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DOAS |
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DOAS
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Photo: J.Kleperis
 DOAS
METHOD
DOAS STATIONS
IN RIGA
Five
DOAS type stations (two - roof-level stations, one - street-level
station, two - street & industrial station) are controlling the
quality of air in Riga
. Four stations belong to Latvian Hydrometeorological Agency
(LHMA) and Riga City Council (RCC) has agreement about data exchange
with LHMA. The measurements from all DOAS stations are collected
in Department of Environment, Riga City Council, after that analysed,
compared and reported. The strong correlation was found between data
of ozone and nitrogen dioxide pollution from all five stations. It
is concluded that air monitoring on roof level as well as on street
level and close to industrial sites in
Riga
is determined mainly by traffic
motion in the city and meteorological conditions.
DOAS
stations in Riga are measuring
6 (7) different gases in air every 5-6 minutes, and
the values of 30 minutes, 1h and 24 h are stored in central
database. These gases are:
- sulphur dioxide (SO2
),
- nitrogen dioxide (NO2
),
- ozone (O3 ),
- benzene (C6H6 ),
- toluene
(C6H5CH3 )
- formaldehyde (HCHO)
- P and M-xylene (C8H10
, LHMA stations)
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