Discipline: Ecology Environmental and Earth Sciences
Cristan Zdanski - North Carolina Central University
Particulate Matter (PM), especially PM 2.5, is considered to be hazardous to human health when elevated levels are exposed to the respiratory system. Traditional PM 2.5 monitoring has a very limited spatial coverage due to fixed physical locations and thus there were many attempts to employ Aerosol Optical Depth (AOD) data derived from moderate-resolution imaging spectroradiometer (MODIS) imagery as an alternative. Research relating to PM 2.5 and AOD at ground level was needed to evaluate the AOD-PM 2.5 correlation at a station level. Previous examinations using data collected on a day in each of the four seasons of the year had a poor temporal correlation but a seasonal variance in the correlations was noted. Ongoing research of archival, 2012, AOD-PM 2.5 correlation of fixed sites in North Carolina in the one kilometer (1200 meter2) range reinforced poor temporal correlation values, but when each site was examined individually the correlated values were promising. The ground level data when looking at the correlated seasonal variance, different correlations for different bands relating to each season, and the promising results of archived individual fixed station sites, the hypothesis that for ground level instruments, the sites examined individually in each season, covering more than four days would result in seasonal correlations in the site to season comparison. Ground level data collected by a MICROTOPS handheld Sun Photometer was used to provide a ground level AOD on a clear day and a handheld continual mass air sampling unit, METONE AEROCET, was used to provide ground level PM readings. The data was collected as follows: North Carolina Central University (NCCU) parking deck, industrial site, residential neighborhood, high traffic intersection, and commercial/retail site. The NCCU parking deck contained a METONE BAM, a fixed site that measured PM 2.5 by beta attenuation mass. This was the control point. The study of data was expanded to cover all three months in each of the four seasons. The purpose of this study in Durham, N.C., was correlating the AOD-PM 2.5 values by site and season of the ground level data collected. The MICROTOPS measured direct solar radiation at five wavelengths: 380, 440, 500, 675, and 870 nanometers (nm) almost instantly. The results of the measurements were ozone concentration and AOD. The METONE AEROCET sampled air in roughly one minute intervals and gave readings on PM1, PM2.5, PM 4, PM 10, and Total Suspended Particles. The METONE AEROCET measured in micrograms. This study only dealt with MICROTOPS individual wavelengths and METONE AEROCET PM 2.5.
The results were as follows: Summer 2015, 380nm, 44onm, 500nm, and 675 nm good, fall 2015, 440nm, and 500nm fair, winter 2015, 675nm, and870nm good, spring 2016, 500nm, and 675nm good. Overall the site correlations were fair. That raises topics for further study. What causes the seasonal variance? The data has been collected for the year and expanding the data to cover the entire year to see if the variance occurs and when it starts to shift. Site correlation has shown some promise. Ground based handheld instruments to measure sites that are far removed from a stationary site, with confidence, is needed.
Funder Acknowledgement(s): National Science Foundation
Faculty Advisor: Zhiming Yang, email@example.com
Role: I was a part of the data collection team. I received the raw data from the data entry person. I analyzed the data and brought it in to EXCEL where I made the data presentable.