Comparison of particle concentration vertical profiles between downtown and urban forest park in Nanjing (China)

This study attempts to characterize and compare the vertical distributions of the PM2.5 and PM10 concentrations in downtown and surrounding national forest park. A contrastive measurement was performed using the portable particle sampler in Nanjing (China), from Apr. 22, 2016 to Jan. 24, 2017. The particle concentrations were found to be negatively associated with height in the forest park. The same but slighter phenomena were also found in the downtown in most time, however, peak values were observed at the height of roadside tall tree (25 m) instead of at the ground level at most of the sampling time. At 100 m, particle concentrations decreased by about 30% in the forest park, and only a 20% attenuation was found in the downtown. An unmanned aerial vehicle (UAV) measurement was conducted under the hypothesis that the roadside trees can limit the vertical diffusion of particles. It was found that the interception of trees could reduce 24% and 26% of the PM2.5 and PM10 concentrations above the road, respectively. The correlation analysis between the particle concentrations and five meteorological parameters (temperature, relative humidity, air pressure, solar energy and precipitation) showed higher correlations in the downtown than in the forest park. Both the temperature and the relative humidity contributed to the variation of the particle concentrations at different heights. This work serves to better understanding of particles dynamic characteristics in urban areas and has a significant implication for assessment of indoor air quality in high-rise buildings.


Ando, M., et al., 1994. Indoor and outdoor air pollution in Tokyo and Beijing super cities. Atmos. Environ. 30, 695–702.

Amato, A., 2015. Drone sales numbers.

Babu, S.S., et al., 2011. Vertical profiles of aerosol black carbon in the atmospheric boundary layer over a tropical coastal station: perturbations during an annular solar eclipse. Atmos. Res. 99, 471–478.

Baroutian, S., et al., 2006. Measuring and modeling particulate dispersion: a case study of Kerman Cement Plant. J. Hazard Mater. 136, 468–474.

Beckett, K.P., et al., 2000. Particulate pollution capture by urban trees: effect of species and wind speed. Global Change Biol. 6, 995–1003.

Bhaskar, B.V., Mehta, V.M., 2010. Atmospheric particulate pollutants and their relationship with meteorology in Ahmedabad. Aerosol. Air Qual. Res. 10, 301–315.

Brauer, M., et al., 2002. Exposure misclassification and threshold concentrations in time series analyzes of air pollution health effects. Risk Anal. 22, 1183–1193.

Bremner, S.A., et al., 1999. Short-term associations between outdoor air pollution and mortality in London 1992-4. Occup. Environ. Med. 56, 237–244.

Calfapietra, C., et al., 2013. Role of Biogenic Volatile Compounds (BVOC) emitted by urban trees on ozone concentration in cities: a review. Environ. Pollut. 183, 71–80.

Chan, C.Y., et al., 2005. Characteristics of vertical profiles and sources of PM2.5, PM10 and carbonaceous species in Beijing. Atmos. Environ. 39, 5113–5124.

Chan, L.Y., Kwok, W.S., 2000. Vertical dispersion of suspended particulates in urban area of Hong Kong. Atmos. Environ. 34, 4403–4412.

Chang, et al., 2017. Health impact assessment in environmental impact assessment in China: status, practice and problems. Environ. Impact Asses. 66, 127–137.

Colls, J.J., Micallef, A., 1999. Measured and modelled concentrations and vertical profiles of airborne particulate matter within the boundary layer of a street canyon. Sic. Total Environ 235, 221–233.

Davidson, C.I., et al., 2005. Airborne particulate matter and human health: a review. Aerosol Sci. Technol. 39, 737–749.

De Paul, F.T., Sheih, C.M., 1985. A tracer study of dispersion in an urban street canyon. Atmos. Environ. 19, 555–559.

Deng, X.J., et al., 2015. Vertical distribution characteristics of PM in the surface layer of Guangzhou. Particuology 20, 3–9.

Doty, S.L., et al., 2007. Enhanced phytoremediation of volatile environmental pollutants with transgenic trees. Proc. Natl. Acad. Sci. Unit. States Am. 104, 16816–16821.

Editoral, 2014. (Barely) living in smog: China and air pollution. Lancet 383 (9920), 845.

Egondi, T., et al., 2016. Measuring exposure levels of inhalable airborne particles (PM2.5) in two socially deprived areas of Nairobi, Kenya. Environ. Res. 148, 500–506.

Fares, S., et al., 2016. Particle deposition in a peri-urban Mediterranean forest. Environ. Pollut. 218, 1278–1286.

Federico, M.R., et al., 1998. Height profile of some air quality markers in the urban atmosphere surrounding a 100 m tower building. Atmos. Environ. 32, 3569–3580.

Franck, U., et al., 2006. Indoor and outdoor submicrometer particles: exposure and epidemiologic relevance (“the 3 indoor Ls”). Environ. Toxicol. 21, 606–613.

Franck, U., et al., 2011. The effect of particle size on cardiovascular disorders–the smaller the worse. Sic. Total Environ 409, 4217–4221.

Harris, T.B., Manning, W.J., 2010. Nitrogen dioxide and ozone levels in urban tree canopies. Environ. Pollut. 158, 2384–2386.

Hasegawa, S., et al., 2007. Vertical profiles of ultrafine to super micron particles measured by aircraft over Osaka metropolitan area in Japan. Atmos. Environ. 41, 717–729.

Herbarth, O., 1995. Risk assessment of environmentally influenced air way disease based on time-series analysis. Environ. Health Perspect. 103, 852–860.

Hitchins, J., et al., 2002. Dispersion of particles from vehicle emissions around high- and low- rise buildings. Indoor Air 12, 64–71.

Hoydysh, W., 1988. Kinematics and dispersion characteristic of flows in asymmetric stray canyons. Atmos. Environ. 22, 2677–2689.

Hu, X.M., et al., 2008. Coupling and evaluating gas/particle mass transfer treatments for aerosol simulation and forecast. J. Geophys. Res. 113, D11.

Iwasaka, Y., et al., 2003. Large depolarization ratio of free tropospheric aerosols over Taklimakan Desert revealed by lidar measurements: possible diffusion and transport of dust particles. J. Geophys. Res. 108, 8652.

Jim, C.Y., Chen, W.Y., 2008. Assessing the ecosystem service of air pollutant removal by urban trees in Guangzhou (China). J. Environ. Manag. 88, 665–676.

Kalaiarasan, M., et al., 2009. Traffic-generated airborne particles in naturally ventilated multi-storey residential buildings of Singapore: vertical distribution and potential health risks. Build. Environ. 44, 1493–1500.

Kim, K.H., et al., 2015. Influence of wind direction and speed on the transport of particlebound PAHs in a roadway environment. Atmos. Pollut. Res. 6, 1024–1034.

Kumar, P., et al., 2008. Pseudo-simultaneous measurements for the vertical variation of coarse, fine and ultrafine particles in an urban street canyon. Atmos. Environ. 42, 4304–4319.

Kwak, H.Y., et al., 2015. A modeling of the rainfall's impact on the air quality via changes of vehicle travel pattern. J. Clim. 10, 4304–4319.

Lei, C., Patterson, J.C., 2003. A direct stability analysis of a radiation-induced natural convection boundary layer in a shallow wedge. J. Fluid Mech. 480, 161–184.

Li, C.L., et al., 2005. Vertical distribution of PAHs in the indoor and outdoor PM2.5 in Guangzhou, China. Build. Environ. 40, 329–341.

Li, X.L., et al., 2007. Vertical variations of particle number concentration and size distribution in a street canyon in Shanghai, China. Sci. Total Environ. 378, 306–316.

Li, X.L., et al., 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. Atmos. Res. 198, 185–193.

Li, X.L., Zhang, H.S., 2014. Soil moisture effects on saltation and dust emission over the Horqin Sandy Land area in China. J. Meteorol. Res. 28, 444–452.

Liu, P.F., et al., 2009. Aircraft study of aerosol vertical distributions over Beijing and their optical properties. Tellus B 61, 756–767.

Longley, I.D., et al., 2004. A case-study of fine particle concentrations and fluxes measured in a busy street canyon in Manchester, UK. Atmos. Environ. 38, 3595–3603.

Manes, F., et al., 2012. Urban ecosystem services: tree diversity and stability of tropospheric ozone removal. Ecol. Appl. 22, 349–360.

MEP (Ministry of Environmental Protection of China), 2016. China environmental status bulletin 2015. Environ. Prot. 11, 43–51.

Minguillon, M.C., et al., 2015. New particle formation at ground level and in the vertical column over the Barcelona area. Atmos. Res. 164, 118–130.

Nanjing Bureau of Statistics, 2014. The Nanjing Statistic Almanac.

Nguyen, T., et al., 2015. Relationship between types of urban forest and PM2.5 capture at three growth stages of leaves. J. Environ. Sci. 27, 33–41.

Nowak, D.J., et al., 2006. Air pollution removal by urban trees and shrubs in the United States. Urban For. Urban Gree 4, 115–123.

Nowak, D.J., et al., 2014. Tree and forest effects on air quality and human health in the United States. Environ. Pollut. 193, 119–129.

Olds, E.G., 1938. Distributions of sums of squares of rank differences for small numbers of individuals. Ann. Math. Stat. 9, 133–148.

Park, S.K., et al., 2004. Dispersion characteristics of vehicle emission in an urban street canyon. Sci. Total Environ. 323, 263–271.

Pateraki, S., et al., 2012. The role of meteorology on different sized aerosol fractions (PM10, PM2.5, PM2.5-10). Sci. Total Environ. 419, 124–135.

Peng, Z.R., et al., 2015. A study of vertical distribution patterns of PM2.5 concentrations based on ambient monitoring with unmanned aerial vehicles: a case in Hangzhou, China. Atmos. Environ. 123, 357–369.

Puth, M.T., et al., 2015. Effective use of Spearman's and Kendall's correlation coefficients for association between two measured traits. Anim. Behav. 102, 77–84.

Qin, Y., Kot, S.C., 1993. Dispersion of vehicular emission in street canyons, Guangzhou City, South China (P.R.C.). Atmos. Environ. Part B Urban Atmos. 27, 283–291.

Quang, T.N., et al., 2012. Vertical particle concentration profiles around urban office buildings. Atmos. Chem. Phys. 12, 5017–5030.

Reddy, K., et al., 2015. Effect of diurnal variation of aerosols on surface reaching solar radiation. J. Atmos. Sol. Terr. Phys. 129, 62–68.

Ren, Z.H., et al., 2008. Influence of synoptic systems on the distribution and evolution process of PM10 concentration in the boundary layer in summer and autumn. Chin. J. Atmos. Sci. 32, 741–751.

Rubino, F.M., et al., 1998. Height profile of some air quality markers in the urban atmosphere surrounding a 100 m tower building. Atmos. Environ. 32, 3569–3580.

Samet, J., Krewski, D., 2007. Health effects associated with exposure to ambient air pollution. J. Toxicol. Environ. Health A. 70, 227–242.

Sasaki, K., Sakamoto, K., 2005. Vertical differences in the composition of PM10 and PM2.5 in the urban atmosphere of Osaka, Japan. Atmos. Environ. 39, 7240–7250.

Strbova, K., et al., 2017. Impact of fugitive sources and meteorological parameters on vertical distribution of particulate matter over the industrial agglomeration. J. Environ. Manag. 203, 1190–1198.

Sun, X., et al., 2013. Seasonal and vertical variations in aerosol distribution over Shijiazhuang, China. Atmos. Environ. 81, 245–252.

Takahashi, M., et al., 2005. Differential assimilation of nitrogen dioxide by 70 taxa of roadside trees at an urban pollution level. Chemosphere 61, 633–639.

Uni, D., Katra, I., 2017. Airborne dust absorption by semi-arid forests reduces pm pollution in nearby urban environments. Sci. Total Environ. 598, 984–992.

Van Donkelaar, A., et al., 2015. Global fine particulate matter concentrations from satellite for long-term exposure assessment. Environ. Health Perspect. 50, 3762–3772.

Villa, T.F., et al., 2017. Determination of the vertical profile of particle number concentration adjacent to a motorway using an unmanned aerial vehicle. Environ. Pollut. 230, 134–142.

Wang, G.H., et al., 2002. Measurements of PM10 and PM2.5 in urban area of Nanjing, China and the assessment of pulmonary deposition of particle mass. Chemosphere 48, 689–695.

Weber, S., et al., 2006. Flow characteristics and particle mass and number concentration variability within a busy street canyon. Atmos. Environ. 40, 7565–7578.

Weingartner, E., et al., 1998. Seasonal variation of size distributions and fine particle formation of continental aerosol at high alpine site. J. Aerosol Sci. 29, S509–S510.

Wu, Y., et al., 2002. Vertical and horizontal profiles of airborne particulate matter near major roads in Macao, China. Atmos. Environ. 36, 4907–4918.

Xiao, Z.M., et al., 2012. Vertical characteristics and source identification of PM10 in Tianjin. J. Environ. Sci. 24, 112–115.

Xie, M., et al., 2016a. Modelling of the anthropogenic heat flux and its effect on regional meteorology and air quality over the Yangtze River Delta region, China. Atmos. Chem. Phys. 16, 6071–6089.

Xie, M., et al., 2016b. Changes in regional meteorology induced by anthropogenic heat and their impacts on air quality in South China. Atmos. Chem. Phys. 16, 15011–15031.

Yli Pelkonen, V., et al., 2017. Urban forests near roads do not reduce gaseous air pollutant concentrations but have an impact on particles levels. Landsc. Urban Plann. 158, 39–47.

Zhao, H., et al., 2013. Characteristics of visibility and particulate matter (PM) in an urban area of Northeast China. Atmos. Pollution Res. 4, 427–434.

Kaynak Göster