Seasonal Levels, Sources, and Health Risks of Heavy Metals in Atmospheric PM2.5 from Four Functional Areas of Nanjing City, Eastern China

Xiao-San Luo,Zhen Zhao,Long Cang,Lichun Wu,Jiangli Yang,Mingwei Tang,Hongbo Li,Jie Yang

doi:10.3390/atmos10070419

Abstract

Aerosol pollution is a serious environmental issue, especially in China where there has been rapid urbanization. To identify the intra-annual and regional distributions of health risks and potential sources of heavy metals in atmospheric particles with an aerodynamic diameter less than or equal to 2.5 μm (PM2.5), this work collected monthly PM2.5 samples from urban, industrial, suburban, and rural areas in Nanjing city during 2016 and analyzed the heavy metal compositions (Cu, Pb, Cd, Co, V, Sr, Mn, Ti, and Sb). Enrichment factors (EFs) and principal component analysis (PCA) were applied to investigate the sources. The atmospheric PM2.5 pollution level was highest in the industrial area, followed by the urban and suburban areas, and was the lowest in the rural area. Seasonally, the concentrations of PM2.5 and associated heavy metals in spring and winter were higher than those in summer and autumn. Besides natural sources, heavy metal pollution in PM2.5 might come from metallurgical dust in the industrial area, while it mainly comes from automobile exhaust in urban and suburban areas. Health risk assessments revealed that noncancerous hazards of heavy metals in PM2.5 were low, while the lifetime cancer risks obviously exceeded the threshold. The airborne metal pollution in various functional areas of the city impacted human health differently.

Highlights

Atmospheric particulate matter (PM) contributes to air pollution continuously [1] and has critical influences on both the environment and human health
Objectives of this study were to investigate and compare the seasonal distribution characteristics, Since previous research has already focused on the air pollution level of heavy metals [17], the sources, and human health risks of PM2.5-bound heavy metals in different functional areas of a typical objectives of this study were to investigate and compare the seasonal distribution characteristics, megacity in eastern China
China released an ambient air quality standard (Chinese NAAQS II) of 75 μg/m3 PM2.5 for 24 h [32], which is lower than the previous threshold value but still much higher than the values of the World Health Organization (WHO) AQG

Summary

Introduction

Atmospheric particulate matter (PM) contributes to air pollution continuously [1] and has critical influences on both the environment and human health. The chemical composition of PM can better identify pollution sources and explain the associated health inhaled into the respiratory tract They remain in the atmosphere for a long time and effects [8]. Heavy metals account for only a small part of the environment can cause various diseases such as asthma, pneumonia, lung cancer, and cerebral the mass concentration of PM2.5, they still pose threats to human health through respiration [11,12,13]. Objectives of this study were to investigate and compare the seasonal distribution characteristics, Since previous research has already focused on the air pollution level of heavy metals [17], the sources, and human health risks of PM2.5-bound heavy metals in different functional areas of a typical objectives of this study were to investigate and compare the seasonal distribution characteristics, megacity in eastern China.

Study Area

Heavy Metal Analyses

Results and Discussion

Seasonal

Source

Sources Implied by PCA

Spatial Characteristics of Human Health Risks of Airborne Metals

Conclusions