The Harvard Six Cities Study established a scientific foundation for amendments to the Clean Air Act and other EPA regulations.


Environmental Poisons

School researchers have long focused on threats to health, including hazardous substances found in air, water, and the workplace. Their investigations have helped set global standards for protection against environmental contaminants.

When the School was founded, factories and industrial trades were literally poisoning workers, and occupational health had emerged as an urgent concern. From its earliest days, the School has also helped define the field of industrial hygiene.

Beginning in the 1920s, the School developed effective methods for resuscitating victims of illuminated gas poisoning and electric shock. Faculty investigated mercury poisoning in the felt hat industry, and in 1925 took a prescient stance against newly introduced leaded gasoline. And the School developed methods for deterring the adverse health effects of dust concentrations in mines, factories, and quarries.

The School also gained national prominence for investigating radium poisoning among workers who painted luminous watch and clock dials. Decades later, scientists at the School investigated the effects of radioactive fallout from Cold War weapons testing, ­ leading to the establishment of maximum permissible standards for all workers exposed to radiation.

In the 1950s, the School helped establish the connection between environmental exposure to airborne pollutants and subsequent increases in asthma, lung cancer, chronic respiratory disease, and overall death rates. Many of these findings served as scientific underpinnings for regulations enacted by the U.S. Environmental Protection Agency (EPA).

The Six Cities Study began in 1974, in response to an energy crisis during which the nation was burning more high-sulfur coal. One of the most influential, innovative, and longest-running investigations of the effects of air pollution on human health, it established a scientific foundation for amendments to the Clean Air Act and other EPA regulations. Scientists discovered that deaths from lung cancer, lung disease, and heart disease were significantly higher in the most polluted of the cities examined. The study also revealed a lethal connection between small particulate matter and cardiovascular deaths. Perhaps most important, it proved that indoor air quality posed a bigger threat to overall health than did outdoor air.

Today, at the cutting edge of molecular epidemiology, School scientists are using DNA in blood samples from Shanghai textile workers to explore links between airway disease, airborne toxins, and genetic factors, and are developing biologic markers for pollution-induced diseases.

Next: Child and Maternal Health