Levels Of Ammonium Nitrate Research Articles

Processes Influencing Secondary Aerosol Formation in the San Joaquin Valley during Winter

Air quality data collected in the California Regional PM10/PM2.5 Air Quality Study (CRPAQS) are analyzed to qualitatively assess the processes affecting secondary aerosol formation in the San Joaquin Valley (SJV). This region experiences some of the highest fine particulate matter (PM2.5) mass concentrations in California (≤188 μg/m3 24-hr average), and secondary aerosol components (as a group) frequently constitute over half of the fine aerosol mass in winter. The analyses are based on 15 days of high-frequency filter and canister measurements and several months of wintertime continuous gas and aerosol measurements. The phase-partitioning of nitrogen oxide (NOx)-related nitrogen species and carbonaceous species shows that concentrations of gaseous precursor species are far more abundant than measured secondary aerosol nitrate or estimated secondary organic aerosols. Comparisons of ammonia and nitric acid concentrations indicate that ammonium nitrate formation is limited by the availability of nitric acid rather than ammonia. Time-resolved aerosol nitrate data collected at the surface and on a 90-m tower suggest that both the daytime and nighttime nitric acid formation pathways are active, and entrainment of aerosol nitrate formed aloft at night may explain the spatial homogeneity of nitrate in the SJV. NOx and volatile organic compound (VOC) emissions plus background O3 levels are expected to determine NOx oxidation and nitric acid production rates, which currently control the ammonium nitrate levels in the SJV. Secondary organic aerosol formation is significant in winter, especially in the Fresno urban area. Formation of secondary organic aerosol is more likely limited by the rate of VOC oxidation than the availability of VOC precursors in winter.

Analysis of urban gas phase ammonia measurements from the 2002 Atlanta Aerosol Nucleation and Real‐Time Characterization Experiment (ANARChE)

Gas phase ammonia (NH3) measurements were made in July and August 2002 during the Atlanta Aerosol Nucleation and Real‐Time Characterization Experiment with two different chemical ionization mass spectrometry techniques. Correlations between the 1 min data from both instruments yielded a slope of 1.17 and an intercept of −0.295 ppbv, with a linear correlation coefficient (r2) of 0.71. Ambient NH3 mixing ratios ranged from 0.4 to 13 ppbv. NH3 observations were compared to the Community Multiscale Air Quality (CMAQ) modeling system as well as a thermodynamic equilibrium model, ISORROPIA, used by CMAQ to predict NH3 partitioning. A morning rise in both observed and modeled NH3 mixing ratios strongly suggests a regional influence due to automobile emissions. However, at midday the predicted NH3 decreased to less than 0.5 ppbv, while the observations remained around 3 ppbv. Both observed and modeled ammonium nitrate levels were too low to support the observed midday NH3 mixing ratios. ISORROPIA calculations of NH3 constrained by the total measured ammonia mass (NH3 + ammonium (NH4+)) agreed well with the observations (slope of 1.25 and r2 of 0.75). For times when the net aerosol charge was near zero the agreement was excellent (slope of 1.22 and r2 of 0.88). These results indicate that for most of the observed conditions, ISORROPIA could accurately predict NH3 partitioning. The observations suggest that local sunlight‐ or temperature‐driven NH3 sources, such as soil emissions, may be responsible for the discrepancy between the model results and measured values.

Fourth year response of aspen seedlings to lime, nitrogen and phosphorus applied at planting and 1 year after planting

This work tested potential aspen planting sites for inadequate levels of calcium (Ca), magnesium (Mg), nitrogen (N) and phosphorus (P). A factorial experiment was carried out with three levels of dolomitic limestone (supplying Ca and Mg), three levels of ammonium nitrate (supplying N) and two levels of triple superphosphate (supplying P). The experiment was conducted at Drayton Valley, Linaria and Manning in Alberta, Canada and treatments were applied at planting and in year 2 to two aspen seed lots at each site. The 12.5 g P (as 64 g triple superphosphate) per tree applied at planting increased height growth 15–18% according to site and increased stem volume growth 42–58% after 4 years. Survival was increased at Drayton Valley (5%) and Manning (12%), with no effect at Linaria. Responses to the same fertilizers applied in May of the second year, to previously unfertilized trees, were small, except that N fertilizers caused mortality of as much as 33% at Drayton Valley. Except at Manning, N treatment increased leaf N concentrations without affecting growth, apparently, because N concentrations were already adequate. At Manning, N increased stem volume in year 1. When increased survival was also considered, the P treatments at Drayton Valley and Manning increased volume on a land area basis 69.6 and 62.6%, but at Linaria, where survival was unaffected, the increase was 49.1%. Dolomitic limestone had a small effect on growth at Manning, which was increased in P treatments also receiving lime. Survival was strongly affected by lime at this site and showed an overall linear increase with lime level, up to 9.4%, with increases of 13–18% in the presence of P. Fertilization at planting was very effective in promoting growth and establishment and the alternative of fertilizing in May of the second year was a failure. Inadequate spring precipitation and competing vegetation might explain this failure.

Short‐term physiological and developmental responses to nitrogen availability in hybrid poplar

Nitrogen fertilization induces dramatic changes in the growth and development of plants, including forest trees. In this study we examined short-term responses of hybrid poplar, Populus balsamifera ssp. trichocarpa x deltoides, to N fertilization. Glasshouse-grown saplings subjected to limiting, intermediate, and luxuriant levels of ammonium nitrate over a 28 d time course demonstrated rapid changes to whole-plant architecture and biomass accumulation. Nitrogen-associated shifts in allocation occurred in temporally distinct stages. Nitrogen availability modulated parameters that affect carbon gain, including light-saturated net photosynthesis and leaf area. These parameters were affected by N-induced changes to leaf maturation and senescence. Leaf area was also affected by N-induced sylleptic branch development. Genes encoding vegetative storage proteins and starch biosynthetic enzymes exhibited contrasting patterns of expression under differential N availability. A gene encoding a previously uncharacterized putative pectin methylesterase inhibitor displayed expression patterns comparable to the starch biosynthetic genes. The results of this study illustrate the phenotypic plasticity that P. balsamifera ssp. trichocarpa x deltoides exhibits in response to differential N availability.

Impact of ammonium nitrate on growth and survival of six European amphibians.

We conducted static experiments to assess the effects of ammonium nitrate fertilizer on embryos and larvae of six European amphibians: sharp-ribbed salamander (Pleurodeles waltl), Iberian painted frog (Discoglossus galganoi), western spadefoot toad (Pelobates cultripes), common toad (Bufo bufo), natterjack toad (Bufo calamita), and common tree frog (Hyla arborea). Embryos were exposed to different and environmentally relevant concentrations of ammonium nitrate (0 to 200 mg NO(3)(-)/L) for 15 days. Hatching took place during the experiments. H. arborea was extremely sensitive and had high mortality after 8 days of exposure even at the lower fertilizer levels. D. galganoi and B. bufo were also very sensitive and had significant mortality after 15 days of exposure. The rest of the species did not suffer lethal effects but suffered abnormalities or decreased growth at the highest fertilizer concentrations. Chemical fertilizers or manure could have contributed to the observed decrease of B. bufo and D. galganoi in agricultural areas of the Iberian Peninsula during recent years. H. arborea was the most sensitive species studied. The results of our study showed that environmentally relevant levels of ammonium nitrate can induce mortality and might affect population dynamics of this species in agricultural environments.

The transformation of outdoor ammonium nitrate aerosols in the indoor environment

Recent studies associate particulate air pollution with adverse health effects; however, the exposure to indoor particles of outdoor origin is not well characterized, particularly for individual chemical species. In response to this, a field study in an unoccupied, single-story residence in Clovis, California has been conducted. Real-time particle monitors were used both outdoors and indoors to quantify PM2.5 nitrate, sulfate, and carbon. The results show that reduced indoor sulfate and carbon levels are primarily due to deposition and penetration losses. However, measured indoor ammonium nitrate levels were often observed to be at significantly lower levels than expected based solely on penetration and deposition losses. The additional reduction appears to be due to the transformation of ammonium nitrate into ammonia and nitric acid indoors, which are subsequently lost by deposition and sorption to indoor surfaces. The size of the effect is dependent upon factors such as temperature, relative humidity, and ventilation rate.

Use of Time- and Chemically Resolved Particulate Data To Characterize the Infiltration of Outdoor PM2.5 into a Residence in the San Joaquin Valley

Recent studies associate particulate air pollution with adverse health effects. The indoor exposure to particles of outdoor origin is not well-characterized, particularly for individual chemical species. In response to this, a field study in an unoccupied, single-story residence in Clovis, CA, was conducted. Real-time particle monitors were used both outdoors and indoors to quantity PM2.5 nitrate, sulfate, and carbon. The aggregate of the highly time-resolved sulfate data, as well as averages of these data, was fit using a time-averaged form of the infiltration equation, resulting in reasonable values for the penetration coefficient and deposition loss rate. In contrast, individual values of the indoor/outdoor ratio can vary significantly from that predicted by the model for time scales ranging from a few minutes to several hours. Measured indoor ammonium nitrate levels were typically significantly lower than expected solely on the basis of penetration and deposition losses. The additional reduction is due to the transformation of ammonium nitrate into ammonia and nitric acid gases indoors, which are subsequently lost by deposition and sorption to indoor surfaces. This result illustrates that exposure assessments based on total outdoor particle mass can obscure the actual causal relationships for indoor exposures to particles of outdoor origin.

Constructing the European aerosol nitrate concentration field from quality analysed data

We report on the construction of the aerosol nitrate concentration field in Europe from an interpolation of data. The first step was an active search for and a subsequent quality assessment of the (long term) data for this semi-volatile component, which is subject to a range of artefacts during sampling. Therefore first an overview of (filter) sampling methods in use in Europe and the associated sampling artefacts are presented. Denuder filter pack combinations have very minor artefacts and data obtained with this technique are therefore used as the starting point. Because of the paucity of data from these devices, values obtained with simple filter sampling were also considered after a critical analysis. We found that the largest artefact associated with inert filters (IF) (Teflon and Quartz) is evaporation of ammonium nitrate. Hence, concentrations obtained with the use of IF are lower values. Next, data from “total nitrate” filters were evaluated. Such filters collect both aerosol nitrate and nitric acid gas and the contribution of the gaseous compound was corrected for. The distances over which nitrate concentrations correlate was then analysed and it was found that in the winter half-year the correlation length was sufficiently long to warrant interpolation of the point data. The nitrate concentration field as obtained from interpolation of nitrate data in the period 1994–1997 was validated with intermediate point data from shorter lasting campaigns. The field has a large area of high nitrate concentrations ranging from southern England over continental western Europe into Poland, with concentrations of nitrate exceeding 5 μg m −3. Strong arguments are provided that the nitrate is predominantly present in the fine aerosol fraction (PM2.5). To the north nitrate concentrations range from 2.5 μg m −3 in southern Sweden to <0.5 μg m −3 in mid-Scandinavia. To the east and west of the central European maximum the nitrate concentration trails off in a more gradual way . It was inferred that the concentration of nitrate in winter in Europe north of the Alps, with the exception of France from which country no data could be found, is 60% or more of that of sulphate. It should further be mentioned that in the Po-Valley ammonium nitrate levels are as high as those in western Europe.

PM 2.5 measurements in ambient aerosol: comparison between Harvard impactor (HI) and the tapered element oscillating microbalance (TEOM) system

A comparison, based on the regression of 32 daily mean PM 2.5 aerosol loadings determined by a tapered element oscillating microbalance (TEOM) and by a Harvard impactor (HI), is reported for the ambient aerosol of Erfurt (Germany). The PM 2.5 concentrations measured by the TEOM were systematically lower then those obtained by the HI. The ratio of the means TEOM/HI was 0.74 and the regression equation is TEOM=0.69×HI+0.071. This result is consistent with reports elsewhere suggesting that semi-volatile aerosol material is lost from the heated sample filter on the TEOM. To verify this assertion, a heating system was developed for the HI which was able to keep the HI sample filter at 50±1°C. After the implementation of this heating system, no systematically differences were observed between the TEOM and the heated HI system. The ratio of means was 1.06 and the regression equation TEOM=1.10×HI−0.668. Because the measured levels of ammonium nitrate were very low in Erfurt, we concluded that other compounds like semi-volatile organics were responsible for the loss of particulate material at 50°C.

Plant regeneration from embryogenic callus of finger millet Eleusine coracana (L.) Gaertn. on higher concentrations of NH 4NO 3 as a replacement of NAA in the medium

The effect of different levels of ammonium nitrate used as macronutrient in the MS medium (Murashige and Skoog, 1962) was investigated for plant regeneration from embryogenic callus of Eleusine coracana in the presence and absence of NAA used as growth regulator. Seeds of Eleusine coracana were cultured on MS medium supplemented with 2.0 mg/l 2,4-D and 0.5 mg/l Kn to obtain embryogenic callus. The callus was transferred on regeneration medium containing 0, 20, 40, 80, 100, 120 mM NH 4NO 3 alone and in combination with 1.0 mg/l NAA. NH 4NO 3 was essential for callus proliferation and regeneration of plants. An interesting observation was that a medium containing two to six times higher than normal level of NH 4NO 3 in the MS medium could also support plant regeneration even in the absence of growth regulator. Moreover, in the presence of higher levels of NH 4NO 3, NAA was rather inhibitory in plant regeneration. Maximum number of plants were regenerated on a medium with 80 mM of NH 4NO 3 without any growth regulator. The results indicate that addition of higher concentrations of NH 4NO 3 can substitute for the growth regulator requirement in the medium for plant regeneration.

Diterpenoid production in hairy root cultures of Salvia miltiorrhiza

Transformed root cultures of Salvia miltiorrhiza have been established by infecting pieces of sterile grown plants with Agrobacterium rhizogenes strains LBA 9402, ATCC 15834, TR 105, R 1601 and A 4 1027. These strains showed different abilities to induce hairy roots on this plant. A promoting effect of acetosyringone on the Agrobacterium-mediated hairy root initiation in Salvia miltiorrhiza was also observed. All transformed root cultures were assayed for opines by TLC, and were positive for agropine and mannopine. A sensitive quantitative HPLC procedure was developed for the simultaneous quantification of tanshinone I, tanshinone II A, tanshinone II B, tanshinone V, dihydrotanshinone I, cryptotanshinone, tanshinone VI, and the colourless diterpene ferruginol. These seven major tanshinones and ferruginol were found not only in the roots, but also in the liquid medium. Apparently, the hairy roots released secondary metabolises into the culture medium. The main products in the hairy root cultures were the tanshinones which are the active principles of this Plant species. The effects of culture conditions on hairy root growth and the diterpene production have also been studied. The most apparent effect was seen when ammonium nitrate levels of the medium were modified.

Suitable source and level of nitrogen for mass production of the VA mycorrhizal fungus, Glomus fasciculatum

Summary The effect of nitrogen as nitrate, ammonium and ammonium nitrate at 0, 0.04, 0.08, 0.16, 0.32 and 0.48 μmol N levels, was studied to select the suitable source and level of N for mass production of the vesicular-arbuscular mycorrhizal (VAM) fungus, Glomus fasciculatum. Ammonium nitrate applied at 0.32 μmol N level, in 2 split doses, resulted in highest per cent root colonisation, spore production and inoculum potential of G. fasciculatum. Maximum plant dry weight was also recorded at this level of ammonium nitrate.

Growth, ammonia accumulation and glutamine synthetase activity in alfalfa (Medicago sativa L.) shoots and cell cultures treated with phosphinothricin

Phosphinothricin is a non-selective herbicide which inhibits glutamine synthetase (EC 6.3.1.2) activity causing an overaccumulation of ammonia in higher plants. Alfalfa (Medicago sativa L) shoot tissue and petiole-derived callus exposed to phosphinothricin show 50 and 70% reductions, respectively, in glutamine synthetase activity with a concomitant rise of 10 and 20 fold, respectively, in endogenous ammonia. The diffusibility of ammonia may limit the use of a detoxifying gene, phosphinothricin acetyltransferase, as a selectable marker for alfalfa transformation. However, the addition of up to 40 times the standard levels of ammonium nitrate to the culture media used in this study had no effect on callus growth, although glutamine synthetase activity was inhibited by 50% and endogenous ammonia increased 27 fold. Therefore, ammonia accumulation may not be the primary cause of cell death in alfalfa after exposure to phosphinothricin. It follows that diffusion of ammonia from cell to cell would not restrict the selection for phosphinothricin acetyltransferase transformed cells, thereby indicating that this enzyme could be used as a selectable marker in transformation experiments.

A comparison of the effects of organic and inorganic nitrogen fertilizers on the growth response of summer cabbage (Brassica oleraceavar.capitatacv. Hispi F1.)

SummaryA systematically designed fertilizer experiment with twenty-five factorial combinations of base and top-dressed inorganic and organic nitrogen (N) fertilizers was carried out on summer cabbages. Crop response to base levels of ammonium nitrate was greater than to the organic materials below an application rate of 250 kg N ha−1. However, at higher rates of application both Protox (derived from the activated sewage process) and feathermeal gave larger yields than ammonium nitrate. Crop response to base-applied dried blood more closely resembled that to inorganic N than the other organic materials. The yield response to surface-applied top-dressings of the organic N materials was only 10-50% of that with ammonium nitrate. This is likely to be due to ammonia (NH3) volatilization leading to inefficient utilization of the organic N sources.

Nitrogen fertilisation and light effects on growth and photosynthesis of lodgepole pine seedlings

SUMMARYSeedlings of Pinus contorta were grown for 16 wk without ectomycorrhizas in the greenhouse at three levels of irradiance (100, 210 and 470 μEm‐2s‐1) and three levels of ammonium nitrate (3, 62 and 248 mg litre‐1 of N). Measurements at 5, 10 and 16 wk of age indicated that plants receiving the highest levels of irradiance and nitrogen had significantly larger biomass, a higher total foliar N and P content and net photosynthesis per unit leaf area than those at lower levels of each factor. Although the root/shoot ratio also increased from low to high irradiance at each harvest, nitrogen application resulted in an increased ratio from 3 to 62 mg litre‐1 N, but decreased ratio at 248 mg litre‐1 N.

Effects of different ammonium nitrate levels on the amounts of exchangeable soil magnesium and applied magnesium in eight mineral soils

Eight mineral soils (pH(CaCl2) 4.6—6.1, clay 4—65 %, org. C 1.9—5.7 %) were treated with ammonium nitrate and magnesium sulphate solutions adding 0, 20 or 40 mg mineral N and 0 or 4 mg Mg per 100 g soil. The soils were incubated for seven weeks at a constant temperatureof 20°C and a 25 % moisture level. After incubation, the exchangeable Mg was extracted with 1 M neutral ammonium acetate. The exchangeable magnesium content seemed to increase in some soils and to decrease in other soils with increasing ammonium nitrate amounts. The applied magnesium was fixed in a non-exchangeable form, especially at the highest ammonium nitrate level, in two clay soils taken from the rapakivi area of south-eastern Finland. In the other soils all applied magnesium was exchangeable irrespective of the amount of ammonium nitrate.

Quantum yields and reaction rates in the photo-oxidation of hydrazine by uranyl ion

Quantitative aspects of the photo-oxidation of hydrazine in HNO3 and HClO4 media by uranyl ion have been investigated in detail as a possible photochemical approach to the reprocessing of nuclear fuel, relying on the photo-production of UIV which acts as a reductant for PuIV(to give solvent-separable PuIII+ UIV). Φ(UIV), which is independent of irradiation wavelength, increases with hydrazine concentration in perchlorate media; a plot of Φ(UIV)–1versus[N2H5+]–1 is linear with an intercept of 3.89, i.e. the limiting value of Φ(UIV) is 0.26. After relatively long irradiation times, when ca. 20–40% of UIV is reduced, the stoicheiometry is approximately N2H4 : UIV : NH3= 2 : 1 : 2 in both HClO4 and HNO3, but at much shorter times (when the few percent loss of N2H4 cannot be determined accurately) the UIV : NH3 ratio is approximately 1 : 1.25. N2H4 quenches the luminescence intensity of [UO22+]* by a dynamic process, and τ for [UO22+]* is systematically reduced on addition of N2H4. The quenching rate is affected somewhat by acidity and variation of ionic strength. A mechanism is proposed which accounts quantitatively for the variations both in quantum yield and lifetime. While the system has considerable interest as regards the efficient production of UIV, its overall potential in the reprocessing of nuclear fuel is limited by the stoicheiometric product of ammonia, resulting, from the waste management viewpoint, in the build-up of unacceptable levels of ammonium nitrate, and attempts to circumvent the partial oxidation (N2H4→ e–+½N2+ NH4+), by addition of catalysts such as CuII, have failed. Alternative related reductants have been considered, but neither hydroxylamine nor its methylated analogues quenches [UO22+]*.

Effect on nodulation by adaptation of Rhizobium trifolii to ammonium nitrate

Training on media containing increasing concentrations of ammonium nitrate resulted in an extension of the range of tolerance of Rhizobium trifolii Dangeard to this salt. Whereas ability to tolerate high levels of ammonium nitrate resulted in an improvement in growth on lower levels, passage back on ammonium nitrate-free media caused a gradual reversion to the original range of tolerance. Ability to tolerate high concentrations of ammonium nitrate was accompanied by a change to a nodulation pattern indicating ineffective symbiosis. Restoration of the original nodulating ability was only possible at the expense of high nitrogen tolerance. The nature of this response was determined as being adaptational rather than mutational.

Regulation of Growth and Pigmentation of Monascus purpureus by Carbon and Nitrogen Concentrations

SUMMARYGrowth and pigment production of Monascus purpureus were affected by the ratio of glucose to ammonium nitrate concentration in a synthetic medium. Mycelial growth increased with an increase of glucose and ammonium nitrate concentrations. Larger amounts of ammonium nitrate were required to give maximum growth in media containing higher concentrations of glucose. The level of ammonium nitrate for maximum pigment production was much lower than that for maximum growth, even at high glucose concentrations. Total pigmentation increased with increased glucose concentration. Greater amounts of red pigments were formed in media containing high levels of ammonium nitrate and low glucose. Mycelial growth and pigment production decreased above 50 g/1 ammonium nitrate.

The influence of mineral amendments on the changes in the organic nitrogen components of composts

A series of straw composts, containing two levels of ammonium nitrate, were incubated with mineral amendments. Rate of decomposition was at a maximum over the first twenty days and was not influenced by the level of added nitrogne. The presence of bentonite and kaolinite reduced the loss of organic material slightly over the period of 150 days. In the low-N series, all the added inorganic nitrogen was immediately immobilized but in the high-N series inorganic N was slightly in excess of the microorganisms requirements. Little or no remineralization occurred. As a result of immobilization there was a rapid increase in amino acid and amino sugar nitrogen over the first 30 days and the values then remained fairly constant. The amino acid and amino sugar levels were slightly higher in the composts containing bentonite and kaolinite.