Μg SO Research Articles

A field evaluation of a SO2 passive sampler in tropical industrial and urban air

Passive samplers have been widely used for over 30 years in the measurement of personal exposure to vapours and gases in the workplace. These samplers have just recently been applied in the monitoring of ambient air, which presents concentrations that are normally much smaller than those found in occupational environments. The locally constructed passive sampler was based on gas molecular diffusion through static air layer. The design used minimizes particle interference and turbulent diffusion. After exposure, the SO 2 trapped in impregnated filters with Na 2 CO 3 was extracted by means of an ultrasonic bath, for 15 min, using 1.0×10 −2 mol L −1 H 2 O 2 . It was determined as SO 4 −2 by ion chromatography. The performance of the passive sampler was evaluated at different exposure periods, being applied in industrial and urban areas. Method precision as relative standard deviation for three simultaneously applied passive samplers was within 10%. Passive sampling, when compared to active monitoring methods under real conditions, used in urban and industrial areas, showed an overall accuracy of 15%. A statistical comparison with an active method was performed to demonstrate the validity of the passive method. Sampler capacity varied between 98 and 421 μg SO 2 m −3 for exposure periods of one month and one week, respectively, which allows its use in highly polluted areas.

A review of air pollution and atmospheric deposition dynamics in southern Saxony, Germany, Central Europe

Abstract This is the first comprehensive compilation of air pollution history in the Erzgebirge region. It presents selected data sets from more than 20 years of continuous research, chosen after rigorous quality control. Gases and particulates, and wet deposition are discussed in sequence. The gases include SO 2 , NO x , O 3 , and fluorine compounds. SO 2 -concentrations declined from about 80 to 120 μg m 3 until 1990 to 5–10 μg SO 2 m 3 air today, while NO x shows little change, and O 3 steadily increases as of 1990. Fluoride deposition decreased with SO 2 . Particle deposition is differentiated by sampling methods and grain sizes, and their chemical composition. The total amount of aerosols has decreased in the past 12 years, and many trace constituents now show 10% of their previous concentrations. Precipitation is represented by wet only, throughfall, fog and cloud water deposition, including major and minor chemical compounds. As with the gases, S-compounds decreased considerably. While NO 3 -N-concentrations show a slight decline (from 13 to 10–11 kg ha −1 a −1 in throughfall deposition); no trend is visible for NH 4 -N. As of the mid-1990s, continuously lower base cation inputs are being measured, and pH-values are on steady increase (now 4.8). The final synopsis rounds up the experience gained from those valuable data sets and can be used for many regions worldwide.

Characterization of Atmospheric Aerosol over XiAn in the South Margin of the Loess Plateau, China

The mass concentrations of TSP, PM-10, several secondary aerosol species, and up to 20 elements were determined for bulk aerosol samples collected from four ground-based monitoring sites in XiAn, China. The samples were collected during four seasons from September 1996 to August 1997; and in July 1998. Daily concentrations of TSP, SO 2 and NO x from 1995 to 1997 were also obtained from the same sampling sites. Representative concentrations (annual averages) of TSP, SO 2 and NO x were 410, 39, 43 μg m −3, respectively. PM-10 accounted for about 60–70% of TSP in summer 1998. The most abundant elements in the samples were Si, Ca, Al, Fe, Cl, P, K and S. A fraction of the Ca, which in typically associated with dust, was from non-crustal sources, especially in coarse particles. In winter, the element with the highest concentration was S, and it was primarily in the form of sulfate. The seasonal mean sulfate concentrations, averaged over all sites, were 100, 340, 59 and 27 μg SO 2− 4 m −3 for autumn, winter, spring and summer, respectively. The corresponding loadings of ammonium ion were 49, 140, 40 and 17 μg NH 4 + m −3 for the same seasons and those for nitrate were 22, 65, 33, 16 μg NO 3 − m −3. Dispersed sources of coal-combustion (most likely residential heating), as opposed to stationary point sources, evidently play an important role in the large increases in TSP and three-fold increases in sulfate, nitrate and ammonium loading during XiAn's space-heating season.

Long-term effects of land use and fertiliser treatments on sulphur transformations in soils from the Broadbalk experiment

Sulphur transformations were monitored in a unique set of arable, grassland and woodland soils from the Broadbalk Classical Experiment, which started in 1843. In an open incubation experiment with periodic leaching, 14–35 mg SO 4 2−-S kg −1 was mineralised in 28 weeks at 25°C, equivalent to 4.4–8.3% soil organic S. Cumulative amounts of S mineralised increased linearly during the 28 weeks, indicating constant rates of mineralisation. The rate of mineralisation was the greatest in the woodland soil (170 μg SO 4-S kg −1 day −1), followed by the grassland (120 μg SO 4-S kg −1 day −1) and the arable soil from the farmyard manure (FYM) plot (110 μg SO 4-S kg −1 day −1). Three soils from arable plots receiving different inorganic fertiliser treatments but no FYM had similar rates of S mineralisation (~70 μg SO 4-S kg −1 day −1). In an incubation experiment with 35SO 4 2−, addition of glucose greatly enhanced S immobilisation. In 132 days, the woodland and grassland soils immobilised more S than the arable soils, with or without glucose amendment. Immobilisation and mineralisation of S occurred concurrently, and both were stimulated by glucose addition. The results show that S mineralisation and immobilisation were influenced strongly by the type of land-use and long-term organic manuring, whereas annual application of sulphate-containing fertilisers for over 150 years had few effects on short-term S transformations.

Selenium adsorption in soils as influenced by different anions

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Effects of sulfur dioxide on the development of powdery mildew of cucumber

Environment is a major factor that does influence host parasite relationships. Air pollution caused by SO 2 may directly alter the environment around the plant and pathogen. It is hypothesised that plants may respond differently to foliar pathogens in air polluted environments. To test this hypothesis, effects of intermittent exposures of SO 2 at 143, 286 and 571 μg m −3 were investigated on the development of powdery mildew of cucumber ( Cucumis sativa) caused by Sphaerotheca fuliginea, using pre-, post- and concomitant-inoculation exposures in closed-top chambers. Sulfur dioxide (except 143 μg m −3) and the fungus acting alone caused chlorosis and/or necrosis, and mildew colonies on leaves, respectively and both reduced the plant growth and yield of cucumber. Fungus colonization was relatively greater on the plants exposed to 143 μg SO 2 m −3, but at the higher concentrations, the colonies were greatly suppressed. Gas injury on fungus-infected plants was also less in the other treatments. Conidia of S. fuliginea collected from exposed plants varied in size. Conidial germination was considerably greater at 143 μg SO 2 m −3. This concentration also promoted germination of the conidia exposed on glass slides. Higher concentrations (286 and 571 μg m −3), however, suppressed the germination of conidia from exposed plants or exposed on glass slides. The number of fibrosin bodies declined at all the concentrations. Synergistic effects of 143 μg SO 2 m −3 and S. fuliginea were recorded on plant growth and yield of cucumber. Sulfur dioxide at 571 μg m −3 and powdery mildew infection had an antagonistic effect on plant growth.

Patterns of Sulfite Residue Persistence in Seedless Grapes During Three Months of Repeated Sulfur Dioxide Fumigations

In 1989, the United States Environmental Protection Agency instituted a sulfite tolerance of 10 µg SO₂ per gram in grapes (<i>Vitis vinifera</i> L.). Accordingly, the residues resulting from repeated weekly SO₂ fumigations of table grapes in storage, a typical industry practice, are a concern. In a simulation of commercial practices, grapes (cv. Thompson Seedless) were fumigated once a week with 2000 or 5000 µL SO₂ per liter of storage volume and aerated 30 minutes while stored at 0°C for at least fourteen consecutive weeks. Each week, grapes were frozen immediately after aeration or stored at 0°C, 10°C, 20°C, or 30°C for 24 hours. The mean SO₂ concentration for the treatment with the highest residues was 2.3 µg/g (5000 µL/L dose, seven fumigations). The maximum residue levels at each dose level were observed between the seventh and eleventh weekly fumigations. The influence of post-fumigation temperature on sulfite residue loss was minor and inconsistent. These data suggest that current industry practices leave sulfite residues well below the official legal tolerance.

Sampling artifacts in the determination of particulate sulfate and SO2(g) in the desert Southwest using filter pack samplers

Particles collected in the desert Southwest on Teflon filters using an annular denuder sampling system absorb SO 2 (g) in a subsequential exposure to SO 2 (g) in the laboratory if the concentration of fine particulate sulfate measured with a filter pack sampling system is greater than the concentration of sulfate measured with the annular denuder sampling system. If the concentrations of sulfate determined using the two sampling systems agreed, no absorption of SO 2 (g) by the denuder-collected particles occurs. These results show that SO 2 (g) may be collected by Southwest desert fine particles during sampling, resulting in measured concentrations of fine particulate sulfate that are higher than the correct concentrations. The magnitude of this filter pack sampling artifact, 0.1-0.4 μg SO 4 2- /m 3 , is small. However, the artifact is important relative to the concentration of particulate sulfate present in the desert Southwest, typically 0.5-2 μg SO 4 2- /m 3 . The magnitude of the filter pack sulfate sampling artifact is not related to either the atmospheric particulate sulfate or SO 2 (g) concentrations.

Turbidimetric determination of sulphate in waters employing flow injection and lead sulphate formation

An analytical flow-injection procedure based on PbSO 4 colloidal formation is proposed as a turbidimetric determination of sulphate in natural waters. Ethanol-water was used as a medium in order to improve the sensibility of the method. Both chemical and flow variables as well as interfering species were studied. A detection limit of 0.3 μg SO 2− 4 ml −1 was found, and the analytical range (according to Beer's law) was 2–20 μg SO 2− 4 ml −1. The precision was better than 3% R.S.D. and the sample throughput was ca. 35 h −1. The method, when compared with a standard methodology, gave good results when applied to water analysis.

Effects of lime and two incubation techniques on sulfur mineralization in a forest soil

Limed and unlimed mor humus was incubated at 15°C in an open system and a closed one to evaluate the sulfur mineralization capacity in a Norway spruce stand in southern Sweden. Samples were collected 6yr after dolomitic lime (8800 kg ha −1) had been applied to determine the long-term effect of liming on sulfur mineralization. The open-incubation columns were periodically leached with a simulated throughfall solution, lacking sulfate. Soil in the open and closed incubation vessels was destructively sampled and extracted with distilled water. Extracts and percolates were analyzed for NO 3 −1, SO 4 2− and total S. Soil microbial activity was monitored as CO 2 evolution. The open incubation resulted in a higher net S mineralization in both the limed and control humus; i.e. 24.47 vs 14.17 and 13.60 vs —0.60μg SO 2− 4-S g −1 dw 82 days −1, in the control and limed treatment respectively. Nitrate formation was mainly affected by the liming itself, and differences related to incubation technique were only observed in the control treatment. Limed humus had a lower net S mineralization regardless of the incubation technique used. Organic S leaching from the open incubation columns was higher in the limed treatment than in the control, 17.6 and 6.9μg Sg −1dw 82 days −1, respectively. Limed humus had the highest microbial activity irrespective of the incubation technique. Immobilization of sulfate seemed to be greater in the limed incubation than in the control. The fact that the organic C-to-S ratio was lower in the limed percolation water than in the control also indicates that such a difference exists.

The interaction of SO 2 and root-knot nematode on tomato

Intermittent exposure of tomato plants (cv. Pusa Ruby) to SO 2 at 286 μg m −3 (3 h every heavy third day for 75 days) induced slight chlorosis of leaves. At 571 μg m −3, considerable chlorosis with browning developed on the foliage. These symptoms were more pronounced and appeared earlier on SO 2-exposed plants infected with Meloidogyne incognita race 1 (Mi), especially in post- and concomitant-inoculation exposures. Mi and/or SO 2 significantly reduced different parameters of plant growth. Synergistic (positive) interactions between SO 2 and Mi occurred in concomitant- and post-inoculation exposures at 286 and 571 μg m −3, respectively. In other treatments, an antagonistic (negative) interaction was observed. However, in a few cases, additive effects of SO 2 and Mi were also recorded. Intensity of root-knot (galling) was enhanced at both concentrations of SO 2, while reproduction (egg mass production) of Mi was enhanced in concomitant-inoculation exposures at 286 μg m −3 and inhibited at 571 μ m −3. Exposure to SO 2 and/or Mi decreased the number and size of stomata but increased the number and length of trichomes on both the leaf surfaces. Stomatal aperture was significantly wider in the plants exposed to 571 μg SO 2 m −3 alone and in pre-, post-, and concomitant-inoculation exposures at 286 or 571 μg m −3. Stomatal aperture was directly related to foliar injury and reductions in growth, yield, and leaf pigments.

Sulfur dioxide concentrations in Western U.S.

Weekly integrated measurements of SO 2 concentrations at National Parks in western U.S., Hawaii and Alaska are presented for the period November 1986–October 1987. The highest and most variable SO 2 concentrations occurred in Hawaii due to the Kilauea Volcano. Annual-average concentrations within parks in the western contiguous states ranged from 0.83 to 1.64 μg m −3; the grand mean was 1.3 μg SO 2 m −3. SO 2 concentrations in western states were generally 10 times greater than the concentrations of the marine-air boundary layer and 10–30 times less than the rural concentrations of eastern U.S.

Effects of sulphur dioxide and hydrogen fluoride, singly and in combination, on growth and yield of wheat in open-top chambers

Wheat ( Triticum aestivum cv. ‘Eradu’) growing in open-top chambers was exposed to the factorial combination of two concentrations of HF (<0.03 and 0.30 μg m −3) and three concentrations of SO 2 (< 14, 133 and 266 μg m −3). Each combination was tested in duplicate chambers. Exposure was for 8 h day −1 from emergence to the onset of grain hardening, 120 days later. Exposure to 133 μg SO 2m −3 had little effect, but 266 μg m −3 substantially reduced growth and yield. It reduced dry weights of shoots, ears and grain by about 25%, and concentrations of leaf chlorophyll a and ascorbic acid by about 60 and 40%, respectively, while slightly increasing grain protein concentrations. HF reduced shoot surface area and grain protein concentration, and increased leaf fluoride concentrations. In addition to main effects there were interactive effects of SO 2 and HF on shoot surface area and grain protein concentration, the effects of HF being larger when SO 2 concentrations were low.

Yield responses of soybean, maize, peanut and navy bean exposed to SO 2, HF and their combination

Soybean ( Glycine max L.), maize ( Zea mays L.), peanut ( Arachis hypogaea L.) and navy bean ( Phaseolus vulgaris L.) were exposed to SO 2 (≈280, ≈140 or < 13 μg/m 3) and HF (≈0.26 or <0.03 μg/m 3) separately or together, for 8 hr per day in a factorial experiment in open top chambers from the seedling stage to harvest. The gases had little effect on soybeans. SO 2 or HF alone caused an accelerated or more even kernel ripening in maize, and their combination increased the dry weight of maize cobs by over 40%. SO 2 alone reduced the number of mature pods and kernels in peanut, but the weight of kernels produced was unchanged. In contrast, HF alone reduced yield (expressed as weight of kernels per plant.) Mixtures of HF and SO 2 induced less than additive responses. Exposure of navy beans to SO 2 or HF alone increased the number of pods and beans per plant. However, average bean weight was reduced by exposure to HF or 290 μg/m 3 of SO 2 resulting in no net change in yield. Yield was, however, increased by exposure to 141 μg/m 3. Mixtures of SO 2 and HF induced less than additive responses in navy bean. Leaf sulfur concentrations were increased by exposure to ≈ 280 μg SO 2/m 3 but unaffected by ≈ 140 μg/m 3.

Yield responses of different crop species to long-term fumigation with sulphur dioxide in open-top chambers

Potted plants of commercial cultivars of rape ( Brassica napus L., cv. ‘callypso’), summer barley ( Hordeum vulgare L., cvs. ‘arena’ and ‘hockey’) and bush beans ( Phaseolus vulgaris L., cvs. ‘rintintin’ and ‘rosisty’) were continuously exposed in open-top chambers to sulphur dioxide (SO 2) for the whole growing season in order to assess effects of this pollutant on growth and various yield parameters. Treatments consisted of charcoal-filtered air (CF) and CF supplemented with four levels of SO 2, resulting in mean exposure concentrations (μg m −3) of approximately 8, 50, 90, 140 and 190. With the exception of the 1000 seeds weight, which was slightly reduced, dry matter production and yield parameters of rape remained unaffected by all SO 2 concentrations or were even stimulated. Compared to CF vegetative growth of both bean cultivars was reduced by 10–26% at all SO 2 levels; however, with significant effects only for cv. ‘rintintin’. While all SO 2 additions reduced significantly the yield (dry weight of pods) of the bean cultivar ‘rosisty’ between 17% and 32%, cv. ‘rintintin’ showed a significant reduction of up to 42% only at the two highest pollutant concentrations. Dry matter production of the barley cultivars was mainly impaired at SO 2 concentrations > 100 μg m −3 with a reduction of 30–52%. While nearly all yield parameters of cv. ‘hockey’ reacted similar to the dry matter production, the yield of cv. ‘arena’ was reduced already at the low SO 2 levels. At a treatment concentration of 90 μg SO 2 m −3 a significant yield loss of 30% was recorded. A reduction of the 1000 grains weight mainly contributed to these yield losses observed for both barley cultivars. From these results, it may be assumed that SO 2 concentrations within the range 50–90 μg m −3 are potentially phytotoxic to some crop species.

Functional changes in the lungs of guinea pigs exposed to sodium sulfite aerosols

Guinea pigs were exposed head only for 1 hr to submicrometer sodium sulfite aerosols (mass median aerodynamic diameter = 0.36 μm, σ g = 2.96) at 474, 669, and 972 μg SO 3 2−/m 3. Respiratory mechanics were measured in unanesthetized animals before, during, and after exposure. Dose-related increases in resistance and decreases in compliance were observed. At 972 μg SO 3 2−/m 3, the sodium sulfite aerosol caused a 50% increase in resistance and a 19% decrease in compliance. These changes were still present 1 hr after the end of exposure. The results were used to assess the irritant potency of sodium sulfite aerosol. Another group of guinea pigs was exposed whole body for 1 hr to the same aerosol at 0, 204, 395, and 1152 μg SO 3 2−/m 3. Immediately after the exposures, lung volume, diffusion capacity for carbon monoxide (DL CO), and wet lung weight were evaluated in anesthetized, tracheotomized animals. As compared to controls, total lung capacity, vital capacity, functional residual capacity, residual volume, and DL CO were all decreased with increasing concentrations of sodium sulfite. Dose-related increases in wet lung weights were also observed. These results were compared with the irritant responses of animals exposed to zinc oxide and sulfur dioxide mixed under different conditions of temperature and humidity.

Effects of SO 2 on the photosynthetic and respiration rates in scots pine seedlings

Exposure to moderate concentrations (90–500 μg SO 2 m −3) of SO 2 for 5–30 days caused a decrease in the photosynthetic rate. Only the lowest concentration (30 μg SO 2 m −3) increased photosynthesis. There was hardly any recovery in photosynthesis after the exposure. All exposure concentrations increased dark respiration. However, the lowest concentration had the smallest effect. Exposure to high concentration (2320 μg SO 2 m −3) of SO 2 for 5 h caused a strong decrease in the photosynthetic rate but there was a complete recovery within 2 weeks.

Mobile measurements of winter SO 2 levels in London, 1983–1984

Regular mobile surveys of SO 2 levels in Central London were made with two vehicles during the winter of 1983–1984. The SO 2 concentrations observed showed a strong inverse dependence on geostrophic wind speed and were higher at low temperatures. If the results are extrapolated to the whole winter, a seasonal mean roadside SO 2 concentration is obtained which is substantially larger than that from fixed point monitors. It is suggested that on busy urban roads a daytime mean of 50 μg SO 2 m −3 may come from motor vehicles.

An evaluation of artifact SO 42− formation on nylon filters under field conditions

The extent of SO 2 conversion on Membrana (Ghia) Nylasorb nylon filters under field conditions has been evaluated and found to be quite variable. The S-SO 4 2− loading on the nylon filters is higher at higher SO 2 concentrations, and on a long term basis approaches a saturatio limit of 2.5 μg S-SO 4 2− on a 47mm disc, at a dosage of 230 μg SO 2 approximately. The % conversion decreases as the SO 2 concentration increases. On a long term basis, at an SO 2 concentration range of 1.0–7.7 μg m −3, the conversion ranges from 8.2% to 2.1%. The dependence of SO 2 conversion on nylon filters on relative humidity displays a diurnal pattern. An expression has been derived to explain the observed % SO 2 conversion on nylon filters as a combined effect of the ambient SO 2 concentration and relative humidity.

Ecotypic Response of Silene cucubalus to Air Pollutants (SO 2, O 3)

Two populations of Silene cucubalus, from a rural and from a heavily polluted industrial area in Central Europe, were fumigated for 6 weeks with 160 μg SO(2)m (-3), for 4 weeks with 70 μg O(3) m (-3), and for 4 weeks with both air pollutants. Both populations were heavily affected in growth and completely hampered in flowering by O(3), alone or in combination with SO(2). The injurious concentration of O(3) stimulated the activity of peroxidase and reductive glutamate dehydrogenase and significantly diminished the concentration of magnesium and manganese in the leaves. SO(2) alone gave no growth reduction of the rural population and stimulated the growth of the industrial one. It diminished, however, the weight of the seed of the rural population by more than 20 %. The increased weight of the seed of the industrial population after SO(2) exposure and its better growth in the presence of SO(2) are discussed in relation of the evolution of SO(2) tolerance. Both populations have a different sensitivity against ozone with the highest sensitivity in the industrial population. This is the first report of a plant species which is able to evolve SO(2) tolerance and heavy metal tolerance.