Smog chamber study comparing blacklight fluorescent lamps with natural sunlight

Laity, John L.

doi:10.1021/es60059a004

Cited by 8 publications

(8 citation statements)

References 5 publications

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“…Its spectral energy distribution, represented by the crosshatched bands in Figure 2, showed only a superficial resemblance to those of sunlight (curve D) or the fluorescent blacklight (curve C) used in previous photochemical investigations of pesticides (Crosby 1969) and in atmospheric simulation (Laity 1971). However, the highly energetic Hg emission at 254 nm (band A) and other UV wavelengths shown to be absent from normal sunlight would be removed effectively by the borosilicate glass window of the lamp (transmission curve B) as well as the filter on the collimator.…”

Section: Resultsmentioning

confidence: 90%

Vapor-phase photodecomposition of aldrin and dieldrin

Crosby

Moilanen

1974

Arch. Environ. Contam. Toxicol.

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A special reactor was constructed to study the vapor-phase photodecomposition of pesticides by ultraviolet (UV) light. The reactor was designed in such a way that wall reactions would be minimized and could be distinguished from actual vaporphase transformations. The vapor-phase photodecomposition of the insecticides aldrin and dieldrin were studied with this reactor. Irradiation of aldrin vapor with UV light resulted in the formation of photoaldrin and dieldrin. Irradiation of either photoaldrin or dieldrin vapor resulted in a single photoproduct, photodieldrin, which was resistant to further photolysis. Hence, irradiation of aldrin vapor ultimately produced photodieldrin by way of two separate pathways: a photoisomerization followed by photooxidation and a photooxidation followed by photoisomerization.

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Section: Resultsmentioning

confidence: 90%

Vapor-phase photodecomposition of aldrin and dieldrin

Crosby

Moilanen

1974

Arch. Environ. Contam. Toxicol.

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“…The Rayonet Photochemical Reactor and its 3500 /~ blacklight lamps, in conjunction with exposure vessels of borosilicate glass, has given excellent results in imitating the effects of sunlight in the formation of photochemical smog (Laity 1971). Kimax (K-33) brand glass is nearly identical to the Pyrex brand of borosilicate glass in its spectro-transmission characteristics.…”

Section: Me~o~mentioning

confidence: 99%

The hydrolysis and photolysis rates of nitrapyrin in dilute aqueous solution

Meikle

Laskowski

Regoli

et al. 1978

Arch. Environ. Contam. Toxicol.

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Abstract. The hydrolysis rate of nitrapyrin (2-chloro-6-(trichloromethyl)pyridine), the active ingredient of N-SERVE | nitrogen stabilizer (a registered trademark of The Dow Chemical Company, Midland, Michigan), in buffered, distilled water followed simple first-order kinetics over the concentration range, 6.2 x 10 -7 to 8.7 • 10-SM. The only product of the reaction was 6-chloropicolinic acid. The rate of the reaction decreased with increasing buffer concentration at 35~ (M buffer concentration-haft-life): 0.005M -1.7 days, 0.02M -2.0 days, 0.067M -4.0 days. The ramifications of this negative salt effect are discussed. The hydrolysis rate was independent of pH over the range, 3.2 to 8.4. Additional data were obtained for rates at 25 ~ and 45~ The activation energy for the reaction under these conditions was 25.0 kcal/mole.Photolysis of nitrapyrin at 25~ in 0.005M phosphate buffers at pH 5.1, 7.1, 8.0, and in a natural water also followed simple first-order kinetics over the nitrapyrin concentration range, 7.1 • 10 -e to 7.5 x 10-tM. Again, there was no observable pH effect on the rate over the pH range investigated, nor was there a rate enhancement in the natural water. The half-life of the reaction under these conditions was 0.5 day. The products of this reaction were 6-chloropicolinic acid (6-C1PA), 6-hydroxypicolinic acid (6-OHPA), and unidentified polar material formed in that order in a series of sequential reactions. Simulation of the set of sequential reactions using determined firstorder rate constants at 25~ and a starting concentration of 1.7 ppm predicts that nitrapyrin will be half gone in 0.5 day, that the concentration of 6-C1PA will peak at 1.3 ppm in 1.8 days, and that the concentration of 6-OHPA will peak at 0.2 ppm in 3.7 days.Nitrapyrin is a compound used as nitrogen-conserving agent (Goring 1962) in agriculture. The disappearance rate of nitrapyrin as a result of hydrolysis and photolysis reactions in water has a direct bearing on its persistence in water resources. The study reported herein defines the rates for these reactions at different pH and temperature values and describes the products.

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“…Chambers are placed either indoors or outdoors with the former having the advantage of a well-controlled environment with constant temperature, light intensity, etc. and the latter being able to use natural sunlight (Laity, 1971;Jeffries et al, 1976;Leone et al, 1985;Carter et al, 2005). For the indoor chambers, a variety of UV light sources can be used including black light lamps (Laity, 1971), xenon, and argon arc lamps (Warren et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

“…and the latter being able to use natural sunlight (Laity, 1971;Jeffries et al, 1976;Leone et al, 1985;Carter et al, 2005). For the indoor chambers, a variety of UV light sources can be used including black light lamps (Laity, 1971), xenon, and argon arc lamps (Warren et al, 2008). The J NO 2 in indoor atmospheric simulation chambers covers a wide range from zero (several metal chambers do not have lights) to as much as around 1 min −1 (Kim et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

A portable dual-smog-chamber system for atmospheric aerosol field studies

et al. 2019

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Abstract. Smog chamber experiments using ambient air as a starting point can improve our understanding of the evolution of atmospheric particulate matter at timescales longer than those achieved by traditional laboratory experiments. These types of studies can take place under more realistic environmental conditions addressing the interactions among multiple pollutants. The use of two identical smog chambers, with the first serving as the baseline chamber and the second as the perturbation chamber (in which addition or removal of pollutants, addition of oxidants, change in the relative humidity, etc.), can facilitate the interpretation of the results in such inherently complex experiments. The differences of the measurements in the two chambers can be used as the basis for the analysis of the corresponding chemical or physical processes of ambient air. A portable dual-smog-chamber system was developed using two identical pillow-shaped smog chambers (1.5 m3 each). The two chambers are surrounded by UV lamps in a hexagonal arrangement yielding a total JNO2 of 0.1 min−1. The system can be easily disassembled and transported, enabling the study of various atmospheric environments. Moreover, it can be used with natural sunlight. The results of test experiments using ambient air as the starting point are discussed as examples of applications of this system.

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Smog chamber study comparing blacklight fluorescent lamps with natural sunlight

Cited by 8 publications

References 5 publications

Vapor-phase photodecomposition of aldrin and dieldrin

Vapor-phase photodecomposition of aldrin and dieldrin

The hydrolysis and photolysis rates of nitrapyrin in dilute aqueous solution

A portable dual-smog-chamber system for atmospheric aerosol field studies

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