Emissions of polycyclic aromatic hydrocarbons from combustion of agricultural and sylvicultural debris (original) (raw)
Related papers
2012
Indoor solid fuel combustion is a dominant source of polycyclic aromatic hydrocarbons (PAHs) and oxygenated PAHs (OPAHs) and the latter are believed to be more toxic than the former. However, there is limited quantitative information on the emissions of OPAHs from solid fuel combustion. In this study, emission factors of OPAHs (EF OPAH ) for nine commonly used crop residues and five coals burnt in typical residential stoves widely used in rural China were measured under simulated kitchen conditions. The total EF OPAH ranged from 2.8±0.2 to 8.1±2.2 mg/kg for tested crop residues and from 0.043 to 71 mg/kg for various coals and 9-fluorenone was the most abundant specie. The EF OPAH for indoor crop residue burning were 1~2 orders of magnitude higher than those from open burning, and they were affected by fuel properties and combustion conditions, like moisture and combustion efficiency. For both crop residues and coals, significantly positive correlations were found between EFs for the individual OPAHs and the parent PAHs. An oxygenation rate, R o , was defined as the ratio of the EFs between the oxygenated and parent PAH species to describe the formation potential of OPAHs. For the studied OPAH/ PAH pairs, mean R o values were 0.16 ~ 0.89 for crop residues and 0.03 ~ 0.25 for coals. R o for crop residues burned in the cooking stove were much higher than those for open burning and much lower than those in ambient air, indicating the influence of secondary formation of OPAH and loss of PAHs. In comparison with parent PAHs, OPAHs showed a higher tendency to be associated with particulate matter (PM), especially fine PM, and the dominate size ranges were 0.7 2.1 µm for crop residues and high caking coals and < 0.7 µm for the tested low caking briquettes.
PAHs emission from cigar burner combustion system and comparison of PAHs content in fly ashes
Thermal Science
Agricultural biomass is considered a preferred renewable energy source in Serbia because of its availability and suitability to limit the use of fossil fuel resources and reduce greenhouse gas emissions. Therefore, constant work has been done to develop technologies that enable its utilization for energy purposes. As an example of these efforts, in the Agricultural Corporation PKB, the soybean straw cigarette-type combustion system has been applied for greenhouse heating for over a decade. However, many volatile and semivolatile organic compounds are emitted directly into the atmosphere or concentrated in ash particles during agricultural biomass combustion. Since some of the emitted compounds, such as polycyclic aromatic hydrocarbons (PAHs), are toxic, monitoring their concentrations in fly ash is recommended. Literature data regarding PAHs content in agricultural biomass ashes are insubstantial, especially in Serbia. For that purpose, PAHs contents in the cyclone (CB) and stack (S...
Air Quality, Atmosphere & Health, 2015
Residential biomass combustion may represent a significant emission source of polycyclic aromatic hydrocarbons (PAHs) and derivatives, some of which are known for their toxicity. In this study, a manually operated batch stove (burning wood logs) and an automatic pellet stove were selected to carry out combustion experiments. Two types of firewood (pine and eucalypt) were used as fuels in the manual stove. Four types of pellets and three agricultural fuels (olive pit, almond shell and shell of pine nuts) were selected for the automatic stove. The particulate matter (PM 10) samples from the exhaust flue gas were solvent extracted and analysed for 26 parent and alkyl-PAHs, 15 nitrated PAHs (NPAHs), 15 oxygenated PAHs (OPAHs) and 4 azaarenes (AZAs) by gas chromatography-mass spectrometry. The global parent PAH emission factors (EFs) for the pellet stove ranged from 0.046 to 0.51 mg kg −1 of fuel burned, dry basis (db). The EFs obtained for the manual stove varied from 0.33 to 1.97 and from 8.65 to 24.3 mg kg −1 (db) for the combustion of eucalypt and pine, respectively. The devolatilisation phase of softwood in the latter appliance is critical because benzo[a]pyrene emissions can be more than 1,000 times higher than the values observed for any other combustion stages, appliance or biofuels. As for parent PAHs, it was observed that emissions of OPAHs, NPAHs and AZAs vary greatly depending on either the biofuel or the combustion technology.
European Chemical Bulletin, 2016
The use of biomass and other solid material as a source of energy is associated with some deleterious effects consequent to incomplete combustion associated with poor ventilation leading to production of a number of chemical compounds that are known or suspected to be a health threat. This study reports the screening of the formation of the polycyclic hydrocarbons during pyrolysis of the fuel materials, namely, coal, dung and wood, commonly used as fuel in rural areas in Lesotho, under poor aeration using a simple in-house pyrolysis unit The method demonstrated sufficient linearity for the standards with correlation coefficient, R 2 ≥ 0.9884 and repeatability (%RSD ≤ 15 %) of the real samples used, coal demonstrated production of naphthalene and pyrene, while from the cake dung formation of naphthalene was detected. Despite not being extensive, the results form a basis for a more rigorous study including employing more identification tools, such as mass spectrometry that enables ide...
Polycyclic Aromatic Hydrocarbons in Smokes of Two Biomasses Used For Domestic Cooking In Nigeria
Chemistry and Materials Research, 2014
Domestic cooking of foods is predominantly carried out in Nigeria through the burning of different types of biomass. Smoke resulting from such burning in most cases is been inhaled by people in the immediate environment where the cooking exercise is taking place. Where incomplete combustion occurs, the smoke may carry some products of incomplete combustion; prominent among these are polycyclic aromatic hydrocarbons (PAHs). Some of these PAHs have been implicated for various health challenges such as cancer. Incomplete combustion of fuels is known to generate PAHs. Smokes from some biomasses have also been established to contain some PAHs.This group of organic compounds is of global environment concern. The composition and concentration of PAHs in the smokes of two biomasses used in domestic cooking in Nigeria were determined. For this purpose, a pyrolytic unit was fabricated and used for the pyrolysis of Wood Charcoal (WC) and Palm Kernel Shell (PKS). Gases resulting from their pyrolysis were collected and analyzed using Gas Chromatography (GC). The results of GC analysis showed that the composition and concentration of PAHs in gas obtained from the pyrolysis of WC were; Acenaphthene (0.218µg/cm 3), Fluorene (0.573 µg/cm 3), Phenanthrene (13.305 µg/cm 3), Anthracene (0.552 µg/cm 3), Fluoranthene (9.069 µg/cm 3), Pyrene (8.677 µg/cm 3), Benzo(a)anthracene (0.660 µg/cm 3), Chrysene (0.660 µg/cm 3), Benzo(b)Fluorene (0.593 µg/cm 3) and Benzo(k)fluoranthene (0.853 µg/cm 3). While the composition and concentration of PAHs in gas obtained from the pyrolysis of PKS were; Acenaphthene (0.208 µg/cm 3), Fluorene (0.567 µg/cm 3), Phenanthrene (14.190 µg/cm 3), Anthracene (0.527 µg/cm 3), Fluoranthene (11.808 µg/cm 3), Pyrene (9.794 µg/cm 3), Benzo(a)anthracene (0.448 µg/cm 3), Chrysene (0.415 µg/cm 3), Benzo(b)Fluoranthene (0.346 µg/cm 3) and Benzo(k)fluoranthene (0.215 µg/cm 3). Source diagnostic ratios calculated for the PAHs found in the pyrolytic gases of the biomasses showed that these PAHs were of pyrogenic origin, thus confirming that they were generated from the pyrolysis of WC and PKS
Environmental Toxicology and Chemistry, 2023
Cookstove studies have reported pollutant concentrations (mainly PM 2.5 , black carbon and CO) without routinely associating it with the design and operating principles of the stoves. Extensive characterization of pollutants from cookstoves and the effect of different operating conditions are required for a better understanding of the mechanisms of pollutant formation. In this study, a forced draft (FD) and a natural draft (ND) gasification-based improved cookstove were tested under controlled conditions. Real-time pollutant concentrations, both particulate (PM 2.5 , lung-deposited surface area and particle number size distribution) and gaseous (CO, CO 2 and NO x), from these stoves using three types of fuel (applewood chips and chunks, cowdung cake and coal) along with different cookstove operating conditions (airflow rates and with or without a cooking pot) were measured and compared. The FD cookstove tended to exhibit higher concentrations of emissions compared to the ND cookstove. Increasing airflow through the FD stove decreased flame length and the residence time of VOCs inside the flame zone, which in turn increased pollutant concentrations. An optimum airflow producing the lowest particulate matter (PM) concentrations was established for the FD cookstove. The CO-CO 2 ratio, an indicator of combustion efficiency, demonstrated strong correlations with PM 2.5 (r = 0.857), particle geometric mean diameter (r = 0.900) and the total surface area concentration (r = 0.908) indicating that CO-CO 2 ratio may be used as a proxy for these PM metrics. Results reported in this study will facilitate further improvements in the design of future cookstoves.
Analytica Chimica Acta, 2004
A method of sampling for the determination of polycyclic aromatic hydrocarbons (PAHs) and their methyl derivatives in smoke samples from the incomplete combustion of different types of biomass is developed. The smoke is used for the smoking of foods, following an artisan procedure used in some places in the Canary Islands. By means of a factorial design, the variables with more influence in the sampling have been optimized: sampling temperature, sampling flow and composition of the adsorbent. The used sampling system is formed by a quartz fibre filter and an adsorbent constituted by PUF/XAD-2/PUF. For the treatment of the sample, the procedure described in UNE-77250 regulation is used, and the determination is carried out by gas chromatography-mass spectrometry. The results obtained in the present work show the necessity to analyse the filter and the adsorbent together, and that the retention efficiencies, when the temperature of the smoke is not too high, are usually >70%. Also, it is shown that for a correct interpretation of the results obtained when establishing the content of PAHs and their methyl derivatives in the smoke samples, it is necessary to take into consideration the temperature of the smoke at the point of sampling.
Emission Factors for Polycyclic Aromatic Hydrocarbons from Biomass Burning
Environmental Science & Technology, 1996
Emission factors for 19 polycyclic aromatic hydrocarbons were measured during wind tunnel simulations of open burning for agricultural and forest biomass fuels including cereal grasses, agricultural tree prunings, and fir and pine wood (slash). Yields of total PAH varied from 5 to 683 mg kg-1 depending principally on burning conditions and to a lesser extent on fuel type. Barley straw and wheat straw loaded at 400-500 g m-2 emitted much higher levels of PAH, including benzo[a]pyrene, than other cereal and wood fuel types burning under more robust conditions. As anticipated, total PAH emission rates increased with increasing particulate matter emission rates and with declining combustion efficiency.
PAH emission from the open burning of agricultural debris
Science of The Total Environment, 2003
The procedure for and results of a test study of polycyclic aromatic hydrocarbon (PAH) emission from the open burning of agricultural debris are discussed. For the investigation of open burning its simulation with emission sampling and analysis were applied. Further investigations also included observations of real instances of the open burning of wastes and collection of data on the structure and volume of combustible material. It was concluded that the open burning of agricultural wastes resulted in significant amounts of PAHs, but mainly the low molecular weight species (naphthalene, acenaphthylene, phenanthrene, fluoranthene, etc.).
Polycyclic aromatic hydrocarbons in smoke particles from wood and duff burning
Atmospheric Environment. Part A. General Topics, 1992
Smoke particles from wood burning and duff burning were analysed for polycyclic aromatic hydrocarbons (PAH) by gas chromatography/mass spectrometry. PAH composition in smoke particles from wood burning was found to resemble those from other environmental samples, such as air particles and sediments where parental PAH are the predominant species: A ~talytic combustor retrofitted on the woodburning stove reduced the PAH concentrations significantly. The reduction was more pronounced for parental PAH than their aikylated homologs. Probably, the molecular configuration affects the catalytic et~ciency. Smoke particles from duff burning contained a strikingly different PAH composition, with phenanthrene, alkylated phenanthrenes, alkylated cycolopenta(def)phenanthrene and dodecahydrochrys. ene as the predominant species.