Using Low-cost sensors to Quantify the Effects of Air Filtration on Indoor and Personal Exposure Relevant PM2.5 Concentrations in Beijing, China

Abstract

Residents of polluted cities frequently use indoor air purifiers in an attempt to improve their health by reducing their exposure to air pollutants, despite the fact that few studies have assessed these devices under relevant field conditions. Low-cost air monitors are increasingly popular for monitoring air pollution exposure; however, they must be calibrated and evaluated in their deployment location first to ensure measurement accuracy and precision. In this study, we developed a 2-step calibration method in which a low-cost monitor is calibrated against a reference analyzer and is then used to calibrate other monitors, shortening the required calibration time and reducing measurement error. The monitors in our experiment measured indoor, outdoor, and personal exposure PM 2.5 concentrations during 1 week each of true and sham filtration in 7 homes in Beijing, China. On average, filtration reduced the indoor and personal exposure relevant concentrations by 72% (std. err. = 7%) and 28% (std. err. = 5%), respectively. This study indicates that minimizing personal exposure, however, also requires reducing the infiltration of outdoor air in homes or decreasing PM 2.5 pollution at the city or country level.

Real‐time measurements of PM2.5and ozone to assess the effectiveness of residential indoor air filtration in Shanghai homes

“…These monitors include Plantower PMS3003 sensors for PM 2.5 and Alphasense OX‐A4 sensors for O 3 . These monitors have been thoroughly evaluated for measuring ambient PM 2.5 in both high and low concentration environments 28,43 and have been used for ambient, indoor, personal exposure, and source measurements of PM 2.5 28,44‐46 and O 3 47,48 . In addition, both the performance of the individual Plantower 49‐55 and specifically the Plantower PMS3003 56‐60 have been widely studied.…”

“…Portable air cleaners are commonly used in highly polluted regions, including China, to reduce indoor PM 2.5 18,19 . Previous work has shown that residential use of portable air cleaners can reduce indoor PM 2.5 in highly polluted regions 21‐29 and, in some cases, can improve health 21‐25 . In addition to PM 2.5 , O 3 concentrations are above WHO health guidelines in many Chinese cities 3 .…”

“…In general, the effectiveness of indoor air filtration is highly variable depending on the filtration device and the environment in which it is deployed, 33 and few studies have focused on measuring the impacts of portable air cleaners on personal exposure to PM 2.5 in Chinese cities 24,27,28 . Although mechanical filtration (eg, HEPA filters) alone can reduce O 3, it may lead to O 3 formation by‐products by increasing the amount of surface area over which O 3 formation can occur.…”

Observed Interactions Among Haze, Fog and Atmospheric Boundary Layer during a Haze-fog Episode in the Yangtze River Delta Region, Eastern China

“…Because of the increasing energy consumption associated with rapid urbanization and industrialization, many regions of China, especially megacities and city clusters in coastal eastern China, have experienced high levels of air pollution (He et al, 2002;Chan and Yao, 2008;Tie and Cao, 2009;He et al, 2013;Ding et al, 2016a;Zhao et al, 2018;Barkjohn et al, 2020). In these regions, fine particular matter (PM2.5; particles with an aerodynamic diameter of 2.5 microns or lower in ambient air) often attains extremely high concentrations during the winter haze period (Ding et al 2013a;Huang et al, 2014;Guo et al, 2014;Zhang et al, 2014;Chen et al, 2017;Ma et al, 2017;Liu et al, 2019).…”

Connecting Air Quality with Emotional Well-Being and Neighborhood Infrastructure in a US City

“…However, the neighborhoods housed by 3 of these 4 monitors did not meet our other neighborhood criteria, so to measure suitable neighborhood PM 2.5 levels we use low-cost air quality sensors that were deployed and evaluated during a number of previous studies. [55][56][57][58] In this study, the monitors were deployed in the backyards of residents' homes. The selection criteria for the homes included no close-proximity (within 10 s of meters) sources (eg, fire pit, back alleyways for cars/parking, lawn mowing; the study was conducted from October to April, limiting lawn mowing and similar activities), no nearby construction (also limited by the choice of study period), and being at least one house away from a street intersection.…”