Long-Term Air Quality Trends in PA Small Business Compliance Advisory Committee January 24, 2018 Harrisburg, PA
Agenda Weather Factors that Influence Air Quality History of Air Pollution in PA - Donora Pollutants of Concern Ozone PM2.5 Sulfur Dioxide (SO2) 2
Weather Factors that Influence Air Quality Historically, specific weather conditions coupled with low-lying emissions have contributed to high air quality concentrations. The weather factors that typically lead to elevated air quality concentrations: - High pressure - Inversions - Stability (light winds leading to limited mixing) 3
High-Pressure Circulation High Pressure = Divergence Sinking Air Air flows out toward areas of Low Pressure Interaction of PGF and Coriolis Force creates Clockwise Flow Figure from Utah State University Website 4
Low-Pressure Circulation Low Pressure = Convergence Rising Air Air flows in toward areas of Low Pressure Interaction of PGF and Coriolis Force creates Counter-Clockwise Flow Figure from Utah State University Website 5
Circulation Between Highs and Lows Altitude also plays a role If the center of this diagram is heated, an unstable temperature gradient will produce low pressure in the center and high pressure at the edges Vertical circulation begins 6
Low pressure Converging leads to rising Counterclockwise wind Promotes storminess Promotes increased wind High pressure Diverging leads to sinking Clockwise wind Promotes clear skies Promotes light winds Low vs. High Pressure 7
Raditional inversion surface cools more quickly than air above on clear, calm nights Subsidence inversion an increase in temperature with height that develops from sinking air causing warming aloft Inversions Pollution trapped below the inversion may remain through the night and / or receive more pollutants Most prevalent when found near the ground Figure from The Atmosphere, 8 h Edition 8
Stability and Impact on Plumes Dry adiabatic rate decreases temperature with increasing height. The environmental rate represents actual stability. Fanning allows little mixing, totally stable, surface inversion, clear nights Fumigation has capping inversion and mixes pollution down Looping - thermals and subsidence impact Coning - neutral Lofting - increasing instability with height 9
Donora Smog Event October 1948 Donora, PA Oct. 26-31, 1948 Air pollution episode left 20 dead out of 14,000 people Figure to the right: Donora at Noon on Oct. 29 10
Donora Dept. of Defense Photo (1941) http://www.calu.edu/business-community/teaching-primary-sources/donora-digital-collection/smog-smoke/index.htm 11
Location of 18 of the 20 Deaths http://www.calu.edu/business-community/teaching-primary-sources/donora-digital-collection/smog-smoke/index.htm 12
Donora Zinc Works of American Steel & Wire Co. http://www.post-gazette.com/news/health/2010/12/12/in-1948-smog-left-deadly-legacy-in-donora/stories/201012120248 13
Donora Mill http://pabook2.libraries.psu.edu/palitmap/donorasmog.html 14
Public Health Service Engineer George Clayton http://pabook2.libraries.psu.edu/palitmap/donorasmog.html 15
Monongahela River Valley Topography Source: Google Maps 16
Monongahela River Valley Topography 17
Monongahela River Valley Topography - Zoomed 18
Monongahela River Valley Topography - Zoomed 19
US Weather Map October 25, 1948 H L 20
US Weather Map October 26, 1948 H L 21
US Weather Map October 27, 1948 L H 22
US Weather Map October 28, 1948 L H 23
US Weather Map October 29, 1948 L H 24
US Weather Map October 30, 1948 L H 25
US Weather Map October 31, 1948 L H 26
US Weather Map November 1, 1948 L H 27
Official October 1948 for Allegheny County Airport 28
COOP October 1948 for Donora, PA 29
Historical 8-hour Ozone Concentrations in PA 30
2016 8-Hour Ozone Design Values 35
Historical 24-hour PM 2.5 Concentrations in PA 36
2016 24-hour PM 2.5 Design Values 38
Historical Annual PM 2.5 Concentrations in PA 39
2016 Annual PM 2.5 Design Values 41
Historical 1-hour SO 2 Concentrations in PA 42
2016 1-hour SO 2 Design Values 46