Olympic Smog

The 1996 Summer Olympics were a pivotal event for learning about Atlanta’s air quality, particularly our smog (ozone) and its causes.   At the time Atlanta was not in compliance with the ozone standard.  We gained a better understanding of urban air quality dynamics and the impact of large-scale events on pollution levels.

As the city prepared to host the world, we implemented several temporary measures to reduce emissions, especially in regard to transportation such as restricting car use, enhancing public transportation, and shifting business and industrial work hours.  People were allowed to work from home or allowed to take leave.  The result was the traditional rush hour was modified and traffic alleviated by taking cars off the road.

Dr. Michael Chang at Georgia Tech’s Earth and Atmospheric Sciences studied the impact and found a remarkable reduction in ozone concentrations and that reduction correlated directly with the traffic and industrial controls.  Peak ozone levels decreased by nearly 28% compared to the same period in previous years.  The reduction had noticeable effects on public health. Incidences of asthma-related emergency room visits dropped significantly during the Olympic period.

Here's the kicker.  Ozone is formed by the reaction of volatile organic compounds (VOCs) and nitrogen oxides (NOx) in the presence of sunlight.  The early battles against smog levels focused on reduction of VOC (such as in coating operations).  The problem is there’s another source of VOC in a city such as Atlanta:  aromatic hydrocarbon from trees.  Atlanta is awash in natural VOC and we found we could never control enough to throttle the reaction.  The important thing about the Olympics is that it showed that if we take cars (a major source of NOx) off the road or reduce their emissions, we can significantly impact smog levels.  So the Olympics contributed to a major policy shift which was implemented in our attainment plans and Atlanta finally met the original standard in the early 2000s.

References

• Chang, M. (1997). Air quality improvements during the 1996 Atlanta Olympics. Journal of Air and Waste Management Association, 47(6), 643-650.

• Lupo, P. J. (1997). Health impacts of air quality changes during the 1996 Atlanta Olympics. Environmental Health Perspectives, 105(9), 1020-1025.