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A new NO(2) measurement collection device developed in this study indicates efficient absorption, enough to be applied to the practical determination of atmospheric NO(2), which should become a useful tool compared with conventional methods.
An isolated rat lung preparation was ventilated with NO2 while being perfused with a medium containing morpholine. After 60 min of ventilation-perfusion, N-nitrosomorpholine was detected in both lung tissue and perfusate.
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We report the unexpected novel finding that exogenously supplied atmospheric NO2 at an ambient concentration is a plant vitalization signal to double shoot size and the contents of cell constituents. When seedlings of Nicotiana plumbaginifolia were grown for 10 wk under natural light and irrigation with 10 mm KNO3 in air containing (+NO2 plants) or not containing (-NO2 plants) 15NO2 (150 +/- 50 ppb), shoot biomass, total leaf area, and contents per shoot of carbon (C), nitrogen (N), sulphur (S), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), free amino acids and crude proteins were all approximately 2 times greater in +NO2 plants than in -NO2 plants. In mass spectrometric analysis of the 15N/14N ratio, it was found that NO2-derived N (NO2-N) comprised < 3% of total plant N, indicating that the contribution of NO2-N to total N was very minor. It thus seems very likely that the primary role of NO2 is as a multifunctional signal to stimulate plant growth, nutrient uptake and metabolism.
The interaction of gaseous NO2 with solid carrier-adsorbed polycyclic aromatic hydrocarbons was studied under laboratory conditions with a specific attention to factors that might possibly influence this reaction, such as type of carrier lighting conditions, NO2 concentration, exposure time, and temperature. At the NO2 concentration of 1.33 ppm there were detected the following nitro derivatives: nitroanthracene, nitropyrene, nitrochrysene, two mononitro derivatives of benzo/a/pyrene, and dinitrobenzo/a/pyrene. The experimental data suggest that the formation of nitroaromates in atmospheric environment is to be expected, provided that there are present, besides polycyclic aromatic hydrocarbons and nitrogen oxides, also suitable types of sorbents, such as silica gel or fly ash.
Nitrous oxide is a greenhouse gas, and NO and NO2 play a key role in atmospheric chemistry. Nitrous oxide, NO, and NO2 fluxes from fertilized soils were measured six times per day by an automated flux monitoring system for one year, beginning on 21 May 1998. Pac choi (Brassica spp.) was cultivated for two months, and the plots were left fallow the remainder of the year. Two types of manure, poultry manure (PM) and swine manure (SM), and a chemical fertilizer, urea, were applied to the soil. The total amount of nitrogen applied in each case was 15 g N m(-2). The total fluxes from PM, SM, and urea for the year were 184, 61.3, and 44.8 mg N m(-2) for N2O, respectively; 9.95, 16.6, and 148 mg N m(-2) for NO, respectively; and -6.21, -7.23, and -7.84 mg N m(-2) for NO2, respectively. A negative correlation was found between the NO flux and the NO concentration of the chamber air just after the chamber was closed, when a flux from the atmosphere to soil was observed for 10 months. The mean gross NO production, the NO uptake rate constant, and the apparent compensation point for this period were 0.79 to 0.95 microg N m(-2) h(-1), 120 to 128 L m(-2) h(-1), and 5.65 to 7.35 ppbv, respectively.
Subacute (7 days) exposure of guinea pigs to 4 ppm NO2 induces transient airway hyperresponsiveness to inhaled histamine (His)-aerosol as does acute exposure to higher concentration of NO2. Thromboxane A2 may play an important role in this transient airway hyperresponsiveness.
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Passive samplers run without electric power supply, are easy to handle and thus are suitable for exposure measurements in epidemiological studies, to evaluate indoor air quality, to control ambient concentrations etc. Passive sampler values agree with continuous measuring apparatus within 85 to 105% and the lower detection limit is 4 micrograms/m3 for a one week exposure or longer.
The influence of HCHO and NO2 on clinical, haematological, immunological, sensory and lung function parameters were tested in 129 children out of 3 classes. As part of a biological monitoring programme formic acid content in urine was determined. Concentration of the pollutants in indoor air was measured by means of passive samples.