A N EW H AMPSHIRE G ROUND -L EVEL O ZONE P OLLUTION F ORECASTING T OOL U SING M ETEOROLOGICAL C RITERIA Northeast Regional Operational Workshop Presenter: 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 occur More problematic to forecast Larger 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  This study followed similar methodology  EPA suggests an air quality climatology as about 4 years (EPA 1999)  Used two datasets of June-August

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

 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

R ESULTS

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 knots Surface wind direction: Westerly to southwesterly Cloud cover: ≤ SCT  Results from Miller State Park varied most from all other sites

Site to Site Comparison VariableThresholdNRange Max Surface Temperature ≥ 80°F °F 12 UTC OBSERVATIONS 850hPa Temperature ≥ 11.4°C °C Wind Speed≤ 14 kts kts Wind Direction ° ° Cloud Cover UTC OBSERVATIONS Wind Speed≤ 14 kts kts Wind Direction ° ° Cloud Cover--- Miller State ParkNashua VariableThresholdNRange Max Surface Temperature ≥ 86 °F °F 12 UTC OBSERVATIONS 850hPa Temperature ≥ 12 °C °C Wind Speed≤ 5 kts150-6 kts Wind Direction °3 Cloud Cover≤ SCT14 CLR- BKN 18 UTC OBSERVATIONS Wind Speed≤ 10 kts kts Wind Direction ° ° Cloud Cover≤ SCT15 CLR- BKN

Results  Comparing criteria among different time periods of data among the same air monitoring site…

Dataset Comparison VariableThresholdNRangeVariableThresholdNRange Max Surface Temperature ≥ 82°F °F Max Surface Temperature ≥ 82°F °F 12 UTC OBSERVATIONS 850hPa Temperature ≥ 12.4°C °C 850hPa Temperature ≥ 12.4°C °C Wind Speed≤ 7 kts191-8 ktsWind Speed≤ 5 kts101-8 kts Wind Direction ° ° Wind Direction ° ° Cloud Cover≤ SCT17CLR-BKNCloud Cover≤ FEW10 CLR- BKN 18 UTC OBSERVATIONS Wind Speed≤ 10 kts ktsWind Speed≤ 8 kts103-9 kts Wind Direction ° ° Wind Direction ° ° Cloud Cover≤ BKN17CLR-OVCCloud Cover≤ SCT10 FEW- 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. [ 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.