scholarly journals Regional sources of airborne ultrafine particle number and mass concentrations in California

2019 ◽  
Vol 19 (23) ◽  
pp. 14677-14702 ◽  
Author(s):  
Xin Yu ◽  
Melissa Venecek ◽  
Anikender Kumar ◽  
Jianlin Hu ◽  
Saffet Tanrikulu ◽  
...  
Keyword(s):  
Los Angeles ◽  
Natural Gas ◽  
San Francisco ◽  
Particle Number ◽  
Ultrafine Particle ◽  
Gas Combustion ◽  
Study Region ◽  
Mobile Sources ◽  
Source Contributions ◽  
Natural Gas Combustion

Abstract. Regional concentrations and source contributions are calculated for airborne particle number concentration (Nx) and ultrafine particle mass concentration (PM0.1) in the San Francisco Bay Area (SFBA) and the South Coast Air Basin (SoCAB) surrounding Los Angeles with 4 km spatial resolution and daily time resolution for selected months in the years 2012, 2015, and 2016. Performance statistics for daily predictions of N10 concentrations meet the goals typically used for modeling of PM2.5 (mean fractional bias (MFB) < ±0.5 and mean fractional error (MFE) < 0.75). The relative ranking and concentration range of source contributions to PM0.1 predicted by regional calculations agree with results from receptor-based studies that use molecular markers for source apportionment at four locations in California. Different sources dominated regional concentrations of N10 and PM0.1 because of the different emitted particle size distributions and different choices for heating fuels. Nucleation (24 %–57 %) made the largest single contribution to N10 concentrations at the 10 regional monitoring locations, followed by natural gas combustion (28 %–45 %), aircraft (2 %–10 %), mobile sources (1 %–5 %), food cooking (1 %–2 %), and wood smoke (0 %–1 %). In contrast, natural gas combustion (22 %–52 %) was the largest source of PM0.1 followed by mobile sources (15 %–42 %), food cooking (4 %–14 %), wood combustion (1 %–12 %), and aircraft (2 %–6 %). The study region encompassed in this project is home to more than 25 million residents, which should provide sufficient power for future epidemiological studies on the health effects of airborne ultrafine particles. All of the PM0.1 and N10 outdoor exposure fields produced in the current study are available free of charge at http://webwolf.engr.ucdavis.edu/data/soa_v3/hourly_avg/ (last access: 20 November 2019).

scholarly journals Sources of Airborne Ultrafine Particle Number and Mass Concentrations in California

2018 ◽  
Author(s):  
Xin Yu ◽  
Melissa Venecek ◽  
Jianlin Hu ◽  
Saffet Tanrikulu ◽  
Su-Tzai Soon ◽  
...  
Keyword(s):  
Los Angeles ◽  
San Francisco ◽  
Particle Number ◽  
San Francisco Bay Area ◽  
Ultrafine Particle ◽  
Bay Area ◽  
Source Contributions ◽  
Performance Statistics ◽  
South Coast Air Basin ◽  
Daily Time

Abstract. Regional concentrations and source contributions are calculated for airborne particle number concentration (PNC) and ultrafine particle mass concentration (PM0.1) in the San Francisco Bay Area (SFBA) and the South Coast Air Basin (SoCAB) surrounding Los Angeles with 4 km spatial resolution and daily time resolution for selected months in the years 2012, 2015, and 2016. Performance statistics for daily predictions of PNC concentrations meet the threshold normally required for regulatory modeling of PM2.5 (MFB 

scholarly journals Toward consistency between trends in bottom-up CO<sub>2</sub> emissions and top-down atmospheric measurements in the Los Angeles megacity

2016 ◽  
Vol 16 (6) ◽  
pp. 3843-3863 ◽  
Author(s):  
Sally Newman ◽  
Xiaomei Xu ◽  
Kevin R. Gurney ◽  
Ying Kuang Hsu ◽  
King Fai Li ◽  
...  
Keyword(s):  
Los Angeles ◽  
Natural Gas ◽  
Power Plants ◽  
Fossil Fuel ◽  
Fuel Combustion ◽  
Fossil Fuel Combustion ◽  
Atmospheric Measurements ◽  
Bottom Up ◽  
Gas Combustion ◽  
Natural Gas Combustion

Abstract. Large urban emissions of greenhouse gases result in large atmospheric enhancements relative to background that are easily measured. Using CO2 mole fractions and Δ14C and δ13C values of CO2 in the Los Angeles megacity observed in inland Pasadena (2006–2013) and coastal Palos Verdes peninsula (autumn 2009–2013), we have determined time series for CO2 contributions from fossil fuel combustion (Cff) for both sites and broken those down into contributions from petroleum and/or gasoline and natural gas burning for Pasadena. We find a 10 % reduction in Pasadena Cff during the Great Recession of 2008–2010, which is consistent with the bottom-up inventory determined by the California Air Resources Board. The isotopic variations and total atmospheric CO2 from our observations are used to infer seasonality of natural gas and petroleum combustion. The trend of CO2 contributions to the atmosphere from natural gas combustion is out of phase with the seasonal cycle of total natural gas combustion seasonal patterns in bottom-up inventories but is consistent with the seasonality of natural gas usage by the area's electricity generating power plants. For petroleum, the inferred seasonality of CO2 contributions from burning petroleum is delayed by several months relative to usage indicated by statewide gasoline taxes. Using the high-resolution Hestia-LA data product to compare Cff from parts of the basin sampled by winds at different times of year, we find that variations in observed fossil fuel CO2 reflect seasonal variations in wind direction. The seasonality of the local CO2 excess from fossil fuel combustion along the coast, on Palos Verdes peninsula, is higher in autumn and winter than spring and summer, almost completely out of phase with that from Pasadena, also because of the annual variations of winds in the region. Variations in fossil fuel CO2 signals are consistent with sampling the bottom-up Hestia-LA fossil CO2 emissions product for sub-city source regions in the LA megacity domain when wind directions are considered.

Research of pressure influence in the gas supply system on the energy consuption level of gas devices

2019 ◽  
Vol 6 (2) ◽  
pp. 56-63
Author(s):  
L. D. Pylypiv ◽  
І. І. Maslanych
Keyword(s):  
Natural Gas ◽  
Residential Buildings ◽  
Supply System ◽  
Normal Operation ◽  
Gas Combustion ◽  
Efficient Operation ◽  
Gas Consumption ◽  
Natural Gas Combustion ◽  
Gas Supply

There are investigated the influence of operating pressures in the gas supply system on the level of such energy indicators as efficiency, gas flow and gas overrun by gas equipment in residential buildings. There is established a relationship between the values of operating pressures in the gas supply system and the gas consumption level of household appliances. The causes of insufficient pressure in the gas networks of settlements are analyzed in the article. There is also developed an algorithm for calculating the change in the efficiency of gas appliances depending on the operational parameters of the gas network. It has been found that the most efficient operation of gas appliances is observed at an overpressure at the inlet of gas appliances of about 1200 Pa.To ensure the required quality of natural gas combustion among consumers and minimize gas consumption there are justified the following measures in the article: coordinating a domestic regulatory framework for assessing the quality of natural gas with international norms and standards; improving the preparation of gas coming from local wells before supplying it to gas distribution networks; auditing low pressure gas pipelines and reconstructing areas affected by corrosion; ensuring standard gas pressure in the network for the normal operation of domestic gas appliances; stating quality indicators of natural gas combustion by gas sales organizations.

Multiflame Patterns in Swirl-Driven Partially Premixed Natural Gas Combustion

2002 ◽  
Vol 125 (1) ◽  
pp. 40-45 ◽  
Author(s):  
K. P. Vanoverberghe ◽  
E. V. Van den Bulck ◽  
M. J. Tummers ◽  
W. A. Hu¨bner
Keyword(s):  
Natural Gas ◽  
Combustion Chamber ◽  
Gas Flow ◽  
State Transition ◽  
Gas Combustion ◽  
Bifurcation Phenomena ◽  
Major Species ◽  
Partially Premixed ◽  
Natural Gas Combustion ◽  
Low Nox Emission

Five different flame states are identified in a compact combustion chamber that is fired by a 30 kW swirl-stabilized partially premixed natural gas burner working at atmospheric pressure. These flame states include a nozzle-attached tulip shaped flame, a nonattached torroidal-ring shaped flame (SSF) suitable for very low NOx emission in a gas turbine combustor and a Coanda flame (CSF) that clings to the bottom wall of the combustion chamber. Flame state transition is generated by changing the swirl number and by premixing the combustion air with 70% of the natural gas flow. The flame state transition pathways reveal strong hysteresis and bifurcation phenomena. The paper also presents major species concentrations, temperature and velocity profiles of the lifted flame state and the Coanda flame and discusses the mechanisms of flame transition and stabilization.

Development of a Natural Gas Combustion System for High Specific Power

MTZ worldwide ◽  
2015 ◽  
Vol 76 (10) ◽  
pp. 30-35
Author(s):  
Bertold Hüchtebrock ◽  
José Geiger ◽  
Avnish Dhongde ◽  
Harsh Sankhla
Keyword(s):  
Natural Gas ◽  
Specific Power ◽  
Combustion System ◽  
Gas Combustion ◽  
High Specific Power ◽  
Natural Gas Combustion

Sequential-Based Process Modeling of Natural Gas Combustion in a Fluidized Bed Reactor

2012 ◽  
Vol 26 (4) ◽  
pp. 2058-2067 ◽  
Author(s):  
Abolhasan Hashemi Sohi ◽  
Ali Eslami ◽  
Amir Sheikhi ◽  
Rahmat Sotudeh-Gharebagh
Keyword(s):  
Natural Gas ◽  
Fluidized Bed ◽  
Process Modeling ◽  
Fluidized Bed Reactor ◽  
Gas Combustion ◽  
Natural Gas Combustion
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