A N EW H AMPSHIRE G ROUND -L EVEL O ZONE P OLLUTION F ORECASTING T OOL U SING M ETEOROLOGICAL C...
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Transcript of A N EW H AMPSHIRE G ROUND -L EVEL O ZONE P OLLUTION F ORECASTING T OOL U SING M ETEOROLOGICAL C...
A NEW HAMPSHIRE GROUND-LEVEL OZONE
POLLUTION FORECASTING TOOL USING
METEOROLOGICAL CRITERIANortheast Regional Operational WorkshopPresenter: Laura Landry, Plymouth State University
2008 November 5
Courtesy: Zach Allen
Introduction
New Hampshire Department of Environmental Services (NHDES) has forecasted ozone pollution for over 15 years Ozone exposure causes a wide range of
respiratory problems (AIRNow 2008)
Primarily concerned with Environmental Protection Agency’s (EPA) National Ambient Air Quality Standard (NAAQS) for ozone Based on daily maximum 8-hour average
ozone concentration
Introduction
Since March 2008, a new NAAQS for ozone has been implemented, lowered from 84ppb to 75ppb Previously used forecasting methods have become
less accurate
Motivation: To develop a new forecasting guide for predicting the new standard of 75ppb
Results will help answer questions of: How much variation in meteorological criteria will
there be between air monitoring sites? How will criteria compare when using two different
time periods of data?
Introduction
Meteorological conditions behind ozone development Sunny skies High surface temperatures Calm to light winds
Transport of pollution New Hampshire lies downwind of major
pollution sources
Methodology
Selection of air quality monitoring sites Sites were selected base on:
1. Locations where most exceedance days occurMore problematic to forecastLarger sample size on which to base
the analysis
2. Locations not adjacent to each other
Methodology
Southern sites report most of exceedance days
Site elevations range from 0 to 150m Miller State Park is an
exception at about 700m
New Hampshire
Methodology
Previous research conducted by Jeffs (2007), a Master’s thesis at Plymouth State University Created an ozone forecasting guide for 65ppb Utilized a dataset from 2002-2005
This study followed similar methodology EPA suggests an air quality climatology as
about 4 years (EPA 1999) Used two datasets of June-August
2004-2007 2002-2007
Methodology
Ozone data Daily maximum 8-hour average ozone
concentration Source: NHDES
Meteorological data Surface observations from KCON, KEEN,
KASH, KPSM, and Miller State Park Source: National Weather Service, Plymouth
State University, NHDES Radiosonde data from KGYX
Source: Plymouth State University
Methodology
Analysis was done using the Criteria Method EPA-recommended method for creating air
quality forecast guides (EPA 1999)
Subjective analysis that focuses on exceedance days
Determines threshold values
Methodology
Methodology
Meteorological parameters: Daily maximum surface temperature 850hPa temperature (12 UTC) Surface wind speed and direction (12 & 18
UTC) Cloud cover (12 & 18 UTC)
Times were chosen based on: 12 UTC: morning conditions prior to a
potential high ozone event 18 UTC: afternoon conditions when ozone
typically reaches its daily maximum value
RESULTS
Results
Comparing criteria of air monitoring site to site… Daily observations
Maximum surface temperature: ≥ 83˚F 12 UTC observations
850hPa temperature: ≥ 12˚C Surface wind speed: ≤ 5 knots Surface wind direction: Southwesterly to
southerly Cloud cover: ≤ FEW
Results
Comparing criteria of air monitoring site to site… 18 UTC observations
Surface wind speed: ≤10 knotsSurface wind direction: Westerly to
southwesterlyCloud cover: ≤ SCT
Results from Miller State Park varied most from all other sites
Site to Site Comparison
2004-2007Variable Thresho
ldN Range
Max Surface Temperature ≥ 80°F 14 73-96°F
12 UTC OBSERVATIONS
850hPa Temperature ≥ 11.4°C 18 9.4-19.6°C
Wind Speed ≤ 14 kts 13 3-14 kts
Wind Direction
200-260° 15 87-295°
Cloud Cover - - -
18 UTC OBSERVATIONS
Wind Speed ≤ 14 kts 13 5-19 kts
Wind Direction
200-250° 14 117-287°
Cloud Cover - - -
Miller State Park Nashua
2004-2007Variable Thresh
oldN Range
Max Surface Temperature ≥ 86 °F 17 77-95°F
12 UTC OBSERVATIONS
850hPa Temperature ≥ 12 °C 17
9.4-19.8°C
Wind Speed ≤ 5 kts 15 0-6 kts
Wind Direction
180-290° 3 180-290°
Cloud Cover ≤ SCT 14CLR-BKN
18 UTC OBSERVATIONS
Wind Speed ≤ 10 kts 16 1-10 kts
Wind Direction
200-300° 13 110-300°
Cloud Cover ≤ SCT 15CLR-BKN
Results
Comparing criteria among different time periods of data among the same air monitoring site…
Dataset Comparison
2002-2007 2004-2007Variable Thresho
ldN Range Variable Thresh
oldN Range
Max Surface Temperature ≥ 82°F 19 81-97°F
Max Surface Temperature ≥ 82°F 10 81-95°F
12 UTC OBSERVATIONS 12 UTC OBSERVATIONS
850hPa Temperature ≥ 12.4°C 19
12.4-20.8°C
850hPa Temperature ≥ 12.4°C 10
12.4-19.8°C
Wind Speed ≤ 7 kts 19 1-8 kts Wind Speed ≤ 5 kts 10 1-8 kts
Wind Direction
190-290° 16 150-290°Wind
Direction190-270° 8 150-270°
Cloud Cover ≤ SCT 17 CLR-BKN Cloud Cover ≤ FEW 10CLR-BKN
18 UTC OBSERVATIONS 18 UTC OBSERVATIONS
Wind Speed ≤ 10 kts 19 3-10 kts Wind Speed ≤ 8 kts 10 3-9 kts
Wind Direction
180-240° 17 120-260°Wind
Direction180-260° 9 120-260°
Cloud Cover ≤ BKN 17 CLR-OVC Cloud Cover ≤ SCT 10FEW-OVC
Portsmouth
Summary
This study developed an ozone forecasting guide for the NHDES
The criteria method from the EPA Subjectively analyzed
meteorological threshold values Threshold values indicate a high
probability of an exceedance day
Conclusions
Air monitoring site to site comparison:
Similar threshold values among sites Miller State Park appeared to be an
outlier Could be due to high elevation Transport may be more of an issue
Dataset to dataset comparison: No significant variation in threshold
values In this study, the length of the dataset
did not have a large effect on results
Questions?
References:
AIRNow, accessed 2008: Ozone and Your Health. [http://www.airnow.gov/index.cfm?action= static.ozone2]
EPA, 1999: Guideline for Developing an Ozone Forecasting Program. EPA: Office of Air Quality Planning and Standards.
Jeffs, Kim, 2007: Development of Meteorological Criteria for Forecasting Air Quality in New Hampshire. Plymouth State University: Master of Science Thesis Project.