scholarly journals Primary and secondary sources of formaldehyde in urban atmospheres: Houston Texas region

2011 ◽  
Vol 11 (12) ◽  
pp. 32601-32645 ◽  
Author(s):  
D. D. Parrish ◽  
T. B. Ryerson ◽  
J. Mellqvist ◽  
J. Johansson ◽  
A. Fried ◽  
...  
Keyword(s):  
Secondary Production ◽  
Motor Vehicle ◽  
Field Studies ◽  
Industrial Facilities ◽  
Secondary Sources ◽  
Mobile Sources ◽  
Volatile Organic ◽  
Ambient Concentrations ◽  
Primary Emissions ◽  
Current Emission

Abstract. We evaluate the rates of secondary production and primary emission of formaldehyde (CH2O) from petrochemical industrial facilities and on-road vehicles in the Houston Texas region. This evaluation is based upon ambient measurements collected during field studies in 2000, 2006 and 2009. The predominant CH2O source (92 ± 4% of total) is secondary production formed during the atmospheric oxidation of highly reactive volatile organic compounds (HRVOCs) emitted from the petrochemical facilities. Smaller contributions are primary emissions from these facilities (4 ± 2%), and secondary production (~3%) and primary emissions (~1%) from vehicles. The primary emissions from both sectors are well quantified by current emission inventories. Since secondary production dominates, control efforts directed at primary CH2O emissions cannot address the large majority of CH2O sources in the Houston area, although there may still be a role for such efforts. Ongoing efforts to control alkene emissions from the petrochemical facilities, as well as volatile organic compound emissions from the motor vehicle fleet, will effectively reduce the CH2O concentrations in the Houston region. We have not addressed other emission sectors, such as off-road mobile sources or secondary formation from biogenic hydrocarbons. Previous analyses based on correlations between ambient concentrations of CH2O and various marker species have suggested much larger primary emissions of CH2O, but those results neglect confounding effects of dilution and loss processes, and do not demonstrate the causes of the observed correlations. Similar problems must be suspected in any source apportionment analysis of secondary species based upon correlations of ambient concentrations of pollutants.

scholarly journals Primary and secondary sources of formaldehyde in urban atmospheres: Houston Texas region

2012 ◽  
Vol 12 (7) ◽  
pp. 3273-3288 ◽  
Author(s):  
D. D. Parrish ◽  
T. B. Ryerson ◽  
J. Mellqvist ◽  
J. Johansson ◽  
A. Fried ◽  
...  
Keyword(s):  
Secondary Production ◽  
Motor Vehicle ◽  
Field Studies ◽  
Industrial Facilities ◽  
Secondary Sources ◽  
Mobile Sources ◽  
Volatile Organic ◽  
Ambient Concentrations ◽  
Primary Emissions ◽  
Current Emission

Abstract. We evaluate the rates of secondary production and primary emission of formaldehyde (CH2O) from petrochemical industrial facilities and on-road vehicles in the Houston Texas region. This evaluation is based upon ambient measurements collected during field studies in 2000, 2006 and 2009. The predominant CH2O source (92 ± 4% of total) is secondary production formed during the atmospheric oxidation of highly reactive volatile organic compounds (HRVOCs) emitted from the petrochemical facilities. Smaller contributions are primary emissions from these facilities (4 ± 2%), and secondary production (~3%) and primary emissions (~1%) from vehicles. The primary emissions from both sectors are well quantified by current emission inventories. Since secondary production dominates, control efforts directed at primary CH2O emissions cannot address the large majority of CH2O sources in the Houston area, although there may still be a role for such efforts. Ongoing efforts to control alkene emissions from the petrochemical facilities, as well as volatile organic compound emissions from the motor vehicle fleet, will effectively reduce the CH2O concentrations in the Houston region. We do not address other emission sectors, such as off-road mobile sources or secondary formation from biogenic hydrocarbons. Previous analyses based on correlations between ambient concentrations of CH2O and various marker species have suggested much larger primary emissions of CH2O, but those results neglect confounding effects of dilution and loss processes, and do not demonstrate the causes of the observed correlations. Similar problems must be suspected in any source apportionment analysis of secondary species based upon correlations of ambient concentrations of pollutants.

scholarly journals Mexico City aerosol analysis during MILAGRO using high resolution aerosol mass spectrometry at the urban supersite (T0) – Part 1: Fine particle composition and organic source apportionment

2009 ◽  
Vol 9 (2) ◽  
pp. 8377-8427 ◽  
Author(s):  
A. C. Aiken ◽  
D. Salcedo ◽  
M. J. Cubison ◽  
J. A. Huffman ◽  
P. F. DeCarlo ◽  
...  
Keyword(s):  
High Resolution ◽  
Mexico City ◽  
Biomass Burning ◽  
Emissions Inventory ◽  
Secondary Sources ◽  
Diurnal Cycles ◽  
Aerosol Mass ◽  
Aerosol Mass Spectrometry ◽  
Order Of Magnitude ◽  
Primary Emissions

Abstract. Submicron aerosol was analyzed during the MILAGRO field campaign in March 2006 at the T0 urban supersite in Mexico City with a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) and complementary instrumentation. Mass concentrations, diurnal cycles, and size distributions of inorganic and organic species are similar to results from the CENICA supersite in April 2003 with organic aerosol (OA) comprising about half of the fine PM mass. Positive Matrix Factorization (PMF) analysis of the high resolution OA spectra identified three major components: chemically-reduced urban primary emissions (hydrocarbon-like OA, HOA), oxygenated OA (OOA, mostly secondary OA or SOA), and biomass burning OA (BBOA) that correlates with levoglucosan and acetonitrile. BBOA includes several very large plumes from regional fires and likely also some refuse burning. A fourth OA component is a small local nitrogen-containing reduced OA component (LOA) which accounts for 9% of the OA mass but one third of the organic nitrogen, likely as amines. OOA accounts for almost half of the OA on average, consistent with previous observations. OA apportionment results from PMF-AMS are compared to the PM2.5 chemical mass balance of organic molecular markers (CMB-OMM, from GC/MS analysis of filters). Results from both methods are overall consistent. Both assign the major components of OA to primary urban, biomass burning/woodsmoke, and secondary sources at similar magnitudes. The 2006 Mexico City emissions inventory underestimates the urban primary PM2.5 emissions by a factor of ~4, and it is ~16 times lower than afternoon concentrations when secondary species are included. Additionally, the forest fire contribution is underestimated by at least an order-of-magnitude in the inventory.

scholarly journals Buildings’ Air Quality in High Traffic

2015 ◽  
Vol 4 (6) ◽  
pp. 23-26
Author(s):  
Литвинова ◽  
Natalya Litvinova
Keyword(s):  
Carbon Monoxide ◽  
Air Quality ◽  
Western Siberia ◽  
Residential Buildings ◽  
Field Studies ◽  
Climatic Conditions ◽  
Sources Of Pollution ◽  
Mobile Sources ◽  
Air Intake ◽  
External Sources

The article presents the results of field studies of air quality depending on mobile sources of pollution. Studies of the carbon monoxide concentration was conducted for the climatic conditions of the South of Western Siberia. The object of the study was residential buildings. The studies were conducted under unfavorable wind speed. Processing of experimental data allowed to obtain the calculated dependences of dimensionless concentration of carbon monoxide (II) on the height of building’s facade under emissions from highways. According to the results of research a nomogram was constructed to determine the optimal air intake height of buildings located near roads of various traffic intensity. Research results and given recommendations allow considering external sources of pollution when designing ventilation of a building.

Pathogen suppression by microbial volatile organic compounds in soils

2019 ◽  
Vol 95 (8) ◽  
Author(s):  
Wietse de Boer ◽  
Xiaogang Li ◽  
Annelein Meisner ◽  
Paolina Garbeva
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Abiotic Factors ◽  
Management Strategies ◽  
Field Studies ◽  
Growth Media ◽  
Soil Borne Pathogens ◽  
Volatile Organic ◽  
Microbial Volatile Organic Compounds ◽  
Pathogen Suppression

ABSTRACT There is increasing evidence that microbial volatile organic compounds (mVOCs) play an important role in interactions between microbes in soils. In this minireview, we zoom in on the possible role of mVOCs in the suppression of plant-pathogenic soil fungi. In particular, we have screened the literature to see what the actual evidence is that mVOCs in soil atmospheres can contribute to pathogen suppression. Furthermore, we discuss biotic and abiotic factors that influence the production of suppressive mVOCs in soils. Since microbes producing mVOCs in soils are part of microbial communities, community ecological aspects such as diversity and assembly play an important role in the composition of produced mVOC blends. These aspects have not received much attention so far. In addition, the fluctuating abiotic conditions in soils, such as changing moisture contents, influence mVOC production and activity. The biotic and abiotic complexity of the soil environment hampers the extrapolation of the production and suppressing activity of mVOCs by microbial isolates on artificial growth media. Yet, several pathogen suppressive mVOCs produced by pure cultures do also occur in soil atmospheres. Therefore, an integration of lab and field studies on the production of mVOCs is needed to understand and predict the composition and dynamics of mVOCs in soil atmospheres. This knowledge, together with the knowledge of the chemistry and physical behaviour of mVOCs in soils, forms the basis for the development of sustainable management strategies to enhance the natural control of soil-borne pathogens with mVOCs. Possibilities for the mVOC-based control of soil-borne pathogens are discussed.

scholarly journals Variability of hydroxyl radical (OH) reactivity in the Landes maritime pine forest: results from the LANDEX campaign 2017

2020 ◽  
Vol 20 (3) ◽  
pp. 1277-1300 ◽  
Author(s):  
Sandy Bsaibes ◽  
Mohamad Al Ajami ◽  
Kenneth Mermet ◽  
François Truong ◽  
Sébastien Batut ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Hydroxyl Radical ◽  
Organic Compounds ◽  
Secondary Products ◽  
Strong Concentration ◽  
Volatile Organic ◽  
Warm Night ◽  
Photolysis Laser ◽  
Primary Emissions ◽  
Comparative Reactivity

Abstract. Total hydroxyl radical (OH) reactivity measurements were conducted during the LANDEX intensive field campaign in a coniferous temperate forest located in the Landes area, southwestern France, during July 2017. In order to investigate inter-canopy and intra-canopy variability, measurements were performed inside (6 m) and above the canopy level (12 m), as well as at two different locations within the canopy, using a comparative reactivity method (CRM) and a laser photolysis–laser-induced fluorescence (LP-LIF) instrument. The two techniques were intercompared at the end of the campaign by performing measurements at the same location. Volatile organic compounds were also monitored at both levels with a proton transfer time-of-flight mass spectrometer and online gas chromatography instruments to evaluate their contribution to total OH reactivity, with monoterpenes being the main reactive species emitted in this forest dominated by Pinus pinaster Aiton. Total OH reactivity varied diurnally, following the trend of biogenic volatile organic compounds (BVOCs), the emissions and concentrations of which were dependent on meteorological parameters. Average OH reactivity was around 19.2 and 16.5 s−1 inside and above the canopy, respectively. The highest levels of total OH reactivity were observed during nights with a low turbulence (u*≤0.2 m s−1), leading to lower mixing of emitted species within the canopy and thus an important vertical stratification characterized by a strong concentration gradient. Comparing the measured and the calculated OH reactivity highlighted an average missing OH reactivity of 22 % and 33 % inside and above the canopy, respectively. A day–night variability was observed on missing OH reactivity at both heights. Investigations showed that during daytime, missing OH sinks could be due to primary emissions and secondary products linked to a temperature-enhanced photochemistry. Regarding nighttime missing OH reactivity, higher levels were seen for the stable and warm night of 4–5 July, showing that these conditions could have been favorable for the accumulation of long-lived species (primary and secondary species) during the transport of the air mass from nearby forests.

scholarly journals A temporally and spatially resolved validation of emission inventories by measurements of ambient volatile organic compounds in Beijing, China

2014 ◽  
Vol 14 (12) ◽  
pp. 5871-5891 ◽  
Author(s):  
M. Wang ◽  
M. Shao ◽  
W. Chen ◽  
B. Yuan ◽  
S. Lu ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Measurement Data ◽  
Suburban Area ◽  
Urban Site ◽  
Emission Inventories ◽  
Relative Contribution ◽  
Volatile Organic ◽  
Current Emission ◽  
Ambient Measurements

Abstract. Understanding the sources of volatile organic compounds (VOCs) is essential for ground-level ozone and secondary organic aerosol (SOA) abatement measures. We made VOC measurements at 27 sites and online observations at an urban site in Beijing from July 2009 to January 2012. Based on these measurement data, we determined the spatial and temporal distribution of VOCs, estimated their annual emission strengths based on their emission ratios relative to carbon monoxide (CO), and quantified the relative contributions of various sources using the chemical mass balance (CMB) model. These results from ambient measurements were compared with existing emission inventories to evaluate the spatial distribution, species-specific emissions, and source structure of VOCs in Beijing. The measured VOC distributions revealed a hotspot in the southern suburban area of Beijing, whereas current emission inventories suggested that VOC emissions were concentrated in downtown areas. Compared with results derived from ambient measurements, the annual inventoried emissions of oxygenated VOC (OVOC) species and C2–C4 alkanes may be underestimated, while the emissions of styrene and 1,3-butadiene may be overestimated by current inventories. Source apportionment using the CMB model identified vehicular exhaust as the most important VOC source, with the relative contribution of 49%, in good agreement with the 40–51% estimated by emission inventories. The relative contribution of paint and solvent utilization obtained from the CMB model was 14%, significantly lower than the value of 32% reported by one existing inventory. Meanwhile, the relative contribution of liquefied petroleum gas (LPG) usage calculated using the CMB model was 6%, whereas LPG usage contribution was not reported by current emission inventories. These results suggested that VOC emission strengths in southern suburban area of Beijing, annual emissions of C2–C4 alkanes, OVOCs and some alkenes, and the contributions of solvent and paint utilization and LPG usage in current inventories all require significant revisions.

A net and a catch-segregating apparatus mounted in a motor vehicle for field studies on flight activity of simuliidae and other insects

1973 ◽  
Vol 63 (1) ◽  
pp. 103-112 ◽  
Author(s):  
L. Davies ◽  
D. M. Roberts
Keyword(s):  
Motor Vehicle ◽  
Field Studies ◽  
Flight Activity ◽  
Flying Insects

AbstractA method for collecting flying insects is described, developed for studies on the dispersal of Simuliidae. The apparatus consists of a net mounted on the roof of a motor vehicle, leading to a catch-segregating apparatus within it, such that the catches over any desired distance at speeds up to 48 km/h can be segregated without stopping until 50 catches have been obtained. The volume of air filtered is measured with a counter anemometer mounted in the net mouth. Specimen results for one day are given as an illustration of the efficiency of the method.

Ulyanovsk urban motor-vehicle transport in 1986–1990

2019 ◽  
pp. 283-291
Author(s):  
Rashit Muchamedov ◽  
Marat Khisamov
Keyword(s):  
Motor Vehicle ◽  
The State ◽  
Urban Transport ◽  
Contemporary History ◽  
State Archive ◽  
Industrial Facilities ◽  
Industrial Enterprises ◽  
Ulyanovsk Region ◽  
Trading Network ◽  
The City

We set the goal to study the development of passenger and freight motor-vehicle transport, the effectiveness of which ensures the continuous operation of large and small industrial enterprises, as well as the urban trading network and the services sector. We analyze the problem on the basis of archival sources drawn from the funds of the State Archive of Contemporary History of the Ulyanovsk Region (SACH UR) and the State Archive of the Ulyanovsk Region (SAUR), which are first put into scientific circulation, as well as materials from a monograph and dissertation research by authors from both regional and Russian level. In the course of the work, we reveal the trends in the development of passenger and freight motor-vehicle transport, its problems and achievements. We consider the measures taken by local party bodies to increase the functioning efficiency of motor-vehicle transport during the twelfth Five-year plan, the development trends of urban transport, as well as its problems and achievements. As a result of the study, we conclude that passenger transport is an important link in the urban economy system, without which the ex-istence of the city as a whole would not have been possible, and its development peak occurred precisely in the years under consideration (1986–1990) when intensive construction of industrial facilities and housing was carried out in the city. The intensive development of urban transport was also associated, with the labor of rationalizers who developed new projects of innovative technologies introduction, which made it possible to increase labor efficiency.

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