Corporate Action to Reduce Air Pollution — Atlanta, Georgia, 1998-1999

Morbidity and Mortality Weekly Report, March 3, 2000

Editorial Note: The metropolitan-Atlanta area ranks first in the United States in annual vehicle miles traveled per household [6]. Because 53% of all nitrogen oxide emissions comes from mobile sources of pollution [7], programs that successfully reduce vehicle miles traveled in Atlanta may substantially reduce ozone-producing emissions and ozone related health effects. Data provided by the PSG partners in this report suggest that PSG program implementation occurred concurrently with an 18%-21% decrease in singleoccupancy commute rates and an 11%-18% decrease in monthly commute miles traveled and associated emissions.

The lack of a standard evaluation method among the PSG partners was an important limitation to these analyses. Georgia Power/Southern Company conducted a prospective survey to establish a baseline of commuter behaviors, and the other PSG partners conducted a retrospective survey. In surveys, employees selected one commuting option that was their "usual" method of commute. In these cases, pre- and post-intervention rates are not directly comparable, since post-intervention data reflect the proportional contribution of alternative commuting days to all commute days. However, Georgia Power/Southern Company estimated vehicle-mile reductions for their employees that were similar to those estimated for the other PSG partners. Subsequent analyses of employee commuting behaviors will be facilitated by a standardized approach to evaluation and by standard metrics to calculate vehicle miles traveled by PSG partners.

These PSG partners may have achieved the 20% reduction in single-occupancy commute rates mandated by the Georgia governor's office; however, how similar success can be achieved in a larger percentage of Atlanta's workforce is unclear. PSG can be expanded to include a greater number of local businesses. However, half of all employees of the three PSG partners in this report are not participating in the alternative commuting programs, although the average distance from these PSG partners to the nearest mass transit station is [less than]1 mile. Increases in alternative commute rates beyond those already achieved may be facilitated by programs that continue to make alternative commuting options viable and accessible to working populations.

Future interventions also need to target commuting behaviors other than those related to the daily commute to work. Atlanta residents drive approximately 100 million miles per day, but only 21% of all automobile trips occur between the home and the workplace [8]. Industrial emissions and nonwork-related behaviors (e.g., noncommute driving, lawn-care practices, and gasoline and chemical solvent use) also contribute substantially to ground-level ozone and related health effects. Research is needed to evaluate whether employer-based programs like PSG also can reduce noncommute emissions among employee participants, their families, and co-workers. The integration of questions that incorporate day-to-day commuter behavior into state-based tracking surveys, such as the Behavioral Risk Factor Surveillance System, might provide an opportunity for this type of population-based program evaluation.