The term “changing climate” refers to different levels and trends of climate variables (e.g., temperature, humidity, precipitation) over time. The term “extreme climate event” refers to events such as wildfires, floods, heat waves, etc. The objective of this project is to examine changes in associations between health outcomes (hospitalization, emergency visit, mortality), APs (ozone, NO2, PM2.5, SO2, and black carbon) and climate change in Canada. In particular, this study focuses on health outcomes caused by respiratory (ICD-10, J00-J99) and circulatory (I00-I99) diseases by examining 3-decade periods: 1991- 2000, 2001-2010, and 2011-2020. This project will address the following three research questions.Q1: How to detect and estimate the association between climate and air pollutants?Q2: How to detect and estimate the influence of changing climate on AP-related health risks?Q3: How to estimate combined effects of extreme climate events and multi-air pollutants on public health risks?