Distribution Characteristics of <sup><sup>7</sup></sup>Be and <sup><sup>210</sup></sup>Pb in Near-Surface Aerosols in Mianyang Area and Their Significance to O<sub>3</sub> Tracer

Abstract

In order to understand the quality of radiation environment in the near surface air in Mianyang area, to grasp the trend of its change, to explore the sources of aerosol substances near the surface and their significance in tracking the concentration of O₃ near the ground, a detailed gamma spectrum analysis of aerosol samples from March 2018 to February 2019 in Anzhou District, Jiangyou City, Zitong County and Pingwu County was carried out. In general, the activity concentration of ^⁷Be is higher in spring and autumn, while it is the lowest in summer. The annual average is 1.90-2.13mBq/m^³, which is basically the same as the distribution characteristics of inland, mid-latitude, and low-altitude areas in the world. The activity concentration of ^²¹⁰Pb is a "U" type distribution feature throughout the year. It is the lowest in late spring or early summer and has an annual average of 1.24-1.66mBq/m^³, which is a relatively high value of ^²¹⁰Pb activity concentration on global land. The correlation analysis between ^⁷Be and ^²¹⁰Pb and O₃ in near-surface aerosols showed that ^⁷Be and O₃ were weakly positively correlated, while the ratio of ^⁷Be/^²¹⁰Pb was significantly positively correlated with O₃, and ^²¹⁰Pb and O₃were significantly negatively correlated; The ^⁷Be/^²¹⁰Pb ratio can be used as a good tracer of O₃ sources in near-surface air. The O₃ source in the near surface air in Mianyang area is greatly affected by the vertical convection activity of the atmosphere.