Smoke Deposits Research Articles

Kitchen Characteristics and Practices Associated with Increased PM2.5 Concentration Levels in Zimbabwean Rural Households.

Household air pollution (HAP) from biomass fuels significantly contributes to cardio-respiratory morbidity and premature mortality globally. Particulate matter (PM), one of the pollutants generated, remains the most accurate indicator of household air pollution. Determining indoor air concentration levels and factors influencing these levels at the household level is of prime importance, as it objectively guides efforts to reduce household air pollution. This paper describes household factors associated with increased PM2.5 levels in Zimbabwean rural household kitchens. Our HAP and lung health in women study enrolled 790 women in rural and urban households in Zimbabwe between March 2018 and December 2019. Here, we report data from 148 rural households using solid fuel as the primary source of fuel for cooking and heating and where indoor air samples were collected. Data on kitchen characteristics and practices were collected cross-sectionally using an indoor walk-through survey and a modified interviewer-administered questionnaire. An Air metrics miniVol Sampler was utilized to collect PM2.5 samples from the 148 kitchens over a 24 h period. To identify the kitchen features and practices that would likely influence PM2.5 concentration levels, we applied a multiple linear regression model. The measured PM2.5 ranged from 1.35 μg/m3 to 1940 μg/m3 (IQR: 52.1-472). The PM2.5 concentration levels in traditional kitchens significantly varied from the townhouse type kitchens, with the median for each kitchen being 291.7 μg/m3 (IQR: 97.2-472.2) and 1.35 μg/m3 (IQR: 1.3-97.2), respectively. The use of wood mixed with other forms of biomass was found to have a statistically significant association (p < 0.001) with increased levels of PM2.5 concentration. In addition, cooking indoors was strongly associated with higher PM2.5 concentrations (p = 0.012). Presence of smoke deposits on walls and roofs of the kitchens was significantly associated with increased PM2.5 concentration levels (p = 0.044). The study found that kitchen type, energy type, cooking place, and smoke deposits were significant predictors of increased PM2.5 concentrations in the rural households. Concentrations of PM2.5 were high as compared to WHO recommended exposure limits for PM2.5. Our findings highlight the importance of addressing kitchen characteristics and practices associated with elevated PM2.5 concentrations in settings where resources are limited and switching to cleaner fuels may not be an immediate feasible option.

Heterogeneous Ozonolysis of Tetrahydrocannabinol: Implications for Thirdhand Cannabis Smoke.

Thirdhand smoke (THS) deposits to surfaces following smoking events and is a source of chemical exposure to humans. However, the evolution of THS in indoor environments is not well understood. Cannabis THS is a chemically distinct and prevalent form of THS, which has not been studied. The heterogeneous reaction of Δ9-tetrahydrocannabinol (THC), a major component of cannabis smoke, with ozone was examined as a pure compound and within cannabis smoke. Oxidative decay via ozonolysis and product formation were monitored by liquid chromatography-tandem mass spectrometry. Epoxide, dicarbonyl, and secondary ozonide THC reaction products were detected from both pure THC and cannabis experiments, with the product ratios dependent on relative humidity. The observed reaction kinetics for loss of THC on glass and cotton surfaces are consistent with a relatively short loss lifetime, which will be strongly dependent on the film thickness, ozone mixing ratio, and ozone reactivity of the surface substrate. The low volatility of THC and its oxidation products suggest that their contributions to thirdhand cannabis smoke will be less significant than the role that nicotine plays in thirdhand tobacco smoke.

Development and Performance Evaluation of an Indirect Heat Copra Dryer with Phase Changer

In the Philippines, farming communities produce copra using traditional open sun drying method that could be severely affected by heavy rainfall, temperature change, and intermittent sunshine, which could cause high microbial infection to the product. On the other hand, kiln drying may avoid these circumstances. However, smoke deposits in the finished product still cause farmers to have low-quality grade copra. Keeping this in view, an indirect heat copra dryer with phase changer (IHCDPC) was designed, fabricated, and evaluated in the hopes of providing farmers an alternative approach in drying copra, which may yield to producing a high-quality grade product. The developed IHCDPC was able to reduce the moisture content in fresh coconut meat from 57.4% w.b. to about 7.2% w.b. for a drying time of twenty-five hours. The IHCDPC was found out to have a thermal efficiency of 30.87%. The copra produced were graded as 84% MGC1, 13% MGC2, and 3% MGC3.

Analysis of Heavy Metals in Smoke Deposits in the Limewash of the Royal Artillery Factory of Seville (17th Century): Contributions to the Location of the Furnaces

The Royal Artillery Factory of Seville in Spain originated from pre‐existing private bronze foundries dating from the 16th century. The paper analyses the stratigraphy of wall cladding in the areas traditionally known as the ‘Old Foundry’ and the ‘New Foundry’, through its characterization by optical microscopy, scanning electron microscopy with energy‐dispersive X‐ray spectrometry (SEM‐EDX), micro‐X‐ray fluorescence (μ‐XRF) and micro‐X‐ray diffraction (μ‐XRD), in order to analyse the metal deposits that have accumulated since the 17th century. The data obtained allowed the verification of the available historiographical information and the location of the original bronze smelting furnaces. The analysis of patinas deposited on the overlapping layers of lime also confirmed that neither the raw materials nor the composition of the alloys used presented any substantial changes.

Evaluation of Accumulated Polycyclic Aromatic Hydrocarbons and Asbestiform Fibers on Firefighter Vehicles: Pilot Study

Firefighters are exposed to toxicants during fire suppression. Smoke deposits and particle residue from fire suppression accumulate on firefighters’ turnout gear, potentially exposing them to carcinogens and related adverse effects such as cancer. Previous studies have found that firefighters in small, rural fire departments tend to store their turnout gear in vehicles, given the broad response areas and limited number of firefighters. However, the scientific literature has little information regarding residual polycyclic aromatic hydrocarbons (PAHs) and asbestiform fibers in vehicles, which present a potential danger for dermal and inhalation exposure. A total of 29 wipe samples were collected from various surfaces in vehicles used to travel to fire sites (n = 10 for fire trucks [FT], n = 19 for personal vehicles [PV]). A polyester fabric wipe (100 cm2) saturated with 70% isopropyl alcohol was applied for each sample. Fifteen different PAHs were quantified using Environmental Protection Agency method 8270D. Eight of the 15 PAHs, which were detected with lower censored data, were considered for further data analysis. These eight were Naphthalene, Naphthalene[1]methyl, Phenanthrene, Anthracene, Fluoranthene, Pyrene, Benz[a]anthracene, and Chrysene. ANOVA of log-transformed concentrations indicated no statistically significant differences between FT and PV (p value > 0.05). However, the level of remaining PAHs in FT was higher than in PV. Using the administered survey, the results of a regression model showed that PAH levels in the vehicles were significantly influenced by container usage (p values < 0.05). Our analyses demonstrated the importance of safe work practices when turnout gear is stored in a vehicle. The knowledge gained through this study will provide firefighters in small, rural fire departments with information critical for implementing needed guidelines on turnout gear storage practices.

Assessment of Health Risk of Children from Traditional Biomass Burning in Rural Households

Indoor air pollution from burning of solid unprocessed biomass fuel and health risk arising from it are a crucial issue in developing countries. Smoke deposits (black soot) from traditional cooking stoves in the kitchen are characterized, and the health risk of children arising from it is assessed. Five types of wood, sissoo (Dalbergia sissoo), banyan (Ficus benghalensis), eucalyptus (Eucalyptus sp.), palm (Borassus flabellifer) and mixed wood were used by the villagers as their main cooking fuels. Black soots were collected and characterization was done by X-Ray fluorescence spectroscopy, atomic absorption spectroscopy and scanning electron microscopy. The highest concentration of lead was observed in soot from sissoo wood burning among the five types of black soots, followed by mixed wood, palm, banyan and eucalyptus. The quantitative estimation of manganese concentration was found to be very high in all varieties of black soot. Surface morphology study revealed that all the surfaces of black soot were similar in nature. Using metal concentration derived from the five types of black soot, exposure of children to heavy metals was calculated via three types of exposure pathways and it was found that the average daily exposure level of all elements was in the order of hand-to-mouth ingestion > dermal contact > inhalation. It was also noted that the non-carcinogenic hazard indexes and carcinogenic risks of metals in black soots were both well under the safe values.

Extraction of low-toxicity nanodiamonds from carbonaceous wastes

ABSTRACTBeing innocuous, nanodiamonds find huge applications in bioimaging, drug delivery and biomedical sensing. Their synthesis is generally carried out by detonation or shock wave methods. This article reports novel, economical and risk-free extraction of nanodiamonds from carbonaceous waste (smoke deposits of Hawan kund). Structural and morphological studies of extracted material revealed that the nanodiamonds have a size range of 4–5 nm and consists of sp3 core and sp2 shell. Extracted nanodiamonds contain various functional groups on its surface which make it suitable for various applications. Cytotoxicity assay revealed very less toxicity of extracted nanodiamonds, which makes them suitable candidate for biological applications. The proposed method offers the possibility of economical and detonation free production of nanodiamonds.

Chemical characterization of biomass burning deposits from cooking stoves in Bangladesh

Biomass burning smoke deposits were characterized from cooking stoves in Brahmondi, Narsingdi, Bangladesh. Arjun, bamboo, coconut, madhabilata, mahogany, mango, rice husk coil, plum and mixed dried leaves were used as biomasses. Smoke deposits were collected from the ceiling (above the stove) of the kitchen on aluminum foil. Deposits samples were analyzed with X-ray fluorescence (XRF) spectroscopy for trace elements determination. UV–visible spectrophotometer was used for ions analysis. The surface morphology of the smoke deposits was studied with scanning electron microscope (SEM). Elevated concentrations of the trace elements were observed, especially for toxic metals (Pb, Co, Cu). The highest concentration of lead was observed in rice husk coil among the determined biomasses followed by mahogany and arjun, whereas the lowest concentration was observed in bamboo. Potassium has the highest concentration among the determined trace elements followed by calcium, iron and titanium. Trace elements such as potassium, calcium, iron showed significant variation among different biomass burning smoke deposits. The average concentrations of sulfate, nitrate, and phosphate were 38.0, 0.60, 0.73 mg kg−1, respectively. The surface morphology was almost similar for these biomass burning deposit samples. The Southeast Asian biomass burning smoke deposits had distinct behavior from European and USA wood fuels combustion.

Smoke oxidation kinetics for application to prediction of clean burn patterns

SUMMARYSmoke deposition patterns are a potentially rich source of information concerning the behavior of a fire. Clean burn patterns are smoke‐free areas where smoke deposits have been oxidized away. In order to predict the formation of clean burn patterns, smoke oxidation kinetics are required. Smoke oxidation kinetics were studied for smokes from acrylonitrile butadiene styrene, polymethylmethacrylate, polypropylene, and gasoline. The fuels were burned below a hood, and smoke samples were collected from the hot gas layer and from the wall surfaces. The smokes from various polymers and gasoline were found to contain no measurable volatile organic chemicals. The kinetics of the smokes from the polymers and gasoline were found to be satisfactorily modeled as first order in both smoke and oxygen with the same kinetic constants for all fuels tested. The activation energy was calculated to be 211 kJ/mol, and the pre‐exponential factor was found to be 4.7 × 1010/s. These kinetic parameters provide a basis for modeling clean burn pattern generation. Copyright © 2011 John Wiley &amp; Sons, Ltd.

Particle puzzle pieces

Particle puzzle pieces

Thirdhand Smoke: Studies Multiply, Catchy Name Raises Awareness

H ealth agencies have warned of the danger of secondhand smoke for decades. Now a small but growing number of scientists are testing the possible health effects associated with the residue that cigarette smoke deposits on furniture, clothing, and other surfaces, a substance some are calling “thirdhand smoke.” The magnitude of the problem, the amount of attention and resources it warrants, and even the defi nition of the term itself remain a matter of debate, however. Some tobacco control experts think any effect from thirdhand smoke will be relatively limited and that the new term has driven recent interest more than scientifi c discoveries have. Despite that skepticism, at least one tobacco research agency has decided that thirdhand smoke and its potential effect on public health warrants greater scrutiny and announced a new funding initiative to support basic research on the potential hazards. Last year, Jonathan Winickoff, M.D., associate professor of pediatrics at Massachusetts General Hospital in Boston, and colleagues made headlines when they published a report on public attitudes about smoke residue, calling it “thirdhand smoke.” On the basis of a nationwide telephone survey, Winickoff’s team reported that individuals who thought thirdhand smoke was dangerous were more likely to ban smoking entirely from their homes than were individuals who did not perceive a health risk from smoke residue. The study attracted widespread media attention. Many of the news stories, though, focused not on the survey results but on the phrase “thirdhand smoke,” reporting that this was a new health hazard associated with cigarettes.

Detection of tobacco smoke deposition by hyperpolarized krypton-83 MRI

Despite the importance of the tobacco smoke particulate matter in the lungs to the etiology of pulmonary disease in cigarette smokers, little is currently known about the spatial distribution of particle deposition or the persistence of the resulting deposits in humans, and no satisfactory technique currently exists to directly observe tobacco smoke condensate in airways. In this proof-of-principle work, hyperpolarized (hp) 83Kr MRI and NMR spectroscopy are introduced as probes for tobacco smoke deposition in porous media. A reduction in the hp-83Kr longitudinal (T1) relaxation of up to 95% under near-ambient humidity, pressure and temperature conditions was observed when the krypton gas was brought into contact with surfaces that had been exposed to cigarette smoke. This smoke-induced acceleration of the 83Kr self-relaxation was observed for model glass surfaces that, in some experiments, were coated with bovine lung surfactant extract. However, a similar effect was not observed with hp-(129)Xe indicating that the 83Kr sensitivity to smoke deposition was not caused by paramagnetic species but rather by quadrupolar relaxation due to high adsorption affinity for the smoke deposits. The 83Kr T1 differences between smoke-treated and untreated surfaces were sufficient to produce a strong contrast in variable flip angle FLASH hp-83Kr MRI, suggesting that hp-83Kr may be a promising contrast agent for in vivo pulmonary MRI.

Experimental and Numerical Smoke Carcinogen Deposition in a Multi-Generation Human Replica Tracheobronchial Model

A better understanding of submicron particle deposition in the respiratory tract is needed to study the health effects caused by carcinogenic particles. Recent studies indicate that random diffusion is not sufficient to describe the motion of these particles in complex geometries, rendering conventional models inaccurate. A solid replica of excised human lung segments was used to create digital and hollow models of the tracheobronchial region to investigate deposition of mainstream (MS) and sidestream (SS) cigarette smoke particles. Particle sizes for the carcinogen Benzo(a)pyrene (BaP) in SS smoke, and total particulate matter (UVPM) in SS and MS smoke were measured and used to compare the simulation to experimental data. Excellent agreement was found between predicted and measured results. Random diffusion was not found to be significant for submicron particles indicating that particles were instead transported to the airway wall by convective diffusion. BaP in SS smoke was an average 0.3 mum compared to 0.36 mum for UVPM in SS smoke. The trends in both experimental and numerical results indicated that the BaP in SS smoke deposits at a slightly higher efficiency than the UVPM, indicating that carcinogen-specific deposition, rather than total particulate matter should be considered when investigating health effects.

Characterization of the fire environments in central offices of the telecommunications industry

AbstractEight free burning and two sprinklered fire tests were performed with electrical cable trays and live digital switch racks in a large enclosure to simulate telecommunications central office (TCO) fires started by electrical overheating. Very‐slow‐growing (non‐flaming), slower‐growing (partially flaming) and low‐intensity‐faster‐growing (flaming) fires releasing gray‐white, gray, and black smoke, respectively, were observed in the tests. Under quiescent conditions present in the unvented enclosure fire tests for cables, very‐slow‐growing fires were detected in about 1452 s, whereas the slower‐growing fires were detected in about 222 s by commercial fire detectors. Under ventilation conditions typical of TCOs, detection times were very similar for the five types of commercial TCOs fire detectors used in the tests. The average detection times for slower‐growing fires (cable fires) and low‐intensity‐faster‐growing fires (digital switch rack fires) were 242±17% and 249±11%s respectively.The TCO procedures to reduce smoke damage from fires (on fire detection, inlet ventilation flow is turned off and exhaust flow is turned on) were found to be beneficial. The extent of smoke damage decreased significantly with an increase in the exhaust flow rate. The chloride ion mass deposition suggested that equipment recovery would be possible in the smoke environment if the cable vapor concentration could be reduced below about 3 g/m3.The metal corrosion rate was found proportional to the 0.6th power of the smoke concentration, similar to that found for the corrosion of metal surfaces exposed to aqueous solutions of HCl and HNO3 and for acid rain with no protective layer at the surface. Sprinkler water was found to wash down the smoke deposits on the surfaces with little indication of corrosion enhancement. Copyright © 2003 John Wiley &amp; Sons, Ltd.

Effects of breathing parameters on sidestream cigarette smoke deposition in a hollow tracheobronchial model.

The effects of variations in cyclic breathing parameters (i.e., tidal volume and breath frequency) have been the subject of few studies devoted to the deposition of submicrometer aerosols in the human respiratory tract. Therefore, a series of experiments was performed to investigate whether the deposition efficiency (DE) of sidestream cigarette smoke is altered by varying tidal volume and breath frequency in a child-size hollow tracheobronchial (TB) model while maintaining a fixed minute ventilation rate of 5 L/min. Under cyclic flow conditions with tidal volumes of 100 mL (50 breaths/min), 250 mL (20 breaths/min), 500 mL (10 breaths/min) and 750 mL (6.7 breaths/min), sidestream cigarette smoke was passed through replicas of an idealized hollow TB model. The smoke deposits were extracted and then quantitated spectrophotometrically. The experiments revealed a significant difference in DE between the 100-mL tidal volume (DE = 6.0%) and the 750-mL tidal volume (DE = 11.1%). Under equivalent steady flow conditions, the mean DE was 21.5%. A trend was evident in the data--DE increased as tidal volume increased (and breathing frequency decreased)--suggesting that the influence of diffusion and secondary flows on DE becomes greater as the air residence time increases and the degree of air turbulence decreases. The results provide evidence of the importance of breathing parameters when attempting to model in vivo deposition of environmental tobacco smoke and other similar-size respirable aerosols.

Effects of Breathing Parameters on Sidestream Cigarette Smoke Deposition in a Hollow Tracheobronchial Model

The effects of variations in cyclic breathing parameters (i.e., tidal volume and breath frequency) have been the subject of few studies devoted to the deposition of submicrometer aerosols in the human respiratory tract. Therefore, a series of experiments was performed to investigate whether the deposition efficiency (DE) of sidestream cigarette smoke is altered by varying tidal volume and breath frequency in a child-size hollow tracheobronchial (TB) model while maintaining a fixed minute ventilation rate of 5 L/min. Under cyclic flow conditions with tidal volumes of 100 mL (50 breaths/min), 250 mL (20 breaths/min), 500 mL (10 breaths/min) and 750 mL (6.7 breaths/min), sidestream cigarette smoke was passed through replicas of an idealized hollow TB model. The smoke deposits were extracted and then quantitated spectrophotometrically. The experiments revealed a significant difference in DE between the 100-mL tidal volume (DE=6.0%) and the 750-mL tidal volume (DE=11.1%). Under equivalent steady flow conditions, the mean DE was 21.5%. A trend was evident in the data—DE increased as tidal volume increased (and breathing frequency decreased)—suggesting that the influence of diffusion and secondary flows on DE becomes greater as the air residence time increases and the degree of air turbulence decreases. The results provide evidence of the importance of breathing parameters when attempting to model in vivo deposition of environmental tobacco smoke and other similar-size respirable aerosols.

AIR POLLUTION FROM ROAD TRANSPORT.

This article summarises the environmental effects on human health and the roadside environment caused by air pollutants from road traffic. The major pollutants are nitrogen dioxide, carbon monoxide, lead, benzene and polyaromatic hydrocarbons. Problems caused include respiratory problems, damage to vegetation, smoke deposits on buildings, acid rain, smog and lead deposits which enter the food chain via roadside vegetation. The European Community and the World Health Organisation have both issued guidelines regarding acceptable values of these pollutants. Technologies for reducing transport emissions are the high compression lean burn engines (which also reduce fuel consumption) or three-way catalytic converters which reduce thermal efficiency and so raise fuel consumption. When used to capacity, public transport can be up to ten times more energy efficient than private cars. Rail based systems are four times more efficient at transporting freight, and light rapid transit systems are electrically powered so do not directly pollute the atmosphere. Measures to restrict private cars, such as road pricing, higher taxes on petrol and preferential rates of tax on new cars with low emission rates, are consistently proposed. The impact of road traffic pollution is particularly harmful since people and vehicles exist in close proximity.

Combustion characteristics of AP/HTPB propellants with burning rate modifiers

Fe2O3, copper chromite catalyst (CC), LiF, and CaCO3 are the four burning rate modifying additives considered in this study. A wide variety of subatmospheric flames are observed for the propellants with additives. Under subatmospheric pressures a dark zone is present; this zone becomes thicker at lower pressure and with finer ammonium perchlorate (AP) particles. A smoldering surface without a gas-phase flame is noted for the additive Fe2O3. From the smoke deposits, obtained from the subatmospheric burning of propellants with burning rate enhancers, it is shown that the breakdown of heavy fuel molecules is better with finer AP particles. The low-pressure deflagration limit is reduced by the addition of Fe2O3 or CC and increased by the addition of LiF or CaCO3. In the presence of LiF or CaCO3, above certain additive concentration levels, reduction in AP particle size is found to depress the burning rate further. LiF, below certain concentration levels, acts as a burning rate enhancer up to a certain pressure and as a depressant thereafter. The type of additive influences the pressure at which the shape of burning AP surface changes from convex to concave and also the pressure at which the AP surface recesses relative to the mean surface.

Equipment

Ultra‐high efficiency cabin air filters that control the spread of bacteria, viruses, dust and cigarette smoke deposits have been supplied for the A320 Airbus.

Transmission electron microscopic studies of morphology and crystallography of particulate emissions in smokes

Arson, sabotage and suicide involving fire are topical problems in forensic science. Transmission electron microscopic (TEM) studies of the morphology and crystallography of particulate carbon from smoke deposits from various fuels were carried out to try to identify the fuel from the soots. Samples of particulates from the combustion of a variety of fuels were examined using bright field TEM for the morphology and selected area diffraction for the composition and structure. Several distinct characteristics were identified. The particles consist of quasispherical subunits of carbon forming chains or clusters. The shape and size of these spherules, the degree of their agglomeration and their crystallinity exhibit quantifiable variations conspicuous enough to identify the parent fuel. The scope of applications is discussed briefly.