Contents lists available at ScienceDirect Urban Climate journal homepage: www.elsevier.com/locate/uclim The role of local meteorology on ambient particulate and gaseous species at an urban site of western India Ravi Yadav a,b, ⁎ , L.K. Sahu b , G. Beig c , Nidhi Tripathi b,d , Sujit Maji c , S.N.A. Jaaffrey e a Department of Environmental Science and Engineering, Fudan University, Shanghai-200438, China b Physical Research Laboratory, Ahmedabad 380009, India c Indian Institute of Tropical Meteorology, Pune 411008, India d Indian Institute of Technology, Gandhinagar Palaj, Gandhinagar, India e Department of Physics, Mohanlal Sukhadia University, Udaipur 313001, India ARTICLE INFO Keywords: Particulate matters Carbon monoxide Meteorology India ABSTRACT Dependencies of ambient concentrations of PM 2.5 , PM 10 , CO and O 3 on meteorology in Udaipur of India have been discussed based on the measurements from April 2011 to March 2012. PM 2.5 and CO were highest in winter due to lower PBL depth and calm winds while PM 10 and O 3 were highest in the pre-monsoon season due to convective activities. Lower wind regimes (< 2 km hr -1 ), highest PM 2.5 and CO were 47 ± 20 μgm -3 and 441 ± 170 μgm -3 indicating the accumulation of pollutants while lower levels of PM 2.5 (36 ± 16 μgm -3 ) and CO (317 ± 114 μgm -3 ) indicated the impact of dispersion at higher wind regimes. A positive slope of ΔPM 10 /ΔWS = 4.4 μgm -3 /km hr -1 indicates predominance of natural sources of coarser particles. Higher concentrations of PM 2.5 and CO with correlation coefficient (0.42 and 0.52) under high RH and low temperature during winter season indicate the strong temperature in- version. Negative correlation between PM 10 and RH (r = -0.70) during monsoon indicates the role of rainfall in wetting the soil reducing its aerosolization and particle washout. Rainfall was significant for PM 10 (~53% reduction) than those observed for PM 2.5 and CO. Overall, this study suggests the strong influence of meteorology in the variation of air pollutants. 1. Introduction Ambient air particulate matters (PMs) refer to suspended dust, smoke, soot, pollen and soil particles. PMs are directly emitted (primary sources) or formed by the reaction of gaseous compounds (secondary sources) (Fuzzi et al., 2015). The size of PMs ranges from a few nanometer (nm) to several hundred micrometer (μm). PMs smaller than 2.5 μm of diameter are referred as fine particles while bigger particles (> 2.5 μm) as coarse (IPCC, 2007). Chemically, ambient PMs are complex mixture consisting of different components from a variety of both natural and anthropogenic sources. The chemical composition of PMs varies depending on emission, weather condition, local/regional contributions. The sizes of PMs are directly linked to their potential for causing health problems (Harrison and Yin, 2010). In particular, attention has been focused on PM 2.5 as a metric more closely coupled with adverse health effects than PM 10. The major anthropogenic sectors contributing to PM s include fossil fuel combustion, biomass burning, automobile exhaust, industrial process sources are major emission sources at an urban city of India (Yadav et al., 2014a; Sahu et al., 2011). The major natural sources include the soil re-suspension, dust storm, volcanic eruption, biological particles, debris, etc. In https://doi.org/10.1016/j.uclim.2019.01.003 Received 10 April 2018; Received in revised form 4 December 2018; Accepted 16 January 2019 ⁎ Corresponding author at: Department of Environmental Science and Engineering, Fudan University, Shanghai, China. E-mail addresses: ravi@prl.res.in, ry@fudan.edu.cn (R. Yadav). Urban Climate 28 (2019) 100449 2212-0955/ © 2019 Elsevier B.V. All rights reserved. T