scholarly journals Effects of Moisture Released during Forest Burning on Fog Formation and Implications for Visibility

2008 ◽  
Vol 47 (5) ◽  
pp. 1287-1296 ◽  
Author(s):  
Gary L. Achtemeier
Keyword(s):  
Ambient Air ◽  
The United States ◽  
Early Morning ◽  
Mixing Ratio ◽  
Number Density ◽  
Radiation Model ◽  
Extinction Coefficients ◽  
Dry Air ◽  
Humidity Measurements ◽  
Water Contents

Abstract Smoke from wildland burning in association with fog has been implicated as a visibility hazard over roadways in the United States. Visibilities at accident sites have been estimated in the range from 1 to 3 m (extinction coefficients between 1000 and 4000). Temperature and relative humidity measurements were taken from 29 “smokes” during 2002 and 2003. These data were converted to a measure of the mass of water vapor present to the mass of dry air containing the vapor (smoke mixing ratio). Smoke temperatures were processed through a simple radiation model before smokes were mixed with ambient air with temperature and moisture observed during the early morning on the days following the burns. Calculations show supersaturations implying liquid water contents (LWC) up to 17 times as large as LWC found in natural fog. Simple models combining fog droplet number density, droplet size, and LWC show that the supersaturation LWC of smokes is capable of reducing visibility to the ranges observed.

Measurements of moisture in smoldering smoke and implications for fog

2006 ◽  
Vol 15 (4) ◽  
pp. 517 ◽  
Author(s):  
Gary L. Achtemeier
Keyword(s):  
Relative Humidity ◽  
Ground Level ◽  
Southern United States ◽  
Formation Temperature ◽  
Mixing Ratio ◽  
Prescribed Burns ◽  
Dry Air ◽  
Ambient Relative Humidity ◽  
Humidity Measurements ◽  
The Impact

Smoke from wildland burning in association with fog has been implicated as a visibility hazard over roadways in the southern United States. A project began in 2002 to determine whether moisture released during the smoldering phases of southern prescribed burns could contribute to fog formation. Temperature and relative humidity measurements were taken from 27 smoldering ‘smokes’ during 2002 and 2003. These data were converted to a measure of the mass of water vapor present to the mass of dry air containing the vapor (smoke mixing ratio). Some smokes were dry with almost no moisture beyond ambient. Other smokes were moist with moisture excesses as large as 39 g kg–1. Calculations show that ground-level smoke moisture excesses have no impact on ambient relative humidity during the day. However, the impact at night can be large enough to increase the ambient relative humidity to 100%. Therefore smoke moisture may be a contributing factor to the location and timing of fog formation.

scholarly journals Monetizing the Burden of Childhood Asthma Due to Traffic Related Air Pollution in the Contiguous United States in 2010

2021 ◽  
Vol 18 (15) ◽  
pp. 7864
Author(s):  
Minaal Farrukh ◽  
Haneen Khreis
Keyword(s):  
United States ◽  
Air Pollution ◽  
Economic Impact ◽  
Childhood Asthma ◽  
Ambient Air ◽  
The United States ◽  
The State ◽  
Cost Calculation ◽  
Cost Burden ◽  
Incident Cases

Background: Traffic-related air pollution (TRAP) refers to the wide range of air pollutants emitted by traffic that are dispersed into the ambient air. Emerging evidence shows that TRAP can increase asthma incidence in children. Living with asthma can carry a huge financial burden for individuals and families due to direct and indirect medical expenses, which can include costs of hospitalization, medical visits, medication, missed school days, and loss of wages from missed workdays for caregivers. Objective: The objective of this paper is to estimate the economic impact of childhood asthma incident cases attributable to nitrogen dioxide (NO2), a common traffic-related air pollutant in urban areas, in the United States at the state level. Methods: We calculate the direct and indirect costs of childhood asthma incident cases attributable to NO2 using previously published burden of disease estimates and per person asthma cost estimates. By multiplying the per person indirect and direct costs for each state with the NO2-attributable asthma incident cases in each state, we were able to estimate the total cost of childhood asthma cases attributable to NO2 in the United States. Results: The cost calculation estimates the total direct and indirect annual cost of childhood asthma cases attributable to NO2 in the year 2010 to be $178,900,138.989 (95% CI: $101,019,728.20–$256,980,126.65). The state with the highest cost burden is California with $24,501,859.84 (95% CI: $10,020,182.62–$38,982,261.250), and the state with the lowest cost burden is Montana with $88,880.12 (95% CI: $33,491.06–$144,269.18). Conclusion: This study estimates the annual costs of childhood asthma incident cases attributable to NO2 and demonstrates the importance of conducting economic impacts studies of TRAP. It is important for policy-making institutions to focus on this problem by advocating and supporting more studies on TRAP’s impact on the national economy and health, including these economic impact estimates in the decision-making process, and devising mitigation strategies to reduce TRAP and the population’s exposure.

Multiscenario, Spatially Detailed Forecasting of Utility Steam Coal for the Ohio River Navigation System

2005 ◽  
Vol 1909 (1) ◽  
pp. 39-46
Author(s):  
Jeff Watkins ◽  
Dale W. Kelz
Keyword(s):  
Ambient Air ◽  
The United States ◽  
Army Corps ◽  
Ohio River ◽  
Army Corps Of Engineers ◽  
Utility Industry ◽  
National Power ◽  
Economics Model ◽  
Coal Supply ◽  
Economic Analyses

The U.S. Army Corps of Engineers has pursued continual refinement in the waterway traffic forecasts used in project economic analyses. The multiscenario forecasting of utility steam coal described in this paper, based on the work of Hill & Associates, Inc. (H&A), is a substantial refinement of previous forecasting efforts. H&A prepares 20-year steam coal forecasts on the basis of the interaction of two major linear programming models: the National Power Model (NPM) and the Utility Fuel Economics Model (UFEM). The NPM is a utility industry model that dispatches all electric generating plants in the United States (coal and noncoal), producing forecasts of generation by fuel type within a context of transmission and environmental constraints. The UFEM makes use of highly detailed coal supply data (for approximately 98 coal types) to allocate fuels among plants and units. These two models develop forecasts of coal demand for electricity generation, by type of coal, which were then “mapped” to the waterway. H&A prepared separate forecast scenarios based on three alternative environmental regulatory futures. The first is a continuation of existing law (in this case, the national ambient air quality standards). The second H&A scenario reflects implementation of the administration's Clear Skies Initiative. The final H&A scenario is an implementation of the Clear Skies Initiative without the proposal's severe mercury restrictions.

In the vicinity of a rendering plant it is very difficult to find a really unpolluted place for the olfactometric measurements. Although the most unpolluted site luff of the plant was chosen, another precaution was taken. As adaption of the panelists to the plant odour could cause one of the greatest errors, some minutes before and during the measurement the panelists inhale solely odourless air from the olfactometer. To prevent discomfort by inhaling completely dry air, the olfactometer Modell 1158 is supplied with a moistening device, fig. 1. Fig. 1. Moistening device. In a standard impinger, filled with destillated water, air is moistened close to saturation. An equal flow of moistened air is mixed to the olfactometer outlet, thus delivering to the panelist a rel. moisture content of nearly 50 %. The panel consisted of 4 persons. The samples are prediluted taken into plastic bags, simultaneously at the inlet (raw air) and at the outlet (cleaned air) of the air cleaners. To receive an unfalsified sample from the outlet of the biofilters, undiluted by ambient air, a "tent” of plastic foil, fig. 2, is placed on the filter surface. The cleaned air blows up the tent and escapes through the sample hole, large enough to prevent a significant increase of pressure. The form of the upblown tent indicates, wether a sample area with normal air flow is chosen, and over the space of the covered filter area of 6,25m2 an average sample is received. Fig. 2. Device for cleaned air samples from biofilter outlet.

1986 ◽  
pp. 238-238
Keyword(s):  
Ambient Air ◽  
Air Samples ◽  
Dry Air ◽  
Filter Surface ◽  
Plastic Bags ◽  
Plastic Foil ◽  
Air Cleaners ◽  
Unpolluted Site ◽  
Filter Area ◽  
To Receive

scholarly journals Temporal variability, sources, and sinks of C<sub>1</sub>-C<sub>5</sub> alkyl nitrates in Coastal New England

2009 ◽  
Vol 9 (6) ◽  
pp. 23371-23418 ◽  
Author(s):  
R. S. Russo ◽  
Y. Zhou ◽  
K. B. Haase ◽  
O. W. Wingenter ◽  
E. K. Frinak ◽  
...  
Keyword(s):  
New England ◽  
New Hampshire ◽  
Dry Deposition ◽  
Ambient Air ◽  
Early Morning ◽  
Secondary Source ◽  
Alkyl Nitrates ◽  
Mixing Ratios ◽  
Alkyl Nitrate ◽  
Marine Source

Abstract. Seven C1-C5 alkyl nitrates were measured both on the mainland and off the coast of New Hampshire using gas chromatographic techniques. Five separate data sets will be presented to characterize the seasonal and diurnal trends and the major sources and loss processes of these compounds. In situ measurements were conducted at the University of New Hampshire (UNH) Atmospheric Observing Station at Thompson Farm (TF) located in southeast NH during winter (January–February) and summer (June–August) 2002 and summer (July–August) 2004. The median (±standard deviation) total alkyl nitrate mixing ratio (ΣRONO2) was 25 (±7) in winter and 16 (±14) pptv in summer. Furthermore, daily canister samples collected at midday and later analyzed in the laboratory from January 2004–February 2008 gave median ΣRONO2 of 23 (±8) in winter and 14 (±10) pptv in summer. Alkyl nitrate mixing ratios increased throughout the morning and were highest in the afternoon reflecting mixing of remnant boundary layer air toward the surface and photochemical production during the day. During summers 2002 and 2004, MeONO2 decreased overnight and reached minimum hourly average mixing ratios in the early morning (05:00–07:00 LT). Comparison with wind speed and trace gas (i.e., hydrocarbons, ozone, carbon monoxide, total reactive nitrogen) trends suggested that dry deposition contributed to the early morning MeONO2 minimum which is a previously unaccounted for removal mechanism. The mean dry deposition rate and velocity of MeONO2 was estimated to be −0.5 nmol m−2 hr−1 and 0.13 cm s−1, respectively. Results from ambient air and surface seawater measurements made onboard the NOAA R/V Ronald H. Brown in the Gulf of Maine during the 2002 New England Air Quality Study and from ambient canister samples collected throughout the Great Bay estuary in August 2003 are also presented. Comparisons between the alkyl nitrate trends with anthropogenic and marine source fingerprints and tracers suggest that a marine source of alkyl nitrates is not significant in coastal New England. Given the apparent prominence of a secondary source, comparisons between observed and predicted alkyl nitrate/parent hydrocarbon ratios were made which demonstrated that background mixing ratios have a continuous and prevalent influence on the alkyl nitrate distribution.

Longitudinal associations between insomnia symptoms and all-cause mortality among middle-aged and older adults: A population-based cohort study

SLEEP ◽  
2022 ◽  
Author(s):  
Asos Mahmood ◽  
Meredith Ray ◽  
Kenneth D Ward ◽  
Aram Dobalian ◽  
Sang Nam Ahn
Keyword(s):  
Older Adults ◽  
The United States ◽  
Early Morning ◽  
Time Varying ◽  
Middle Aged ◽  
Insomnia Symptom ◽  
All Cause Mortality ◽  
Longitudinal Associations ◽  
Insomnia Symptoms

Abstract To date, there is no scientific consensus on whether insomnia symptoms increase mortality risk. We investigated longitudinal associations between time-varying insomnia symptoms (difficulty initiating sleep, difficulty maintaining sleep, early-morning awakening, and non-restorative sleep) and all-cause mortality among middle-aged and older adults during 14 years of follow-up. Data were obtained from 2004 through 2018 survey waves of the Health and Retirement Study in the United States for a population-representative sample of 15,511 respondents who were ≥50 years old in 2004. Respondents were interviewed biennially and followed through the end of the 2018 survey wave for the outcome. Marginal structural discrete-time survival analyses were employed to account for time-varying confounding and selection bias. Of the 15,511 cohort respondents (mean [±SD] age at baseline, 63.7 [±10.2] years; 56.0% females), 5,878 (31.9%) died during follow-up. At baseline (2004), 41.6% reported experiencing at least one insomnia symptom. Respondents who experienced one (HR=1.11; 95% CI: 1.03–1.20), two (HR=1.12; 95% CI: 1.01–1.23), three (HR=1.15; 95% CI: 1.05–1.27), or four (HR=1.32; 95% CI: 1.12–1.56) insomnia symptoms had on average a higher hazard of all-cause mortality, compared to those who were symptom-free. For each insomnia symptom, respondents who experienced difficulty initiating sleep (HR=1.12; 95% CI: 1.02–1.22), early-morning awakening (HR=1.09; 95% CI: 1.01–1.18), and nonrestorative sleep (HR=1.17; 95% CI: 1.09–1.26), had a higher hazard of all-cause mortality compared to those not experiencing the symptom. The findings demonstrate significant associations between insomnia symptoms and all-cause mortality, both on a cumulative scale and independently, except for difficulty maintaining sleep. Further research should investigate the underlying mechanisms linking insomnia symptoms and mortality.

Variational Assimilation of Radar Data and GLM Lightning-Derived Water Vapor for the Short-Term Forecasts of High-Impact Convective Events

2019 ◽  
Vol 147 (11) ◽  
pp. 4045-4069 ◽  
Author(s):  
Alexandre O. Fierro ◽  
Yunheng Wang ◽  
Jidong Gao ◽  
Edward R. Mansell
Keyword(s):  
Water Vapor ◽  
Radar Data ◽  
The United States ◽  
High Impact ◽  
Added Value ◽  
Mixing Ratio ◽  
Short Term ◽  
Short Term Forecast ◽  
Term Forecast ◽  
Vapor Mass

Abstract The assimilation of water vapor mass mixing ratio derived from total lightning data from the Geostationary Lightning Mapper (GLM) within a three-dimensional variational (3DVAR) system is evaluated for the analysis and short-term forecast (≤6 h) of a high-impact convective event over the northern Great Plains in the United States. Building on recent work, the lightning data assimilation (LDA) method adjusts water vapor mass mixing ratio within a fixed layer depth above the lifted condensation level by assuming nearly water-saturated conditions at observed lightning locations. In this algorithm, the total water vapor mass added by the LDA is balanced by an equal removal outside observed lightning locations. Additional refinements were also devised to partially alleviate the seasonal and geographical dependence of the original scheme. To gauge the added value of lightning, radar data (radial velocity and reflectivity) were also assimilated with or without lightning. Although the method was evaluated in quasi–real time for several high-impact weather events throughout 2018, this work will focus on one specific, illustrative severe weather case wherein the control simulation—which did not assimilate any data—was eventually able to initiate and forecast the majority of the observed storms. Given a relatively reasonable forecast in the control experiment, the GLM and radar assimilation experiments were still able to improve the short-term forecast of accumulated rainfall and composite radar reflectivity further, as measured by neighborhood-based metrics. These results held whether the simulations made use of one single 3DVAR analysis or high-frequency (10 min) successive cycling over a 1-h period.

scholarly journals Early Morning Food Intake as a Risk Factor for Metabolic Dysregulation

Nutrients ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 756
Author(s):  
Ellen R. Stothard ◽  
Hannah K. Ritchie ◽  
Brian R. Birks ◽  
Robert H. Eckel ◽  
Janine Higgins ◽  
...  
Keyword(s):  
Food Intake ◽  
Caloric Intake ◽  
The United States ◽  
Early Morning ◽  
Shift Workers ◽  
Wake Time ◽  
Metabolic Dysregulation ◽  
Obesity And Diabetes ◽  
Increased Risk ◽  
The Impact

Increased risk of obesity and diabetes in shift workers may be related to food intake at adverse circadian times. Early morning shiftwork represents the largest proportion of shift workers in the United States, yet little is known about the impact of food intake in the early morning on metabolism. Eighteen participants (9 female) completed a counterbalanced 16 day design with two conditions separated by ~1 week: 8 h sleep opportunity at habitual time and simulated early morning shiftwork with 6.5 h sleep opportunity starting ~1 h earlier than habitual time. After wake time, resting energy expenditure (REE) was measured and blood was sampled for melatonin and fasting glucose and insulin. Following breakfast, post-prandial blood samples were collected every 40 min for 2 h and the thermic effect of food (TEF) was assessed for 3.25 h. Total sleep time was decreased by ~85 min (p < 0.0001), melatonin levels were higher (p < 0.0001) and post-prandial glucose levels were higher (p < 0.05) after one day of simulated early morning shiftwork compared with habitual wake time. REE was lower after simulated early morning shiftwork; however, TEF after breakfast was similar to habitual wake time. Insufficient sleep and caloric intake during a circadian phase of high melatonin levels may contribute to metabolic dysregulation in early morning shift workers.

scholarly journals An Assessment of Annual Mortality Attributable to Ambient PM2.5 in Bangkok, Thailand

2020 ◽  
Vol 17 (19) ◽  
pp. 7298 ◽  
Author(s):  
Nathaniel R. Fold ◽  
Mary R. Allison ◽  
Berkley C. Wood ◽  
Pham T. B. Thao ◽  
Sebastien Bonnet ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Air Quality ◽  
Quality Standards ◽  
Ambient Air ◽  
The United States ◽  
Air Pollutant ◽  
World Health ◽  
Ambient Air Quality ◽  
Air Quality Standards ◽  
Ambient Air Quality Standards

Multiple studies indicate that PM2.5 is the most deleterious air pollutant for which there are ambient air quality standards. Daily concentrations of PM2.5 in Bangkok, Thailand, continuously exceed the World Health Organization (WHO) and the Thai National Ambient Air Quality Standards (NAAQSs). Bangkok has only recently begun to measure concentrations of PM2.5. To overcome this paucity of data, daily PM2.5/PM10 ratios were generated over the period 2012–2018 to interpolate missing values. Concentration-response coefficients (β values) for PM2.5 versus non-accidental, cardiopulmonary, and lung cancer mortalities were derived from the literature. Values were also estimated and were found to be comparable to those reported in the literature for a Chinese population, but considerably lower than those reported in the literature from the United States. These findings strongly suggest that specific regional β values should be used to accurately quantify the number of premature deaths attributable to PM2.5 in Asian populations. Health burden analysis using the Environmental Benefits Mapping and Analysis Program (BenMAP) showed that PM2.5 concentration in Bangkok contributes to 4240 non-accidental, 1317 cardiopulmonary, and 370 lung cancer mortalities annually. Further analysis showed that the attainment of PM2.5 levels to the NAAQSs and WHO guideline would reduce annual premature mortality in Bangkok by 33%and 75%, respectively.

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