Influence of Meteorological Factors on Submicron Particles in the Urban Atmosphere in Hangzhou

Abstract

With rapid economic development, the size of road vehicle fleet has increased dramatically in China. In order to characterise the impact of meteorological factors on the emission of submicron particles from vehicles in the urban atmosphere, a model study was conducted in Hangzhou, a fast-developing contemporary city located along the Southeast coast of China. An autoregressive integrated moving average model was used to explore the effects of the meteorological factors on the ultrafine particle (UFP) and particulate matter 1.0 (PM1.0) concentrations. Results showed that the average UFP concentration was 45,805 (10,428~147,350) particles cm-3 and the average concentration of PM1.0 was 217 (30 ~506) g m-3 during the survey period. While relative humidity (p=0.011) was positively correlated with the UFP concentration, barometric pressure (p<0.001) and wind velocity (p=0.003) were inversely correlated with the UPF concentration. Relative humidity (p=0.022) and wind speed (p=0.023) were also significant predictors of the PM1.0 concentration. Results from this study suggest that meteorological factors should be taken into consideration in interpretation of air monitoring results for submicron particles as unfavourable meteorological factors may play a role in the formation of new air pollutants and change the ability of the atmosphere to scatter/disperse air pollutants. This study provides first hand information on UFP and PM1.0 emission levels and a model that can be used in future with large scale time series data to predict the impact of meteorological factors on submicron particle concentrations in the urban atmosphere.