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, examines 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. Established in 1973, the prize is administered by the USC Dornsife College of Letters, Arts and Sciences. Each of the Tyler Prize laureates, who will split a $200,000 prize, received a gold medallion at a ceremony held on April 27 in Beverly Hills.
“This is the 39th year the Tyler Prize has been given, and USC is very proud of its role in its administration,” said Stephan Haas, vice dean of research at USC Dornsife and professor of physics and astronomy. “Much more credit goes to the executive committee of the Tyler Prize, which did an outstanding job in selecting this year’s recipients.”
On April 26, the laureates gave public lectures at the Ronald Tutor Campus Center, followed by a reception at the Tyler Environmental Prize Pavilion.
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 1970s, he created a mathematical model of the Los Angeles atmosphere — the first ever of an urban atmosphere. The Clean Air Act now requires states to use such models to direct air-pollution control planning.
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, such as 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 Los Angeles Basin.
Air quality in Los Angeles is far better today than it was when he arrived in 1967, Seinfeld said, an improvement he credited to a catalytic converter, an exhaust emission control device.
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, such as wood or dung, in rural homes. After developing and deploying small, inexpensive microchip-based monitors for field measurements, he conducted studies in India, China, Nepal, Mexico and Guatemala, where 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, he 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.”