Welcome To Website IAS

Hot news
Achievement

Independence Award

- First Rank - Second Rank - Third Rank

Labour Award

- First Rank - Second Rank -Third Rank

National Award

 - Study on food stuff for animal(2005)

 - Study on rice breeding for export and domestic consumption(2005)

VIFOTEC Award

- Hybrid Maize by Single Cross V2002 (2003)

- Tomato Grafting to Manage Ralstonia Disease(2005)

- Cassava variety KM140(2010)

Centres
Website links
Vietnamese calendar
Library
Visitors summary
 Curently online :  10
 Total visitors :  7471518

Reducing secondary organic aerosol formation from gasoline vehicle exhaust
Monday, 2017/07/10 | 08:00:04

Yunliang Zhao, Rawad Saleh, Georges Saliba, Albert A. Presto, Timothy D. Gordon, Greg T. Drozd, Allen H. Goldstein, Neil M. Donahue, and Allen L. Robinson

ENVIROMENTAL SCIENCES

Figure 1: Emissions and SOA production data from photooxidation experiments with dilute gasoline vehicle exhaust for different vehicle classes: (A) NMOG emissions, (B) end-of-experiment SOA production, and (C) effective SOA yields. The boxes represent the 75th and 25th percentiles of the data from individual vehicle tests with the centerline being the median. The whiskers are the 90th and 10th percentiles. The SOA production from SULEV was comparable to that measured during dynamic blank experiments, indicated by the dashed line in B. As discussed in the text, the SOA yields for SULEV vehicles were not estimated due to the large uncertainty in SOA production. This figure combines data from 14 newly tested vehicles (1 pre-LEV, 3 LEV, 3 ULEV, and 7 SULEV vehicles) with previously published data for 11 additional vehicles (3 pre-LEV, 3 LEV, and 5 ULEV vehicles) from Gordon et al. (5).

Significance

Secondary organic aerosol (SOA) is a major component of atmospheric fine particles, which pose serious health risks and influence Earth’s climate. We combine laboratory measurements and computational modeling to investigate SOA formation from gasoline vehicle exhaust—an important source of air pollution in urban environments. We find a strong dependence of SOA formation from gasoline vehicle exhaust on oxides of nitrogen (NOx) concentrations. Our results suggest that changing atmospheric NOx levels over the next two decades will likely dramatically reduce the effectiveness of stricter new gasoline vehicle emissions standards to lower SOA concentrations in Los Angeles and other urban areas.

Abstract

On-road gasoline vehicles are a major source of secondary organic aerosol (SOA) in urban areas. We investigated SOA formation by oxidizing dilute, ambient-level exhaust concentrations from a fleet of on-road gasoline vehicles in a smog chamber. We measured less SOA formation from newer vehicles meeting more stringent emissions standards. This suggests that the natural replacement of older vehicles with newer ones that meet more stringent emissions standards should reduce SOA levels in urban environments. However, SOA production depends on both precursor concentrations (emissions) and atmospheric chemistry (SOA yields). We found a strongly nonlinear relationship between SOA formation and the ratio of nonmethane organic gas to oxides of nitrogen (NOx) (NMOG:NOx), which affects the fate of peroxy radicals. For example, changing the NMOG:NOx from 4 to 10 ppbC/ppbNOx increased the SOA yield from dilute gasoline vehicle exhaust by a factor of 8. We investigated the implications of this relationship for the Los Angeles area. Although organic gas emissions from gasoline vehicles in Los Angeles are expected to fall by almost 80% over the next two decades, we predict no reduction in SOA production from these emissions due to the effects of rising NMOG:NOx on SOA yields. This highlights the importance of integrated emission control policies for NOx and organic gases.

 

See: http://www.pnas.org/content/114/27/6984.abstract.html?etoc

PNAS July 3 2017; vol.144; no.27: 6984–6989

Back      Print      View: 599

[ Other News ]___________________________________________________
  • Genome-wide analysis of autophagy-associated genes in foxtail millet (Setaria italica L.) and characterization of the function of SiATG8a in conferring tolerance to nitrogen starvation in rice.
  • Arabidopsis small nucleolar RNA monitors the efficient pre-rRNA processing during ribosome biogenesis
  • XA21-specific induction of stress-related genes following Xanthomonas infection of detached rice leaves.
  • Reducing the Use of Pesticides with Site-Specific Application: The Chemical Control of Rhizoctonia solani as a Case of Study for the Management of Soil-Borne Diseases
  • OsJRL, a rice jacalin-related mannose-binding lectin gene, enhances Escherichia coli viability under high-salinity stress and improves salinity tolerance of rice.
  • Production of lipopeptide biosurfactants by Bacillus atrophaeus 5-2a and their potential use in microbial enhanced oil recovery.
  • GhABF2, a bZIP transcription factor, confers drought and salinity tolerance in cotton (Gossypium hirsutum L.).
  • Resilience of cassava (Manihot esculenta Crantz) to salinity: implications for food security in low-lying regions.
  • Cellulose synthase complexes act in a concerted fashion to synthesize highly aggregated cellulose in secondary cell walls of plants
  • No adverse effects of transgenic maize on population dynamics of endophytic Bacillus subtilis strain B916-gfp
  • Identification and expression analysis of OsLPR family revealed the potential roles of OsLPR3 and 5 in maintaining phosphate homeostasis in rice
  • Functional analysis of molecular interactions in synthetic auxin response circuits
  • Titanium dioxide nanoparticles strongly impact soil microbial function by affecting archaeal nitrifiers.
  • Inducible Expression of the De-Novo Designed Antimicrobial Peptide SP1-1 in Tomato Confers Resistance to Xanthomonas campestris pv. vesicatoria.
  • Toward combined delignification and saccharification of wheat straw by a laccase-containing designer cellulosome
  • SNP-based discovery of salinity-tolerant QTLs in a bi-parental population of rice (Oryza sativa)
  • Pinpointing genes underlying the quantitative trait loci for root-knot nematode resistance in palaeopolyploid soybean by whole genome resequencing.
  • Transcriptome- Assisted Label-Free Quantitative Proteomics Analysis Reveals Novel Insights into Piper nigrum -Phytophthora capsici Phytopathosystem.
  • Brassinosteroids participate in the control of basal and acquired freezing tolerance of plants
  • Rapid hyperosmotic-induced Ca2+ responses in Arabidopsis thaliana exhibit sensory potentiation and involvement of plastidial KEA transporters

 

Designed & Powered by WEBSO CO.,LTD