TY - JOUR
T1 - Application of roadside air purifiers in urban street canyons
T2 - A pilot-scale study in Hong Kong
AU - Li, Xinwei
AU - Han, Shuwen
AU - Wang, Pengge
AU - Mei, Han
AU - Ning, Zhi
AU - Dong, Fan
AU - Cui, Long
AU - Huang, Yu
AU - Wang, Tao
AU - Leu, Shao Yuan
AU - Wang, Meng
AU - Lee, Shun cheng
N1 - Publisher Copyright:
© 2023 Elsevier B.V.
PY - 2024/2/20
Y1 - 2024/2/20
N2 - The implementation of roadside air purifiers has emerged as an effective active control measure to alleviate air pollution in urban street canyons. However, technical questions raised under real conditions remain challenging. In this study, we conducted a pilot-scale investigation involving seven units of self-designed roadside air purifiers in an urban street canyon in Hong Kong. The air cleaning effects were quantified with an air quality sensor network after rigorous quality control. The removal efficiencies of Nitrogen dioxide (NO2), Fine suspended particulates (PM2.5), Carbon monoxide (CO), and Nitric oxide (NO) were determined by comparing with simultaneously measured ambient concentrations, with hourly average efficiencies of 14.0 %–16.9 %, 3.5–10.0 %, 11.9 %–18.7 %, and 19.2 %–44.9 %, respectively. Generally, the purification effects presented variations depending on the ambient pollutants' levels. Higher ambient concentrations of NO2, PM2.5, CO correlated with increased purification effects, while NO presented the opposite trend. The influence of interval distance combined with spatial distribution indicated the operation of purifiers will induce local NO2 attenuation even at an interval distance of four meters. Statistical analysis delivered evidence the air cleaning ability exhibited optimal performance when relative humidity level is ranged from 70 % to 90 %, aligning with the prevailing conditions in Hong Kong. Additionally, improved purification effects were observed at the downwind direction, and their performance was enhanced when the wind speed exceeded 2.5 m/s. Moreover, we estimated the operational lifetime of the air purifiers to be approximately 130 days, offering crucial information regarding the filter replacement cycle. This work serves as a pioneering case study, showcasing the feasibility and deployment considerations of roadside air purifiers in effectively controlling air pollution in urban environments.
AB - The implementation of roadside air purifiers has emerged as an effective active control measure to alleviate air pollution in urban street canyons. However, technical questions raised under real conditions remain challenging. In this study, we conducted a pilot-scale investigation involving seven units of self-designed roadside air purifiers in an urban street canyon in Hong Kong. The air cleaning effects were quantified with an air quality sensor network after rigorous quality control. The removal efficiencies of Nitrogen dioxide (NO2), Fine suspended particulates (PM2.5), Carbon monoxide (CO), and Nitric oxide (NO) were determined by comparing with simultaneously measured ambient concentrations, with hourly average efficiencies of 14.0 %–16.9 %, 3.5–10.0 %, 11.9 %–18.7 %, and 19.2 %–44.9 %, respectively. Generally, the purification effects presented variations depending on the ambient pollutants' levels. Higher ambient concentrations of NO2, PM2.5, CO correlated with increased purification effects, while NO presented the opposite trend. The influence of interval distance combined with spatial distribution indicated the operation of purifiers will induce local NO2 attenuation even at an interval distance of four meters. Statistical analysis delivered evidence the air cleaning ability exhibited optimal performance when relative humidity level is ranged from 70 % to 90 %, aligning with the prevailing conditions in Hong Kong. Additionally, improved purification effects were observed at the downwind direction, and their performance was enhanced when the wind speed exceeded 2.5 m/s. Moreover, we estimated the operational lifetime of the air purifiers to be approximately 130 days, offering crucial information regarding the filter replacement cycle. This work serves as a pioneering case study, showcasing the feasibility and deployment considerations of roadside air purifiers in effectively controlling air pollution in urban environments.
KW - Hong Kong roadside
KW - Meteorological variables
KW - Roadside air purifiers
KW - Urban air pollution
UR - http://www.scopus.com/inward/record.url?scp=85178381302&partnerID=8YFLogxK
U2 - 10.1016/j.scitotenv.2023.168671
DO - 10.1016/j.scitotenv.2023.168671
M3 - Journal article
AN - SCOPUS:85178381302
SN - 0048-9697
VL - 912
JO - Science of the Total Environment
JF - Science of the Total Environment
M1 - 168671
ER -