Sulphur and nitrogen deposition in Norway,status and trends

The total deposition of sulphur (S) and nitrogen (N) components in Norway during the period 1988–1992 has been estimated on the basis of measurement data of air- and precipitation chemistry from the national monitoring network. There are large regional variations in depositions with highest values in the southwestern part of Norway. Time series analysis of annual mean concentrations of sulphur dioxide (SO₂) and sulphate (SO₄ ^––) in air, non marine SO₄ ^––, nitrate (NO₃ ^–) and ammonium (NH₄ ⁺) in precipitation, shows a significant reduction in the S concentrations both in air and precipitation. In precipitation the concentrations are reduced by 30–45 percent in Southern Norway and 45–55 percent in Central and Northern Norway. Even larger reductions are observed in air concentrations with 50–65 percent reduction in Southern Norway and 65–88 percent reduction further north. For N components there are generally no significant trends in concentration levels nor in precipitation or air. The observed trends are comparable with reported trends in emission.     

Precipitation Composition in the Ohio River Valley: Spatial Variability and Temporal Trends

Sulfate (SO₄ ^2?), nitrate (NO₃ ^?) and ammonium (NH₄ ⁺) concentrations in precipitation as measured at NADP sites within the Ohio River Valley of the Midwestern USA between 1985 and 2002 are quantified and temporal trends attributed to changes/ variations in (i) the precipitation regime, (ii) emission patterns and (iii) air mass trajectories. The results indicate that mean SO₄ ^2? concentrations in precipitation declined by 37–43% between 1985 and 2002, while NO₃ ^? concentrations decreased by 1–32%, and NH₄ ⁺ concentrations exhibited declining concentrations at some sites and increasing concentrations at others. The change in SO₄ ^2? concentrations is in broad agreement with estimated reductions in sulfur dioxide emissions. Changes in NO₃ ^? concentrations appear to be less closely related to variations in emissions of oxides of nitrogen and exhibit a stronger dependence on weekly precipitation volume. Up to one quarter of the variability in log-transformed weekly NO₃ ^? concentrations in precipitation is explicable by variations in precipitation volume. Trends in annual average log-transformed SO₄ ^2? concentrations exhibit only a relatively small influence of variability in weekly precipitation amount but at each of the sites considered the variance explanation of annual average log-transformed SO₄ ^2? by sampling year was increased by removing the influence of precipitation volume. Annual mean log-transformed ion concentrations detrended for precipitation volume (by week) and emission changes (by year) exhibit positive correlations at all sites, indicating that the residual variability of SO₄ ^2?, NO₃ ^? and NH₄ ⁺ may have a common source which is postulated to be linked to synoptic scale variability and air mass trajectories.     

Chemical Composition of Air, Soil and Vegetation in Forests of the Silesian Beskid Moutains, Poland

For the first time concentrations of trace nitrogenous (N) air pollutants, gaseous nitric acid (HNO₃), nitrous acid (HNO₂), ammonia (NH₃), and fine particulate nitrate (NO₃) and ammonium (NH₄), were measured in the montane forests of southern Poland. Determinations were performed in two forest locations of the Silesian Beskid Mountains in the western range of the Carpathian Mountains, and in an industrial/urban location in Karowice, Poland. The measurements performed in summer 1997 with honeycomb denuder/filter pack systems showed elevated concentrations of the studied pollutants. These findings agree with the low carbon/nitrogen (C/N) ratios and the results of ¹⁵N analyses of soil and moss samples. High concentrations of N air pollutants help to explain previously determined high levels of NO₃ and NH4 deposition to Norway spruce (Picea abies Karst.) canopies in these mountains. Ambient concentrations of sulfur dioxide (SO2) and ozone (O3) were elevated and potentially phytotoxic. Deficiencies of phosphorus (P) and magnesium (Mg) in Norway spruce foliage were found while concentrations of other nutrients were normal.     

Sulphur and nitrogen input to the Ratanica forested catchment (Carpathian Foothills,southern Poland)

The study covers 1991–1994 concentrations of SO₂ and NO₂ in the air, concentrations of sulphur and nitrogen in bulk precipitation, throughfall and stemflow as well as input of S and N to the Ratanica forested catchment (S. Poland), which is exposed to moderate anthropogenic pollution are presented. There was high input of sulphur (26 kg ha^?1) and nitrogen (24 kg ha^?1) to the catchment, mainly in NH4⁺ (18 kg ha^?1). The significant contribution of NH₄ ⁺ connected with intensive agriculture in surrounding fields has led to eutrophication of the ecosystem.     

Effects of air pollution on the searching behaviour of an insect parasitoid

To assess the impact of air pollutants on the population dynamics of herbivores, the effects of pollutants on their natural enemies including predators, parasites, and pathogens must be evaluated in addition to direct effects and indirect effects mediated via the host plant. Insect parasitoids are an important group of such natural enemies providing many examples of partial or complete biological control of pest species. This study examined the effects of air pollutants (ozone (O₃), sulphur dioxide (SO₂), and nitrogen dioxide (NO₂)) on the searching behaviour of insect parasitoids. A series of experiments comprising short-term, closed chamber fumigations of O₃, SO₂, and NO₂ (100 nl l^?1) of the braconid parasitoid (Asobara tabida) and aggregated distributions of its host larvae (Drosophila subobscura) was set up. Analysis of chamber results showed that the proportion of hosts parasitised and the searching efficiency of the parasitoids were both significantly reduced with O₃ fumigation, but not with NO₂ or SO₂ fumigations. O₃ fumigation reduced percentage parasitism by approximately 10%. Parasitoids were able to avoid patches with no hosts, both in filtered air controls and when exposed to pollutants. However in the O₃ and NO₂ treatments they appeared less able to discriminate between different host densities, suggesting that pollutants may interfere with the olfactory responses of the parasitoids. These results indicate the potential for air pollutants, particularly O₃, to negatively influence the searching behaviour of parasitoids, and hence reduce the efficiency of natural enemy control of many pest species.     

Evaluation of extreme pollution episodes over Lithuania in 1980–1994

The investigation of SO₂, NO₂, benzo(a)pyrene (BP) and soot (C_el) has been carried out daily in the atmospheric air in the background station Preila (East shore of the Baltic Sea) since 1980. Over this period, daily concentrations of pollutants varied in the wide intervals in warm and cold period as well. From 15 years data typical episodes of highest and lowest concentrations of pollutants are chosen and analysed with respect to the air masses trajectories and meteorological conditions. The highest concentrations of SO₂, NO₂, BP, Cd were fixed, when the air masses passing Lithuania have been formed over Great Britain and Central Europe.     

Effects of gaseous air pollutants on secondary chemistry of Scots pine and norway spruce seedlings

Plant secondary compounds have an important role in defense responses against herbivores and pathogens. This study summarises published and some unpublished data from a series of fumigation experiments where Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) seedlings were exposed to different concentrations of gaseous air pollutants, ozone (O₃), sulphur dioxide (SO₂) or nitrogen dioxide (NO₂), in growth chambers. Concentrations of monoterpenes, resin acids and total phenolics were studied. Overall, needle monoterpenes were not affected by pollutants. Only very high level of O₃ (600 ppb) decreased concentration of some individual monoterpenes in pine needles. O₃ did not have effect on concentrations of resin acids in pine needles. In contrast, the concentration of some individual resin acids increased in O₃-exposed pine shoots and in O₃-exposed needles of one spruce clone. The highest dose of SO₂ decreased concentrations of resin acids in pine needles, but low exposure levels did not have effects. However, SO₂ had no effects on the resin acids concentrations of spruce needles, except some minor individual compounds were affected in clonal spruces. Increased concentrations of resin acids was found in pine shoots exposed to NO₂. Total phenolics of needles were not affected by pollutants. These observations suggest that among secondary compounds there is variation in sensitivity to air pollutants and genetically different trees have different responses to air pollutants.     

Characteristics of Nitrogenous Air Pollutants at Urban and Suburban Forested Sites, Western Japan

Nitrogenous air pollutants including nitrogen dioxide (NO₂), nitric acid (HNO₃), nitrate (NO ₃ ^? ), ammonia (NH₃), ammonium (NH ₄ ⁺ ), and nitrous acid (HONO) were characterized at an urban forested (UF) site in Hiroshima and at a suburban forested (SF) site in Fukuoka, western Japan, using an annular denuder system for 1?year from May 2006 to May 2007 to compare the concentrations and chemical species of atmospheric nitrogenous pollutants between UF and SF sites. The proximity of the urban area was reflected in higher NO₂ concentrations at the UF site than at the SF site. NO₂ was more oxidized at the SF site because it is farther from an urban area than the UF site, which was reflected in higher concentrations of HNO₃ at the SF site than the UF site. HNO₃ and acidic sulfate is neutralized by NH₃, existing as ammonium nitrate (NH₄NO₃) and ammonium sulfate [(NH₄)₂SO₄] at the UF site. At the SF site, acidic sulfate is neutralized by NH₃, existing as (NH₄)₂SO₄, but NH₄NO₃, had scarcely formed at the SF site. A much higher HONO concentration was observed at the UF site than at the SF site, especially in winter and spring at night, which could be explained by higher NO₂ concentrations at the UF site because of its proximity to an urban area and stagnant meteorological conditions. Atmospheric HONO determination was critical in evaluating the possibility of damage to trees in UF areas.     

Characteristics of SO2, NO2, Soot and Benzo(a)Pyrene Concentration Variation on the Eastern Coast of the Baltic Sea

The investigation of SO₂, NO₂, soot and benzo(a)pyrene (BP) has been performed at the background station on the eastern coast of the Baltic Sea since 1980. A significant decreasing trend has been observed for SO₂ and NO₂, while soot and BP concentrations were changing insignificantly. The decreasing SO₂ and NO₂ high concentrations (>10µg·m^?3) have been determined in the air masses coming from the Western and Central Europe to Lithuania since 1900. The concentration of SO₂ in a range of 0–5µg·m^?3 and the concentration of NO₂ in a range of 0–10µg·m^?3 are characteric of the background atmospheric air.     

A Cost-Effective Methodology for Spatial Concentration Distributions of Urban Air Pollutants

A methodology to determine economically the spatial concentration distribution of the air pollutants of carbon monoxide (CO), sulphur dioxide (SO₂), nitrogen monoxide (NO), nitrogen dioxide (NO₂), oxides of nitrogen (NO_x) and traffic rates (TR) is described. It involves the immediate transfer of samples from field to analysers for measurement and a subsequent statistical treatment. The proposed methodology has been applied in Patras using 5 and 50-l Teflon air sample bags, sampling at least 12 to 36-l actual volumes within a 20-min time interval. Totally, 221 pairs of 5-l and 112 single 50-l samples were randomly picked in morning rush hours of working days from 64 locations of a 40.0-km² area during a winter period, when peaks of primary air pollutants usually occur due to high traffic rates and systematic inversions. Measurements were used to statistically calculate spatial average levels approximating 1-h mean concentrations with acceptable mean probable errors less than 25 % for indicative random sampling. The 1-h levels were strongly correlated to the corresponding traffic rates. Iso-concentration diagrams indicated possible zones susceptible to high pollution levels and helped to check the location appropriateness of the existing monitoring stations for (a) fixed urban-background measurements at the Vas. Georgiou A’ Sq., which was ideal, and (b) fixed traffic-oriented measurements, which should be relocated to the Ipsilon Alonion Sq. In addition, data helped to determine other points where indicative measurements should be performed. Data could be very useful for the Patras air quality assessment in conjunction with model predictions and/or objective estimation methods.     

Characterizing Groundwater Dynamics Based on Impact of Pulp and Paper Mill Effluent Irrigation and Climate Variability

Automated synoptic weather typing and robust orthogonal stepwise regression analysis (via principal components analysis) were applied together to develop within-weather-type air pollution prediction models for a variety of pollutants (specifically, carbon monoxide – CO, nitrogen dioxide – NO₂, ozone – O₃, sulphur dioxide – SO₂, and suspended particles – SP) for the period 1974–2000 in south-central Canada. The SAS robust regression procedure was used to limit the influence of outliers on air pollution prediction algorithms. Six-hourly Environment Canada surface observed meteorological data and 6-hourly US National Centers for Environmental Prediction (NCEP) reanalysis data of various weather elements were used in the analysis. The models were developed using two-thirds of the total years for meteorological and air pollution data; the remaining one-third (randomly selected) was used for model validation. Robust stepwise regression analysis was performed to analytically determine the meteorological variables that might be used to predict air pollution concentrations. There was a significant correlation between observed daily mean air pollution concentrations and model predictions. About 20, 50, and 80% of the 80 prediction models across the study area possessed R ² values ≥ 0.7, 0.6, and 0.5, respectively. The results of model validation were similar to those of model development, with slightly smaller model R ² values.     

Nitrogen and Sulfur Deposition and Forest Nutrient Status in the Valley of Mexico

Mexico City experiences some of the most severe air pollution in the world. Ozone injury has been documented in sensitive tree species in urban and forested areas in the Valley of Mexico. However, little is known of the levels of other atmospheric pollutants and their ecological effects on forests in the Valley of Mexico. In this study bulk throughfall deposition of inorganic nitrogen (N) and sulfur (S) was measured for one year at a forested site upwind (east) and downwind (southwest) of Mexico City. Edaphic and plant (Pinus hartwegii Lindl.) indicators of N and S nutrient status were also measured. Streamwater NO₃ ^- and SO₄ ^2- concentrations were also determined as an indicator of watershed-level N and S loss. Annual bulk throughfall deposition of inorganic N and S at the high-pollution forested site 23 km southwest of Mexico City (Desierto de los Leones National Park; DL) was 18.5 and 20.4 kg ha^-1. Values for N and S deposition at Zoquiapan (ZOQ), a relatively low-pollution site 53 km east of Mexico City, were 5.5 and 8.8 kg ha^-1 yr^-1. Foliar concentrations of N, foliar N:P and C:N ratios, extractable soil NO₃ ^-, and streamwater NO₃ ^- concentrations indicate that the forest at DL is N enriched, possibly as a result of chronic N deposition. Sulfur concentrations in current-year foliage were also slightly greater at DL than at ZOQ, but S concentrations in one-year-old foliage were not statistically different between the two sites. Streamwater concentrations of NO₃ ^- ranged from 0.8 to 44.6 μEq L^-1 at DL compared to 0.0 to 11.3 μEq L^-1 at ZOQ. In summary, these findings support the hypothesis that elevated N deposition at DL has increased the level of available N, increased the N status of P. hartwegii, and resulted in export of excess N as NO₃ ^- in streamwater.     

Chemical Composition of Precipitation, Throughfall and Soil Solutions at Two Forested Sites in Guangzhou, South China

Rain water at two forested sites in Guangzhou (south China) show high concentrations of SO₄ ^2?, NO₃ ^? and Ca²⁺ and display a remarkable seasonal variation, with acid rain being more important during the spring and summer than during the autumn and winter. The amount of acid rain represents about 95% of total precipitation. The sources of pollutants from which acid rain developed includes both locally derived and long-middle distance transferred atmosphere pollutants. The seasonal variation in precipitation chemistry was largely related to the increasing neutralizing capacity of base cations in rainwater in winter. Soil acidification is highlighted by high H⁺ and Al³⁺ concentrations in soil solutions. The variation in elemental concentration in soil solution was related to nitrification (H⁺, NH₄ ⁺ and NO₃ ^?) and cation exchange reaction (H⁺, Al³⁺) in soil. The negative effect of soil acidification is partly dampened by substantial deposition of base cations (Ca²⁺, Mg²⁺ and K⁺) in this area.     

Acidification and nutrient imbalance in forest soils subjected to nitrogen deposition

Emission of nitrogen oxides (NO_x) and ammonia (NH₃) from a fertilizer factory and the resulting input of nitrates (NO₃ ^?) and ammonium (NH₄ ⁺) into the soil were the main reasons of nitrogen (N) cycle disturbance in forest ecosystems near Novgorod, North-Western Russia (50°31′ North, 31°17′ East). Total N atmospheric input was about 100 kg/ha annually. NH₃ was a dominant pollutant, causing the increase of atmospheric precipitation pH within the polluted region compared to background territories (6.0–6.5 and 4.5–5.0, respectively). Soil acidification through NH₄ ⁺ nitrification was observed. N-NO₃ ^? concentrations in soil solution reached 20–30 mg/l, and proton (H) production was equal to 4.1 keq/ha per warm season (from April to October). Compared with soil status in 1983, pH decrease by 0.2 pH units was found in A horizon. The content of exchangeable calcium (Ca) and magnesium (Mg) decreased by the factor of 2–3 and 1.5–2 in A and B horizons, respectively. Triple increase of exchangeable aluminium (Al) content was detected in A horizon. Through recent decrease of pollutant emission, the polluted territory is now a suitable subject for recovery studies.     

Effects of Salinity and Nitrogen on Growth,Contents of Pigments,and Ion Accumulation of a Euhalophyte Suaeda Salsa in an Intertidal Zone and on Saline Inland

The different responses of two populations of Suaeda salsa (Linn.) Pall. (saline seepweed) from an intertidal zone and a saline inland zone to salinity [1 or 500 mM sodium chloride (NaCl)] and nitrogen [N; 0.05, 1, or 10 mM nitrate (NO₃ ^?)‐N] were investigated. Greater NO₃ ^?‐N supply (10 mM) increased shoot dry weight for the two populations of S. salsa, especially for S. salsa from the saline inland zone. Greater NO₃ ^?‐N supply (10 mM) increased the concentrations of chlorophyll and carotenoid in leaves and the NO₃ ^? and potassium (K⁺) concentrations in shoots for both populations. Greater NO₃ ^?‐N supply (10 mM) increased shoot Na⁺ in S. salsa from the intertidal zone. In conclusion, S. salsa from the saline inland zone is more responsive to NO₃ ^?‐N supply than the intertidal population. Greater NO₃ ^?‐N supply can help the species, especially the intertidal population, to grow and to mediate ion homeostasis under high salinity.     

Evaluation of Air Pollution Burden from Contribution of Motorcycle Emission in Bangkok

This study investigated the relationship between exhaust emission from motorcycles and ambient air quality in Bangkok Metropolitan Region (BMR). The test result revealed that averagepollutant concentrations of the test motorcycles in terms of hydrocarbon, carbon monoxide and nitrogen dioxide were 8.38, 16.69 and 0.04 g km^-1, respectively. The finding also indicated that two-stroke motorcycles emitted 1.5 and 5 times more carbon monoxide and hydrocarbon emission, respectively perkilometer driven than do four-stroke motorcycles. Four air sampling stations were strategically established to evaluate the air pollution problems in Bangkok arising from vehicle exhaust emission. Investigation was carried out to determine the correlation between average air pollutant concentration with different traffic configuration in each traffic zone of Bangkok Metropolitan Region (BMA) during peak/non peak hours, day/night times and weekday/weekend. The average concentrationsof PM₁₀ particulate matter, carbon monoxide, nitrogen dioxide and sulphur dioxide in Bangkok street air were found tobe 84.33 μg m^-3 (24 hr ave.), 7.05 mg m^-3 (8 hr ave.), 56.74 μg m^-3 (1 hr ave.) and 9.60 μg m^-3 (24 hr ave.), respectively.     

Dry Deposition of Atmospheric Sulphur and Nitrogen in Russia and the Former USSR

Generally, dry deposition processes are very important for atmospheric chemistry of pollutants providing up to 30–80 % of the removal for certain compounds from the atmosphere. The model for calculating of dry deposition fluxes for a large territory seems unsophisticated in spite of the dependence on surface characteristics, pollutant properties and atmospheric conditions. The approach of combining monthly average concentrations measured at the Integrated Background Monitoring Network (IBMoN) and EMEP stations and linear dry deposition velocity was used to calculate total sulphur and nitrogen fluxes for the whole of the former Soviet Union (FSU) taking into account large-scale geographical variability in climate and lands. Most values of all SO₂ and SO₄ ^2? concentrations were below 2.9 and 3.1 mgS/m³, and NO₂ concentration were 1.5 mgN/m³ over European part and 0.6 mgN/m³ in Western Siberia. The long-term trends of oxidised sulphur and nitrogen compounds in the atmosphere were examined for 1982–1998 in certain FSU regions. Annual dry deposition of sulphur was estimated as 3.64 Mt S (in sulphate form) and 2.76 Mt S (in SO₂ form) for the whole area of FSU. Annual removal of NO₂ by dry deposition was calculated at 1.27 Mt N. These values constituted between 44 and 50% of total oxidised sulphur and nitrogen deposition.     

Changes of Some Components of Precipitation in East Germany after the Unification

A network of 15 sites of precipitation monitoring was built-up to characterize the spatial and temporal changes of pollutants over East Germany. Rain water samples were analysed and characterized regarding their acidity, conductivity, main water soluble components (Cl^-, NO₃ ^-, SO₄ ^2-, Na⁺, NH₄ ⁺, K⁺, Ca²⁺, Mg²⁺), volume and the meteorological parameters. Dependent on the changes of emission of pollutants, resulting from the reformation of industry, the decrease of stock farming, and increase of traffic (by the factor of ≈1.5) in East Germany, a drop could be observed with the sulphate and calcium concentrations in the precipitation by 20 to 50 and 30 to 70%, respectively. An increase could not be ascertained with the nitrate concentration and the acidity.     

Atmospheric Concentrations of Sulfur Dioxide and Nitrogen Dioxide in China and Korea Measured by Using the Improved Passive Sampling Method

The results of ambient sulfur dioxide (SO₂) and nitrogen dioxide (NO₂) concentrations measured in ten cities of China and Korea by the improved passive samplers are reported. The property of this sampler is the utilization for the long-term exposure to the high level of SO₂ and NO₂. In this method, the conversion coefficients from the analytical data to the ambient concentrations were obtained from the comparison with the direct concentrations through the automatic analyzers for SO₂ and for NO₂, respectively. The interesting monthly variations were observed in the ambient SO₂ and NO₂ concentrations measured by this passive sampler method, which seems to give important information to the formation of acid rain in these countries.     

Nitrogen compounds in atmospheric precipitation

The paper presents results of a stoichiometric calculation of a nitrogen (N) compounds in precipitation of World Meteorological Organization's Global Atmosphere Watch (WMO GAW) stations. Long-term trends of ammonium sulphate ((NH₄)₂SO₄) and ammonium nitrate (NH₄NO₃) contents i the North-West of Russia as well as in Byelorussia, Scandinavia, Western and Eastern Europe during the periods of 1958–1990 and 1972–1985 were investigated. A relatively, steady annual trend for the mean NH₄NO₃ concentrations was found typical of pure regions (5–15μeq^* 1^?1). The concentrations in industrial regions are from 4 to 5 times higher than the background close to natural. The analysis of the trend for (NH₄)₂SO₄ content in precipitation shows a wide range of a variations of mean annual concentrations with an explicit tendency to their significant decrease in some European regions in the mid-eighties. Nitric acid (HNO₃) has not been discovered in precipitation from the European WMO GAW stations while calculations based on the US data revealed its remarkable content and tendency to its increase. Nitric acid and ammonium sulphate are not contained in precipitation over ocean, ammonium nitrate is present in insignificant amounts.