The MPIC Environment-related Asthma Risk (MEAR) Dataset provides global evidence on associations between environmental exposure and risk of childhood and adult asthma. In the current stage, evidence on associations between long-term postnatal exposure to ambient fine particulate matters (PM2.5) is provided. The summarized evidence is from literatures published until May 2023, including the risk for asthma prevalence, incidence, and mortality. We will be updating the evidence and corresponding data continuously. In the near future, evidence on associations between prenatal air pollution exposure and risk of childhood asthma will be publically avaiable. If the MEAR dataset is used, please cite the following publication and our zenodo record: 10.5281/zenodo.13376288, thank you. Ni, R., Su, H., Burnett, R. T., Guo, Y., and Cheng, Y. Long-term exposure to PM2.5 has significant adverse effects on childhood and adult asthma: A global meta-analysis and health impact assessment. One Earth, 2024. https://doi.org/10.1016/j.oneear.2024.09.022