Epiphytic macrolichens contribute to North American biodiversity, play integral ecological roles, and are useful biomonitors of environmental change. We wished to understand the risks posed to the distribution of 359 common epiphytic macrolichen bioindicators in North America from current levels of air pollution and future climate change. Our dataset consisted of 574,756 records from the Consortium of North American Lichen Herbaria and the USDA-Forest Service Lichens and Air Quality biomonitoring database collected between 1960 and 2024. To map current air pollution vulnerability, we calculated current critical load exceedances for acidity and nutrient nitrogen for each species historic range using 2021 data from the US Environmental Protection Agency Community Multiscale Air Quality v.5.4 and the North American Climate Integration and Diagnostics - Nitrogen Deposition v.1 models. To map climate variability, we used Random Forest, a machine learning method for presence-only data, to model the probability of species’ detections under historical climates and distributions across the US, Canada, and Mexico, integrating 30- year normals for 11 climate variables from the University of British Columbia's ClimateNA. We then input future climate values under the IPCC AR6's Shared Socioeconomic Pathway 5 (+ 8.5 W/m² warming by 2100) and mapped species probabilities of occurrence in 2041-2070. Air pollution threats were greatest in the eastern US and urban corridors of the western US. Future climate conditions reduced median species-level probabilities of detection at their known sites by 15% (upper quartile 20%, range 0-93%) by 2041-2070, with rare species accounting for the largest decreases. Species richness declines can be expected across most of the US except the maritime PNW and highest elevations in the western mountains; the largest contiguous area of highest future species detection declines was the Great Lakes region. In contrast, future climates in southeastern Canada, the Yucatan Peninsula, and parts of southwestern Canada and Alaska suited more species and may offer refugia for species able to migrate there. Results can aid decision-making in air quality management and biodiversity conservation.