scholarly journals Multiyear trends in volatile organic compounds in Los Angeles, California: Five decades of decreasing emissions

2012 ◽  
Vol 117 (D21) ◽  
pp. n/a-n/a ◽  
Author(s):  
Carsten Warneke ◽  
Joost A. de Gouw ◽  
John S. Holloway ◽  
Jeff Peischl ◽  
Thomas B. Ryerson ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Los Angeles ◽  
Organic Compounds ◽  
Volatile Organic

A Future Multi-Platform Atmospheric Chemistry Measurement Campaign to Study Oxidation in Mixed Anthropogenic-Biogenic Air Masses

2021 ◽  
Author(s):  
Christopher Cantrell ◽  
Vincent Michoud ◽  
Paola Formenti ◽  
Jean-Francois Doussin ◽  
Stephanie Alhajj Moussa ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Los Angeles ◽  
Organic Compounds ◽  
Atmospheric Chemistry ◽  
Vapor Pressures ◽  
Air Masses ◽  
Measurement Campaign ◽  
Secondary Species ◽  
Volatile Organic ◽  
Urban Plumes

<p>It is well known that the high population density of urban regions leads to significant degradation of the quality of the air because of the emissions of pollutants that are by-products of energy production, transportation, and industry. The composition and chemistry of urban air has been studied for many decades and these studies have led to detailed understanding of the factors controlling, for example, the formation of ozone, peroxyacetyl nitrate and other secondary species. In the last 20 to 30 years, significant progress has been made in reducing emissions of volatile organic compounds (VOCs) and oxides of nitrogen (NO<sub>x</sub>) in urban atmospheres. Substantial reductions in the abundance of secondary compounds, though, have been more elusive.</p><p>Research has continued to reveal more and more details of the complex processes involved in the atmospheric degradation of wide varieties of volatile organic compounds (VOCs) of anthropogenic and biospheric (BVOCs) origins. BVOCs include isoprene, monoterpenes and sesquiterpenes, and oxygenated VOCs (OVOCs, such as small alcohols). Emissions of BVOCs depend on several factors such as plant or tree species, temperature, and photosynthetically active radiation. They consist almost exclusively of unsaturated compounds with chemistry somewhat different from those of typical urban organic compound emissions. Oxidation of VOCs can lead to molecules of low volatility that are prone to uptake into the aerosol phase.</p><p>Recent studies conducted in megacities such as Paris, Mexico City, Los Angeles and those in China have led to significant advances in our understanding of the chemical evolution of urban plumes. However, important scientific questions remain on how mixing of anthropogenic and biogenic air masses modifies the composition of urban plumes and hence their impacts. Indeed, the proximity of cites to areas of strong biogenic emissions is not unusual. Many major cities at mid-latitudes are surrounded by forested areas.</p><p>ACROSS (Atmospheric ChemistRy Of the Suburban foreSt) is an integrative, innovative, multi-scale project awarded under the “Make Our Planet Great Again” (MOPGA) framework that seeks to definitively improve understanding of the impacts of mixing urban and biogenic air masses on the oxidation of atmospheric VOCs. The ACROSS working hypothesis is that this leads to changes in the production of oxygenated VOCs whose properties (e.g. vapor pressures) alter their importance in incorporation into SOA and their roles in production of ozone and other secondary species. Changes are also expected in the efficiency of radical recycling affecting the atmospheric oxidative capacity. Particularly important is NO<sub>x</sub> transport to suburban biogenic environments and the resulting modification of key chemical processes.</p><p>A key highlight of ACROSS is an intensive, multi-platform measurement campaign in the summer of 2022. It will use instruments staged on an airborne platform, a tower in the Rambouillet Forest near Paris, and other ground sites. The data collected from this campaign will be analyzed and studied to extract information about tropospheric oxidation chemistry generally, but also changes observed in the situation of mixed urban and biogenic air masses.</p><p>This presentation will summarize plans for the ACROSS campaign.</p>

scholarly journals Chemical and Biological Characterization of Particulate Matter (PM 2.5) and Volatile Organic Compounds Collected at Different Sites in the Los Angeles Basin

2020 ◽  
Vol 10 (9) ◽  
pp. 3245
Author(s):  
Arthur K. Cho ◽  
Yasuhiro Shinkai ◽  
Debra A. Schmitz ◽  
Emma Di Stefano ◽  
Arantza Eiguren-Fernandez ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Volatile Organic Compounds ◽  
Los Angeles ◽  
Organic Compounds ◽  
Inflammatory Responses ◽  
Biological Properties ◽  
Heme Oxygenase 1 ◽  
Tnf Α ◽  
Volatile Organic

Background: Most studies on air pollution (AP) exposure have focused on adverse health effects of particulate matter (PM). Less well-studied are the actions of volatile organic compounds (VOCs) not retained in PM collections. These studies quantified chemical and biological properties of both PM2.5 and VOCs. Methods: Samples were collected near the Port of Los Angeles (Long Beach, LB), railroads (Commerce, CM), and a pollution-trapping topography-site (San Bernardino, SB). Quantitative assays were conducted: (1) chemical—prooxidant and electrophile content, (2) biological—tumor necrosis factor-α (TNF-α) and heme oxygenase-1 (HO-1) expression (3), VOC modulation of PM effects and (4), activation of the antioxidant response element (ARE) using murine RAW 264.7 macrophages. Results: SB site samples were the most potent in the chemical and biological assays, followed by a CM railroad site. Only PM2.5 exhibited significant proinflammatory responses. VOCs were more potent than PM2.5 in generating anti-inflammatory responses; further, VOC pretreatment reduced PM-associated TNF-α expression. VOCs significantly increased ARE activation compared to their corresponding PM2.5 which remained at background levels. Conclusion: Ambient VOCs are major contributors to adaptive responses that can modulate PM effects, in vitro, and, as such, need to be included in comprehensive assessments of AP.

scholarly journals Photochemical aging of volatile organic compounds in the Los Angeles basin: Weekday-weekend effect

2013 ◽  
Vol 118 (10) ◽  
pp. 5018-5028 ◽  
Author(s):  
Carsten Warneke ◽  
Joost A. de Gouw ◽  
Peter M. Edwards ◽  
John S. Holloway ◽  
Jessica B. Gilman ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Los Angeles ◽  
Organic Compounds ◽  
Weekend Effect ◽  
Los Angeles Basin ◽  
Volatile Organic ◽  
Photochemical Aging
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