Short summary: With a focus on climate change and air pollution, this project involves a longitudinal data collection effort across metro areas in USA, Italy, and China. Survey, news, social media, weather, and air pollution data will be collected on a daily basis. Partnering institutions: Bocconi University, Columbia University (USA), Princeton University (USA), Peking University (China) Research focus: attitudes and behaviors related to climate change and air pollution. Secondarily we are measuring attitudes related to immigration, unemployment, terrorism, and the economy. Target cities: Milan (Italy), Rome (Italy), New York (USA), Dallas (USA), Beijing (China), and Shanghai (China) metropolitan areas. Data sources: survey responses, social media activity, and news articles related to climate change, air pollution, and the additional topics. Timeline: all data collected on a rolling basis for at least 10 months. Summary: Attitudes about environmental problems can vary substantially from one person to another, from one country to another, and from one day to the next. What causes attitudes about climate change to rally or dissipate in humans? How much of an effect does extreme weather have? Does coverage of climate change or air pollution in the news influence opinions? Can the public perceive dangerous levels of air pollution? In this project we are shedding light on the drivers of attitudes and action on climate change and air pollution. We have designed a survey instrument that measures citizens’ attitudes about climate change, air pollution, and other issues (terrorism, immigration, unemployment, and problems with the economy) in three countries (Italy, USA, and China). We are targeting six cities and their metropolitan areas (Milan, Rome, New York, Dallas, Beijing, and Shanghai). In addition to the survey data, we are collecting and analyzing public records of discussions about climate change, air pollution, and the other target issues on social media and news media. Additionally, we are recording daily weather and air pollution measurements in our target cities. The multi-method dataset built with this project will allow an unprecedented view of what influences attitudes and behaviors related to climate change and air pollution. By learning more about what influences public attitudes and action, we can refine climate and air pollution policies, communications, and long-term mitigation strategies. Data collection will be ongoing for at least ten months. By measuring citizens’ attitudes and behaviors over time we can unveil the impact of events such as marches, speeches, policy changes, extreme storms, film releases, and more.