Supporting data for: "T-Rex: the Transportable Radon-222 Explorer for Environmental or Public Health studies" by Hariharan et al.

This file contains atmospheric radon data from two measurement intercomparison periods that form the basis of discussion in the following article submitted to Journal of Environmental Research T-Rex: the Transportable Radon-222 Explorer for Environmental or Public Health studies Abstract We describe the development and testing of a “suitcase sized” 100 L two-filter dual flow-loop radon monitor, weighing ~18 kg, flow rate ~5 L∙min-1, Rn-222 sensitivity ~0.02 s-1∙(Bq∙m-3)-1, temporal resolution 30-minutes, and operational range ~0.3 – 30,000 Bq∙m-3. Its portability and sensitivity make it an ideal “crossover instrument” between the needs of the Public Health and Environmental research communities. Performance was compared with a 200 L two-filter monitor (1.65 m tall, ~80 kg), sampling outdoor air over 3 weeks during which radon varied between 0.14 Bq∙m-3 and 9.1 Bq∙m-3. The distribution (10th/50th/90th percentile) of absolute hourly bias was 0.03/0.19/0.54 Bq∙m-3. A separate comparison was made with an AlphaGUARD PQ2000 Pro and DF2000 over 8 days during which radon ranged from 0.6 Bq·m-3 to 9.9 Bq·m-3. The reported 8-day average radon was 3.5±1.97 Bq·m-3 (100 L monitor), 4.01±2.92 Bq·m-3 (PQ2000 Pro) and 4.24±2.65 Bq·m-3 (DF2000). Daily mean absolute bias reached 1.7 Bq·m-3, and absolute bias of 6-hourly means reached 3.2 Bq·m-3. For the PQ2000 and DF2000, hourly measurement uncertainty reached 30 % at 6 Bq·m-3 and 4.5 Bq·m-3, respectively (c.f. manufacturers reported detection limit of 2 Bq·m-3). The 100 L monitor reached 30 % uncertainty at 0.35 Bq·m-3. While this does not meet the measurement criteria for Global Atmosphere Watch “baseline” monitoring (detection limit ≤0.05 Bq∙m-3), the monitor would be well suited for many environmental monitoring purposes and portable enough for indoor use.