[Emission Characteristics and Ozone Formation Potential of VOCs from Mobile Sources in the Beijing-Tianjin-Hebei Region]
These videos have been matched automatically. Contact us if they are not relevant.
These videos have been matched automatically. Contact us if they are not relevant.
View abstract on PubMed
Summary
This summary is machine-generated.Mobile sources are major emitters of volatile organic compounds (VOCs) in the Beijing-Tianjin-Hebei Region, significantly contributing to ozone pollution. This study quantifies VOCs emissions and ozone generation potential to guide pollution control strategies.
Area Of Science
- Environmental Science
- Atmospheric Chemistry
- Pollution Control
Context
- Mobile sources are the primary anthropogenic source of volatile organic compounds (VOCs) in the Beijing-Tianjin-Hebei Region.
- Understanding VOCs speciation and ozone formation potential is critical for effective air pollution management.
- Previous inventories may not fully capture the complexity of mobile source emissions in this region.
Purpose
- To establish a detailed emission inventory of VOCs from mobile sources in the Beijing-Tianjin-Hebei Region for 2021.
- To identify key contributing sources and chemical components of VOCs emissions.
- To estimate the ozone generation potential (OFP) of these VOCs and identify major reactive species.
Summary
- Total VOCs emissions from mobile sources in 2021 were 214.6 kt, with on-road vehicles, particularly gasoline motor vehicles (72.70%), being the dominant contributors.
- Aromatics, alkanes, and alkenes were the highest emitted VOC components, while alkenes, aromatics, and OVOCs showed the greatest OFP.
- Gasoline motor vehicles were the primary source of both VOCs emissions and OFP across Beijing, Tianjin, and Hebei, with other sources like construction machinery and civil aviation also noted.
Impact
- Provides a comprehensive VOCs emission inventory and OFP assessment for mobile sources in a critical air pollution region.
- Identifies specific high-emission vehicle types and VOCs species, enabling targeted control measures.
- Informs policy decisions for reducing ground-level ozone and improving regional air quality.
These videos have been matched automatically. Contact us if they are not relevant.
These videos have been matched automatically. Contact us if they are not relevant.
Related Concept Videos
Simple unsubstituted benzene has six aromatic protons, all chemically equivalent. Therefore, benzene exhibits only a singlet peak at δ 7.3 ppm in the 1H NMR spectrum. The observed shift is far downfield because the aromatic ring current strongly deshields the protons. Any substitution on the benzene ring makes the aromatic protons nonequivalent, and the protons split each other. The peak is, therefore, no longer a singlet and the splitting pattern and their associated coupling...
In ozonolysis, ozone is used to cleave a carbon–carbon double bond to form aldehydes and ketones, or carboxylic acids, depending on the work-up.
Ozone is a symmetrical bent molecule stabilized by a resonance structure.
Ozonolysis proceeds through an oxidative cleavage reaction. The first step is the electrophilic addition of ozone across the alkene double bond, forming an unstable molozonide intermediate, which reacts further to form a carbonyl and a carbonyl oxide. These intermediates...
In general, the term ‘aromatic’ indicates a pleasant smell or fragrance from fresh flowers, freshly prepared coffee, etc. In the early history of organic chemistry, many benzene derivatives were isolated from the pleasant odor oils of the plants. For example, vanillin was isolated from the oil of vanilla, methyl salicylate from the oil of wintergreen, and cinnamaldehyde from the oil of cinnamon. They all had a pleasant odor; hence the name aromatic was given.
In 1825, Faraday...
The benzylic position describes the position of a carbon atom attached directly to a benzene ring. Benzene by itself does not undergo oxidation. In contrast, the benzylic carbon is quite reactive in the presence of strong oxidizing agents such as KMnO4 or H2CrO4. Therefore, alkylbenzenes are readily oxidized to benzoic acid, irrespective of the type of alkyl groups.
Halogen and nitro substituents on a benzene ring remain unaffected by these oxidizing agents.
When more than one alkyl side...
Upon ionization, aromatic compounds generate a molecular ion that is observed as a prominent peak in their mass spectra. For example, the molecular ion peak for benzene appears at a mass-to-charge ratio of 78, while toluene is observed at a mass-to-charge ratio of 92. The molecular ion benzene is highly stable and does not readily undergo further fragmentation due to the significant amount of energy required to disrupt the aromatic stability of the benzene ring. In contrast, the molecular ion...
Benzylic halogenation takes place under conditions that favor radical reactions such as heat, light, or a free radical initiator like peroxide.
The reaction of toluene with an excess of chlorine can produce multiple benzylic chlorinations. However, the reaction of N-bromosuccinimide or NBS with toluene in the presence of a peroxide forms benzyl bromide. Halogenation of larger alkyl side chains are highly regioselective and occur primarily at the benzylic position. Bromination of ethylbenzene...