<sod > "If a building is very open to the outside, it's less of a problem," Doctor said.< eod>< sod > "If a building is very open to the outside, it's less of a problem," Doctor said. "If you look at our buildings in downtown Calgary, where for six or eight months of the year the buildings are tight, tight, tight and there's a certain amount of air recirculation, it could potentially be more of a problem.< eod>