[Characteristics and Health Risk Assessment of Trace Elements in Atmospheric PM1 During Autumn and Winter in Qingdao]

Abstract

From November 1,2018 to January 31,2019 (OP_2018-2019) and from November 1,2019 to January 20, 2020 (OP_2019-2020), PM₁ measurement was conducted daily for two consecutive years. The concentration of trace elements in the atmospheric PM₁ in Qingdao in autumn and winter was analyzed. The observation period was divided into four air quality levels (Level Ⅰ, Level Ⅱ, Level Ⅲ, and Level Ⅳ), and the characteristics and sources of the concentration of trace elements in PM₁ were analyzed. The non-carcinogenic risks (Zn, Pb, Mn, Cu, and V) and carcinogenic risks (As, Cr, Ni, Cd, and Co) of different people with different air quality levels were evaluated. The results showed that the changes in total metal element concentrations were associated with changes in Ca, K, and Al concentrations at different air quality classes during OP_2019-2020 compared to those during OP_2018-2019 and were more influenced by dust and biomass combustion sources. Compared with that during OP_2018-2019, the V concentration in different air quality levels (Level Ⅰ, Level Ⅱ, Level Ⅲ, and Level Ⅳ) during OP_2019-2020 decreased by 19.0%, 60.5%, 82.7%, and 77.5%, respectively. This was presumed to be related to the implementation of the Domestic Emission Control Area (DECA) policy for ships, which led to the significant reduction in V concentration due to the change in fuel quality of ships in the waters around Qingdao. The results of the enrichment factor, the ratio method, and the backward trajectory of airflow further indicated that the changes in V concentrations were mainly influenced by the DECA policy. However, after the implementation of the DECA, the V/Ni value as a limit for judging the influence of ship sources in the area required further exploration. The health risk assessment results showed that the risk factor of Mn ranged from 0.07 to 1.22 during OP_2018-2019 and OP_2019-2020. It was recommended to strengthen the management and control of Mn-containing pollution sources. The lifetime carcinogenic risk (ILCR) value of As and Cd under different air qualities during OP_2018-2019 and OP_2019-2020 was lower than 10^-4 but higher than 10^-6, indicating that there was a carcinogenic probability, although it was still at an acceptable level. During OP_2018-2019, when the air quality was Ⅳ, the ILCR value of Cr was higher than 10^-4, and there was a risk of cancer.

Keywords: PM1; Qingdao; health risk assessment; ship emissions; trace elements.