Air quality has deteriorated in Hong Kong over more than 15 yr. As part of a program of public accountability, photographs on Poor and Better visibility days were used as representations of the relationships among visibility, air pollution, adverse health effects, and community costs for health care and lost productivity. Coefficients from time-series models and gazetted costs were used to estimate the health and economic impacts of different levels of pollution. In this population of 6.9 million, air quality improvement from the annual average to the lowest pollutant levels of Better visibility days, comparable to the World Health Organization air quality guidelines, would avoid 1335 deaths, 60,587 hospital bed days, and 6.7 million doctor visits for respiratory complaints each year. Direct costs and productivity losses avoided would be over US$240 million a year. The dissemination of these findings led to increased demands for pollution controls from the public and legislators, but denials of the need for urgent action arose from the government. The outcome demonstrates the need for more effective translation of the scientific evidence base into risk communication and public policy.