John Seinfeld researches air pollution from the top down. The Louis E. Nohl Professor and professor of chemical engineering at the California Institute of Technology studies the tiny particles in the atmosphere for a broader sense of air quality.
Kirk Smith examines air pollution from the ground up. The professor of global environmental health at the University of California, Berkeley, researches the health consequences of household air pollution from simple biomass fuels such as wood used to heat stoves in rural kitchens.
Both scientists have won the 2012 Tyler Prize for Environmental Achievement, the premier award honoring environmental science of great benefit to humankind. The Tyler Prize laureates will split a $200,000 prize. Each was presented a gold medallion at an April 27 ceremony at the Four Seasons Hotel in Beverly Hills.
Established in 1973, the prize is administered by USC Dornsife. On April 26, the laureates gave public lectures at USC’s Ronald Tutor Campus Center, followed by a reception at the Tyler Environmental Prize Pavilion.
“This is the 39th year the Tyler Prize has been given and USC is very proud of its role in its administration,” Stephan Haas, vice dean of research in USC Dornsife and professor physics and astronomy, said before the lectures. “Much more credit goes to the executive committee of the Tyler Prize who have done an outstanding job in selecting this year’s recipients.”
Seinfeld is an expert in the causes and modeling of pollution in the tropospheric — or the lowest portion of the Earth’s atmosphere. His groundbreaking work has led to the understanding of the origin, chemistry and evolution of particles in the atmosphere.
Decades ago, Seinfeld realized that in order to determine how to curtail smog, a comprehensive model of the atmosphere was needed. In the early ’70s, he created a mathematical model of the Los Angeles atmosphere — the first-ever model of an urban atmosphere. The Clean Air Act now requires states to use such models to direct their air-pollution control planning.
During his lecture, Seinfeld spoke about how soot billowing from diesel trucks and industrial smokestacks may be causing harmful warming effects that could create more severe weather patterns and hotter temperatures worldwide.
“Humans are responsible for the warming that has occurred,” he said. “This is unequivocal.”
Airborne particles, also called aerosols, he said, play an important role in the Earth’s climate. The presence of aerosols like sulfur, nitrate and organic carbon are formed in the atmosphere and cause global cooling. These aerosols serve to mask as much as 50 percent of human-induced global warming, contributing to the uncertainty of knowing to what extent humans are affecting global climate.
“Aerosols cancel some of the warming but the magnitude is uncertain,” Seinfeld said. “This is important in terms of future planning. Imagine that there was no aerosol cooling effect. If there was no aerosol cooling effect we would get the full extent of heating that C02 and the other greenhouse gases are imparting to the Earth.”
Seinfeld also discussed leading a research team that administered one of the largest air-quality experiments in the L.A. Basin.
Air quality in L.A. is far better today than it was when he arrived in 1967, Seinfeld said, an improvement he credits to cleaner cars such as catalytic converters.
Smith was the first to demonstrate that one of the world’s greatest health threats comes from exposure to smoke from the burning of biomass fuels like wood or dung in rural homes. After developing and deploying small, inexpensive microchip-based monitors for field measurements, he has conducted studies in India, China, Nepal, Mexico and Guatemala. In these countries, he has documented a heightened risk of pneumonia, cataracts, tuberculosis, heart disease, and chronic lung disease.
“The next worst thing you can do besides smoking yourself is be around smoke,” Smith said. “Indoor fires are like being around a thousand burning cigarettes per hour. Babies may not smoke, but they are in these homes.”
Since half the world’s population uses these biomass fuels, Smith said, the total health impacts of this exposure represents the second largest environmental risk after contaminated water supplies.
Smith has shown that babies born to mothers cooking with biomass fuel weighed less than those whose mothers used propane, natural gas or electricity. In that study, Smith worked with an international research team at the East-West Center in Honolulu, and analyzed demographic, socioeconomic and health information for a random sample of mothers in Zimbabwe who had given birth from 1993 to 1998. Unlike babies born in most developing countries, those in Zimbabwe routinely have their weights measured at birth. In all, the researchers analyzed 3,559 births.
Because air pollution is so strongly associated with power plants, vehicles and cities, the problem of indoor pollution in Third World countries often flies under the radar.
“But [power plants and vehicles] are not where the highest air pollution levels occur,” Smith said. “This is a kind of a forgotten population. The poor women in rural areas of developing countries are about as low on the totem pole, globally, as you can get. They don’t have anybody speaking for them.”