Transcript Air quality monitoring

Air quality monitoring
Air and meteorological monitoring parameters
Environmental monitoring
Air quality monitoring
Classification of air pollutants
• Primary pollutants (emitted directly to the atmosphere)
• Secondary pollutants (formed by reactions involving primary pollutants and
other constituents within the atmosphere)
Classification of sources of air pollutants
• Stationary sources
• Mobile sources
Sources
• Natural sources
• Anthropogenic sources
• Urban sources
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Primary air pollutants
Secondary air pollutants
are formed from sunlight that results in photochemical reactions of O2 with one or more of
the primary air pollutants.
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Legislation regarding the concentration limits
Order no. 592/2002 revized by Order 448/2007 for establishing the limit values and the
evaluation methods of several primary pollutants in the environmental air (imisii)
Pollutant
Hourly limit value
(average 1 h)
Daily limit value
(average 24 h)
Annually limit value for
human health protection
(average 1 year)
Annually limit value for
vegetation protection
(average 1 year)
SO2
350 μg/m3
125 μg/m3
-
20 μg/m3
NO+NO2
200 μg/m3
-
40 μg/m3
30 μg/m3
Particulate
Matter (PM10)
-
50 μg/m3
20 μg/m3
-
Lead
-
-
0.5 μg/m3
-
Benzene
-
-
5 μg/m3
-
CO
-
10 mg/m3
-
-
Ozone
120 μg/m3
-
18.000 μg/m3h
-
Arsenic*
-
-
6 μg/m3
-
Cadmium*
-
-
5 μg/m3
-
Nickel*
-
-
20 μg/m3
-
*Added by Order 448/2007
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Air quality monitoring
Legislation regarding the concentration limits
Order no. 592/2002 for establishing the limit values and the evaluation methods of several
primary pollutants in the environmental air (imisii)
Reference methods for concentration measurement
SO2
Fluorescence in ultraviolet
NO+NO2
Chemiluminescence
Particulate
Matter (PM10)
Collection of PM10 on filters and mass measurement (gravimetric) or
TEOM method
Lead
Collection of lead on filters and AAS
Benzene
Aspiration on a filter cartridge and gas chromatography
CO
Nondispersive infrared spectrophotometry (NDIR)
Ozone
UV photometry
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National Network for Air Quality Monitoring (RNMCA)
www.calitateaer.ro
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Romanian legislation regarding the concentration limits
Order no. 462/1993 regarding emissions from stationary sources (emisii)
Refers to emissions produced by
• Stationary sources
• Vehicles
• Infrastructures designed to transportation
• Burning installations
• Fuel burning
Measurements are mandatory for the installation owner.
The results are to be registered and archived by the owner.
The limits are given according to the source.
If the limits are exceeded, the polluter pays.
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Order no. 462/1993
Burner supplied with liquid fuel
Thermal power [kW/t]
Pollutant
Unit
< 100
100 - 300
300 - 500
> 500
Suspended particulates
mg/Nm3
50
50
50
50
CO
mg/Nm3
170
170
170
170
SOx (expressed in SO2)
mg/Nm3
1700
1700
1700
1700
NOx (expressed in NO2)
mg/Nm3
450
450
450
450
Burner supplied with solid fuel
Thermal power [kW/t]
Pollutant
Unit
< 100
100 - 300
300 - 500
> 500
Suspended particulates
mg/Nm3
100
100
100
100
CO
mg/Nm3
250
250
250
250
SOx (expressed in SO2)
mg/Nm3
2000
2000
400
400
NOx (expressed in NO2)
mg/Nm3
500
400
400
400
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Air quality monitoring
Order no. 462/1993
Burner supplied with natural gas
Thermal power [kW/t]
Pollutant
Unit
< 100
100 - 300
300 - 500
> 500
Suspended particulates
mg/Nm3
5
5
5
5
CO
mg/Nm3
100
100
100
100
SOx (expressed in SO2)
mg/Nm3
35
35
35
35
NOx (expressed in NO2)
mg/Nm3
350
350
350
350
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Methods and instrumentation
• Passive sampling methods
• Active sampling methods
• Automatic methods
• Remote optical - long path analyzers
Any instrument measures 3 types of values:
• Instantaneous value
• TWA (Time Weighted Average)
• STEL (Short Term Exposure Limits)
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Methods and instrumentation
Gas measurement using spectroscopic methods
Spectrophotometry is based on the interaction of the gas molecules with light.
 
hc

Absorbtion techniques – it is measured the intensity of light after passing through
a gaseous medium. Usually absorption is measured at several frequencies in order to
avoid offests and interferences with other species. There are 4 principles:
• Differential Optical Absorption Spectroscopy (DOAS)
• Fourier Transform Infrared (FTIR)
• Non-Dispersive Infrared (NDIR)
• Tunable Laser Diode Absorption Spectroscopy (TLDAS)
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Methods and instrumentation
Gas measurement using spectroscopic methods
Emission techniques – excite molecules of the gas and then examine the light
emitted as they return to their ground state. The signal is passed through a narrowband filter and measured with a photomultiplier tube.
• Flame photometry
• Chemiluminescence
• UV fluorescence
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Measurement of carbon monoxide (CO) by IR photometry
Beer’s law
A = log(I/Io) = abC
I0
λ  4,61μm
A = absorbance
a = absorbtion coefficient
b = path length
C = concentration
I
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Measurement of carbon monoxide (CO)
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Measurement of carbon monoxide (CO) by IR photometry
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Measurement of carbon monoxide (CO) by IR photometry
Schematic of a NDIR head
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Measurement of nitric oxides (NOx) by chemiluminescence
Chemiluminescent reaction
NO + O3 ==> NO2+ O2 + hv (0.6 – 3 μm)
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Measurement of sulphur dioxide (SO2) by UV fluorescence
Excitation
S0 + hνex → S1
Fluorescence (emission)
S1 → S0 + hνem + heat
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Measurement of sulphur dioxide (SO2) by UV fluorescence
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Measurement of sulphur dioxide (SO2) by UV fluorescence
Teledyne 100E
UV Fluorescence
SO2 Analyzer
Ranges: 0-50 ppb to 0-20,000 ppb full scale, user selectable or autoranging
Units: ppb, ppm, µg/m3, mg/m3
Zero noise: < 0.2 ppb (RMS)
Span noise: < 0.5% of reading (RMS) above 50 ppb
Lower Detectable Limit (LDL): 0,4 ppb
Linearity: 1% of full scale
Precision: 0.5% of reading above 50 ppb
Analog outputs: 10V, 5V, 1V, 0.1V, selectable
Serial outputs:
Serial Port 1: RS-232 (DB-9M)
Serial Port 2: standard RS-232 or optional
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RS-485 (DB-9F), Ethernet
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Gas chromatography
Gas chromatography
(video clip)
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Measurement of Volatile Organic Compounds (VOC)
Photo-Ionization Detector (PID)
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Measurement of Volatile Organic Compounds (VOC)
Photo-Ionization Detector (PID)
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Measurement of suspended particles (particulate matter – PM)
Fraction
Size range
PM10
(thoracic fraction)
≤ 10 μm
PM2.5
(respirable fraction)
≤ 2.5 μm
PM2.5 – PM10
(coarse fraction)
2.5 - 10 μm
PM1
(fine fraction)
≤ 1 μm
Ultrafine (UFP or UP)
≤ 0.1 μm
Aerosol = particles + gas
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Measurement of suspended particles (particulate matter – PM)
Gravimteric method
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Measurement of suspended particles (particulate matter – PM)
Beta Attenuation Method
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Measurement of suspended particles (particulate matter – PM)
Beta Attenuation Method
Model: BAM-1020 EnviroTechnology
Technical specifications
Source Carbon-14 (C-14), < 3.7 MBq
Measurement Range 0 to 1.0, 2.0, 3.0, 5.0, 10.0 mg/m3
0 to 100, 1,000, 2,000, 3,000, 5,000, 10,000 μg/m3
Minimum Detection Limit 6 μg/m3 (1/2 hour), 4 μg/m3 (1hour)
3 μg/m3 (3 hour), 1 μg/m3 (24-hour)
Resolution 0.1 μg/m3
Precision ±2.0 μg/m3 < 80 μg/m3, 4-5 μg/m3 > 80 μg/m3 (24-hour average)
Accuracy (for mass measurement) ± 5% using NIST-traceable mass foil set
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Measurement of suspended particles (particulate matter – PM)
Optical method
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Measurement of suspended particles (particulate matter – PM)
Tapered Element Oscillating Microbalance (TEOM)
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Measurement of gaseous pollutants using electrochemical sensors
O2
SnO2-x
R  A  [C ]
O2
Gaz
O2
SnO2-x
SnO2-x
SnO2-x
R = resistance
A, α = constants
E eV
în aer
C = gas concentration
Metallic oxide
E
eV
în prezenţa gazelor de
reducere
Detected gases
TiO2, Fe2O3, CoO, ZnO, ZrO2, SnO2, La2O3
O2
Cr2O3, NiO, ZnO, ZrO2, SnO2, In2O3
CO
Fe2O3, Fe3O4, Co3O4, ZnO
CH4
SnO2, VO
NOx
ZnO, Al2O3, SnO2
halogens
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