Breathing rate

Animal breathing rate 30 kg air per day containing 6 /rg fluoride per cubic meter of air (STP)... 

TLV/OEL-TWA can be tolerated for 8 hr exposure with no symptoms and no permanent damage OEL-STEL 10 min Breathing rate increased by 50%... 

Inhalation of earbon dioxide eauses the breathing rate to inerease (Table 8.6) 10% CO2 in air ean only be endured for a few minutes at 25% death ean result after a few hours exposure. 

Table 8.6 Effect of carbon dioxide exposure on breathing rates...

The useful life of a eanister should be estimated based on the probable eoneentration of eontaminant, period of use, breathing rate and eapaeity of the eanister. 

Overbreath in using a respirator, when the wearer s breathing rate exceeds the ability of the respirator to provide a volume of air sufficient to ensure that a positive pressure is maintained inside the face piece. 

BR = Breathing rate, ni /d DUR = Exposure duration period, yr ABW = Average body weight, kg LIFE = Lifetime exposure of 70 yr... 

Effects noted from exposures of 2-2.5 hours at 1,000 ppm include impaired visual-motor coordination (measured by groove-type hand steadiness, depth perception, and pegboard tests) (Vernon and Ferguson 1969) and, at 200 ppm, an increase in heart and breathing rates when trichloroethylene was inhaled simultaneously with ethanol ingestion (Windemuller and Ettema 1978). This latter study found no effect without ethanol ingestion. An 8-hour exposure (two 4-hour exposures separated by 1.5 hours) to 110 ppm... 

James AC. 1878. Lung deposition of sub-micron aerosols calculated as a function of age and breathing rate. In National Radiological Protection Board annual Research and Development Report. National Radiological Protection Board. Harwell, United Kingdom,71-75. 

The breathing rate data used to define the BR variable were adapted from the reported distribution generated from Shamoo et al.3 In the Shamoo study, a different distribution was identified for several activity patterns, and for this simulation the slow, medium, and fast rate classifications were combined. The distribution is shown in Figure 3. 

Figure 3 Monte Carlo simulation breathing rate distribution.

Means and standard deviations for these distributions were normalized to daily breathing rates (m3/day), and an acceptable range was defined. It was assumed that the "day" represents the duration of time within a working day that chlorpyrifos may be handled by an individual (0.25 to 6.0 hr). It was also assumed that exposures would be negligible for the remainder of the working day following application or other contact. Both the dermal and inhalation exposures were assumed to follow lognormal distributions, which is consistent with common practice for exposure data distributions (for example, in the Pesticide Handlers Exposure Database, PHED). 

Each of the activities conducted on the lawn was categorized as rest, light activity, or heavy activity, as the type of activity influenced the breathing rate. Frisbee and touch football were classified as heavy activity (120 min) weeding was classified as light activity (30 min) and the combination of picnicking and sunbathing was classified as rest (90 min). The total duration of the activity period was 4 hr. 

A third generally accepted source of values is the collection of TLVs (Threshold Limit Values) published by the American Conference of Governmental Industrial Hygienists (9) and utilized by the Occupational Safety and Health Administration. Conversion of these to Dp (10) involves three factors The first is division by 7/5 (= 1.4) to convert from a normal 5-day workweek to a 7-day exposure week. The second is division by 100 this allows for exceptionally sensitive individuals, who would not normally be part of the work force, and takes into consideration the completely involuntary and unsuspected nature of the exposure. The third factor converts from TLV (expressed in mg m-3) to a total dose the breathing rate, RB, for a 70-kg person (BW = body weight) doing light work is taken as 12.1 m3/8-hr day (10). Thus,... 

TLV) for occupational exposures breathing rate, exposure time, safety factor >of 10 2 ... 

Breathing rate for 8-hr work day)x(TLV)x(5 day work week) (Body weight)x(7 day work week)x(safety factor)... 

Interval between the successive groups of action potentials of the inspiratory neurons, which determines the rate or frequency of breathing (as the interval shortens, the breathing rate increases)... 

Exposure Human breathing rate m3/(person day) 18 GLOBOX... 

The breath rate is influenced by one s relative blood acidity. 

In Figure 1 are plotted the ERF and DRF as a function of the filtration rate from measurements in an atmosphere with an aerosol concentration in the range 50.000-100.000 cm"3, with an average aerosol diameter of 0.10 micrometer. The doses are calculated for the groups infants 1 year, children 6 and 10 years, and adults, breathing rates 0.45, 0.75 and 1.20 m3 1. It appears that it is possible to lower the PAEC, as expressed by the ERF, to about 15 % of the unfiltrated value, while at the same time the average dose, represented by the DRF, is reduced to about 50 % of the unfiltrated value. 

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