10
ObservAir
Operating Manual
2.2.
Measurement performance
Table 3.
Measurement performance specifications
Me
a
s
u
re
m
e
n
t
Ra
n
g
e
Li
m
it
o
f
de
te
c
ti
o
n
Re
s
o
lu
ti
o
n
Ac
c
u
ra
c
y
Pr
e
c
is
io
n
90%
re
s
p
o
n
s
e
(s
e
c
)
P
o
w
e
r-
o
n
st
a
b
il
iz
a
ti
o
n
(m
in
)
0
-
500
µ
g/
m
3
50
n
g
/
m
3
1
n
g
/
m
3
±
5%
*
±
3%
8
30
CO
0
-
500
p
p
m
2
p
p
m
0.
1
p
p
m
±
3%
±
2%
<
30
60
NO
2
0
-
20
p
p
m
0.
1
p
p
m
0.
1
p
p
m
±
5%
±
5%
<
30
60
SO
2
0
-
20
p
p
m
0.
3
p
p
m
0.
1
p
p
m
±
3%
±
3%
<
30
60
H
2
S
0
-
50
p
p
m
0.
3
p
p
m
0.
1
p
p
m
±
2%
±
2%
<
30
60
O
3
0
-
20
p
p
m
0.
1
p
p
m
0.
1
p
p
m
±
2%
N/
A
<
30
60
Et
h
a
n
o
l
0
-
200
p
p
m
0.
2
p
p
m
0.
1
p
p
m
±
2%
±
2%
<
60
30
Re
la
ti
v
e
Hu
m
id
it
y
0
-
80
%
N/
A
0.
1
%
R
H
±
1.
5
%R
H
0.
2
%
R
H
10
<
1
Te
m
p
.
0
-
40
ºC
N/
A
0.
1
ºC
±
0.
2
ºC
0.
15
ºC
>
2
<
1
50
-
200
c
c
m
5
c
c
m
0.
1
c
c
m
±
5%
±
3%
2
<1
*R
e
la
ti
v
e
t
o
e
x
is
ti
n
g
a
e
ro
s
o
l
a
b
s
o
rp
ti
o
n
p
h
o
to
m
e
te
rs
Bl
a
c
k
C
a
rb
o
n
Gas
es
Env
iro
.
F
lo
w
R
a
te
11
ObservAir
®
Operating Manual
Data logging interval 2 sec
15 sec
1 min
1 hour
BC (
μ
g/m
3
)
0.3
0.1
0.05
0.01
CO (ppm)
0.8
0.3
0.2
0.1
NO
2
(ppm)
0.5
0.2
0.1
0.05
SO
2
(ppm)
0.1
0.03
0.02
0.01
H
2
S (ppm)
0.3
0.3
0.3
0.3
O
3
(ppm)
0.1
0.1
0.1
0.1
Ethanol (ppm)
0.2
0.2
0.2
0.2
Temperature (ºC)
0.01
RH (
%)
0.01
Flow rate (ccm)
0.5
Table 4.
Baseline measurement noise at various data logging intervals
2.3.
Operational limits and warnings
•
Environmental limits:
Only operate the ObservAir within the conditions
listed in Table 1: Temperature and relative humidity must remain
between 5 to 40ºC and 15 to 80%, respectively. Exceeding these limits
may damage the sensor.
•
Moisture/rain:
Even when fitted with the weatherproof cover, the
ObservAir must not be directly exposed to rain or moisture of any kind
without an appropriate DST enclosure. When fitted with external
sampling lines, these must be fitted with rain covers or water catches
to ensure that water is not aspirated into the sensor. Exposure or
aspiration of moisture may permanently damage the sensor.
•
Direct sunlight:
Do not operate the ObservAir in direct sunlight for
extended periods without an appropriate DST enclosure. Doing so may
result in the sensor overheating, and/or erroneous data generation.
•
Filter replacement:
Filter tab must be changed regularly for best BC
measurement performance. Failure to replace the filter over extended
periods may result in damage to the pump. NEVER OPERATE THE
OBSERVAIR WITHOUT A FILTER TAB LOADED.
•
Gas cells:
Electrochemical cells must be calibrated regularly and
replaced every 2 to 5 years for best performance. Please contact DST
for information on our calibration services.