3 EN
ozone meter OZ-ONE
Information about the device
Device description
The device OZ-ONE is an ozone meter for measuring the ozone
concentration in the air. It can also be used to determine the air,
dew point and wet-bulb temperature as well as the humidity
level of indoor areas.
For assessing the measurements, a Max/Min function
(maximum and minimum value), the time-weighted average, the
short-term exposure limit and a Hold function for freezing the
currently measured value are also available.
When not in use, an automatic switch-off saves the batteries.
Formation, perception and distribution of ozone
The word ozone has become an integral part of our vocabulary
and the colourless, toxic gas is part of our everyday life. The
irritant effect ozone can have on our eyes and airways has been
common knowledge for a few years now, especially since the
increasing ozone volume can be attributed to the so-called
summer smog. Ozone is further generated during certain
industrial processes.
Ozone (chemical symbol: O3) consists of three oxygen atoms.
Ozone is created wherever oxygen molecules(O2) in the air are
turned into atoms(O) due to electrical energy or UVradiation. It
is these atoms that can react with the oxygen molecules to form
ozone(O3).
In case of a high solar irradiation ozone forms involving other air
pollutants. The nitrogen oxides(NOx) from automobiles,
domestic heating systems, power plants and the industry play a
major role in this.
Depending on the concentration, ozone can have a very intense
smell similar to chlorine, hay or carnations. By nature, the
human nose is already vastly superior to most measuring
devices: It detects the gas with a concentration of as little as
0.01ml/m3. What this means when compared to other irritant
gases is that we humans can already detect even minor
quantities of ozone which gives us the opportunity to take
corresponding precautions to avoid any hazard caused by the
gas in due time. However, our nose also has a crucial
disadvantage compared with measuring devices: the so-called
habituation effect. After only a brief period of time spent in an
ozone-polluted environment we become so acclimated to the
smell that we go noseblind.
The impact of ozone on human beings
The sensitivity to ozone depends on its concentration and varies
for each individual. Ozone is an oxidative irritant gas, affecting
eyes, nose, pharynx and lungs even at low concentrations. The
mucous membranes are unable to stop it seeing as ozone is
hardly soluble in water. As a result, the gas can be carried
deeper into the lungs than other irritant gases. Concentrations
of 200 µg/mm3 and higher can cause the following symptoms:
• irritations of the mucous membranes, eyes and the
respiratory tract
• hoarseness, coughs and headaches
• feeling of constriction behind the sternum
• reduced physical performance
The main damage is caused in the respiratory tract which can
lead to breathing difficulties and a reduced respiratory volume.
Late complications can include nosebleeds, a bronchitis (or
tracheitis) or a pulmonary oedema. But the transition from
irritations without lasting consequences to long-term changes
with pathological significance is very smooth.
Ozone threshold and target values
The information threshold for ozone concentrations amounts to
180µg/m3 (1-hour value) and the alert threshold is 240µg/m3
(1-hour value). From an ozone concentration of 180µg/m3 the
media starts to inform the public of the recommended
behaviour. Furthermore, a target value has been specified to
protect human health: Averaged over three years, the daily
maximum 8-hour value of 120µg/m3 must not be exceeded on
more than 25days per calendar year. In the long run, the
maximum average values determined over an 8-hour period are
not supposed to exceed 120µg/m3 altogether. To protect the
vegetation, a target value of 18,000µg/m3 applies for a 5-year
average. This is the summed up difference between the hourly
average values above 80µg/m3 measured during the daylight
hours (8a.m. to 8p.m.) in the main growing season between
May and July and 80µg/m3.
