Related Experiment Video
Updated: Jul 21, 2026
09:34
Extraction and Characterization of Surfactants from Atmospheric Aerosols
Published on: April 21, 2017
Small scale structure in the atmosphere: implications for chemical composition and observational methods.
R L Jones1, S M Ball, D E Shallcross
1Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, UK, CB2 1EW.
Faraday Discussions
|September 16, 2005
Summary
Atmospheric mixing rates significantly alter air composition. This study reveals that nitrogen oxides (NOx) and nitrate radical (NO3) chemistry influence volatile organic compound (VOC) oxidation and ozone (O3) deposition.
Area of Science:
- Atmospheric chemistry
- Environmental science
Background:
- Non-linear chemical processes are crucial in atmospheric science.
- Urban plumes interact with the background atmosphere, influencing air quality.
Purpose of the Study:
- To investigate the impact of mixing rates on atmospheric composition using an idealized plume model.
- To understand the role of nitrogen oxides (NOx), ozone (O3), and volatile organic compounds (VOCs) in plume chemistry.
- To assess the significance of NO3 chemistry in biogenic VOC oxidation.
Main Methods:
- Simulations using an idealized plume model.
- Analysis of chemical relaxation of an urban plume into the background atmosphere.
- Evaluation of the influence of initial conditions and mixing rates on atmospheric chemistry.
Main Results:
- Initial concentrations of NOx, O3, and VOCs affect downstream chemistry.
- Atmospheric mixing rates significantly alter atmospheric composition.
- NO3 chemistry is a key pathway for oxidizing biogenic VOCs.
- Formation of long-lived organic nitrates impacts NOy speciation and can leave the planetary boundary layer.
- O3 surface deposition can be inhibited under specific NOx conditions, affecting the O3 budget.
Conclusions:
- Mixing rates are a critical factor in determining atmospheric composition and chemical transformations.
- NO3 chemistry plays a significant role in the oxidation of VOCs and influences NOy.
- The interaction between urban plumes and the background atmosphere has complex implications for atmospheric chemistry and air quality, particularly concerning ozone levels.
Related Concept Videos
01:24Mass Spectrum: Interpretation
An unknown compound can be established by identifying the molecular ion peak in the mass spectrum. The molecular ion peak is often weak or absent due to the predominance of fragmentation in high-energy electron beams. In such cases, a soft-energy electron beam can be used to scan the spectrum to enhance the intensity of the molecular ion peak. Additionally, chemical ionization, field ionization, and desorption ionization spectra are used to obtain a relatively intense molecular ion peak.To...
01:27Atomic Spectroscopy: Effects of Temperature
Atomization, converting samples into gas-phase atoms and ions, is essential for atomic spectroscopy. The flame temperature required for atomization affects the efficiency of the atomic spectroscopic methods by increasing the atomization efficiency and the relative population of the excited and ground states.
At thermal equilibrium, the relative populations of excited and ground state atoms can be estimated using the Maxwell–Boltzmann distribution. For example, an increase in temperature from...
At thermal equilibrium, the relative populations of excited and ground state atoms can be estimated using the Maxwell–Boltzmann distribution. For example, an increase in temperature from...
01:25Atomic Absorption Spectroscopy: Atomization Methods
Atomic Absorption Spectroscopy (AAS) atomizes samples through flame atomization or electrothermal atomization. Flame atomization typically involves a nebulizer and spray chamber assembly to combine the sample with a fuel–oxidant mixture, creating a fine aerosol mist that enters a burner. Typically, the fuel and oxidant are combined in an approximately stoichiometric ratio. However, for atoms that are easily oxidized, a fuel-rich mixture may be more advantageous. Only about 5% of the aerosol...
01:21Atomic Absorption Spectroscopy: Lab
For AAS measurements, samples must be introduced as clear solutions, often requiring extensive preliminary treatment to dissolve materials like soils, animal tissues, and minerals. Common methods for sample preparation include treatment with hot mineral acids, wet ashing, combustion in closed containers, high-temperature ashing, or fusion with reagents.
Solutions containing organic solvents, such as low-molecular-mass alcohols, esters, or ketones, enhance absorbances by increasing nebulizer...
Solutions containing organic solvents, such as low-molecular-mass alcohols, esters, or ketones, enhance absorbances by increasing nebulizer...
01:20Atomic Emission Spectroscopy: Overview
Atomic emission spectroscopy (AES) is an analytical technique used to determine the elemental composition of a sample by analyzing the light emitted from excited atoms. In AES, atoms in a sample are excited to higher energy levels by thermal energy from high-temperature sources, such as plasma, arcs, or sparks. When these excited atoms return to lower energy states, they emit light at specific wavelengths characteristic of each element. The resulting atomic emission spectrum, which consists of...
01:30Atomic Emission Spectroscopy: Interference
In atomic emission spectroscopy (AES), high-temperature atomizers excite a broad range of elements and molecules that generate complex emissions from sources such as oxides, hydroxides, and flame combustion products in the flame or plasma. Several strategies can be employed to minimize spectral interferences caused by overlapping emission lines or bands. These include increasing instrument resolution, choosing alternative emission lines, optimally placing the detector in low-background regions,...