Environmental smog” chamber

Ten Brink, H. M., and H. Spoelstra, The Dark Decay of HONO in Environmental (Smog) Chambers, Atmos. Environ., 32, 247-251 (1998). 

M. C. Dodge, Combined Use of Modeling Techniques and Smog Chamber Data to Derive O ne-Precursor Relationships,Repott No. EPA-600/3-77-001a, U.S. Environmental Protection Agency, Research Triangle Park, N.C., 1977. 

Perhaps the most direct experimental means of examining the relationship between emissions and air quality is to simulate atmospheric conditions using large chambers. Measured concentrations of the primary pollutants are injected into these environmental (or smog) chambers, as they are called. These are then irradiated with sunlight or lamps used to mimic the sun, and the time-concentration profiles of the primary pollutants as well as the resulting secondary pollutants are measured. The primary pollutant concentrations as well as temperature, relative humidity, and so on can be systematically varied to establish the relationship between emissions and air quality, free from the complexities of continuously injected pollutant emissions and meteorology, both of which complicate the interpretation of ambient air data. 

Although the entire MCM has been tested in atmospheric models, and through intercomparison with the results of chamber-validated mechanisms (e.g. Derwent et al, 1998 Jenkin et al, 2002), it has only been partially tested using environmental chamber data. It has been used in a number of studies involving die European Photoreactor (EUPHORE) in Valencia (EUPHORE, 2002), providing the basis for validation of the mechanisms for selected VOC. MCM v3 chemistry has thus already been tested for the photo-oxidation of a-pinene-NOx mixtures at comparatively low NOx concentrations (Saunders et al, 2003). The aromatic mechanisms in MCM v3 and MCM v3.1 have also been evaluated against a set of smog-chamber experiments the evaluation was focused on four representative species of the... 

The workshop created a unique forum for scientists to present the new scientific applications of environmental chambers as well as the technical developments of these installations, including the advantages and drawbacks of the different types of smog chambers that are in use. Scientists from eastern European countries had the opportunity to learn firsthand about chamber techniques and dialogue with chamber users helped to identify potential applications of the techniques to their own environmental problems. 

N.A. Kelly andP. Wang, (1996) Part 1 Indoor Smog Chamber Study of Reactivity in Kelly, N.A. Wang, P. Japar, S.M. Hurley, M.D. and WaUington, T.L (1996). Measurement of the Atmosphere Reactivity of Emissions from Gasoline and Alternative-Fueled Vehicles Assessment of Available Methodologies, Second-Year Final Report, CRC Contract No. AQ-6-1-92 and NREL Contract No. AF-2-112961. Environmental Research Consortium, (September). 

Fig. 7.5 Evacuable photochemical smog chamber at National Institute for Environmental Studies, Tsukuba, Japan...

Clearly, environmental chamber studies are very useful tools in examining the chemical relationships between emissions and air quality and for carrying out related (e.g., exposure) studies. Use of these chambers has permitted the systematic variation of individual parameters under controlled conditions, unlike ambient air studies, where the continuous injection of pollutants and the effects of meteorology are often difficult to assess and to quantitatively incorporate into the data analysis. Chamber studies have also provided the basis for the validation of computer kinetic models. Finally, they have provided important kinetic and mechanistic information on some of the individual reactions occurring during photochemical smog formation. 

---