scholarly journals On the Origin of Carbonaceous Particles in American Cities: Results of Radiocarbon “Dating” and Chemical Characterization

Radiocarbon ◽  
1983 ◽  
Vol 25 (2) ◽  
pp. 603-614 ◽  
Author(s):  
L A Currie ◽  
G A Klouda ◽  
R E Continetti ◽  
I R Kaplan ◽  
W W Wong ◽  
...  
Keyword(s):  
Los Angeles ◽  
Power Plants ◽  
Fine Particles ◽  
Chemical Characterization ◽  
Receptor Modeling ◽  
Organic Chemical ◽  
Dispersion Modeling ◽  
Radiation Balance ◽  
Statistical Characterization ◽  
Carbonaceous Particles

During the past three years radiocarbon assay has emerged as a primary tool in the quantitative assignment of sources of urban and rural particulate pollution. Its use in several major field studies has come about because of its excellent (fossil/biogenic) discriminating power, because of advances in 14C measurements of small samples, and because of the increased significance of carbonaceous particles in the atmosphere. The problem is especially important in the cities, where increased concentrations of fine particles lead to pollution episodes characterized by poor visibility and changes in the radiation balance (absorption, scattering), and immediate and possibly long-term health effects. Efforts in source apportionment in such affected areas have been based on emissions inventories, dispersion modeling, and receptor modeling – ie, chemical and physical (and statistical) characterization of particles collected at designated receptor sites. It is in the last category that 14C has become quite effective in helping to resolve particle sources. Results are presented for studies carried out in Los Angeles, Denver, and Houston which incorporated 14C measurements, inorganic and organic chemical characterization, and receptor modeling. The 14C data indicated wide ranging contributions of biogenic and fossil carbon sources – eg, <10% to 60% contemporary (biogenic) in Houston – depending on meteorological, biological, and anthropological activity. The combined (chemical, isotopic, statistical) data point to sources such as vehicles, wood combustion, power plants, and vegetation.

scholarly journals Effects of model resolution on the interpretation of satellite NO<sub>2</sub> observations

2011 ◽  
Vol 11 (22) ◽  
pp. 11647-11655 ◽  
Author(s):  
L. C. Valin ◽  
A. R. Russell ◽  
R. C. Hudman ◽  
R. C. Cohen
Keyword(s):  
New Mexico ◽  
Los Angeles ◽  
Power Plants ◽  
Loss Rate ◽  
Nonlinear Effects ◽  
Model Resolution ◽  
Transport Models ◽  
Chemical Transport Models ◽  
Four Corners ◽  
Tropospheric No2

Abstract. Inference of NOx emissions (NO+NO2) from satellite observations of tropospheric NO2 column requires knowledge of NOx lifetime, usually provided by chemical transport models (CTMs). However, it is known that species subject to non-linear sources or sinks, such as ozone, are susceptible to biases in coarse-resolution CTMs. Here we compute the resolution-dependent bias in predicted NO2 column, a quantity relevant to the interpretation of space-based observations. We use 1-D and 2-D models to illustrate the mechanisms responsible for these biases over a range of NO2 concentrations and model resolutions. We find that predicted biases are largest at coarsest model resolutions with negative biases predicted over large sources and positive biases predicted over small sources. As an example, we use WRF-CHEM to illustrate the resolution necessary to predict 10 AM and 1 PM NO2 column to 10 and 25% accuracy over three large sources, the Four Corners power plants in NW New Mexico, Los Angeles, and the San Joaquin Valley in California for a week-long simulation in July 2006. We find that resolution in the range of 4–12 km is sufficient to accurately model nonlinear effects in the NO2 loss rate.

scholarly journals Characteristics of PM<sub>2.5</sub> speciation in representative megacities and across China

2011 ◽  
Vol 11 (1) ◽  
pp. 1025-1051 ◽  
Author(s):  
F. Yang ◽  
J. Tan ◽  
Q. Zhao ◽  
Z. Du ◽  
K. He ◽  
...  
Keyword(s):  
Los Angeles ◽  
Atmospheric Pollution ◽  
Urban Areas ◽  
Fine Particles ◽  
Chemical Species ◽  
Northern Region ◽  
Eastern Region ◽  
Mobile Source ◽  
Combustion Source ◽  
Geographical Regions

Abstract. Based on PM2.5 chemical database from literature and our observations, chemical species and reconstructed speciation of PM2.5 in several representative Chinese megacities and across China were compared to draw insights into the characteristics of PM2.5 speciation. PM2.5 mass and speciation varied substantially over geographical regions in China. Near six-fold variations in average PM2.5 concentrations (34.0–193.4 μg m−3) across China were found with high PM2.5 levels (>100 μg m−3) appearing along northern region and in western urban areas. At both urban and rural sites in eastern region, sum of sulfate, nitrate, and ammonia (SNA) typically constituted 40–57% of PM2.5 mass, indicative of the regional characteristics of fine particulate pollution and more intensive "complex atmospheric pollution" compared to western region. Particulate organic matter (POM) had constant and significant contribution to PM2.5 mass. POM plus SNA accounted for 62–90% of PM2.5 mass at most of the sites. PM2.5 speciation in China was also characterized by high content of mineral dust. In four representative megacities (i.e. Beijing, Chongqing, Shanghai, and Guangzhou) with substantially higher levels of all the species except that NO3−, NH4+, and EC in PM2.5 than those in Los Angeles, distinct differences in nitrate and sulfate levels and their mass ratio [NO3−]/[SO42−] imply that mobile source is likely more important than stationary (coal combustion) source in Guangzhou whereas in Chongqing the situation is contrary. The observed intra-city variations in PM2.5 mass and speciation indicate that local emissions and regional transportation both contributed significantly to high fine particles levels in Beijing, while local contribution likely played a predominant role in Chongqing. During the ten-year period from 1999 through 2008 in urban Beijing, both SNA and [NO3−]/[SO42−] exhibited steadily increasing trends, implying that the characteristic of "complex atmospheric pollution" and the contribution from mobile sources were both being enhanced.

scholarly journals Occupational Exposure to Fine Particulate Matter (PM4 and PM2.5) during Hand-Made Cookware Operation: Personal, Indoor and Outdoor Levels

2020 ◽  
Vol 17 (20) ◽  
pp. 7522
Author(s):  
Busisiwe Shezi ◽  
Angela Mathee ◽  
Nokulunga Cele ◽  
Sipho Ndabandaba ◽  
Renee A. Street
Keyword(s):  
Particulate Matter ◽  
Occupational Exposure ◽  
Fine Particles ◽  
Fine Particulate Matter ◽  
Health And Safety ◽  
Chemical Characterization ◽  
Personal Exposure ◽  
Targeted Prevention ◽  
Fine Particulate ◽  
Indoor And Outdoor

(1) Exposure of informal artisanal cookware makers to fine particles has not yet been characterized. The aim of this study was to characterize occupational exposure to fine particulate matter (PM4 and PM2.5) levels and fine particulate matter (PM2.5) elemental components; (2) Artisanal cookware makers were recruited from five cookware making sites. Exposure to fine particulate matter was measured for 17 male participants. SidePak personal aerosol monitors (AM520) were used to measure personal exposure to PM4, while a DustTrak monitor and an E-sampler were used to assess indoor and outdoor PM2.5 levels, respectively. A questionnaire was administered to capture information on demographic characteristics. The chemical characterization of indoor and outdoor PM2.5 filter mass was conducted using Wavelength Dispersive X-ray Fluorescence. Time series record of 15-min averages for indoor and outdoor PM2.5 levels were assessed; (3) The median (range) was 124 µg/m3 (23−100,000), 64 µg/m3 (1−6097) and 12 µg/m3 (4−1178), respectively, for personal PM4, indoor and outdoor PM2.5. The highest levels for many of the elemental components of PM2.5 were found in the outdoor PM2.5 filter mass and (4). The information generated during this study may assist in extending occupational health and safety strategies to artisanal cookware makers and developing targeted prevention initiatives.

scholarly journals Sources and atmospheric dynamics of organic aerosol in New Delhi, India: insights from receptor modeling

2020 ◽  
Vol 20 (2) ◽  
pp. 735-752 ◽  
Author(s):  
Sahil Bhandari ◽  
Shahzad Gani ◽  
Kanan Patel ◽  
Dongyu S. Wang ◽  
Prashant Soni ◽  
...  
Keyword(s):  
Source Apportionment ◽  
Chemical Characterization ◽  
Organic Aerosol ◽  
Receptor Modeling ◽  
World Health ◽  
Aerosol Composition ◽  
Time Resolved ◽  
Online Measurements ◽  
Using Data ◽  
Health Organization

Abstract. Delhi, India, is the second most populated city in the world and routinely experiences some of the highest particulate matter concentrations of any megacity on the planet, posing acute challenges to public health (World Health Organization, 2018). However, the current understanding of the sources and dynamics of PM pollution in Delhi is limited. Measurements at the Delhi Aerosol Supersite (DAS) provide long-term chemical characterization of ambient submicron aerosol in Delhi, with near-continuous online measurements of aerosol composition. Here we report on source apportionment based on positive matrix factorization (PMF), conducted on 15 months of highly time-resolved speciated submicron non-refractory PM1 (NR-PM1) between January 2017 and March 2018. We report on seasonal variability across four seasons of 2017 and interannual variability using data from the two winters and springs of 2017 and 2018. We show that a modified tracer-based organic component analysis provides an opportunity for a real-time source apportionment approach for organics in Delhi. Phase equilibrium modeling of aerosols using the extended aerosol inorganics model (E-AIM) predicts equilibrium gas-phase concentrations and allows evaluation of the importance of the ventilation coefficient (VC) and temperature in controlling primary and secondary organic aerosol. We also find that primary aerosol dominates severe air pollution episodes, and secondary aerosol dominates seasonal averages.

scholarly journals Regional and traffic-related air pollutants are associated with higher consumption of fast food and trans fat among adolescents

2018 ◽  
Vol 109 (1) ◽  
pp. 99-108 ◽  
Author(s):  
Zhanghua Chen ◽  
Megan M Herting ◽  
Leda Chatzi ◽  
Britni R Belcher ◽  
Tanya L Alderete ◽  
...  
Keyword(s):  
Air Pollution ◽  
Fast Food ◽  
Air Pollutants ◽  
Fine Particles ◽  
Health Study ◽  
School Age Children ◽  
Dispersion Modeling ◽  
Trans Fat ◽  
Acid Vapor ◽  
Increased Risk

ABSTRACT Background Air pollution exposures are novel contributors to the growing childhood obesity epidemic. One possible mechanism linking air pollution exposures and obesity is through changes in food consumption patterns. Objective The aim of this study was to examine the longitudinal association between childhood exposure to air pollutants and changes in diet among adolescents. Design School-age children were enrolled in the Southern California Children's Health Study during 1993–1994 (n = 3100) and were followed for 4–8 y. Community-level regional air pollutants [e.g., nitrogen dioxide (NO2), elemental carbon (EC), and fine particles with aerodynamic diameter &lt;2.5 µm (PM2.5)] were measured at central monitoring stations. Line dispersion modeling was used to estimate concentrations of traffic-related air pollutants based on nitrogen oxides (NOx) at participants’ residential addresses. In addition, self-reported diet information was collected annually using a structured youth/adolescent food-frequency questionnaire during 1997–2001. Generalized linear mixed-effects models were used in the association analyses. Results Higher exposures to regional and traffic-related air pollutants were associated with intake of a high-trans-fat diet, after adjusting for confounders including socioeconomic status and access to fast food in the community. A 2-SD (12.2 parts per billion) increase in regional NO2 exposure was associated with a 34% increased risk of consuming a high-trans-fat diet compared with a low-trans-fat diet (OR: 1.34; 95% CI: 1.05, 1.72). In addition, higher exposures to acid vapor, EC, PM2.5, and non-freeway NOx were all associated with higher consumption of dietary trans fat (all P &lt; 0.04). Notably, higher exposures to regional NO2, acid vapor, and EC were also associated with a higher consumption of fast food (all P &lt; 0.05). Conclusions Childhood exposures to regional and traffic-related air pollutants were associated with increased consumption by adolescents of trans fat and fast foods. Our results indicate that air pollution exposures may contribute to obesogenic behaviors. This study was registered at clinicaltrials.gov as NCT03379298.

Fine particles and meteorological conditions are associated with lung function in children with asthma living near two power plants

Public Health ◽  
2005 ◽  
Vol 119 (5) ◽  
pp. 418-425 ◽  
Author(s):  
R. Peled ◽  
M. Friger ◽  
A. Bolotin ◽  
H. Bibi ◽  
L. Epstein ◽  
...  
Keyword(s):  
Lung Function ◽  
Power Plants ◽  
Fine Particles ◽  
Meteorological Conditions ◽  
Children With Asthma

Dispersion Modeling of Leachates from Thermal Power Plants

2007 ◽  
Vol 133 (12) ◽  
pp. 1088-1097
Author(s):  
Gurdeep Singh ◽  
S. K. Gupta ◽  
Ritesh Kumar ◽  
M. Sunderarajan
Keyword(s):  
Power Plants ◽  
Thermal Power ◽  
Dispersion Modeling ◽  
Thermal Power Plants

Airborne Lidar Plume and Haze Analyzer (ALPHA-1)

1980 ◽  
Vol 61 (9) ◽  
pp. 1035-1043 ◽  
Author(s):  
Edward E. Uthe ◽  
Norman B. Nielsen ◽  
Walter L. Jimison
Keyword(s):  
Boundary Layer ◽  
Los Angeles ◽  
Power Plants ◽  
Particle Concentration ◽  
Layer Structure ◽  
Airborne Lidar ◽  
Test Program ◽  
Lidar System ◽  
Four Corners ◽  
Terrain Features

A new two-wavelength airborne lidar system has been constructed and field-tested. The system was designed to observe the distribution of particle concentrations over large regional areas. During a one-week field-test program, the system was used to observe boundary layer structure over the Los Angeles area and the downwind structure of particulate plumes from the Navajo (Page, Ariz.) and Four Corners (Farmington, N.Mex.) power plants. Data examples presented show the importance of terrain features in influencing particle concentration distributions over regional areas.

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