Tropospheric Ozone: The Dynamics of Human Exposure

1989 ◽  
Vol 5 (3) ◽  
pp. 493-504 ◽  
Author(s):  
Paul J., Lioy ◽  
Raymond V., Dyba
Keyword(s):  
Human Exposure ◽  
Weighted Average ◽  
Ambient Air ◽  
Quality Standard ◽  
Threshold Limit Value ◽  
Ozone Exposure ◽  
Ambient Atmosphere ◽  
Limit Value ◽  
Time Weighted Average ◽  
Ambient Air Quality Standard

The conditions in the ambient atmosphere conducive to ozone exposure are examined, and placed into a context of the time arid locations where individuals would be expected to be affected by high ozone. This is done for both 1 h and 8 h averaging times. Concentrations of ozone in the ambient atmosphere can violate the National Ambient Air Quality Standard (NAAQS) and also the Time Weighted Average-Threshold Limit Value (TWA-TLV) for workers. Exposures that occurred in a 1982 episode associated with a health effects study are described in detail. The effective dose received by a camper at a children's summer camp appeared to be similar to that delivered to volunteers during a controlled human exposure study in which effects on pulmonary function were observed.

Use of Methanol as a Coolant During Machining of Aluminum in a Shipbuilding Environment: A Failure to Assess and Manage Risk

2014 ◽  
Vol 955-959 ◽  
pp. 1061-1064 ◽  
Author(s):  
Thomas Neil McManus ◽  
Assed N. Haddad
Keyword(s):  
Weighted Average ◽  
Threshold Limit Value ◽  
Breathing Zone ◽  
Short Term ◽  
Limit Value ◽  
Diffusion Tubes ◽  
Exposure Limit ◽  
Long Duration ◽  
Short Term Exposure ◽  
Time Weighted Average

Minimization of harm during the conduct of work is one of the most important tenets of industrial hygiene. Organizations make changes to solve perceived problems. What appears to be expedient for solving a problem can create serious risks totally unrecognized by the proponent. This investigation reports on such a situation involving the use of methanol as a lubricant during machining of aluminium panels using a router. Spot samples for methanol were measured using colorimetric detector tubes and samples of long duration by colorimetric diffusion tubes utilizing similar chemistry. Both were positioned in the breathing zone. Most of the spot samples exceeded the 8-hour TLV-TWA (Threshold Limit Value-Time-Weighted Average) of 200 ppm and the TLV-STEL (Short-Term Exposure Limit) of 250 ppm. The two long duration samples also exceeded the TLV-TWA. A change in the operation prevented collection of additional long duration samples. By these measures, workers were overexposed to methanol during this activity. An additional serious consequence from use of methanol in this manner was risk of fire. This situation illustrates the complexity of decisions affecting workplace operations. What appears to be expedient for solving a problem may be totally inappropriate.

scholarly journals Medición de concentraciones de formaldehído en un laboratorio de anatomía humana, comparándolas con estándares internacionales

2017 ◽  
Vol 11 (1-2) ◽  
pp. 7-13 ◽  
Author(s):  
Ernesto Hurtado ◽  
Andrea Vallecampo ◽  
Karen De Liévano ◽  
Beatriz De Artiga ◽  
Guadalupe Vásquez
Keyword(s):  
Weighted Average ◽  
Threshold Limit Value ◽  
International Agency ◽  
Limit Value ◽  
Threshold Limit ◽  
Time Weighted Average

Introducción. El Laboratorio de Anatomía Humana dispone de cadáveres que han sido sometidos al proceso de fijación y conservación de tejidos mediante la aplicación de formaldehído (al 10%), sustancia tóxica y cancerígena para el ser humano, según lo estipulado por la International Agency for Research on Cancer (iarc), a la que están expuestos estudiantes, profesores y técnicos. La presente investigación tuvo como propósito medir las concentraciones de formaldehído en el ambiente dentro de las instalaciones de un laboratorio de Anatomía Humana y compararlas con estándares laborales internacionales. Metodología. El diseño del estudio fue transversal con enfoque descriptivo. La muestra del estudio fue de 640 mediciones realizadas con el aparato digital hal-hfx105 HalTech y aplicando la norma técnica de prevención ntp 587, validada para la determinación de gases y vapores orgánicos en el aire dentro del laboratorio. Resultado. La concentración de formaldehído promedio estimada en general dentro de las instalaciones del Laboratorio de Anatomía fue de 0.24 ppm. ConclusIón. El promedio de concentración de formaldehído encontrado en el presente estudio es inferior al límite de exposición profesional estimado por la American Conference of Industrial Hygienists (acgih), cuyo valor tlv-twa (Threshold Limit Value-Time Weighted Average) para un día laboral de 8 horas y una semana de 40 horas, y como límite máximo a las concentraciones que cualquier trabajador puede ser expuesto día tras día sin efectos adversos, es de 0.3 ppm.CREA CIENCIA Vol. 11 No 1-2 ISSN 1818-202X enero-diciembre 2017, p. 7-13

Comparison of human exposures to selected chemicals with thresholds from NTP carcinogenicity studies in rodents

2003 ◽  
Vol 22 (9) ◽  
pp. 501-506 ◽  
Author(s):  
William J Waddell
Keyword(s):  
Volatile Compounds ◽  
Human Exposure ◽  
Methylene Chloride ◽  
Allyl Isothiocyanate ◽  
Ambient Air ◽  
Threshold Limit Value ◽  
Ethyl Benzene ◽  
Human Consumption ◽  
Limit Value ◽  
The Usa

The National Toxicology Program (NTP) Technical Reports online database was reviewed to find chemicals that were reported to show clear evidence of carcinogenicity in the NTP rodent studies and for which data on human exposure could be found. Six representative compounds were selected. Three volatile compounds: ethyl benzene, perchloroethylene, and methylene chloride; two drugs in current use: phenytoin and primidone; and one naturally occurring, widely used, flavor: allyl isothiocyanate, were selected. The carcinogenicity data from each of the NTP Technical Reports were plotted using the Rozman scale to determine the threshold for carcinogenicity from the rodent studies. The human exposures for each chemical were calculated and compared with that threshold. The thresholds for carcinogenicity of the three volatile compounds were several orders of magnitude above the levels present in ambient air in the USA. The Threshold Limit Value (TLV) of the American Conference of Governmental Industrial Hygienists (ACGIH) for these three compounds varied between several orders of magnitude below the carcinogenicity threshold to being at the threshold. The maximum recommended doses of both drugs were at the carcinogenicity threshold. The estimated mean daily human consumption of the natural flavor was less than 100 × below the carcinogenicity threshold. This method of comparison between human exposure and animal carcinogenicity studies is more objective and informative than those in current use.

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