Students at CCNY and affiliated with the NOAA Hollings Program will carry the Portable Ozone Monitor (POM) [Andersen et al., 2010] and the Personal Air Monitor (PAM) developed at 2B Tech (Boulder, Colorado), concurrently with the Portable Optical Particle Spectrometer (POPS) [Gao et al., 2016] developed by NOAA CSL, in mesh bags attached to a backpack through NYC. The PI will also be in the field and will engage with the students and the CCNY scientists in order to monitor emerging scientific questions. We are aware that we are tasking healthy individuals with exposing themselves to poor air quality and perhaps for extended periods in a way that is outside their normal envelope of exposure. Mitigation options will be pursued such as providing N95 masks for participants and limits in exposure time.
As a starting point, the routes are planned to be mainly between Inwood and Times Square in NYC, with repetitive walks in Inwood Hill Park, Fort Tryon Park, Highbridge Park and Central Park where maximum ozone levels and minimum PM2.5 levels are expected. In contrast, sampled routes will include Broadway, St Nicholas Avenue, Sherman Avenue, George Washington Bridge and Times Square, where minimum ozone levels and maximum PM2.5 levels are expected due to high nitrogen oxide emissions, from car exhaust and other sources, which destroy ozone. We will also include playgrounds and outdoor recreation facilities. Planned routes will cover South Bronx and lower Manhattan as well and the sampled routes will evolve to meet the community's interests.
The deployment will rely on three air quality forecast models (RAP-Chem, WRF-Chem, RAQMS) to inform our deployment so that they occur before, during and after a heat wave event. We are planning on 3 weeks of deployment (21 days that includes 21 July - 18 August 2023) to be coordinated with the CUPiDS campaign research flights which will occur around the same timeframe (15 July - 15 August 2023).
The POM uses the UV absorption at 254 nm technique to measure ozone. Its precision and its accuracy are greater than 1.5 ppb or 2% of the reading. The detection limit is 3 ppbv and the measurement interval is 10 s. It weighs 360 g without the battery and 450 g with the battery. Before being deployed, the POMs will be calibrated against NOAA CSL calibration units.
The PAM measures PM2.5 (fine particulate matter - tiny particles or droplets in the air - that are two and one half microns or less in diameter) using Plantower PMS7003 (laser scattering). The particle size range is 0.3-10 µm. The mass concentration range is 0-999 µm m-3. The count accuracy is 50% at 0.3 µm and 98% at 0.5 µm and above. The response time is less than 10 s. The PAM weighs 440 g.
The POPS is an optical particle sizer that uses a 405 nm diode laser to count and size particles between 0.14-3 µm of diameter. The counting efficiency above 140 nm is greater than 80% with a 1 s temporal resolution. It weighs ~800 g and has a limited power consumption (5W).