The 2020 coronavirus pandemic and the following quarantine measures have led to significant changes in daily life worldwide. Preliminary research indicates that air quality has improved in many urban areas as a result of these measures. This study takes a neighborhood-scale approach to quantifying this change in pollution. Using data from a network of citizen-hosted, low-cost particulate matter (PM) sensors, called Air Quality & yoU (AQ&U), we obtained high-spatial resolution measurements compared to the relatively sparse state monitoring stations. We compared monthly average estimated PM 2.5 concentrations from February 11 to May 11, 2019 at 71 unique locations in Salt Lake County, UT, USA with the same (71) sensors’ measurements during the same timeframe in 2020. A paired t -test showed significant reductions (71.1% and 21.3%) in estimated monthly PM 2.5 concentrations from 2019 to 2020 for the periods from March 11-April 10 and April 11-May 10, respectively. The March time period corresponded to the most stringent COVID-19 related restrictions in this region. Significant decreases in PM 2.5 were also reported by state monitoring sites during March (p < 0.001 compared to the previous 5-year average). While we observed decreases in PM 2.5 concentrations across the valley in 2020, it is important to note that the PM 2.5 concentrations did not improve equally in all locations. We observed the greatest reductions at lower elevation, more urbanized areas, likely because of the already low levels of PM 2.5 at the higher elevation, more residential areas, which were generally below 2 μg/m 3 in both 2019 and 2020. Although many of measurements during March and April were near or below the estimated detection limit of the low-cost PM sensors and the federal equivalent measurements, every low-cost sensor (51) showed a reduction in PM 2.5 concentration in March of 2020 compared to 2019. These results suggest that the air quality improvement seen after March 11, 2020 is due to quarantine measures reducing traffic and decreasing pollutant emissions in the region.
ObjectiveTo determine whether hamster and human tissues generate similar amounts of aerosolized particles using common otolaryngology surgical techniques.Study DesignQuantitative experimental research.Study SettingUniversity research laboratory.MethodsDrilling, electrocautery, and coblation were performed on human and hamster tissues. Particle size and concentration were measured during the surgical procedures using a scanning mobility particle sizer and an aerosol particle sizer (SMPS‐APS) and GRIMM aerosol particle spectrometer.ResultsSMPS‐APS and GRIMM measurements detected at least 2‐fold increases in aerosol concentrations compared to baseline during all procedures. Procedures performed on human and hamster tissues produced similar trends and order of magnitude of aerosol concentrations. Generally, hamster tissues produced higher aerosol concentrations compared to human tissues, and some of these differences were statistically significant. Mean particle sizes for all procedures were small (<200 nm), although statistically significant differences in particle size were identified between human and hamster tissues during coblation and drilling.ConclusionAerosol‐generating procedures performed on human and hamster tissue produce similar trends in aerosol particle concentrations and sizes, although we observed some differences between the 2 tissue types. Further studies should be performed to understand the clinical significance of these differences.
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