1. Impact of Climate Change on Air Quality for Three Midwestern USA Cities
Abhishek,* Joo-Youp Lee,** and Tim C. Keener*
*Department of Civil & Environmental Engineering
**Department of Chemical & Materials Engineering
University of Cincinnati
Cincinnati, Ohio
Y. Jeffery Yang
National Risk Management Research Laboratory
U. S. Environmental Protection Agency
MS 690, 26 W. Martin Luther King Drive,
Cincinnati, Ohio 45268, U.S.A.

2. PRESENTATION OUTLINE Climate Change Data Mining and Analysis Results
Need for Wind Speed Study
Data Mining and Analysis
Results
Ozone Season Analysis
Possible Causes
Implications

3. Climate Change Factors Important for Air Quality
Temperature
The frequency and pattern of cloud cover
Circulation and precipitation patterns

4. Importance of Wind Speed Study
Ventilates the pollutants
Transfers heat and moisture between the earth’s surface and the atmosphere
Affects engineering design
Used for energy generation
Affects human comfort
Affects ozone formation

5. 2. DATA MINING AND ANALYSIS

6. Data Mining and Analysis
Data was obtained from the National Oceanic and Atmospheric Administration (NOAA) website.
Three Midwest USA Cities selected were: Cincinnati (Ohio), Indianapolis(Indiana) and Little Rock (Arkansas).
The data was available from for Indianapolis and Little Rock and from for Cincinnati.
All wind data was in the form of hourly recordings of wind speeds (in m/s).

7. Latitude and Longitudes
City
Latitude
Longitude
Cincinnati
39° 9' N
84° 31' W
Indianapolis
39° 44' N
86° 17' W
Little Rock
34° 44' N
92° 14' W

8. Why these cities?
Because their topography is relatively flat and unaffected by large mountain ranges or other major topographical features,
They represent important regional economic centers in the Midwest,
Undergone major air quality management efforts over the past 35 years in order to meet the National Ambient Air Quality Standards.

9. Data Mining and Analysis
Annual calms for all three cities were counted. Calms were defined as when wind speed is zero
Hourly readings when the wind speed is zero is divided by the total number of hourly data of the year giving the calms frequency for that year,
Similarly the frequency of wind speeds for the following bins were calculated: >0 – 2.1 m/s; >2.1 – 4.1 m/s; >4.1 – 6.2 m/s; >6.2 – 8.2 m/s; and, >8.2 m/s.

10. 3. RESULTS

11. Results
Most striking results is that calms have increased significantly in frequency for all three cities.
For the combined 3-city average, calms have increased from ~3 % in the mid-1940s to a value of ~10% in 2008, an increase of over 600 hours on a yearly basis.

12. Results Calms Frequency:
Little Rock>Cincinnati>Indianapolis
Little Rock now averages around 15% of the year with calm conditions as compared to ~10 % for Cincinnati and ~6% for Indianapolis.

16. OZONE SEASON ANALYSIS

17. Climate Change and Ozone
Conditions conducive to ozone (O3) formation and accumulation are
abundant sunshine,
high temperatures,
stagnant air.
Summertime pollutant in the United States.
It is now well understood that year-to-year variability in summer climate is strongly correlated with the number of days that exceed O3 air quality standards.

18. Climate Change effect on Ozone Precursors
=> Higher Temperatures
=> increases in biogenic emissions of VOCs
=> High Ozone!!
=> warmer and wetter climate
=> increase in the rate of natural production of NOx by lightning
=> High Ozone

19. Results: Ozone Season Analysis
For all three cities, increase in ozone season calms is more than the annual increase in calms for the entire period.

20. Ozone Season Vs Annual Calms
City
Annual slope (1)
Ozone season slope (2)
Years of data (3)
Annual calms Increase % (1)*(3)
Ozone season calms increase % (2)*(3)
Cincinnati
0.1249
0.1609 61
7.6189
9.8149
Indianapolis
0.0606
0.0755 66
3.996
4.983
Little Rock
0.2368
0.2692

21. 4. POSSIBLE CAUSES

22. Possible Causes
Wind speed is related to the surface pressure gradient, which in turn is a function of the temperature gradient.
The enhanced warming at higher latitudes compared to the tropics
=> decreased pressure gradient over the United States
=> reduced wind speeds.
Another way that temperature changes may affect surface winds is by altering the near-surface vertical temperature gradient and thus the turbulent mixing.

23. Possible Causes
The IPCC has reported that observations of extratropical storm track movement poleward over the last few decades have implications for the increased frequency and duration of synoptic stagnation events.
A number of recent modeling studies suggest that this trend could continue into the future, resulting in significant changes in winds, precipitation, and temperature patterns in mid-latitudes.

24. Possible Causes
Major cyclic global weather indices can be used to track these global changes which affect temperature, precipitation and surface wind trends in the United States.
These include the North Atlantic Oscillation (NAO), the Pacific/ North American pattern (PNA), the Southern Oscillation Index (SOI), and the Pacific Decadal Oscillation (PDO).

25. IMPLICATIONS

26. Implications
Reductions in wind speed would ventilate pollutants from urban areas less effectively (leading to increased exposure to pollutants and thereby exacerbating lung and heart diseases in the area).

27. Implications Fewer days with high wind speeds
=> problem for wind energy generation because wind power varies as the cube of the speed.
Increased stagnant conditions
=> Increased human discomfort during summertime
=> increased time spent indoors
=> increased energy demand
=> more emissions!!

28. Implications
Reduced wind can have implications on transport of pollen and mold in the area.
The efficiency of heat and moisture transfers between the earth’s surface and the atmosphere is reduced if days with lower wind speed are increasing
Impact on Ozone Formation.

29. Implications
Climate modeling studies indicate potential increases in the O3 events in the Midwest and Northeast that can be directly traced to the weaker frontal systems and decreased frequency of surface cyclone activity due to a poleward storm track shift.

30. Consistent Findings
Klink (1999) looked at the 1961–90 trends at several U.S monitoring stations and found that mean monthly minimum wind speed are decreasing.
Klink (2002) analyzed seven stations in Minnesota and the Dakotas. Record lengths varied from 22 to 35 years. Most of the seven stations showed a trend toward reduced mean annual wind speeds.
Keimig and Bradley (2002) analyzed 15 Canadian and Alaskan stations. 64% of the monthly trends in wind speed were negative (decreasing wind speed).
Gower (2002) investigated the trends and variations in 6 to 27 years of wind speed data from buoys off the west coast of Canada and the USA and observed decreasing wind speeds.

31. Questions Please