Emission factors from residential combustion appliances burning Portuguese biomass fuels

Smoke from residential wood burning has been identified as a major contributor to air pollution, motivating detailed emission measurements under controlled conditions. A series of experiments were performed to compare the emission levels from two types of wood-stoves to those of fireplaces. Eight types of biomass were burned in the laboratory: wood from seven species of trees grown in the Portuguese forest (Pinus pinaster, Eucalyptus globulus, Quercus suber, Acacia longifolia, Quercus faginea, Olea europaea and Quercus ilex rotundifolia) and briquettes produced from forest biomass waste. Average emission factors were in the ranges 27.5-99.2 g CO kg(-1), 552-1660 g CO(2) kg(-1), 0.66-1.34 g NO kg(-1), and 0.82-4.94 g hydrocarbons kg(-1) of biomass burned (dry basis). Average particle emission factors varied between 1.12 and 20.06 g kg(-1) biomass burned (dry basis), with higher burn rates producing significantly less particle mass per kg wood burned than the low burn rates. Particle mass emission factors from wood-stoves were lower than those from the fireplace. The average emission factors for organic and elemental carbon were in the intervals 0.24-10.1 and 0.18-0.68 g kg(-1) biomass burned (dry basis), respectively. The elemental carbon content of particles emitted from the energy-efficient "chimney type" logwood stove was substantially higher than in the conventional cast iron stove and fireplace, whereas the opposite was observed for the organic carbon fraction. Pinus pinaster, the only softwood species among all, was the biofuel with the lowest emissions of particles, CO, NO and hydrocarbons.     

Air quality assessment of benzo(a)pyrene from asphalt plant operation

A study has been carried out to assess the contribution of Polycyclic Aromatic Hydrocarbons (PAHs) from asphalt plant operation, utilising Benzo(a)pyrene (BaP) as a marker for PAHs, to the background air concentration around asphalt plants in the UK. The purpose behind this assessment was to determine whether the use of published BaP emission factors based on the US Environmental Protection Agency (EPA) methodology is appropriate in the context of the UK, especially as the EPA methodology does not give BaP emission factors for all activities. The study also aimed to improve the overall understanding of BaP emissions from asphalt plants in the UK, and determine whether site location and operation is likely to influence the contribution of PAHs to ambient air quality. In order to establish whether the use of US EPA emissions factors is appropriate, the study has compared the BaP emissions measured and calculated emissions rates from two UK sites with those estimated using US EPA emission factors. A dispersion modelling exercise was carried out to show the BaP contribution to ambient air around each site. This study showed that, as the US EPA methodology does not provide factors for all emission sources on asphalt plants, their use may give rise to over- or under-estimations, particularly where sources of BaP are temperature dependent. However, the contribution of both the estimated and measured BaP concentrations to environmental concentration were low, averaging about 0.05 ng m(-3) at the boundary of the sites, which is well below the UK BaP assessment threshold of 0.25 ng m(-3). Therefore, BaP concentrations, and hence PAH concentrations, from similar asphalt plant operations are unlikely to contribute negatively to ambient air quality.     

Monitoring of the Phytosanitary State of Navarra's Forests, Spain

Between 1988 and 1993 six surveys on the condition of forests in Navarra (North Spain) were carried out. The results, relating to 408 trees in 17 sampling points, showed that the overall percentage of damaged trees increased from 2.86% in 1988 to 18.6% in 1993, which indicates a general large-scale deterioration of forest condition. Among the most common groups of trees, the most severely affected species were Quercus faginea, Quercus robur and Pinus sylvestris. Furthermore, it was observed that defoliation and discoloration processes did not occur randomly between stand trees, but the trees that were damaged one year (1992) were more predisposed to suffer damage in the next year (1993).     

洛阳市2017年大气氨排放清单的建立及其空间分布特征

基于洛阳市不同类型氨排放源的活动水平数据,主要采取排放因子法构建了2017年洛阳市大气氨排放清单,并以GIS技术为基础进行2 km分辨率的空间网格分配。通过研究得出,2017年洛阳市的大气氨排放量为63.2 kt,排放强度达到4 t/km~2以上,全市主要的氨排放源为畜禽养殖和农田生态系统,排放量分别为43.7 kt和10.4 kt,分别占氨排放总量的69.2%和16.5%。在畜禽养殖源中,肉牛是最大的贡献源,贡献率为30.4%;在农田生态系统中,氮肥施用是最大的贡献源,贡献率为87.7%。各区县中,宜阳县和伊川县排放量最大,共占氨排放总量的32.0%;偃师市、伊川县为排放强度最高;空间分布特征上呈现北部氨排放量大、南部排放量少、在城市区周边氨排放量较突出的现象。     

Measurements of biogenic hydrocarbons and carbonyl compounds emitted by trees from temperate warm Atlantic rainforest, Brazil

This study is part of a three-year project on biogenic volatile organic compound (VOC) emissions from trees of the temperate warm Atlantic rainforest found in the metropolitan area of Sao Paulo City (MASP). No study of VOC emission rates from plant species has been carried out in the temperate warm Atlantic rainforest of Brazil prior to this work. Eleven species were selected (Alchornea sidifolia, Cupania oblongifolia, Cecropia pachystachia, Syagrus romanzoffiana, Casearia sylvestris, Machaerium villosum, Trema micrantha, Croton floribundus, Myrcia rostrata, Solanum erianthum and Ficus insipida) and some of them were studied in urban, sub-urban and forest areas inside the MASP in order to evaluate biogenic VOC composition at sites characterized by different emission sources. Biogenic VOC emissions were determined by placing branches of plants in a dynamic enclosure system, an all-Teflon cuvette, and by sampling the compounds in the air leaving the cuvette. Pre-concentration using adsorbents to retain the VOC, followed by GC-MS after thermal desorption of the sample, was employed to determine the amount of biogenic hydrocarbons. The collection of carbonyl compounds on a 2,4-dinitrophenylhydrazine coated silica followed by HPLC-UV was used to analyze low molecular weight carbonyl compounds. Emission rates of isoprene, alpha-pinene, camphene and limonene ranged from 0.01 to 2.16 microg C h(-1) g(-1) and emission rates of aldehydes (C(2)-C(6)), acrolein, methacrolein and 2-butanone ranged from 1.5 x 10(-2) to 2.3 micro g C h(-1) g (-1). Ambient and leaf temperatures, relative humidity, light intensity, O(3) and NO(x) levels in the local atmosphere were monitored during experiments. It was possible to identify different biogenic VOCs emitted from typical plants of temperate warm Atlantic rainforest. The emission rates were reported as a function of the type of site investigated and were only provided for compounds for which quantification was feasible. Other biogenic compounds were only identified.     

Trace Element Analyses in an Epiphytic Lichen and its Bark Substrate to Assess Suitability for Air Biomonitoring

Total concentrations of Cd, Cr, Fe, Ni, Pb and Zn were compared from October 1996 to April 1998 in Physcia biziana (Massal.) Zhalbr. v. leptophylla Vezda and in the bark of Quercus ilex L. sampled from the same trees at an urban park. Trace metal concentrations were also measured in the bark covered by the lichen thalli. The lichens showed significantly higher Cr, Fe, Ni and Zn concentrations than both uncovered and covered barks. By contrast, both types of barks had higher concentrations of Cd and Pb than lichens. Trace elements showed a wide temporal variation of concentrations both in the lichens and barks. No relationship was found between the analysed matrices as regards the time course of trace element concentrations.     

Influence of processing parameters on VOC emission from particleboards

Volatile organic compound (VOC) emissions from furnishings have created a major indoor air pollution problem in China. The aim of this study was to investigate the VOC emission of larch particleboard under different processing conditions. VOCs collection chamber, parts per billion VOC monitor, and gas chromatography–mass spectrometer were used to analyze the VOC components and quantities. The results were shown as follows: (1) concentration and emission rate of VOCs were significantly affected by hot-pressing temperature and time. With the increase of hot-pressing temperature and time, both the earlier emission concentration and the amount of total volatile organic compounds increased. (2) The composition of VOCs was also influenced by temperature and time, especially the variety of terpene, benzene, and derivative. The existence and quantities of esters were still the main components of VOCs emissions.     

THE IMPACT OF GEOTHERMAL POWER PLANTS ON FOREST VEGETATION. A CASE STUDY AT TRAVALE (TUSCANY, CENTRAL ITALY)

A survey of the crown status of Turkey oak Quercus cerris L.) trees in the boron-rich area atTravale (Southern Tuscany, Italy) was carried outin order to evaluate the impact ofgeothermal power plants. Crown thinness was assessed andmorphological and chemical tests werecarried out on leaf samples. Leaf area and dry weight weredetermined as morphological parameters;while the chemical measurements performed included nitrogenand potassium (among the nutrients),and sulphur, boron, arsenic and mercury (among the elements ofgeothermal origin). Acute damagewas found only in the area immediately adjacent to the outletsand is the result of the action of boron;crown thinness, on the other hand, is affected by the natureof the geological substrate. High quantitiesof sulphur were found in leaves throughout the survey area,due both to the availability of this elementin the geopedological substrate and to the atmospheric inputof geothermal H2S. The leafcontent of this element correlates negatively with thedistance from the power plants. Boron andarsenic are the other geothermal origin elements most commonlyfound in plant matrices. The presenceof these two elements is associated with leaf area reductionand/or an increase of specific dry weight.The most significant impact on the environment appears to beexerted by the southernmost powerplant, where there is an unfavourable ratio between quantityof emissions and height of the chimneys.     

An Evaluation of Microscopic Emission Models for Traffic Pollution Simulation Using On-board Measurement

As a result of the continuously increasing numbers of motor vehicles in metropolitan areas worldwide, road traffic emission levels have been recognized as a challenge during the planning and management of transportation. Experiments were conducted to collect on-road emission data using portable emission measurement systems in two Chinese cities in order to estimate real traffic emissions and energy consumption levels and to build computational models for operational transport environment projects. In total, dynamic pollutant emissions and fuel consumption levels from dozens of light duty vehicles, primarily from four different vehicle classes, were measured at a second-by-second level. Using the collected data, several microscopic emission models including CMEM, VT-Micro, EMIT, and POLY were evaluated and compared through calibration and validation procedures. Non-linear optimization methods are applied for the calibration of the CMEM and EMIT models. Numerical results show that the models can realize performance levels close to the CMEM model in most cases. The VT-Micro model shows advantages in its unanimous performance and ability to describe low emission profiles while the EMIT model has a clear physics basis and a simple model structure. Both of them can be applied when extensive emission computation is required in estimating environmental impacts resulting from dynamic road traffic.     

Nitrous oxide emissions from waste water

The estimation of nitrous oxide emissions is complicated by the high degree of uncertainty on the emission factors involved and by the limited acquaintance with all significant nitrous oxide sources. A potentially important source for which emission data are lacking is the sewage system transporting waste water from human activities. For this study an experimental measurement campaign has been carried out on waste water sampled at different sewage treatment plants. The nitrous oxide developing from the water samples was monitored by means of gas chromatography. The methodological analysis was based on the concentration/time curves obtained. Our results indicate that the formation of nitrous oxide from the waste water matrices results from microbiological denitrification. We deduced tentative emission factors for the waste water types studied.     

Simulation of Urban-Scale Air Pollution Patterns in Luxembourg: Contributing Sources and Emission Scenarios

The aim of this study is to investigate the air pollution situation in an urban area in southwestern Luxembourg and to simulate annual NO₂ and PM₁₀ concentrations in response to changes in meteorological conditions and emissions using a Gaussian dispersion model. Simulations are carried out for the years 1998–2006. Emission scenarios related to road transport and nonindustrial combustion are performed in order to predict changes of air pollution levels. Road transport is by far the most important local emission source in the study area. Scenarios with more stringent emission standards for vehicles, less traffic, and fewer heavy-duty vehicles lead to reductions of NO_x and primary PM₁₀ emissions. As a result, the annual NO₂ concentrations are decreasing in most parts of the study area and are below the European annual limit value of 40 μg?m^?3. In contrast, a scenario with increased use of wood pellets for domestic heating shows an increase in urban PM₁₀ concentration. The year-to-year variability of meteorological conditions accounts for the same magnitude of absolute NO₂ and PM₁₀ concentration changes as the emission scenarios. The comparison with measurements located in the study area shows that the model is able to predict urban-scale annual average air pollution. The proposed application results show that the model can be appropriate for policy-driven air quality management and planning queries.     

Volatile hydrocarbon emissions from vehicles and vertical ventilations in the Hsuehshan traffic tunnel, Taiwan

The concentrations of 56 volatile organic hydrocarbons (VOCs) were measured simultaneously in the southbound bore, the northbound bore and the exhaust air shafts of the Hsuehshan tunnel near Yilan, Taiwan during 2007 and 2008. A total of 60 integrated air samples were collected using stainless steel canisters and analyzed using GC/FID and GC/MS. The highest temperature and lowest relative humidity were observed at the exit of the tunnel owing to the accumulation in the tunnel of waste heat that was exhausted from vehicles. The five most abundant species in all samples were ethylene, acetylene, isopentane, propylene, and toluene. The exit/entrance ratios of total non-methane hydrocarbon (NMHC) concentration were 7.8 and 4.8 for the southbound and northbound bores, respectively. Furthermore, the most abundant species of emission rate (ER) is toluene (21.93-42.89 mg s(-1)), followed by isopentane, ethylene, propylene and 1-butene, with ER ranging from 2.50 to 9.31 mg s(-1) for the three shafts. The ozone formation potential (OFP)/total NMHC ratios in three exhaust air shafts show that the reactivities of these emissions are similar to those of vehicle emissions.     

Monitoring dioxins and furans in the vicinity of an old municipal waste incinerator after pronounced reductions of the atmospheric emissions

In order to get an overall picture of the environmental impact of an old municipal solid waste incinerator (MSWI) from S. Adrià del Besòs (Barcelona, Catalonia, Spain), a monitoring program addressed at determining the levels of a number of pollutants in the vicinity of the facility was initiated in 1998. In March 1999, an adaptation was carried out due to EU legislation on pollutant emissions from the stack. As a result, emissions of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) were notably reduced, and a significant (30%) decrease was found in the levels of PCDD/F in herbage samples collected in the vicinity of the MSWI. In March 2001, herbage samples were collected at the same sampling points and the PCDD/F levels measured again. The current PCDD/F concentrations range from 0.23 to 1.43 ng I-TEQ kg(-1) (dry matter), with median and mean values of 0.58 and 0.66 ng I-TEQ kg(-1) (dry matter), respectively, while in the 2000 survey the PCDD/F concentrations ranged from 0.22 to 1.20 ng I-TEQ kg(-1) (dry matter), with median and mean values of 0.57 and 0.61 ng I-TEQ kg(-1) (dry matter), respectively. Although the current PCDD/F concentrations in herbage samples are comparable to those found in recent surveys carried out in various places of Catalonia, an exhaustive evaluation of the data, including principal component analysis, indicates that other emission sources of PCDD/Fs also have a notable environmental impact on the area under direct influence of the MSWI.     

Seasonal Variations in Isoprene Emission from Tropical Deciduous Tree Species

Isoprene is a dominant constituent of the global biogenic volatile organic compounds budget. It plays an important role in regulating the atmospheric trace gas composition including tropospheric ozone concentrations. In this study, monthly measurements of isoprene emission rates were carried out over a 1-year period (December 2002–November 2003) from four Indian deciduous tree species, namely Ficus relegiosa, Ficus infectoria, Pongamia pinnata, and Morus alba, using branch enclosure method. Significantly high monthly variations in isoprene emission rates were observed in all four-plant species. Also, each plant species exhibited pronounced seasonal variation in isoprene emission. Maximum isoprene emissions were observed during summer and minimum during the winter or spring months.     

Spatial and temporal variation of surface ozone,NO and NO2 at urban,suburban, rural and industrial sites in the southwest of the Iberian Peninsula

Surface ozone is one of the most important photochemical pollutants in the low atmosphere, causing damage to human health, vegetation, materials and climate. The weather (high temperatures and high solar radiation), orography (presence of the Guadalquivir valley) and anthropogenic (the cities of Cádiz, Córdoba, Huelva and Seville and two important industrial complexes) characteristics of the southwestern Iberian Peninsula make this region ideal for the formation and accumulation of ozone. To increase the knowledge of ozone behaviour in this area, the monthly, daily and weekly variations of ozone and its precursors, nitrogen oxides (NO_x?=?NO?+?NO₂), were analysed over a 4-year period (2003 to 2006). Using the k-means cluster technique, 12 representative stations of five different areas with different ozone behaviour were selected from a total of 29 monitoring sites. This is the first time that the analysis of these atmospheric pollutants has been carried out for the whole area, allowing therefore a complete understanding of the dynamics and the relationships of these compounds in this region. The results showed an opposite behaviour among ozone and NO and NO₂ concentrations in urban and suburban zones, marked by maximums of ozone (minimums NO_x) in spring and summer and minimums (maximums) in autumn and winter. A seasonal behaviour, with lower amplitude, was also observed in rural and industrial areas for ozone concentrations, with the NO and NO₂ concentrations remaining at low and similar values during the year in rural zones due to the absence of emission sources in their surroundings. The daily cycles of ozone in urban, suburban and industrial sites registered a maximum value in the early afternoon (14:00–17:00 UTC) while for NO_x two peaks were observed, at 7:00–10:00 UTC and 20:00–22:00. In the case of rural stations, no hourly peak of ozone or NO_x was registered. The weekend effect was studied by using a statistical contrast tests (Student’s t). The results indicated that only areas influenced by important traffic emissions presented a weekend effect for NO and NO₂, whereas an ozone weekend effect was not detected in any case.     

Mercury emission and dispersion models from soils contaminated by cinnabar mining and metallurgy

The laboratory flux measurement system (LFMS) and dispersion models were used to investigate the kinetics of mercury emission flux (MEF) from contaminated soils. Representative soil samples with respect to total Hg concentration (26-9770 μg g(-1)) surrounding a decommissioned mercury-mining area (Las Cuevas Mine), and a former mercury smelter (Cerco Metalúrgico de Almadenejos), in the Almadén mercury mining district (South Central Spain), were collected. Altogether, 14 samples were analyzed to determine the variation in mercury emission flux (MEF) versus distance from the sources, regulating two major environmental parameters comprising soil temperature and solar radiation. In addition, the fraction of the water-soluble mercury in these samples was determined in order to assess how MEF from soil is related to the mercury in the aqueous soil phase. Measured MEFs ranged from less than 140 to over 10,000 ng m(-2) h(-1), with the highest emissions from contaminated soils adjacent to point sources. A significant decrease of MEF was then observed with increasing distance from these sites. Strong positive effects of both temperature and solar radiation on MEF was observed. Moreover, MEF was found to occur more easily in soils with higher proportions of soluble mercury compared to soils where cinnabar prevails. Based on the calculated Hg emission rates and with the support of geographical information system (GIS) tools and ISC AERMOD software, dispersion models for atmospheric mercury were implemented. In this way, the gaseous mercury plume generated by the soil-originated emissions at different seasons was modeled. Modeling efforts revealed that much higher emissions and larger mercury plumes are generated in dry and warm periods (summer), while the plume is smaller and associated with lower concentrations of atmospheric mercury during colder periods with higher wind activity (fall). Based on the calculated emissions and the model implementation, yearly emissions from the "Cerco Metalúrgico de Almadenejos" decommissioned metallurgical precinct were estimated at 16.4 kg Hg y(-1), with significant differences between seasons.     

PASSIVE MONITORING OF TRACE ELEMENTS BY MEANS OF TREE LEAVES, EPIPHYTIC LICHENS AND BARK SUBSTRATE

Total concentrations of Al, Cu, Fe, Hg, Mn, Mo and Zn in theepiphytic lichen Parmelia caperata, substrate bark andleaves of oaks (Quercus cerris and Q. pubescens)from a background area in Tuscany (central Italy) werecompared. The elemental composition of unwashed samples,especially bark, was clearly affected by soil dustcontamination, thereby leading to incorrect interpretations ofbaseline concentrations and relationships between elements.The normalization of total element concentrations to thesurface soil composition (digested and analyzed by the sameprocedures), using Al as reference element, gave more reliablebaseline values and allowed comparison between differentbiomonitors. The suitability of lichens, leaves and barks forstudying the environmental distribution of trace elements interrestrial ecosystems is discussed.     

The African experience with the IPCC methodology for estimating greenhouse gas emissions

In order to arrive at transparent and comparable inventories, the IPCC, in cooperation with the OECD, is currently developing a common methodology and reporting guidelines for the estimation of anthropogenic greenhouse gas emissions. To gain experience with the IPCC methodology, inventories are currently being carried out in various countries. This paper describes the African experience regarding emission inventories and preliminary results of the studies. It focuses on several important sources of non-CO₂ greenhouse gas emissions in Africa: biomass burning; rice cultivation; and animals.     

Crown condition surveys in Italian forests: issues in reporting findings

This study examines defoliation and discoloration findings collected throughout the Italian Level I network between 1997 and 2000. Prior to this period no Quality Assurance procedures had been implemented, so that earlier findings cannot be considered reliable. The aim of the study is to compare differentindices used in reporting findings, in order to determine the full potential and limitations of each. In international surveys,findings are normally expressed in terms of individual trees presenting a defoliation level greater than 2 %; this criterion,however, has been challenged since it is not based on scientificevidence. By analysing the distribution of defoliation values(grouped in 5% classes) relating to the main species (Fagus sylvatica, Quercus pubescens, Quercus cerris, Picea abies), the study examines the behaviour of statistical indices such as the median, the mode and the mean. Instead of using the traditional 25% threshold to determine the part of the population with the highest defoliation values, a procedureis suggested whereby a different threshold can be determined foreach species. It is established based on the 90° percentile of cumulative defoliation values recorded over the four-year period. Each index used to report findings possessesits own information potential, and the findings may at times appear contradictory. The use of a combined defoliation and discoloration index (Ilce = Lacking Crown Equivalent Index) is also proposed, but the results obtained do not differin substance from the results relating to defoliation alone. Thefunctional limitations of this index are due mainly to the way the data are collected: for this reason suggestions are made onhow to improve the procedure in future surveys.