Transcript Network Design Principles for Population

Ambient Monitoring Networks and
Monitoring Strategies
Judith C. Chow ( [email protected] )
John G. Watson
Desert Research Institute
Reno, NV, USA
presented at:
The Workshop on Air Quality Management, Measurement,
Modeling, and Health Effects
University of Zagreb, Zagreb, Croatia
24 May 2007
Objectives
• Discuss network design principles
and philosophy
• Define monitoring objectives
• Evaluate air quality monitoring
strategies
Ambient Monitoring Needs
• Sampling locations that represent regional,
urban, neighborhood, and source-oriented spatial
scales
• Sampling periods and durations that represent
range of source contribution conditions
• Long term record to detect trends and control
strategy effectiveness
• Comparability of analytical methods with source
profile measurements
Statement of Problem
• Many networks are designed mainly to
detect maximum concentrations
• Many monitoring sites measure similar
concentrations and are redundant
• An objective methodology is needed to
design monitoring networks that
represent exposure where people live,
work, and play
Watson et al., 1997
Zones of Representation
• Collocated
1 to 10 m
• Microscale
10 to 100 m
• Middle-scale
100 to 500 m
• Neighborhood-scale
500 m to 4 km
• Urban-scale
4 to 100 km
• Regional-scale
100 to 1,000 km
• Continental-scale
1,000 to 10,000 km
• Global-scale
>10,000 km
U.S. EPA’s Pyramid Approach to Air
Quality
• 7 Urban areas
• ~54 Trends
• ~250 Source
Apportionment
• ~165 IMPROVE Visibility
Research
Supersites
(short-term except
Fresno, CA)
Assessment
Chemical
Speciation
Compliance
PM2.5 Mass
• ~1050 FRM
• ~200
Continuous
Compliance monitoring cannot serve all
objectives!
Compliance Network
Non-urban and urban PM2.5
networks
Interagency Monitoring
of PROtected Visual
Environments
(IMPROVE) Network
Virgin Islands
Chemical Speciation
Network (CSN)
Neighborhood- and Urban-Scale
Monitoring Objectives
• Determine compliance with air quality
standards
• Provide air quality forecasting and
issue alerts
• Assess source/receptor relationships
• Evaluate health, radiative, and
ecological effects
Urban and/or Health Network
Characteristics
• Multi-year duration
• Urban-scale zone of representation near
compromised populations
• Hourly to daily frequency and averaging
times
• Particle concentrations by size, surface area,
composition, and bioavailability
• Gas and meteorological co-factors
Regional-Scale Monitoring
Objectives (primary)
• Determine air quality in urban, non-
urban, and remote areas
• Observe long-term temporal and
spatial pollution trends
• Monitor progress made by emission
reduction measures
• Conduct atmospheric process research
Regional-Scale Monitoring
Objectives (secondary)
• Conduct photochemical or other
air quality model simulation
• Relate changes in secondary pollutant
concentrations to changes in
precursor gas emissions
Regional Network Characteristics
• Represent boundary conditions,
source, and receptor areas that
characterize regional-scale
phenomena
• Minimize influences from local sources
• Include background (upwind),
transport, and receptor (downwind)
locations
Siting Considerations
• Emission sources
• Terrain
• Meteorology
• Population density
• Existing air quality measurements
Siting Considerations
• Adequate exposure – minimize nearby barriers
and particle deposition surfaces
• Minimum nearby emitters – monitor should be
outside zone of influence of specific emitters
• Collocated measurements – other air quality
and meteorological measurements can aid in
the interpretation of high or variable PM levels
• Long-term site commitment – sufficient
operating space, accessibility, security, safety,
power, and environmental control
Monitoring Strategies
•Level III: Portable, inexpensive filter and
continuous sampling at a large number of
locations with a low investment in site
infrastructure and maintenance.
– Hardware is already in use for indoor and
exposure studies. Some accuracy and precision
is traded for greater spatial coverage.
Temporary, dense networks of this type
surrounding Level I and Level II sites would
establish the zones of representation for the
permanent monitors.
(NRC 2004)
Examples of Portable and
Inexpensive Monitoring Devices
4002.0
4001.5
DAIU
Mass Concentration
(ug/m3)
4001.0
62
61
60
59
58
57
56
55
54
53
52
51
50
49
48
47
46
45
44
DAIP
YOD
4000.5
COP
GRA
4000.0
UTMN
C05
GRAS
3999.5
SFE
3999.0
ORE
3998.5
3998.0
3997.5
H43
3997.0
3996.5
808.0
808.5
809.0
809.5
810.0
810.5
811.0
811.5
812.0
812.5
UTME
0
1
2
Kilometers
3
Average Site Concentration (ug/m3)
44.00
48.00
52.00
56.00
60.00
to
to
to
to
to
48.00
52.00
56.00
60.00
64.00
4
Concentration
contours of
average PM10
mass around the
Corcoran site
during the
CRPAQS fall
intensive
(10/09/00 11/14/00).
Monitoring Strategies (continued)
•Level II: Fixed sites with proven
technology, similar to compliance sites, but
with locations and observables intended to
serve multiple purposes.
– These would have real-time access for
forecasting and episode alerts. Resources
directed at urban sites no longer needed for
compliance could be used to establish
background, boundary, and transport sites.
Discontinued Level II compliance sites could be
replaced with Level III monitors to address
community and environmental justice concerns.
PM2.5 Federal Reference
Methods (FRMs)
Andersen RAAS BGI PQ-200
Thermo Fisher
Scientific, formerly
Andersen Instruments,
Smyrna, GA
BGI, Inc., Waltham, MA
Partisol Sampler
Thermo Fisher Scientific,
formerly Rupprecht &
Patashnick, Albany, NY
URG MASS
URG Corp.,
Raleigh, NC
Speciation Monitors (EPA Speciation Network)
Mass Aerosol Sampling System (MASS)
URG Corporation, Raleigh, NC
Reference Ambient Air Sampler (RAAS)
Andersen Instruments, Smyrna, GA
Spiral Aerosol Speciation Sampler (SASS)
Met One Instruments, Grants Pass, OR
Interagency Monitoring of Protected Visual
Environments (IMPROVE) Sampler
Air Resource Specialists, Ft. Collins, CO
Other Speciation Monitors
Partisol 2300 Speciation Sampler
Rupprecht & Patashnick, Albany, NY
Dual Channel
Sequential Filter Sampler
and Sequential Gas Sampler
Desert Research Institute, Reno, NV
Dichotomous Virtual Impactor
Andersen Instruments, Smyrna, GA
Paired Minivols
Airmetrics, Inc., Springfield, OR
URG 3000N
Speciation Sampler
URG Corporation,
Raleigh, NC
Dichotomous Partisol-Plus Sampler
Rupprecht and Patashnick, Albany, NY
Monitoring Strategies (continued)
•Level I: Fixed sites with proven and novel
technology, similar to those of supersites.
– A few of these locations would be located in
contrasting environments with different
sources, meteorology, and PM composition to
test new technology, understand atmospheric
processes, and support health studies. These
would have instrumentation similar to that of
Level III and Level II sites to determine
comparability, as well as detailed size ranges,
PM chemistry, and precursor gases. They
would provide an infrastructure for the testing
and evaluation of new measurement concepts
and the development of procedures to
implement at Level II and III sites.
Supersite Measurements
Fresno Supersite
Conclusions
• Optimize information gained with available
resources by careful network design.
• Design based on existing emissions,
meteorology, temporal cycles, and aerosol
composition data.
• Conduct short-term neighborhood-scale
monitoring with densely located monitors to
determine spatial representation.
• Daily sampling may be needed during the
most-polluted season, with less frequent
sampling during other seasons.
Conclusions (continued)
• Provide information to assist in control
strategy development, emission tracking,
trend analysis, and exposure assessment.
• Maintain consistent data quality with
standard calibration and operating
procedures and data reporting formats.
• Develop infrastructure to support
long-term nationwide or regional networks.
References
Chow, J.C.; Engelbrecht, J.P.; Watson, J.G.; Wilson, W.E.;
Frank, N.H.; and Zhu, T. (2002). Designing monitoring
networks to represent outdoor human exposure.
Chemosphere, 49(9):961-978.
NRC (National Research Council) (2004). Air Quality
Management in the United States. The National Academies
Press, Washington, DC.
Watson, J.G.; Chow, J.C.; DuBois, D.W.; Green, M.C.; Frank,
N.H.; and Pitchford, M.L. (1997). Guidance for network
design and optimal site exposure for PM2.5 and PM10.
Report No. EPA-454/R-99-022. U.S. Environmental
Protection Agency, Research Triangle Park, NC.
http://www.epa.gov/ttn/amtic/pmstg.html.