Rural / low-income U.S. communities have high risks of experiencing health impacts induced by extreme heat and poor air quality events. The primary care safety net community health centers (CHCs) serving these populations are uniquely positioned to prepare for and mitigate these impacts, as CHCs are trusted care providers in their communities and have expertise in improving their health. To intervene successfully, CHCs need to be equipped with evidence on: (1) how extreme heat and poor air quality events impact health outcomes in CHC populations (which differ substantially from those in other care settings); and (2) what interventions CHCs can enact to effectively prepare for and mitigate these impacts. The Community Catalyst (ImpaCts of extreme heAT and Air quaLitY reSearch cenTer) Center will provide this evidence, and the proposed planning process will prepare the Center to do so as follows. Our Administrative Core will assemble a transdisciplinary team of experts in extreme heat / poor air quality and health, contextual drivers of health and related interventions, intervention development and implementation / dissemination, community-engaged research, and primary care in CHCs. The Administrative Core will also create the data infrastructure needed to study the health impacts of extreme heat and poor air quality events in CHC populations by linking existing, robust, geocoded research-ready electronic health record data from the OCHIN Practice-based Research Network (>1,700 CHC clinic sites in 36 states) with existing granular data on extreme heat events and air quality created by the Confluence Project. Our Research Program Core will use this dataset in novel analyses to identify how extreme heat and poor air quality impact hypertension and asthma incidence and exacerbation in CHC patients, and the effect modifiers of these impacts. Our Community Engagement Core will convene a learning community of researchers and representatives from CHCs (leaders, staff, patients) and other relevant community organizations (e.g., public health departments). In a multidirectional, iterative process, this Center learning community will identify: (1) interventions that have potential to mitigate the health impacts of extreme heat and poor air quality events in CHC populations, and (2) the research needed to generate evidence on such interventions’ effectiveness. The Center will then be prepared to immediately begin conducting research that is led by community-researcher partnerships and designed to address community-identified evidence needs on how CHCs can prepare for and mitigate the health impacts of extreme heat and poor air quality events in their populations.