Comment on amt-2021-407

doi:10.5194/amt-2021-407-rc3

Abstract

Excessive reactive oxygen species (ROS) in the human body is an important factor leading to diseases. Therefore, research on the content of reactive oxygen species in atmospheric particles is necessary. In order to more conveniently and accurately detect the content of reactive oxygen in atmospheric particles hour by hour. Here, to modify the instrument, it is added a DTT experimental module that is protected from light and filled with nitrogen at the end, based on the Monitor for AeRosols and Gases in ambient Air (MARGA). The experimental study found that the detection limit of the modified instrument is 0.024 nmol min−1. And the accuracy of the online instrument is determined by comparing the online and offline levels of the samples, which yielded good consistency (slope 0.97, R2 = 0.95). It shows that the performance of the instrument is indeed optimized, the instrument is stable, and the characterization of ROS is accurate. Meanwhile, reactive oxygen and inorganic ions in atmospheric particles are quantified using the online technique in the northern suburbs of Nanjing. It is found that the content of ROS during the day is higher than that at night, especially after it rains, ROS peaks appear in the two time periods of 08:00–10:00 and 16:00–18:00. In addition, examination of the online ROS and water-soluble ions (SO42−, NO3−, NH4+, Na+, Ca2+, K+), BC and polluting gases (SO2, CO, O3, NO, NOx) measurements revealed that photo-oxidation and secondary formation processes could be important sources of aerosol ROS. This method breakthrough enables the quantitative assessment of atmospheric particulate matter ROS at the diurnal scale, providing an effective tool to study sources and environmental impacts of ROS.

Highlights

Air quality is a major issue affecting human health, and prolonged exposure to high ambient particulate concentrations can lead to a significant increase in the probability of respiratory and cardiovascular diseases, which can seriously impair human health (Delfino et al, 2005; Ghio et al, 2012; Pöschl and Shiraiwa, 2015)
Pathophysiological mechanism proposed, and excessive reactive oxygen species can cause an imbalance between the oxidative system and the antioxidant system, causing oxidative stress and tissue damage (Ahmad et al, 2021; Akhtar et al, 2010; Borm et al, 2007; Delfino et al, 2013; Lodovici and Bigagli, 2011)
Before on-site deployment, the online DTT inspection instrument was optimized by filling in nitrogen gas and shielding the whole from light

Summary

Introduction

Air quality is a major issue affecting human health, and prolonged exposure to high ambient particulate concentrations can lead to a significant increase in the probability of respiratory and cardiovascular diseases, which can seriously impair human health (Delfino et al, 2005; Ghio et al, 2012; Pöschl and Shiraiwa, 2015). Understanding the generation mechanism and source characteristics of reactive oxygen species is essential for making reasonable pollution control decisions and reducing their impact on human health. To provide a simpler and quicker way to determine the oxidation potential of environmental particulate matter, cell-free methods such as electron spin (or paramagnetic) resonance (OPESR), dithiothreitol assay (OPDTT), ascorbic acid assay (OPAA), high-performance liquid chromatography (HPLC) and glutathione assay (OPGSH) are often used as the main measurement methods for ROS (Bates et al, 2019; Ghio et al, 2012). Through the comparison and analysis of these various methods by a large number of researchers, the DTT method is generally considered to be the most common and comprehensive method to reflect the magnitude of the chemical oxidation potential of particulate matter (Hedayat et al, 2014; Xiong et al, 2017)

Methods

Results

Conclusion