A University of Arizona researcher has created a new system to dramatically show American cities their relative level of vulnerability to bioterrorism.

Walter W Piegorsch, an expert on environmental risk, has placed 132 major cities from Albany, New York to Youngstown, Ohio on a colour-coded map that identifies their level of risk based on factors, including critical industries, ports, railroads, population, natural environment and other factors.

A professor of mathematics in the College of Science and member of the UA's BIO5 Institute, Piegorsch has created a map that marks high-risk areas as red (for example, Houston and Boise), mid-range risk as yellow (San Francisco) and lower risk as green (Tucson).

The map showed a wide swath of highest-risk urban areas running from New York down through the Southeast and into Texas. Boise was the only high-risk urban area that lies outside the swath.

The research, published in the journal Risk Analysis, employed what risk experts called a benchmark vulnerability metric, which showed risk managers each city's level of risk for urban terrorism.

Piegorsch said terrorism vulnerability involves three dimensions of risk -- social aspects, natural hazards and construction of the city and its infrastructure. He added the allocation of funds for preparedness and response to terrorism should take into account these factors of vulnerability.

"Our capacity to adequately prepare for and respond to these vulnerabilities varies widely across the country, especially in urban areas," Science Daily quoted him as saying.

Piegorsch argued that 'any one-size-fits-all strategy' of resource allocation and training ignores the reality of the geographic differences identified in his study.

Such failures, he concluded, would 'limit urban areas' abilities to prepare for and respond to terrorist events.