4.
Background
4.1
Ozone Generator
The generator installed by Ozone Services was operated under the following specification.
The ozone generator used was an Airzone Port O Go Maxi, which provides 1000 mg ozone per
hour.
This unit was
incorporated into a ducte
d system whereby clean air was draw
n with an in
–
line
fan form the outside through a filter, through the generator, split into 5 ducts and channelled
through louvers into 5 different strategic positions with the pub. A remote digi
tal controller was
installed within easy reach of management and ozone output adjusted according to the level of
contamination manually.
Normally, a level of between 0.04 ppm and 0.1 ppm. which are the recommended levels, would
be achieved. Output was lim
ited during occupied hours and flooded when unoccupied using a
timer type system.
4.2
Environmental Tobacco Smoke (ETS)
ETS, a significant indoor air pollutant with serious healthy effects, is composed of a large variety of
contaminants. When a cigarette is
smoked, approximately one
–
half or more of the smoke
generated is sidestream smoke emitted from the smouldering cigarettes. The principal contributor
to ETS is “sidestream smoke”. Other components of ETS include exhaled mainstream smoke and
compounds dif
fused through the wrapper. “Mainstream smoke” is the complex mixture that exists
from the mouthpiece of a burning cigarette when a puff is inhaled by the smoker. The chemical
composition of mainstream smoke has been more extensively characterized than th
at of sidestream
smoke, but they are produced by the same fundamental process, such that many chemical
constituents are present in both. Over 4,000 individual constituents have been identified in
mainstream smoke, and approximately 400 compounds have been
measured quantitatively in both
mainstream and sidestream smoke.
Health effects linked with ETS include eye, nose and throat irritation, headaches and lung
cancer. For children it may lead to an increased risk of lower respiratory tract infections (e.g.
bronchitis and pneumonia), ear infections, build
–
up of fluid in the ear, increased severity and
frequency of asthma episodes and decreased lung function (US EPA 1996).
High exposure to ETS can be expected in public buildings where smoking is prevalent,
h
owever, effects can be experienced anywhere tobacco is smoked. The most commonly used
measure of ETS is re
spirable suspended particulates
(RSP).
Therefore
for the
purpose of this stage of the assessment RSP were used as a
surrogate measurement the effec
tiveness and efficiency of the control measures
installed (ozone generator), although other measures were conducted to back
–
up
these measurements (formaldehyde, volatile organic compounds).
Measurements of RSP in buildings with smokers have been found
to be 150
–
430 ug/m
3
(micrograms). Poor ventilation exacerbates the situation and therefore an increase in fresh air
intake in building were smoking is allowed would reduce concentrations of ETS.
The US EPA National Ambient Air Quality Standards, have b
een employed during the course
of this assessment. The PM10 (Particulate Matter less than 10 micron in diameter) Standard
3
for a 24
–
hour period is set as 150 ug/m
3
. The South African Standard set by the Department
of Environmental Affairs and Tourism is 1
80 ug/m.
All speciated substances measured have been compared to The US EPA National Ambient
Air Quality Standards.
4.3
Ozone
Ozone is an irritant and affects mucous membranes, lung tissue and lung functions. At
levels above 100 parts per billion, sensitiv
e individuals, particularly during exercise, can
experience impaired lung function accompanied by respiratory symptoms. Ozone is
not a
carcinogen (a cancer forming substance).
The US EPA National Ambient Air Quality Standard for ozone is 80 ppb.
5.
Ev
aluation of Results
5.1
Respirable Suspended Particulates: As can be seen from the results there was a
marked decrease in RSP once the ozone generator had been installed (Table 1)
5.2
There was a decrease in total volatile organic
compounds (Table 4) and in
formaldehyde (Table 3).
5.3
Obviously there was an increase in ozone concentration (Table 2) once the ozone
generator had been installed. However, the US EPA National Air Quality Standards
4
were not exceeded at any o
f the Sampling Locations.