[Components Characteristic and Source Apportionment of Fine Particulate Matter in Transition Period of Heating Season in Xi'an with High Time Resolution].

Influenced by heating, the concentration of atmospheric fine particulate matter (PM) rises in autumn and winter in northern cities. In this study, Q-ACSM, AE33, and Xact 625 were used to carry out online monitoring of PM chemical components with high time resolution in Xi'an from October 25 to November 17, 2019, to analyze the characteristics of PM pollution during the transition period of the heating season. Additionally, we analyzed the sources of PM in combination with the positive matrix factorization model.

Heterogeneous characteristics and absorption enhancement of refractory black carbon in an urban city of China.

In this study, field measurement was conducted using an integrated online monitoring system to characterize heterogeneous properties and light absorption of refractory black carbon (rBC). rBC particles are mainly from the incomplete combustion of carbonaceous fuels. With the data collected from a single particle soot photometer, thickly coated (BC) and thinly coated (BC) particles are characterized with their lag times.

High time-resolution source apportionment and health risk assessment for PM-bound elements at an industrial city in northwest China.

To better respond to heavy air pollution, the local government of Baoji City, a traditionally industry dominated city in northwest China, released several warning levels between December 2019 and January 2020. The system aims to provide a more efficient control of pollution sources. In this study, a high-time resolution measurement of PM-bound elements was applied to capture the diurnal-scale dynamic processes associated with major pollution activities in northwest China.

Chemical characteristics and sources of nitrogen-containing organic compounds at a regional site in the North China Plain during the transition period of autumn and winter.

Organic nitrogen constitutes a significant fraction of the nitrogen budget in particulate matter (PM). However, the composition and sources of nitrogen-containing organic compounds (NOCs) in PM remain unclear currently in North China Plain (NCP), China. Rare local or regional studies on NOCs were conducted.

Optical properties of mountain primary and secondary brown carbon aerosols in summertime.

Brown carbon (BrC) can affect atmospheric radiation due to its strong absorption ability from the near ultraviolet to the visible range, thereby influencing global climate. However, given the complexity of BrC's chemical composition, its optical properties are still poorly understood, especially in mountainous areas. In this study, the black carbon (BC) tracer method is used to explore the light-absorbing properties of primary and secondary BrC at Mount Hua, China during the 2018 summer period.

Impacts of primary emissions and secondary aerosol formation on air pollution in an urban area of China during the COVID-19 lockdown.

Restrictions on human activities were implemented in China to cope with the outbreak of the Coronavirus Disease 2019 (COVID-19), providing an opportunity to investigate the impacts of anthropogenic emissions on air quality. Intensive real-time measurements were made to compare primary emissions and secondary aerosol formation in Xi'an, China before and during the COVID-19 lockdown. Decreases in mass concentrations of particulate matter (PM) and its components were observed during the lockdown with reductions of 32-51%.

Chemical composition and sources of submicron aerosols in winter at a regional site in Beijing-Tianjin-Hebei region: Implications for the Joint Action Plan.

The Ministry of Environmental Protection released a Joint Action Plan for Control of Air Pollution (Hereafter, Joint Action Plan, JAP), to reduce PM concentrations in the Beijing-Tianjin-Hebei region (BTH) during the winter of 2017. To investigate the effectiveness of the controls, we deployed an aerosol chemical speciation monitor and collected filter samples at Xianghe, a representative site for the BTH, to characterize the aerosol composition during the implementation of the JAP. Those results were compared with earlier data obtained from a literature survey and reanalysis of studies in the BTH.

Wintertime Optical Properties of Primary and Secondary Brown Carbon at a Regional Site in the North China Plain.

The light-absorbing properties of atmospheric brown carbon (BrC) are poorly understood due to its complex chemical composition. Here, a black-carbon-tracer method was coupled with source apportionments of organic aerosol (OA) to explore the light-absorbing properties of primary and secondary BrC from the North China Plain (NCP). Primary emissions of BrC contributed more to OA light absorption than secondary processes, and biomass burning OA accounted for 60% of primary BrC absorption at λ = 370 nm, followed by coal combustion OA (35%) and hydrocarbon-like OA (5%).