PM2.5-Bound Heavy Metals in Southwestern China: Characterization, Sources, and Health Risks

Yan Han,Huanbo Wang,Mi Tian,Jiawei Zhou,Fumo Yang,Shumin Zhang,Guangming Shi,Zhichao Wang,Hanxiong Che,Yang Chen

doi:10.3390/atmos12070929

Abstract

The health risks of PM2.5-bound heavy metals have attracted extensive attention recently. In order to evaluate those deleterious effects on human health more accurately, and to propose proper measures to reduce health risks of air pollution, the conduction of a source-specific health risk assessment is necessary. Based on daily collected PM2.5 samples at different functional sites during winter 2019 in a megacity Chongqing, China, combining source apportionment results from PMF and health risk assessment from the U.S. EPA, the source-specific health risks from PM2.5-bound heavy metals were given. Six types of PM2.5 sources have been identified, coal burning (25.5%), motor vehicles (22.8%), industrial emissions (20.5%), biomass burning (15.9%), dust (7.8%), and ship emissions (7.5%). Results showed that the total hazard quotient (HQ) was 0.32 and the total carcinogenic risks (CR) were 2.09 × 10−6 for children and 8.36 × 10−6 for adults, implying certain risks for local residents. Industrial emissions related with Cr posed both the highest carcinogenic risk and noncarcinogenic risk (contributing 25% CR and 36% HQ). Coal combustion (associated with Cr, As, and Mn) contributed 15.46% CR and 20.64% HQ, while biomass burning and motor vehicles shared 19.99% and 19.05% of the total CR, respectively. This work indicated that health risks of air pollution sources were the combined effects of the source contribution and chemical components. In order to control the health risks of PM2.5 to the local residents, the priority of targeted emission sources should be adopted for industrial emissions, biomass burning, vehicle emissions, and coal combustion sources.

Highlights

We focused on heavy metals (HMs) pollution in southwest China, an area topographically isolated as it is surrounded by highlands and characterized by high relative humidity and low wind speeds [21]
For the five sites on average, we identified the following 6 PM2.5 sources in descending order: coal burning (25.5%), motor vehicles (22.8%), industrial emissions (20.5%), biomass burning (15.9%), dust (7.8%), ship emissions (7.5%) Figure 3
PM2.5 and associated heavy metals were measured from 6 January

Summary

Introduction

Inhaled PM2.5 can settle in the lungs and blood, causing harmful effects on human health, respiratory diseases such as bronchitis and asthma, as well as heart disease, which are more likely to occur or worsen in areas with high levels of PM2.5 pollution [3,4,5]. Some PM2.5 components can be highly deleterious at low concentrations, such as heavy metals (HMs), which have been shown to cause dysfunctions and carcinogenicity even though only at the level of nanograms per cubic meter in the air [6,7]. The inhaled PM2.5 is an important approach for HMs get into human body and accumulate in the organs and blood [5].

Methods

Results

Conclusion