Yes, it will truly be a shame if Beijing’s air pollution prevents the world’s premier athletes from performing at their best in the 2008 Olympics. It will point a frightening, symbolic finger at what our civilization is doing. But Anna Michel, post doctoral mechanical engineer at Princeton University, reminds people that there is much more at stake globally.
Urban air pollution knows no justice. It does not remain some localized wound, deservedly inflicting only the area that negligently fostered it. The real tragedy is the many thousands who are suffering from these toxic emissions worldwide. Right now, these toxins are ruining the ozone for a small schoolgirl in Ireland and adding to a senior’s asthma in South Brunswick.
Michel is part of nine-a scientist team at Princeton that is finalizing the development of a laser spectroscopy sensor that will be tested at the 2008 Olympics. If it proves successful, it could be a very useful tool in determining air quality worldwide. But will this beneficial device find a production company? Or will it get clogged in that notorious bottleneck between academe and industry where so many needed inventions are lost? To help ease this academic discovery-to-marketplace bottleneck, Princeton is holding its annual University-Industry Research Symposium on Monday and Tuesday, March 17 and 18, at 7:30 a.m. at the Friends Center Auditorium. Cost: $150. Visit www.prism.princeton.edu.
This event will present a host of inventive speakers, displaying their wares within two categories: "Materials for Energy," and "Photonics, Sensors & Networks." Developed at several universities, the inventions range from energy efficient devices based on nanostructured thin films, to ultrafast optical information processors. Representing her team, Michel will present "Laser Spectroscopy from the Laboratory to the Stratosphere: New Instrumentation for Understanding Global Climate Change."
The team is drawn mostly from MIRTHE – Mid-Infrared Technologies for Health and Environment. It includes professors Claire Gmachl and Jim Smith, director and deputy director of MIRTHE, respectively. Along with these, Michel continues to refine the system. A native of Stratford-on-Avon, England, Michel emigrated to the United States and entered MIT, earning a bachelor’s in mechanical engineering in l998. She remained at MIT to complete her doctorate, then moved to Woods Hole Oceanographic Center, where she studied the chemical makeup of the seas. "It’s not a great a leap from oceans to air as you might think," she says, "In each case I was using laser spectroscopy." She joined the Princeton MIRTHE as a postdoctoral associate in September.
After "Eureka!" Once created, each of the seminar’s highly technical applications face two possible fates. They can end up as a written paper or journal article and gather dust in the Firestone Library archives. Or they go forward as products to the shelves and possibly bring some benefit to society. The symposium sponsors very much want the later.
PRISM – Princeton Institute for Science and Technology of Materials – was founded to help cross academic boundaries and aid in the development of multidiscipline prototypes. Likewise, co-sponsor MIRTHE is a Princeton University research center seeking interdisciplinary applications to aid the environment and homeland security. Joe Montemarano, who acts as industrial liaison for both sponsoring groups, and John Rutter, head of Princeton’s Technology Transfer Office, have brought several inventions to market. And both see great potential for Michel’s sensor.
Our filthy air. If one is going to fix the problems of pollution, one must first know the polluter. To determine the what and where of urban pollution, Michel and the MIRTHE team focused on the three most threatening and prolific air pollutants: ozone, ammonia, and carbon dioxide.
Industrial and auto-emitted ozone present one of the biggest health challenges to millions of urban dwellers. Airborne ammonia, often an agricultural byproduct, penetrates deep into the lungs, causing untold pulmonary and cardiovascular injuries. Carbon dioxide is the prime greenhouse gas, engendering potentially disastrous climate change. Measuring these trace gases and finding the sources is the first step toward control. Recent tests showing that a third of New Jersey’s carbon dioxide emissions are transportation based has given the NJDEP new direction.
Sensing pollution. The Princeton MIRTHE team’s sensor employs a quantum cascade laser technology that senses and reports back the three trace gases to be analyzed. The lasers are mounted on a high point in the city and fired at a mirror 100 to 200 yards away. The laser radiation is then reflected back from the mirror to a detector, having passed through air, laced with the trace particles, along the way. Each of the selected particles effects the amount of light returning to the detector. Thus the amount of returning light indicates the quantities of ozone, ammonia, or carbon dioxide.
The detector is connected to a data acquisition system (the amazingly innovative part of the process) and a computer. From here various algorithms are employed to determine the concentrations and a spectrographic chart can be printed out.
The experimental fine tuning for all this is painstaking and tedious. The quantum cascade lasers are tiny tunable laser sources with an extremely broad wavelength. The good news is that this wavelength range falls within the prime absorption areas of the three trace gases. Each gas detection, however, entails its own precise setting and variables, such as water vapor, bound to skew results.
Versions of the device have been tested in Baltimore and New York. Maxion technologies has designed the laser transmitter and Daylight Solutions has developed a field pack for the unit. With these industrial collaborators, and continued experimentation, the team should be ready by June for its big event.
Olympian proving ground. This year’s Olympics will test more than the globe’s top athletes. "Every serious team from all over the world with an air quality sensor will have it operating at the Beijing Olympics," says Michel. Will the Princeton MIRTHE team take the gold? "I think we have the state of the art technology, but it (the sensor) is not finished yet and we are racing."
Once the team brings its sensor it will set it up with their partner, the Institute of Atmospheric Physics, in the Chinese Academy of Science. The Academy building is located sufficiently close to the Olympic stadium to get accurate readings for all three gasses. Since Beijing has planned to shut down several industries and limit auto traffic, the effects should vary the city’s normal air quality dramatically. Thus to get a full picture, the team will arrive early in June and keep its sensor up and running through August, in hopes of recording before, during, and after data.
At the end of August, the Chinese Institute and the Princeton team will jointly process the data and determine the results. If the quantum cascade laser proves to be the top precision tool for measuring air quality, it could be further refined and prepared for commercial production.
"Cities could potentially use this system for measuring specific pollutants in their air, and take action to limit the particles," says Michel.