Applications of Machine Olfaction - The Electronic Nose Artificial Olfaction Technology - page 231

Table 8.12 Various human symptoms according to the BAC level [ 49 ]
Blood alcohol concentration (BAC) (%) Symptoms

[0.05 Measurable mental impairment

[0.10 Unsteady gait

[0.15 Slurred speech

[0.40 Unconsciousness

[0.50 Difficulty in breathing, heart failure, death

Table 8.13 Breath and blood alcohol concentration unit
Breath alcohol concentration (BRAC) units
milligrams per liter mg/l

Micrograms per 100 ml lg/100 ml, lg%

Microgram per liter lg/l

Breath alcohol concentration (BAC) units
Milligrams per 100 ml Mg/100 ml,

mg %

Percent blood alcohol [grams of alcohol per 100 ml of blood or 210 l of
breath]

%BAC, %BAL

Promiile [weight/volume] [grams of alcohol per liter of blood] % g/l

Promiile[ weight / weight] [grams of alcohol per kilogram of blood] % g/kg

outcome is about a BAC of 0.4 %. Above 0.5 % BAC, basic body functions such
as breathing or the beating action of the heart can be low down leading to death.
The major symptoms taking place in a person intoxicated by alcohol are listed in
Table 8.12 and units of breath and blood alcohol concentration are listed in
Table 8.13 [ 49 ].
In modern times, the number of traffic accidents due to drunken state of drivers
has increased extensively. By checking the concentrations of the gas breathed by a
driver, we can evaluate whether a driver drinks alcohol and also know the quantity
of the alcohol. Herbert et al. found in their restricted environment study and
demonstrated that officers were able to derive only limited information from
alcohol odor. Also note that for the low probability of detecting an alcohol breath
odor, it might be wise for officers to use a breath testing device whenever a driver
reveals behaviors associated with alcohol use [ 50 ].
Gases come out in the exhaled breath as by-products of different metabolic
pathways or after oral eating/drinking can be detected and measured. Hence,
ethanol measurement has set up broad applications in the control of alcohol use by
drivers. One interesting device developed by installing devices called Alcolocks or
alcohol interlock systems in transportation vehicles in Sweden [ 8 ], is an automatic
control system designed to prevent driving after excessive alcohol intake by
requiring the driver to blow into an in-car breathalyzer before starting the ignition.
The alcohol interlock can be set at different levels and limits.