|
The
Current Network
|
|
Mobile
Station
|
Birmingham centre
|
Birmingham East
|
Hodge
Hill
|
Roadside
1 (Soho Road A41)
|
Roadside
2 (Stratford Rd A34)
|
Birmingham West
|
|
Dates
|
1987 - present
|
1992 - present
|
1993 - present
|
1994 - present
|
1996 - present
|
1996 - present
|
1997 - 2000
|
|
Type
|
Various
|
City
Centre
|
Urban
Background
|
Urban
Background with heavy industry and motorway
|
Roadside
|
Roadside
|
Urban
Background with heavy industry
|
|
NOx
(chemiluminescence)
|
x
|
x
|
x
|
x
|
x
|
x
|
x
|
|
CO
(Infra
red)
|
x
|
x
|
x
|
x
|
x
|
x
|
x
|
|
SO2
(UV
fluorescence)
|
x
|
x
|
x
|
x
|
|
|
x
|
|
PM10
(TEOM)
|
x
|
x
|
x
|
x
|
x
|
x
|
x
|
|
PM10
(Gravimetric)
|
|
|
x
|
|
|
|
|
|
PM2.5
(TEOM)
|
x
|
|
|
x
|
|
|
|
|
Ozone
(UV
absorption)
|
x
|
x
|
x
|
|
|
|
x
|
|
Benzene
(absorption tube + gas chromatography)
|
|
|
|
|
|
x
|
|
Operation
of the Network
Each monitoring station
is equipped with a telephone connection (either landline or mobile). This
enables data to be collected from the station remotely. This allows any
unexpected data to be investigated quickly. The instruments at each station are
calibrated once every 2 weeks in line with UK national practice.
Development
of The Network
The current network was
started in 1987 with a single mobile station. This was used to investigate
specific problems, mostly associated with industry. In 1992, 1993 and 1994
permanent sites were added. These were placed in locations that had formerly
been used for measuring SO2, black smoke, lead and CO via traditional methods
for many years previously. The sites
chosen were designed to give; a typical city centre level; a typical urban
background; and an urban background close to heavy industry and a motorway.
Later
sites focussed more upon road traffic, which has become the most significant
source of pollution in the city. These were placed next to two major roads with
the highest traffic flows and which also suffered from severe congestion.
All stations are placed
in areas where people are living.
The
aim has been to maintain continuous data from key representative sites over
long periods. This means that newer developments to the network can be compared
to long-term data from these sites.
Pollutants that are
known to be close to limits are monitored at the greatest number of sites, for
example NO2. Pollutants that are unlikely to exceed limits, such as benzene,
are monitored at only on ‘worst case’ site. The monitoring network includes
elements of research, such as the co-location of gravimetric and TEOM analysers
for PM10 at one site, and the co-location of PM10 and PM2.5 at 2 sites. The
reason for this is that particle limits are likely to be a major issue for the
city in coming years. It is therefore useful to build up long-term data in
advance to assist in understanding this issue.
NO2 Diffusion Tubes
In addition to the
monitoring stations the network includes the use of NO2 diffusion tubes. These
are used to monitor NO2 levels at 76 sites in 18 areas of the city. These are
placed at busy roadside sites, with some tubes being co-located with monitoring
stations to allow data to be verified. The NO2 diffusion tube sites are all
operated for at least 1 year in order to obtain reliable data. The programme of sites is varied periodically
to allow all busy roads to be checked. In this way the NO2 tube surveys act as
a screening tool and widen the reach of the permanent monitoring stations. |