Operational Heat/Health Warning Systems and Application in Urban Environmental Hazard Management

Dr. Laurence S. KalksteinCenter for Climatic Research

University of Delaware

Challenges in Urban Meteorology: A Forum for Users and ProvidersRockville, MarylandSeptember, 2004

Cook County, Illinois: July, 1995

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-- During the hottest days, mortality increased by over 100 %

Maximum Temperature vs. Daily Mortality: New York and Jacksonville, Florida

New York Jacksonville

-- The impact of weather is relative rather than absolute.

What can be done when a heat emergency is called?

Intervention Actions Taken byPhiladelphia Department of Public Health When Health

Warning is Issued

• Media announcement

• Promotion of the “buddy system”

• Activation of the “heatline”

• Home visits

• Nursing and personal care boarding home intervention

• Halt of utility service suspensions

• Increased emergency medical service staffing

• Daytime outreach to the homeless

• Air conditioned service facility capability

New Orleans Intervention Activities

Very little

Steps That can be Taken When Alerts or Emergencies are Called

1. NWS alerts appropriate city agency (e.g., Department of Health, Office of Aging, etc.)

2. City develops (or already has in place) intervention plans

3. Effectiveness of system can be monitored in three manners,and improvements are implemented if there are shortcomings:--forecasting effectiveness (false positives or negatives)--accuracy in estimating health impacts of offensive weather --noting if we are saving lives.

Effectiveness of Philadelphia Heat Health System (based on Ebi et. al.*)

• Study evaluated effectiveness of Philadelphia system for the summers of 1995-98.

• It is estimated that 2.6 lives were saved on average, for each warning day and for the following three days.

• Therefore, based on the number of warning called by the Philadelphia Weather Service Forecast Office, the watch warning system saved an estimated 117 lives over the four summer period

---------* Ebi, K.L., T. J. Teisberg, L.S. Kalkstein, L.Robinson, R.F. Weiher. Heat Watch/Warning Systems Save Lives: Estimated Costs

and Benefits for Philadelphia 1995-1998. Bulletin of the American Meteorological Society, August 2004.

How can we make cities cooler?

Key Strategies to Reduce Heat Islands

• Urban Vegetation

• Cool Roofing

• Cool Pavements

Modeling Exercise to Implement These Strategies in Los Angeles

• By increasing the urban area’s solar reflectivity (albedo), the intensity of heat and associated deaths should drop.

• For Los Angeles, average heat-related mortality dropped by over 20% during hot humid air masses.

• Similar results were obtained from Philadelphia.

• The costs of adding reflective roofs to inter-city dwellings is not expensive.

• The added benefit of vegetation is questionable:– provides shading

– but increases relative humidity