Overview of air pollution measurement methods

AUTOMATED MONITORING STATIONS MANUAL STATIONS SUPPLEMENTARY METEOROLOGICAL PARAMETERS DESCRIPTIONS OF METHODS

Overview of Measuring Methods in the Network of Automated Monitoring Stations (AMS)

Component	Abbreviation	Method	Type of method
SO₂	UVFL	ultraviolet fluorescence	reference
NO_x	CHML	chemiluminiscence	reference
PM₁₀	RADIO	radiometry	equivalent
PM₁₀	TEOM	tapered element oscillating microbalance	equivalent
CO	IRABS	IR correlation absorption spectrometry	reference
O₃	UVABS	ultraviolet absorption photometry	reference
BTX	GCH-FID	gas chromatography-flame-ionization detection	reference
BTX	GCH-PID	gas chromatography-photo-ionization detection	reference
Hg	AFS	low-temperature gas atomic fluorescence

Overview of measuring methods in the network of manual stations

Component	Abbreviation	Method	Type of method
SO₂	WGAE	spectrophotometry using TCM and fuchsin (West-Gaeke)	reference
	IC	ion chromatography	equivalent
	FUCEL	electrochemical fuel cell	equivalent
	CLM	coulometry	equivalent
NO₂	CLM	coulometry	equivalent
NO_x	FUCEL	electrochemical fuel cell	equivalent
	GUAJA	guajacol (modified Jakobs-Hochheiser) spectrophotometry	equivalent
	TLAM	trietriethanolamine spectrophotometry	equivalent
SPM	GRV	gravimetry	reference
TK/HM	AAS	atomic absorption spectrometry	reference
	PLRG	polarography	equivalent
	ICP-AS	inductively coupled plasma - atomic emission spectrometry	equivalent
	XRF	X-ray fluorescence	equivalent
	ICP-MS	inductively coupled plasma - mass spectrometry	equivalent
SO₄^2-	XRF	X-ray fluorescence	equivalent
NH₃	BERTH	Berthelot spectrophotometry
NH₄⁺	BERTH	Berthelot spectrophotometry
VOC	GCH-VOC	gas chromatography	reference
PAH	GCH-MS	gas chromatography with mass detection
PAH	HPLC	high performance liquid chromatography

Overview of measuring methods of supplementary meteorological elements

Wind direction and velocity	OPEL	optoelectronically
Wind direction and velocity	U-SONIC	ultrasonic anemometer
Global radiation (GLRD)	TDM	temperature difference method

Descriptions of methods

Atomic absorption spectrometry

Samples are taken on membrane nitrocellulose filters Synpor, followed by mineralization using hot nitric acid and hydrogen peroxide, final AAS analysis.Same chemicals, but in a microwave field (MLS 1200 MEGA) are used in CHMI.
Use: CHMI metals in SPM, after 1998 only Cd, Pb, since 2001 As, HS and ORGREZ stations

Berthelot method - spectrometry

Ammonium ions are captured on the first located teflon filter, gaseous NH₃ is captured on the filter impregnated with oxalic acid, NH₄⁺ ions eluated by demineralized water react with alkaline solution of phenol and NaClO. Spectrophotometrical measurement at 630 nm is used.
Use: NH₃,NH₄⁺

Coulometry

Electrochemical method where electrolytical current is proportional to gas concentration according to Faraday's law.
Use: SO₂, NO₂

El. fuel cell

A semiautomatic method, APM analyzer of City Technology Corp. with a selective micro-fuel cell.
Use: SO₂, NO_x at HS stations

Gravimetry

The sample is taken through continuous filtration of ambient air on selected filtering material (membrane nitrocellulose with a mean pore size of 0.85 ľm, teflon with a mean pore size of 2 ľm or glass fibre with capturing capacity >99.5). The difference between the weight of the filter prior to and after the exposure is determined gravimetrically.
Use: SPM at manual stations, PM₁₀ at Black Triangle stations

Guajacol (modified Jakobs-Hochheiser) spectrophotometry

After oxidation NO₂ is absorbed into the solution of NaOH with addition of guajacol and is converted to nitrites. Reaction in acid medium of H₃PO₄ with a solution of sulfanilamide and N-(1-naphthyl)ethylene diamine dihydrochloride (NEDA) follows to form a red colour. The intensity of the colour is measured spectrophotometrically at 560 nm
Use: NO_x, NO₂ at manual stations

Mass spectrometry with inductively coupled plasma

High-volume sampling on glass-fibre filters, mineralization, ICP-MS (mass spectrometry) analysis.
Use: SPM at manual stations, Black Triangle

Chemiluminescence

Nitrogen molecule excitation by ozone. With the conversion of the molecule into the basic energetic level, release of radiation as chemiluminescence occurs. This radiation is detected by a photomultiplier.
Use: NO, NO₂, NO_x

Ion chromatography

The air is drawn through a filter to capture sulphate particles and then through another filter impregnated with sodium hydroxide to determine sulphur dioxide. The exposed filters are leached out using deionized water with peroxide and the sulphate ion is determined by ion chromatography.
Use: sulphates, SO₂ at manual stations

IR- correlation absorption spectrometry

The radiation from an infra-red source passes through two parallel cells, one of which contains a non-absorbing background gas, the other contains the analyzed flowing sample of ambient air. The difference in energy between the sample and the reference cell is proportional to the carbon monoxide concentration.
Use: CO at AIM stations

Low-temperature gas atomic fluorescence

Mercury vapour is captured in the block with ultra-clean golden absorbent in the form of amalgam from which mercury is released by heating and decoded.
Use: Hg at AIM stations

Optoelectronic method

The wind direction and velocity are measured using a wind vane and an anemometer. The position of the vane is taken optoelectronically or transferred to electrical voltage using a circular potentiometer. The rotation speed of the anemometer sensor is measured optoelectronically or transferred to electrical voltage using a tachodynamo.
Use: wind direction and velocity at AIM stations

Tapered element oscillating microbalance

It measures the mass of the sample captured on a replaceable filter according to the oscillating tapered element frequency variation. The air sample passes through a filter where the dust particles are captured and runs through a hollow tapered element to a vacuum pump with an electronic flow control.
Use: PM₁₀ at AIM HS stations

Gas chromatography -photo-ionization detection

Continual measurement of aromatic hydrocarbons (benzene, toluene, ethylbenzene and xylenes) by BTX analyzers Chrompac and gas chromatography method. It is a case of standard linkage to a sampling probe in a container. The method is based on photoionization detection. Use: Ústí n. L, .Praha-Libu, Pardubice-Rosice

Gas chromatography -flame-ionization detection

Continual measurement of aromatic hydrocarbons (benzene, toluene, ethylbenzene and xylenes) by BTX analyzers Syntech and gas chromatography method. It is a case of standard linkage to a sampling probe in a container.Ionization of organic substances in flame (hydrogen- air), increase of ion current proportional to the concentration of the measured substances at constant gas flow. Use: Praha-Libu, Praha-Strahovský tunel, Rudolice, Mikulov, Sedlec, Most, Ostrava-Přívoz.

Gas chromatography (POPs)

Persistent organic pollutants (POPs) are captured on glass-fibre and polyurethan filters using high-volume pump sampling. Exposed filters are eluated with dichlormethane. After purification and preconcentration the selected POPs are measured by gas chromatography with mass detection Use: CHMI- MS Koetice, HS stations

Gas chromatography (VOC)

Volatile organic compounds (VOCs) are determined by gas chromatography. Air samples taken in special vacuum steel canisters on Monday and Thursday of each week at 12:00 UTC for a period of 10 minutes (CHMI). At Public Health Service's stations the 24-hour samples are taken every 6th day during the heating period (November-March) and every 12th day in the non-heating period (April-October). Samples from transportation canisters are modified by cryogenic concentration prior to the GCH analysis. Use: CHMI and HS stations

Polarography

Sampling on membrane filter, acid decomposition, differential pulse polarography DPPAFW.
Use: HM at HS stations up to 1991-93

Potentiometry

Potentiometric titration to equiv. point pH 4.5
Use: SO₂ at ORGREZ stations

Radiometry - absorption of beta radiation

It stands on beta-ray absorption in a sample captured on filtering material. The difference between the beta-ray absorption of the exposed and non-exposed filtering material, which is proportional to the mass of the captured suspended particulate matter, gives the information on its concentration.
Use: SPM, PM₁₀ at AIM stations

X-ray fluorescence

Non-destructive analysis with sampling on teflon filter exposed to X-rays.
Use: metals and sulphates in SPM

Spectrophotometry with TCM and fuchsin - West-Gaeke

The sulphur dioxide is absorbed into a sodium tetrachloromercury solution (TCM) containing Chelaton III. The compound formed reacts with fuchsin and formaldehyde in acid medium to yield a red-purple colour, which is measured spectrophotometrically at 586 nm.
Use: SO₂ at manual stations

Temperature difference method

Energy of solar radiation (GLRD) is measured in W.m^-2 using temperature difference method. The temperature difference of black and white coloured segments of sensor surface with different reflection to short-wave solar radiation is measured.

Triethanolamine spectrophotometry

After oxidation NO₂ is absorbed into the solution of thiethanolamine with sulfanilic acid in acid medium of H₃PO₄ using NEDA. The intensity of the colour is measured spectrophotometrically at 540 nm.
Use: NO_x at manual HS stations

Ultrasonic anemometer

Comparison of the times taken for an ultrasonic puls to travel between ultrasonic transducers.

UV absorption

The method rests upon absorption of radiation with the wavelength of 254 nm by ozone in the analyzed sample. The radiation source is an UV-lamp and clean air (zero) and the sample itself are alternately measured in cell.
Use: ozone at AIM stations

UV fluorescence

The analysed sample is exposed to UV-lamp irradiation with energetic excitation of SO₂ molecule. With the backward conversion of the molecule into the basic energetic level, energy as fluorescing radiation is released. This radiation is proportional to the sulphur dioxide concentration and is detected by a photomultiplier.
Use: SO₂, H₂S at AIM stations

High performance liquid chromatographyGas chromatography - mass detection (for PAH)

Samples are captured on a filter and further adsorbing material for PAH in gaseous phase. The samples are processed in a chemical laboratory and analyzed by the HPLC method or GSH-MS method.