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/m³ 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.

2020 年冠状病毒大流行和以下隔离措施已导致全球日常生活发生重大变化。初步研究表明，由于采取了这些措施，许多城市地区的空气质量有所改善。本研究采用邻域尺度方法来量化这种污染变化。使用来自公民托管的低成本颗粒物 (PM) 传感器网络的数据，称为空气质量和您 (AQ&U)，与相对稀疏的状态监测站相比，我们获得了高空间分辨率测量值。我们将2019 年 2 月 11 日至 5 月 11 日期间美国犹他州盐湖县 71 个独特地点的月平均估计 PM _2.5浓度与2020年同一时间范围内相同 (71) 个传感器的测量值进行了比较。- 测试显示，2019 年至 2020 年 3 月 11 日至 4 月 10 日和 4 月 11 日至 5 月 10日期间，估计的每月 PM _2.5浓度分别显着降低（71.1% 和 21.3%） 。3 月时间段对应于该地区最严格的 COVID-19 相关限制。_{3 月份州监测站点也报告了 PM 2.5}的显着下降（与之前的 5 年平均值相比，p < 0.001）。_{虽然我们观察到 2020 年整个山谷的 PM 2.5}浓度有所下降，但需要注意的是，所有地点的 PM _2.5浓度并未均等地改善。我们观察到海拔较低、城市化程度更高的地区减少幅度最大，这可能是因为 PM 水平已经很低_2.5海拔较高，住宅区较多，2019 年和 2020 年均低于 2 μg/m ^3。虽然 3 月和 4 月的许多测量值接近或低于低成本 PM 传感器的估计检测限，但联邦等效测量，每个低成本传感器 (51) 显示，与 2019 年相比，2020 年 3 月的 PM _2.5浓度有所降低。这些结果表明，2020 年 3 月 11 日之后的空气质量改善是由于隔离措施减少了交通和减少区域内污染物排放。