The Role of Street Trees in Mitigating Particulate Matter Pollution: A Case Study of PM₂.₅ and PM₁₀ Concentrations in Urban Street Canyon
Article Sidebar
Main Article Content
Abstract
This study evaluates the effectiveness of street trees in reducing particulate matter (PM₂.₅ and PM₁₀) concentrations in an urban street canyon along Sukhumvit Road, Samut Prakan Municipality, Thailand. Field measurements were conducted at pedestrian level (1.5 m height) across three sidewalk microenvironments: beneath tree canopies, between trees, and in open, non-vegetated areas. Real-time particle counters monitored PM levels, temperature, humidity, and wind speed over a two-week period. Results demonstrated consistently lower PM concentrations on sidewalk with street trees. Relative Difference in Concentration (RDC) analysis revealed negative values for 70.8% of PM₂.₅ (17/24) and 75.0% of PM₁₀ (18/24) measurements, with average reductions of 3.74% and 4.11%, respectively, beneath tree canopies. Statistical analysis (ANOVA) confirmed significant PM₁₀ reduction (p = 0.030), while PM₂.₅ differences were marginally non-significant (p = 0.058). Tree canopies also moderated microclimate conditions, lowering ambient temperature by 0.33°C and wind speed by 0.83 m/s compared to non-vegetated areas. These findings highlight street trees as effective, sustainable interventions for urban air quality improvement, particularly for coarse particle (PM₁₀) mitigation. The study provides actionable insights for urban planners and policymakers advocating nature-based solutions in high-density built environments.
Article Details
References
World Health Organization. 2021. WHO Global Air Quality Guidelines: Particulate Matter (PM2.5 and PM10), Ozone, Nitrogen Dioxide, Sulfur Dioxide and Carbon Monoxide. Geneva: World Health Organization.
Thapsaeng, N., Konisranukul, W., and Jirakhajornkul, S. 2019. The influence of urban green spaces on airborne particulate matter pollution. The 6th National and International Academic Conference, Educational Innovation for Sustainable Social Development at Northeastern University (NEUNIC), Thailand on July 20, 2019.
Yli-Pelkonen, V., Setälä, H., and Viippola, V. 2017. Urban forests near roads do not reduce gaseous air pollutant concentrations but have an impact on particles levels. Landscape and Urban Planning. 158: 39-47.
Chen, M., Dai, F., Yang, B., and Zhu, S. 2019. Effects of neighborhood green space on PM2.5 mitigation: Evidence from five megacities in China. Building and Environment. 156: 33-45.
Irga, P.J., Burchett, M.D., and Torpy, F.R. 2015. Does urban forestry have a quantitative effect on ambient air quality in an urban environment? Atmospheric Environment. 12(15): 173-181.
Miao, Y., Zhou, W., Qiu, L., and Liu, H. 2020. How the morphology of urban street canyons affects suspended particulate matter concentration at the pedestrian level: An in-situ investigation. Sustainable Cities and Society. 55: 102042.
Buccolieri, R., Santiago, J.-L., Rivas, E., and Sanchez, B. 2018. Review on urban tree modelling in CFD simulations: Aerodynamic, deposition and thermal effects. Urban Forestry and Urban Greening. 31: 212-220.
Chen, X., Pei, T., Zhou, Z., Teng, M., He, L., Luo, M., and Liu, X. 2015. Efficiency differences of roadside greenbelts with three configurations in removing coarse particles (PM10): A street scale investigation in Wuhan, China. Urban Forestry and Urban Greening. 14(2): 354-360.
Buccolieri, R., Gromke, C., Di Sabatino, S., and Ruck, B. 2009. Aerodynamic effects of trees on pollutant concentration in street canyons. Science of the Total Environment. 407(17): 5247-5256.
Diener, A., and Mudu, P. 2021. How can vegetation protect us from air pollution? A critical review on green spaces’ mitigation abilities for air-borne particles from a public health perspective. Science of the Total Environment. 796: 148605.
Setälä, H., Viippola, V., Rantalainen, A., Pennanen, A., and Yli-Pelkonen, V. 2013. Does urban vegetation mitigate air pollution in northern conditions? Environmental Pollution. 183: 104-112.
Brantley, H.L., Hagler, G.S.W., Deshmukh, P.J., Baldauf, R.W. 2014. Field assessment of the effects of roadside vegetation on near-road black carbon and particulate matter. Science of the Total Environment. 468-469: 120-129.
Gromke, C., and Ruck, B. 2012. Pollutant concentrations in street canyons of different aspect ratio with avenues of trees for various wind directions. Boundary-Layer Meteorology. 144(1): 41-64.
Aristodemou, E., et al. 2018. How tall buildings affect turbulent air flows and dispersion of pollution within a neighbourhood. Environmental Pollution. 233: 782-796.
Vos, P.E.J., Maiheu, B., Vankerkom, J., and Janssen, S. 2013. Improving local air quality in cities: To tree or not to tree? Environmental Pollution. 183: 113-122.
Zhu, C., and Zeng, Y. 2018. Effects of urban lake wetlands on the spatial and temporal distribution of air PM10 and PM2.5 in the spring in Wuhan. Urban Forestry and Urban Greening. 31: 142-156.
Li, X., Ma, Y., Wang, Y., Liu, N., and Hong, Y. 2017. Temporal and spatial analyses of particulate matter (PM10 and PM2.5) and its relationship with meteorological parameters over an urban city in northeast China. Atmospheric Research. 198: 185-193.
Wang, J., Han, J., Li, T., Wu, T. and Fang, C. 2023. Impact analysis of meteorological variables on PM2.5 pollution in the most polluted cities in China. Heliyon. 9(7): e17609.
Xu, Y., Xue, W., Lei, Y., Huang, Q., Zhao, Y., Cheng, S., Ren, Z., and Wang, J. 2020. Spatiotemporal variation in the impact of meteorological conditions on PM2.5 pollution in China from 2000 to 2017. Atmospheric Environment. 224: 117215.
Chen, L., Liu, C., Zhang, L., Zou, R., and Zhang, Z. 2018. Variation in tree species ability to capture and retain airborne fine particulate matter (PM2.5). Scientific Reports. 7(1): 3206.
Miao, Y., Li, Y., and Zhang, Y. 2017. The impact of urban green spaces on particulate matter pollution in metropolitan areas. Environmental Pollution. 229: 186-194.
Miao, C., Yu, S., Hu, Y., Liu, M., Yao, J., Zhang, Y., He, X., and Chen, W. 2021. Seasonal effects of street trees on particulate matter concentration in an urban street canyon. Sustainable Cities and Society. 73: 103097.
Air and Noise Quality Management Division. 2022. Report on the status and management of air and noise pollution in Thailand for the year 2022. Bangkok: Pollution Control Department.
Zhan, N., Lyu, G., Li, X., and Zhang, S. 2020. Study on air pollutants distribution in street canyons affected by interaction of hedgerows and trees. Environmental Science and Technology. 43(6): 101-107.
Nowak, D.J., Hirabayashi, S., Bodine, A., and Greenfield, E. 2013. Modeled PM2.5 removal by trees in ten U.S. cities and associated health effects. Environmental Pollution. 178: 395-402.
Jeanjean, A.P.R., Buccolieri, R., Eddy, J., Monks, P.S., and Leigh, R.J. 2017. Air quality affected by trees in real street canyons: The case of Marylebone neighbourhood in central London. Urban Forestry and Urban Greening. 22: 41-53.
Zhang, K., Batterman, S., and Dion, F. 2011. Vehicle emissions in congestion: Comparison of work zone, rush hour and free-flow conditions. Atmospheric Environment. 45(11): 1929-1939.
Morakinyo, T.E., and Lam, Y.F. 2016. Simulation study of dispersion and removal of particulate matter from traffic by urban trees. Atmospheric Environment. 132: 120-128.
Cai, M., Xin, Z., and Yu, X. 2017. Spatiotemporal variations in PM leaf deposition: A meta-analysis. Environmental Pollution. 231: 207-218.
Mandal, M., Popek, R., Przybysz, A., Roy, A., Das, S., and Sarkar, A. 2023. Breathing fresh air in the city: Implementing avenue trees as a sustainable solution to reduce particulate pollution in urban agglomerations. Plants. 12(7): 1545.
Rahman, M.A., Stratopoulos, L.M.F., Moser-Reischl, A., Zölch, T., Häberle, K.H., Rötzer, T., Pretzsch, H., and Pauleit, S. 2020. Traits of trees for cooling urban heat islands: A meta-analysis. Building and Environment. 170: 106606.
Zender-Świercz, E., Galiszewska, B., Telejko, M., and Starczewska, M. 2024. The effect of temperature and humidity of air on the concentration of particulate matter – PM2.5 and PM10. Atmospheric Research. 312: 107733.
Singh, B.P., Singh, D., Kumar, K., and Jain, V.K. 2021. Study of seasonal variation of PM2.5 concentration associated with meteorological parameters at residential sites in Delhi, India. Journal of Atmospheric Chemistry. 78: 161-176.
Danek, T., Weglińska, E., and Zaręba, M. 2022. The influence of meteorological factors and terrain on air pollution concentration and migration: A geostatistical case study from Krakow, Poland. Scientific Reports. 12: 11050.
Dawson, J.P., Adams, P.J., and Pandis, S.N. 2007. Sensitivity of PM2.5 to climate in the Eastern United States: A modeling case study. Atmospheric Chemistry and Physics. 7(16): 4295-4309.
Abhijith, K.V., Kumar, P., Gallagher, J., McNabola, A., Baldauf, R., Pilla, F., and Pulvirenti, B. 2017. Air pollution abatement performances of green infrastructure in open road and built-up street canyon environments: A review. Atmospheric Environment. 162: 71-86.
Xing, Y., and Brimblecombe, P. 2019. Role of vegetation in deposition and dispersion of air pollution in urban parks. Atmospheric Environment. 201: 73-83.
Liu, J., Zheng, B., Xiang, Y., and Fan, J. 2022. The impact of street tree height on PM2.5 concentration in street canyons: A simulation study. Sustainability. 14(19): 12378.
Emmanuel, R., and Johansson, E. 2006. Influence of urban morphology and sea breeze on hot humid microclimate: The case of Colombo, Sri Lanka. Climate Research. 30: 189-200.
Bowler, D.E., Buyung-Ali, L., Knight, T.M., and Pullin, A.S. 2010. Urban greening to cool towns and cities: A systematic review of the empirical evidence. Landscape and Urban Planning. 97(3): 147-155.
