Rashmi Prava Mohanty, Mark A. Buchheim, PhD, Estelle Levetin, PhD, FAAAAI; University of Tulsa, Tulsa, OK, University of Tulsa. RATIONALE: Microscopic analysis of air samples fails to determine the pollination season overlap between various species with morphologically similar pollen such as members of the Cupressaceae and Poaceae. Previously, we showed it was possible to use PCR to identify Juniperus ashei pollen from air samples. The present study was undertaken to determine if qPCR could be used to determine airborne pollen counts for three Juniperus species and define the pollination season overlap. METHODS: The atmosphere in Tulsa, OK(USA) was monitored with a Burkard sampler and analyzed by microscopy using standard methods. A second Burkard sampler was used from 2013 to 2015 for molecular analysis; 109 samples were tested with species-specific primers and probes designed for J.ashei, J.pinchotii and J.virginiana. Numbers of pollen grains obtained from microscopy were compared with numbers obtained from qPCR by Spearman correlation coefficient. RESULTS: Cupressaceae pollen was detected in the Tulsa atmosphere from October through April. The qPCR counts for total Juniperus pollen showed a significant correlation with the microscope counts, R50.92, p<0.001. Quantitative PCR data showed overlapping pollen seasons. In the fall, data indicated five days (in two years) with both J.pinchotii and J.ashei pollen. Similarly, in January and February eight days (in two years) indicated both J.ashei and J.virginiana pollen in the air. CONCLUSIONS: This approach is a rapidmethod to identify and quantify specific pollen types and the pollen season overlap where species and genera cannot be distinguished by microscopy. Defining the exact pollination season will be a benefit for patients sensitive to pollen from specific taxa.