Evaluation of Direct-Oxidative DNA Damage on Human Lung Epithelial Cells Exposed to Urban Airborne Particulate Matter

Airborne particulate matter (PM) extracts were investigated for their content of organic compounds and for the direct and oxidative DNA damage induced on lung epithelial cells A549. PM₁₀ was seasonally collected at two monitoring sites (Stations 1 and 2), characterized by different traffic loads. The cells were exposed for 30 min to extracts of PM₁₀ diluted at 0.025%, 0.05%, and 0.1% for summer samples, and at 0.05%, 0.1%, and 0.15% for winter samples. Oxidative and direct DNA damage were evaluated by formamidopyrimidine glycosylase (fpg) comet assay analyzing tail moment (TM) values from fpg-enzyme-treated cells (TMenz) and enzyme untreated cells (TM) respectively and by comet percentage analysis. Measurements relating to Station 2 showed higher levels of polycyclic aromatic hydrocarbons (PAHs), and their methyl-(methyl-PAHs) and nitro-(nitro-PAHs) derivatives in both the seasons. Nitro-PAH concentrations were higher in summer than in winter at both the stations. We found a significant increase of comet percentages at the highest dose of extract from both stations in summer and from Station 2 in winter. The TM and TMenz values relative to the summer sampling showed an early oxidative DNA damage induction also followed by direct DNA damage more evident at Station 2, that seems to correlate with the presence of higher nitro-PAH concentrations during the warm season. At both monitoring stations, the results from winter sampling campaign showed a direct DNA damage induction at 0.1% of extract and oxidative-direct DNA damage at the highest dose (0.15%).     

Oxidation of SO2 in Clouds at Whiteface Mountain

In-cloud oxidation of SO₂ byH₂O₂ was investigated using a tracertechnique based on SO^2– ₄/Se ratios atWhiteface Mountain, New York during summer months from1990 to 1998. Cloud water samples collected at themountain's summit (1.5 km above mean sea level) andaerosols at a below cloud site (Lodge) located at 0.6km amsl and in cloud interstitial air at the summitwere analyzed for SO^2– ₄ and selectedtrace elements. Gaseous SO₂ andH₂O₂were measured in realtime. Cloud water pH wasgenerally below 5.0 with a mean value of 3.6. Theresults show that significant in cloud oxidation occursin clouds during summer months varying from belowdetection to 62% with on average approximately 24% ofthe cloud water SO^2– ₄ produced from in-situ SO₂ oxidation. During summer the clouds wereoxidant limited for approximately one third of thetime.     

Field Intercomparison of Main Components in Air in EMEP

Within the European monitoring network (EMEP, ) several different sampling procedures for measuring the main air components have been applied. This has contributed to systematic concentration differences and a comparability problem. Since 1997 co-located experiments in 15 countries have been carried out to quantify these differences. In addition, three major measurement campaigns were organized by EMEP between 1985 and 1991. Differences among results depend on the concentration level and methods used. The decrease in SO₂ concentrations over the last twenty years has placed greater demands on the methodology. Absorbing solutions methods for SO₂, (H₂O₂ and tetrachloromercurate (TCM)) typically have higher detection limits than the reference method, which uses KOH impregnated filters. The TCM method also has problems with negative interference, especially in summertime. UV fluorescence monitors have in a few cases proven to give good results, but interferences, detection limit and poor maintenance can be problems. For NO₂, many countries are using the TGS absorption solution method, which has a higher detection limit than the reference method using NaI impregnated glass sinters. The Salzmann method gives unreliable results at concentrations below 1 μgN/m³, and even at higher concentrations the uncertainty is rather unsatisfactory. The chemiluminescence monitor with molybdenum converters tends to systematically overestimate NO₂ concentrations, possibly because zero-drift problems and the non-specific response to NO₂. Particulate sulphate measurements in general have lower bias and uncertainties than gas and other aerosol measurements.     

Air Pollution Effects on Forest Trees in Balikesir,Turkey

Air pollution has become an actual problem in Balikesir because of rapid urbanisation and increasing of the polluting sources. Air pollutionproblems occur under the unfavorable meteorological conditions which increase in frequency of occurrence in winter due to use of low quality lignite coals for heating. The `Protection of Air Quality' in Turkey dated 1986 is based on the human health criteria. But the critical limit values are lethal for the forest trees as far as SO₂ is concerned. The field observations showed that leaves of the trees have yellow spots indicating acid burns in Balikesir. This study aims at determining the relationships between the SO₂ concentrationsin the air under selected climatic conditions, and the effects of air pollution on forest trees in Balikesir. Samples of leaves were collected from the City Parks in Balikesir, Deirmenboaz forested area located 10 km far fromBalikesiron the Balikesir-Bursa highway, and from the forestation areas near the Balikesir-Edremit highway. Sulfur contents of the leaves were very high especially in the city (2650–5300 g m^-3).Samples from other areas had values lower than this range but above the usual values (850–3612 g m^-3). The diameter increments of the trees were found to be lower and these results clearly showed the adverse impacts. Negative correlations were found between these sulfur concentrations and the daily mean temperatures and wind speeds. Positive correlation was seen between these concentrations and pressures, humidities. Emission sources must be controlled in order to safeguard the forests which protects the soil, facilitate water production, assimilate carbon dioxide in air and produce oxygen. It must be considered that the problems are not only regional but have a global identity.     

Sensitivity of Water Quality Model Results for the Dutch Coastal Zone to the Distribution Coefficient of Cadmium

Results of a water quality model of the Dutch coastal zone appeared to be highly sensitive for the distribution coefficient particulate/dissolved (K_d) of cadmium.Field data of the Dutch coastal zone were used to calculate the annual and seasonal trend in the distribution coefficient of cadmium over the years 1983–88. A strong seasonal and spatial gradient in the distribution coefficient was found with relatively high values in summer and lower values in winter (K_d=3.0–7.0 log l/kg). Near the coast (2 km) the K_d was lower than more offshore (70 km from the coast). In addition, values for the distribution coefficient for cadmium were extracted from the literature (K_d=2.9–4.7 log l/kg).The range of K_d values obtained from the field data was used to perform model simulations for cadmium, in order to determine the sensitivity of the model to the distribution coefficient. The modelled yearly averaged concentrations of dissolved cadmium at one location 10 km from the coast, ranged from 0.005–0.035 μg/l, depending on the magnitude of the K_d used in the simulation. These concentrations are low compared to measured values (0.053 μg/l) due to an underestimation of the cadmium input to the North Sea, or possibly the occurrence of bottom-water exchange processes which the model does not include.     

The Transit of 35SO4 2- and 3H2O Added In Situ to Soil in a Boreal Coniferous Forest

A solution containing ³⁵SO₄ ^2- and ³H₂O was applied to four plots (5 × 5 m) in a boreal coniferous forest in the Laflamme Lake watershed, Québec, under two contrasting conditions: in summer (plots 1 and 2), and on the snowpack before snowmelt (plots 3 and 4). The transit of both these tracers in the soil solution was then followed through a network of soil lysimeters located at different depths. Four months after the summer application, ³H₂O had infiltrated the whole soil profile at plot 1, while ³⁵SO₄ ^2- was only observed in the LFH and Bhf horizons. A ³⁵SO₄ ^2- budget calculated from mid-August to November indicated that 89 and 10.6% of the added ³⁵SO₄ ^2- was retained within the LFH and the Bhf layers, respectively. Fifteen months later, the added ³⁵SO₄ ^2- was distributed in the following proportions within the soil horizons: LFH (73.7%), Bhf (11.8%) and Bf (12.8%), for a total retention rate of 98.3%. The superficial penetration of ³H₂O at plot 2 was indicative of a major lateral water movement that prevented the calculation of a ³⁵SO₄ ^2- budget. This situation also was observed at plot 4 during snowmelt. At plot 3, ³H₂O moved freely through the soil profile and a significant fraction of the added ³⁵SO₄ ^2- reached the B horizons, where it was presumably adsorbed on aluminum (Al) and ferric (Fe) oxides. The ³⁵SO₄ ^2- budget for plot 3 from March to November indicated that 87% of the added ³⁵SO₄ ^2- was retained within the soil profile, with most being retained in the B horizons (LFH = 33.1%, Bhf = 33.1%, Bf = 20.8%). The contrasting retention patterns of ³⁵SO₄ ^2- within the soil profile following the summer addition and snowmelt likely was caused by the contrastingsoil temperatures and soil solution residence times within the differentsoil layers. The persistence of ³⁵SO₄ ^2- in the soil solution of the entire profile long after the initial tracer infiltration, and the relative temporal stability of specific activity of SO₄ ^2-, point to the establishment of an isotopic equilibrium between the added ³⁵SO₄ and the active S-containing reservoirs within a given soil horizon. Overall, the results clearly illustrate the very strong potential for ³⁵SO₄ ^2- retention and recycling in forest soils.     

Exposure Programme on Atmospheric Corrosion Effects of Acidifying Pollutants in Tropical and Subtropical Climates

Many national exposure programmes have been performed in tropical and subtropical climates during the last 50 years. However, ambitious programmes involving more than a few countries are scarce. In this paper a recently formed network of test sites is described involving 12 test sites in Asia (India, Vietnam, Thailand, Malaysia and China including Hong Kong) and four test sites in Africa (South Africa, Zambia and Zimbabwe). This effort is part of the 2001–2004 Swedish International Development Agency (SIDA) funded Programme on Regional Air Pollution in Developing Countries (RAPIDC). Corrosion attack after one (2002–2003) year of exposure (carbon steel, zinc, copper, limestone and paint coated steel) are presented together with environmental data (SO₂, NO₂, HNO₃, O₃, particles, amount and pH of precipitation, temperature and relative humidity) for all the test sites. The obtained corrosion values are substantially higher than expected for limestone, higher than expected for carbon steel and lower than expected for zinc compared to values calculated using the best available dose–response functions.     

Measurement of Traffic Related Toxic Air Pollutants in an Urban Atmosphere

Nose-level measurements of air toxics were made along a busy urban street in Ottawa, Canada for 2 hr periods during morning, noon, and afternoon rush hours in the winter and summer of 2000. Measurements were also made in a commuter car and a transit bus during morning and afternoon commutes in 2000. The main objectives of the study were to establish a database, to determine temporal and seasonal variations and to determine the contribution of motor vehicle traffic to the measured toxic substance concentrations. Ottawa is an appropriate choice of location for the measurement of motor vehicle related toxic and reactive compounds, as it has virtually no industrial sources that could be contributing to the ambient loadings. Samples were collected for a total of 165 volatile organic compounds and 25 carbonyl compounds. Sampling and analytical methodologyare discussed and results are presented. Toluene, ethylene andformaldehyde were the most abundant pollutants in Ottawa during both winter and summer. Total non-methane hydrocarbon concentrationwas measured as 100 g m^-3 at nose-level measurements in Ottawa.     

Development of Stream Water Chemistry during Spring Melt in a Northern Hardwood Forest

The role of snowmelt and subsurface hydrology in determiningthe chemistry of a small headwater stream in the TurkeyLakes Watershed (TLW) was evaluated for the spring meltperiods 1992 to 1996. Spring runoff is the dominanthydrological event at the TLW each year. Processesoccurring within the snowpack during snowmelt wereprincipally responsible for the above-ground changes inchemical fluxes relative to bulk deposition (the effect ofwinter throughfall was minimal). Large changes in chemicalfluxes occurred below ground. Organic matter decomposition,weathering, nitrification, and element cycling are some ofthe more important below-ground processes that operateduring the snow accumulation and ablation season and controlthe composition of the water ultimately appearing in thestream. Maximum stream discharge was accompanied byelevated concentrations of H⁺, NO₃ ^-, K⁺,NH₄ ⁺, DOC, Al and Mn, but reduced levels ofCa²⁺, Mg²⁺, SO₄ ^2- and SiO₂. Theconcentration-discharge relationships were consistent withwater movement through and above the forest floor duringpeak discharge, a flowpath facilitated by rapid infiltrationof meltwater and the existence of a relatively impermeablelayer in the mineral soil creating a perched water table. Averaged over the five periods of snow accumulation andablation, it was estimated that pre-melt stream flow, andwater routed through the forest floor and through the uppermineral soil contributed 9, 28 and 63%, respectively, ofthe discharge measured at the outlet of the catchment. Theforest floor contribution would be greater at peak dischargeand at higher elevations. An end-member mixing modelestimated concentrations of SO₄ ^2-, NO₃ ^-,Cl^-, Ca²⁺, Mg²⁺, Na⁺ and Al that werecomparable to average values measured in the stream. Othervariables (NH₄ ⁺, H⁺, K⁺ and DOC) wereover-estimated implying retention mechanisms operatingoutside the model assumptions.     

Deposition Velocities of SO2 and O3 over Agricultural and Forest Ecosystems

The results of field studies that measured the flux anddeposition velocity of SO₂ and O₃ are reported. Three of the studies were over agricultural crops (pasture, corn, and soybean), and two were over forest (a deciduous forest and a mixed coniferous–deciduous forest). In all cases the deposition velocity for SO₂ was higher than that for O₃. Diurnal cycles of SO₂ deposition velocity were similar in shape, but not magnitude for all surfaces; however those for O₃ showed some difference between forest sites where the peak was in the morning, and the agricultural sites where the peak occurred at mid-day. Seasonal cycles of SO₂ were affected by deposition to surfaces when leaves were not active, yet surface conductance is significant, but not for O₃ where stomatal uptake is the primary pathway for deposition.(On assignment to the National Exposure Research Lab., US EPA) (e-mail:     

Study of Trace and Heavy Metals in Rural and Urban Aerosols of Uludağ and Bursa (Turkey)

The concentrations of heavy, trace elements and major ions measuredin the Uluda and Bursa aerosols were investigated to assess size distributions, spatial and temporal variability, sources and source regions affecting the composition of aerosols in Uluda and Bursa. A total of 81 samples were collected in two sites, one in Bursa city and another in the Uluda Mountain during two sampling campaigns. Daily samples were collected using a high volume sampler on Whatman 41 cellulose filters in Uluda, while three days interval samples were collected in Bursa using an automatic dichotomous sampler on PTFE Teflon filters. Samples were analysed for 15 trace and heavy metals (Al, Fe, Ba, Na, Mg, K, Mn, Ca, Cu), (V, Pb, Cd, Cr, Ni, Zn), and 4 major ions (SO₄ ^2-, NO₃ ^-, Cl^-), (NH₄ ⁺) using ICP-AES, GFAAS, HPLC and UV/VIS Spectrophotometer,respectively. In general, concentrations of the metals measured inUluda aerosols were lower than those in Bursa. The concentrations of crustal elements were higher in summer than winter, while anthropogenic elements had higher concentrations in winter than summer. Most of the mass of crustal elements was concentrated in the coarse mode while the mass of the heavy metals was concentrated in the fine mode. Factor analysis revealed four factors with sources including crustal, industrial and combustion. Back trajectory calculations were used to determine long range contributions. These calculations showed that contributions were mostly from European countries, former Soviet Union countries, Black Sea and North Africa.     

The Control of SO2 Dry Deposition on to Natural Surfaces by NH3 and its Effects on Regional Deposition

Two years of continuous measurements of SO₂deposition fluxes to moorland vegetation are reported. The mean flux of 2.8 ng SO₂ m^-2 s^-1 is regulated predominantly by surface resistance (r _c) which, even for wet surfaces, was seldom smaller than 100 s m^-1. The control of surface resistance is shown to be regulated by the ratio of NH₃SO₂ concentrations with an excess of NH₃ generating the small surface resistances for SO₂. A dynamic surface chemistry model is used to simulate the effects of NH₃ on SO₂ deposition flux and is able to capture responses to short-term changes in ambient concentrations of SO₂, NH₃ and meteorological conditions. The coupling between surface resistance and NH₃/SO₂ concentration ratios shows that the deposition velocity for SO₂ is regulated by the regional pollution climate. Recent long-term SO₂ flux measurements in a transect over Europe demonstrate the close link between NH₃/SO₂ concentrations and rc (SO₂). The deposition velocity for SO₂ is predicted to have increased with time since the 1970s and imply a 40% increase in v _d at a site at which the annual mean ambient SO₂ concentrations declined from 47 to 3 g m^-3 between 1973 and 1998.     

Effects of Duststorms on the Air Pollution in Beijing

The objective of this study was to investigate the air pollutionin Beijing before, during, and after duststorms occur. There aretwo different phenomena of air pollution in Beijing during a duststorm; one being related to the concentration of particulatematter and the second related to gaseous chemical pollutant concentrations. In this study, the concentrations of the chemicalpollutants, such as SO₂, NO_x and CO, were high prior to the occurrence of the duststorms. At the beginning of the two duststorms studied, the air quality related to these chemicalconstituents was improved due to a strong wind blowing away the chemical pollutants, which caused a decrease in the concentrations of SO₂, CO and NO_x. During the duststorm, the concentration of particulate matter, quantified by PM₁₀, wasobserved to increase and the atmospheric visibility decreased.     

Neutralisation of Sulphur Dioxide Deposition in a Coniferous Canopy

Previously, it has been observed that the internal circulation (ion leakage) of calcium from a coniferous forest is caused by uptake of sulphur dioxide (SO₂). Here we show that this correlation was not changed when the forest floor is covered with a roof. The reaction takes place in the canopy and is not influenced by deposition and root uptake of calcium and sulphate. The ion leakage of calcium is linked to the loss of acidity in throughfall. The process can, for one of the catchments, schematically be written: SO₂ + H₂O + 0.5 O₂ + 0.58 CaA₂→ SO₄ ^2- + 0.94 H⁺ + 0.58 Ca²⁺ + 1.16 HA, in which A denotes the anion to a weak acid. This reaction also takes place today when the SO₂ concentration is very low, but when the precipitation is still acidic. The ion leakage of manganese also is caused by the uptake of SO₂, but only 0.12 manganese ions are released per SO₂ molecule.     

Coal fly ash based carbons for SO2 removal from flue gases

Two different coal fly ashes coming from the burning of two coals of different rank have been used as a precursor for the preparation of steam activated carbons. The performance of these activated carbons in the SO₂ removal was evaluated at flue gas conditions (100 °C, 1000 ppmv SO₂, 5% O₂, 6% H₂O). Different techniques were used to determine the physical and chemical characteristics of the samples in order to explain the differences found in their behaviour. A superior SO₂ removal capacity was shown by the activated carbon obtained using the fly ash coming from a subbituminous–lignite blend. Experimental results indicated that the presence of higher amount of certain metallic oxides (Ca, Fe) in the carbon-rich fraction of this fly ash probably has promoted a deeper gasification in the activation with steam. A more suitable surface chemistry and textural properties have been obtained in this case which explains the higher efficiency shown by this sample in the SO₂ removal.     

Indoor Air Quality Assessment of Elementary Schools in Curitiba, Brazil

The promotion of good indoor air quality in schools is of particular public concern for two main reasons: (1) school-age children spend at least 30% of their time inside classrooms and (2) indoor air quality in urban areas is substantially influenced by the outdoor pollutants, exposing tenants to potentially toxic substances. Two schools in Curitiba, Brazil, were selected to characterize the gaseous compounds indoor and outdoor of the classrooms. The concentrations of benzene, toluene, ethylbenzene, and the isomers xylenes (BTEX); NO₂; SO₂; O₃; acetic acid (HAc); and formic acid (HFor) were assessed using passive diffusion tubes. BTEX were analyzed by gas chromatography–ion trap mass spectrometry and other collected gasses by ion chromatography. The concentration of NO₂ varied between 9.5 and 23?µg m^?3, whereas SO₂ showed an interval from 0.1 to 4.8?µg m^?3. Within the schools, BTEX concentrations were predominant. Formic and acetic acids inside the classrooms revealed intermediate concentrations of 1.5?µg m^?3 and 1.2?µg m^?3, respectively.     

Sources and Variability of Indoor and Outdoor Gaseous Aerosol Precursors (O3, NOx and VOCs)

Measurements of indoor and outdoor aerosol concentrations and their gaseous precursors (O₃, NO and NO₂) as well as volatile organic compounds (VOCs) concentrations were performed at two houses in the Oslo metropolitan area. The variability of the concentration of gaseous compounds was studied in respect to their sources in the indoor and outdoor environments. Domestic heating during the winter and photochemical production during the summer were the main sources for outdoor NOx and O₃. In the indoor environment infiltration of outdoor air, candle burning, smoking and indoor chemical reactions were the main sources affecting their concentrations. The concentrations of VOCs outdoors were enhanced during the summer due to biogenic emissions whereas in the indoor environment their values were affected mostly by emissions from materials used during the recent refurbishing of the houses (>0.4 mg/m³).     

Study on desulfurization performance of MnO<Subscript>2</Subscript>-based activated carbon from waste coconut shell for diesel emissions control

Increasing concern about the air pollution caused by sulfur dioxide (SO₂) from diesel exhaust has resulted in the improvement of low-temperature desulfurization materials for the combined SO₂ trap. In this study, coconut shell activated carbon (AC) is pretreated by nitric acid to prepare MnO₂-based activated carbon materials for SO₂ removal. The prepared materials are characterized intensively by SEM, TEM, BET, XRD, FTIR, and XPS. The SO₂ capture capacity of these materials are measured at low temperature by thermogravimetry, and the SO₂ equilibrium adsorption characteristic is also investigated. The results show that the concentrations of nitric acid do not significantly change the textural properties of MnO₂-based AC materials. The content of surface-oxygenated groups (carbonyl carbon and transition) initially increases with the HNO₃ concentration rising and reaches the maximum value when the HNO₃ concentration is 10 mol/L, resulting in the enhancement of the SO₂ capture capacity. SO₂ capture capacity of MnO₂-based activated carbon decreases after regeneration and keeps stable after several cycles of thermal regeneration. The experimental data for SO₂ adsorption on MnO₂-based AC composite can fit the Freundlich model well in comparison with Langmuir model.     

Recovery of coagulant from water supply plant sludge and its effect on clarification

Spent coagulant in water supply plant sludge was extracted with H₂SO₄ and the efficiency of the reused coagulant was studied. The optimum pH values for coagulant extraction and clarification with the reused coagulant were 3.0–4.0 and about 6, respectively. In treating raw influent obtained from a sewage treatment plant and wastewater from a coastal landfill site, the removal of chemical oxygen demand (COD), total nitrogen, and total phosphorous with the recovered coagulant was higher than that with commercial aluminum sulfate or polyaluminum chloride. In addition, the sludge settling properties, the extra sludge mass formation, the supernatant quality, and the cost of reagents were also studied. The coagulant recovered from water supply plant sludge by H₂SO₄ extraction could be successfully reused for the clarification of domestic and food industry wastewaters.