed suppression of ozone formation at extremely high temperatures due to chemical and biophysical feedbacks.

Steiner Allison L AL Davis Adam J AJ Sillman Sanford S Owen Robert C RC Michalak Anna M AM Fiore Arlene M AM

Proceedings of the National Academy of Sciences of the United States of America 20101101 46

Ground level ozone concentrations ([O(3)]) typically show a direct linear relationship with surface air temperature. Three decades of California measurements provide evidence of a statistically significant change in the ozone-temperature slope (Δm(O3-T)) under extremely high temperatures (> 312 K). This Δm(O3-T) leads to a plateau or decrease in [O(3)], reflecting the diminished role of nitrogen oxide sequestration by peroxyacetyl nitrates and reduced biogenic isoprene emissions at high temperat ...[more]

PMID: 21041679

Similar Datasets

Project description:UnlabelledSevere and persistent bacterial lung infections characterize cystic fibrosis (CF). While several studies have documented the microbial diversity within CF lung mucus, we know much less about the inorganic chemistry that constrains microbial metabolic processes and their distribution. We hypothesized that sputum is chemically heterogeneous both within and between patients. To test this, we measured microprofiles of oxygen and sulfide concentrations as well as pH and oxidation-reduction potentials in 48 sputum samples from 22 pediatric patients with CF. Inorganic ions were measured in 20 samples from 12 patients. In all cases, oxygen was depleted within the first few millimeters below the sputum-air interface. Apart from this steep oxycline, anoxia dominated the sputum environment. Different sputum samples exhibited a broad range of redox conditions, with either oxidizing (16 mV to 355 mV) or reducing (-300 to -107 mV) potentials. The majority of reduced samples contained hydrogen sulfide and had a low pH (2.9 to 6.5). Sulfide concentrations increased at a rate of 0.30 µM H2S/min. Nitrous oxide was detected in only one sample that also contained sulfide. Microenvironmental variability was observed both within a single patient over time and between patients. Modeling oxygen dynamics within CF mucus plugs indicates that anoxic zones vary as a function of bacterial load and mucus thickness and can occupy a significant portion of the mucus volume. Thus, aerobic respiration accounts only partially for pathogen survival in CF sputum, motivating research to identify mechanisms of survival under conditions that span fluctuating redox states, including sulfidic environments.ImportanceMicrobial infections are the major cause of morbidity and mortality in people living with CF, and yet microbial growth and survival in CF airways are not well understood. Insufficient information about the chemistry of the in vivo environment contributes to this knowledge gap. Our documentation of variable redox states corresponding to the presence or absence of sulfide begins to fill this void and motivates understanding of how different opportunistic pathogens adapt in these dynamic environments. Given the changing chemical state of CF sputum over time, it is important to consider a spectrum of aerobic and anaerobic lifestyles when studying CF pathogens in the laboratory. This work not only provides relevant constraints that can shape the design of laboratory experiments, it also suggests that sulfide might be a useful proxy for assessing the redox state of sputum in the clinic.

Dataset Information

Observed suppression of ozone formation at extremely high temperatures due to chemical and biophysical feedbacks.

Publications

Observed suppression of ozone formation at extremely high temperatures due to chemical and biophysical feedbacks.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets