Photochemical ozone formation in the irradiation of ambient air samples by using a mobile smog chamber

1981 ◽  
Vol 15 (6) ◽  
pp. 661-665 ◽  
Author(s):  
Katsuo. Shibuya ◽  
Tsunekazu. Nagashima ◽  
Senro. Imai ◽  
Hajime. Akimoto
Author(s):  
Peter K. Mueller ◽  
Glenn R. Smith ◽  
Leslie M Carpenter ◽  
Ronald L. Stanley

At the present time the primary objective of the electron microscopy group of the Air and Industrial Hygiene Laboratory is the development of a method suitable for use in establishing an air quality standard for asbestos in ambient air and for use in its surveillance. The main concept and thrust of our approach for the development of this method is to obtain a true picture of fiber occurrence as a function of particle size and asbestos type utilizing light and electron microscopy.We have now available an electron micrographic atlas of all asbestos types including selected area diffraction patterns and examples of fibers isolated from air samples. Several alternative approaches for measuring asbestos in ambient air have been developed and/or evaluated. Our experiences in this regard will be described. The most promising method involves: 1) taking air samples on cellulose ester membrane filters with a nominal pore size of 0.8 micron; 2) ashing in a low temperature oxygen plasma for several hours;


2019 ◽  
Vol 1 (1) ◽  
pp. 79-89 ◽  
Author(s):  
Ajit Ghimire ◽  
Albert Leo N. dela Cruz ◽  
Roberto Wong ◽  
Panida Navasumrit ◽  
Stephania Cormier ◽  
...  

In the vicinity of a rendering plant it is very difficult to find a really unpolluted place for the olfactometric measurements. Although the most unpolluted site luff of the plant was chosen, another precaution was taken. As adaption of the panelists to the plant odour could cause one of the greatest errors, some minutes before and during the measurement the panelists inhale solely odourless air from the olfactometer. To prevent discomfort by inhaling completely dry air, the olfactometer Modell 1158 is supplied with a moistening device, fig. 1. Fig. 1. Moistening device. In a standard impinger, filled with destillated water, air is moistened close to saturation. An equal flow of moistened air is mixed to the olfactometer outlet, thus delivering to the panelist a rel. moisture content of nearly 50 %. The panel consisted of 4 persons. The samples are prediluted taken into plastic bags, simultaneously at the inlet (raw air) and at the outlet (cleaned air) of the air cleaners. To receive an unfalsified sample from the outlet of the biofilters, undiluted by ambient air, a "tent” of plastic foil, fig. 2, is placed on the filter surface. The cleaned air blows up the tent and escapes through the sample hole, large enough to prevent a significant increase of pressure. The form of the upblown tent indicates, wether a sample area with normal air flow is chosen, and over the space of the covered filter area of 6,25m2 an average sample is received. Fig. 2. Device for cleaned air samples from biofilter outlet.


2018 ◽  
Vol 20 (3) ◽  
pp. 544-552 ◽  
Author(s):  
Anteneh Assefa ◽  
Mats Tysklind ◽  
Jana Klanova ◽  
Karin Wiberg

A combination of PCDD/F patterns and metal source markers in ambient air samples together with stable air mass back trajectories can reveal the most significant atmospheric sources of PCDD/Fs.


2004 ◽  
Vol 15 (5) ◽  
pp. 646-651 ◽  
Author(s):  
Pedro Afonso de P. Pereira ◽  
Leilane Maria B. Santos ◽  
Eliane Teixeira Sousa ◽  
Jailson B. de Andrade

2010 ◽  
Vol 28 (6) ◽  
pp. 1199-1205 ◽  
Author(s):  
S. K. Sharma ◽  
T. K. Mandal ◽  
B. C. Arya ◽  
M. Saxena ◽  
D. K. Shukla ◽  
...  

Abstract. In this paper, we present the effect of total solar eclipse on surface O3, NO, NO2, NH3, CO mixing ratio and the meteorological parameters on 15 January 2010 at Thiruvanathapuram, India. On the day of total solar eclipse (i.e., 15 January 2010), the decrease in mixing ratio of surface O3 and NO2 is observed after the beginning of the solar eclipse events (11:15 to 15:30). Decrease in surface O3 may be due to decreased efficiency of the photochemical ozone formation, whereas, mixing ratio of NO and NH3 have been changed following the night time chemistry. Surface O3 reduced to 20.3 ppb after 22 min of full phase of the eclipse. During the solar eclipse period, the ambient temperature and wind speed have decreased, whereas, relative humidity has increased as expected.


2004 ◽  
Vol 1 (2) ◽  
pp. 65 ◽  
Author(s):  
Donald H. Stedman

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