experimental exposure to propylene glycol mist in aviation emergency training: acute ocular and respiratory effects

by:Frank Tech     2020-06-27
Target propylene alcohol (PG)(1-2 propylene; CAS No 57–55–6)
It is a non-toxic compound widely used as food additives, pharmaceutical preparations, cosmetics and workplaces-
For example, water-based coatings, de-
Freeze liquid and cool liquid.
Smoke generators in disco, theater and aviation emergency training may be exposed to PG smoke.
Propylene alcohol may cause contact allergies, but there is little information about the health impact of occupational exposure to PG. METHODS Non-
Volunteers for asthma (n=27)
Under realistic training conditions, it is exposed to PG fog for more than 1 minute in the aircraft simulator.
The average concentration of PG geometry is 309 mg/m3 (
176-851 mg/m3)
The highest concentration in the afternoon.
Medical investigations were conducted before and after exposure (
Within 15 minutes).
It includes estimation of rupture time of tear film stability, nasal smoothness measured by nasal acoustics, dynamic lung activity measurement, and a doctor\'s questionnaire survey of symptoms.
Results the tear film stability decreased after 1 minute of exposure to PG fog, eye and throat symptoms increased, and 1 second forced breath/forced lung activity (FEV1/FVC)
Slightly decreased, and the severity of self-test for difficulty breathing increased slightly.
No smooth nose and lung capacity were found (VC)
Nose symptoms, skin symptoms, solvent odor, or any systemic symptoms.
The increase in throat symptoms in people exposed to higher concentrations in the afternoon was more obvious, and the decrease in tear film stability was more obvious.
Of the four subjects who reported irritating cough during exposure to PG, v1 decreased by 5%, but in those who did not have cough, v1 did not change.
People with cough also feel more about mild breathing difficulties.
Conclusion PG fog exposed to an artificial smoke generator for a short period of time may lead to non-acute eye and upper airway stimulation
Subjects with asthma
There are also some that respond to cough and mild airway obstruction.
Materials and Methods: Population Health
Volunteers for asthma (n=27)
22 men and 5 women underwent medical examination before and after exposure to PG fog.
Most of them are pilots working in civil aviation. Mean (SD)
The age of the group is 44 years old (11)
Over the years, 22% are current smokers and 44% are formersmokers.
A total of 30% had a history of allergies, 15% had pollen fever, and 15% had a history of eczema in children, but no one reported allergies to furry animals.
In general, two women and six men have a history of allergies, while three women and 16 men have no allergies,
In women, the incidence of allergies is significant but higher in numbers.
No one has had respiratory diseases, including asthma or chronic bronchitis diagnosed by a doctor, and no one has had any fever respiratory infections the week before the investigation.
The subjects were naive because no one had professional contact with PG before.
The survey was conducted during normal aviation emergency training one week before the start of the pollen season in March 1998. Sweden.
The flight simulator belongs to the training center of the Scandinavian Aviation System Flight Academy (SAS).
The manual smoke generator is placed in a flight simulator with a commercial PG solution for smoke generation.
Exposure was carried out as part of a pilot\'s regular training program designed to train pilots to evacuate in case of a fire emergency.
Personal factors assessment collects information on personal factors using general medical questionnaires, including medical diseases, medicines, occupational data, family environment and smoking habits. 28-
30 Atopy is defined as having a history of childhood eczema in Sweden or an allergic history associated with exposure to common IgE-mediated allergens (
Tree pollen, grass pollen, or furry animals).
In the interview, the current smoker is defined as reporting actual smoking (
> 1 cigarette/day)
Or stop smoking less than a year ago.
Information on current symptoms about current symptoms was obtained from two questionnaires used in previous surveys.
The first questionnaire included 10 scoring criteria for current eye, nose, throat symptoms, difficulty breathing, poor odor, and systemic symptoms.
33 answers were given on the 100mm visual simulation score scale (VAS-scale)
Adapted from Kjellberg and others, 34 goes from \"not at all\" to \"almost unbearable \".
The second questionnaire contains 23 \"yes\" or \"no\" questions about different types of eye, respiratory and skin symptoms and systemic symptoms --
Headache, nausea and fatigue, for example.
Both 30 questionnaires were conducted before and after exposure to PG.
Evaluation of tear film stability by standardized method self-report tear film stability rupture time measurement of time when subjects keep their eyes open without pain, when looking at a fixed point on the wall
In our introduction, this method is called tear film stability and has been used before.
It has been shown that it has a good association with the fluorescence method used to detect the stability of the tear film.
2627 in addition, subjects reporting eye symptoms had lower tear film stability.
28 acoustic nose measurement (Rhin 2000; wideband noise;
Continuous transmission)
It is used to measure the smoothness of the nose.
The measurement is carried out in a standardized form (sitting)
After five minutes of rest
By acoustic reflection, the minimum cross-sectional area (MCAs)
On both sides of the nose from 0 and 22mm respectively (MCA1)
From 23 and 54mm (MCA2)
From the nose
Nasal volume on the right and left side is also measured from 0 and 22mm (VOL1)
From 23 to 54mm (VOL2).
The mean is calculated from three subsequent measurements on both sides of the nose.
The data on nasal size in this study are shown as the sum of values recorded on the right and left sides.
Download figureOpen\'s new tabDownload powerpoint tair concentration of propylene glycol in aviation emergency training (
1 minute measurement)
As a function of the time of the day.
The respiratory function of lung function test was studied by dynamic lung activity measurement.
Lung capacity (VC)
Compulsory lung capacity (FVC)
Peak tidal flow (PEF)
, Forced breathing flow within 1 second (FEV1)
With Vitalograph (
British, Buckingham, Vitalograph)
This is calibrated every day.
In addition, fev/FVC is calculated.
All tests were conducted in a standardized manner by a trained nurse with the same lung capacity meter.
In order to avoid disturbing the smooth nose, the nasal clip is not used.
Three measurements were taken for each subject and the highest values were recorded.
When the deviation between the two best tests is less than 5%, the test is considered sufficient.
Using the reference value of Uppsala, standardized by age, gender, height, smoking habits and weight, the results are expressed as a percentage of the normal value.
35 test sequence all physiological measurements and questionnaires were conducted by a doctor in a modern office building, and smoking was prohibited in the room.
In addition, during the test, smokers were not allowed to smoke and during the Test started 15 minutes before exposure, when the subjects were asked to sit down.
During this period, the tear film stability test was performed first, and then two symptom questionnaires were conducted.
After about 5 minutes, the acoustic nose measurement was performed and then the dynamic lung capacity was measured.
Subjects then entered the smoke training unit, exposed to PG smoke for 1 minute, and went out to sit and wait for a repeat medical investigation.
The same test sequence was applied before and after exposure to PG and completed within 15 minutes of exposure.
When all the tests were completed, the general medical questionnaire was answered.
The test was conducted within two days from 0930 to 1500, with lunch breaks ranging from 1200 to 1300.
The assessment of exposure temperature and relative air humidity was measured by Assman psymeter.
The flight simulator of propylene glycol is sampled and sampled, and the synthetic polymer tube (XAD-7;
SKC 226-95, USA).
The sample time is 1 minute, and the sample rate is 200/min. The XAD-
7 Release the adsorption tube with 1 ml sub-Alpha chlorine and analyze PG, the method has been described.
36 it is assumed that PG on The XAD tube is restored by 100%, as shown by higher concentrations of PG in the early separation efficiency test.
36 in order to control the possibility that PG may lead to overload of the absorbent tube, the measuring layer and the control layer of the tube are analyzed.
Since the particle PG fog is likely to be adsorbed on the glass cotton plug at the entrance of the sampling tube, the glass cotton is separately adsorbed with another 1 ml of the sub-armour.
Exposure to formaldehyde in flight simulators is measured by pumping samples on a fiberglass filter soaked with 2-4-
Dinatro ammonia (2,4-DNF)
The flow rate is 200 ml/min for 4 hours.
The filter was analyzed by liquid chromatography.
In order to detect other specific volatile organic compounds in the flight simulator, the sampling is pumped on the traditional charcoal adsorption tube (SKC 226–01)was performed (4 h; 200 ml/min).
1 ml of the carbon dioxide adsorption of charcoal.
Analysis of PG and other specific compounds by HP 5890 gas chromatography equipped with Mass Selective Detectors (HP 5970)(GC-MS)
, Using a 50-meter cross-linked methyl silicone capillary column (HP-
Month, Hewlett Packard)
The inner diameter is 0.
The thickness is 32mm and the thickness of the film is 1 μm.
At 35oC, the oven temperature was programmed to be initially maintained for 5 minutes, after which the temperature rose to 200oC at a rate of 15 oc/min. Carrier gas (helium)
The flow rate is 1 mL/min.
Mass spectrometry and retention time were evaluated for each substance.
36 statistical analysis differences in VAS score, nasal smoothness and lung function before and after PG exposure were compared and analyzed by st test of students.
Due to uneven distribution of tear film stability, the change of tear film stability was analyzed by Wilcoxon paired sign rank test.
Changes in symptoms were measured by McNemar test as a binary outcome variable.
Results 22 was measured at room temperature. 0ºC–22.
At 5 °c, the average relative air humidity in the flight simulator is 34%.
PG measurements were performed 11 times for 1 minute.
The geometric average concentration of PG in flight simulator is 309 mg/m3 (GSD=1. 7).
The arithmetic mean concentration of PG is 360 mg/m3 (
176-851 mg/m3)
The arithmetic average in the morning was 220 mg/m3 and the arithmetic average in the afternoon was 520 mg/m3.
The distribution of 11-point measurements in the day can be seen in Figure 1.
Most of the detected PG was detected in the measurement layer of the sampling tube, only 5%-10% was detected in the control layer, and
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