Coarse particles compensate for missing daytime sources of nitrous acid and enhance atmospheric oxidation capacity in a coastal atmosphere.

Large missing sources of daytime atmospheric nitrous acid (HONO), a vital source of hydroxyl radicals (OH) through its photolysis, frequently exist in global coastal regions. In this study, ambient HONO and relevant species were measured at a coastal site in the Pearl River Delta (PRD), China, during October 2019. Relatively high concentrations (0.

Sources of atmospheric oxygenated volatile organic compounds in different air masses in Shenzhen, China.

As precursors of photochemical secondary pollutants, oxygenated volatile organic compounds (OVOCs) play an important role in atmospheric photochemistry. In this study, 23 OVOCs were monitored using a commercial proton transfer reaction time-of-flight mass spectrometer at an urban site in Shenzhen, China. During the campaign, the mean total concentration of OVOCs was 23.

Global ginseng trade networks: structural characteristics and influencing factors.

Ginseng is a rare and highly valued Chinese materia medica with a rich trading history and has a wide range of application, including medicine, food, healthcare, and daily chemical production. However, the global trade of ginseng exhibits diverse features and uneven development across different countries and regions. Surprisingly, the intricate network relationship and the underlying characteristics and influencing factors of ginseng trade networks remain unexplored.

Characterizing formation mechanisms of secondary aerosols on black carbon in a megacity in South China.

Refractory black carbon (rBC) aerosols emitted from incomplete combustion are important climate forcers. Understanding the chemical characteristics and evolution of rBC-related components is particularly crucial to assess rBC environmental impacts. Here, we explored the chemical components of rBC in Shenzhen, China, using a soot-particle aerosol mass spectrometer (SP-AMS).

Decisive role of ozone formation control in winter PM mitigation in Shenzhen, China.

During the COVID-19 lockdown, atmospheric PM in the Pearl River Delta (PRD) showed the highest reduction in China, but the reasons, being a critical question for future air quality policy design, are not yet clear. In this study, we analyzed the relationships among gaseous precursors, secondary aerosols and atmospheric oxidation capacity in Shenzhen, a megacity in the PRD, during the lockdown period in 2020 and the same period in 2021. The comprehensive observational datasets showed large lockdown declines in all primary and secondary pollutants (including O).

Trends and Challenges Regarding the Source-Specific Health Risk of PM-Bound Metals in a Chinese Megacity from 2014 to 2020.

Identifying the health risk of PM is essential for urban air pollution control. In 2013, China announced the ever-strict national Air Pollution Prevention and Control Action Plan, and its health benefit should be evaluated to provide reference for future policymaking. In this study, we conducted a seven-year (2014-2020) continuous observation of PM in Shenzhen, the third largest city in China, which has relatively good air quality.

TEMPO-oxidized cellulose fibers from wheat straw: Effect of ultrasonic pretreatment and concentration on structure and rheological properties of suspensions.

Cellulose and TEMPO-oxidized cellulose fibers (TOCF) from the wheat straw were prepared with ultrasonic and chemical treatments to investigate structure and functionalities. Sol-gel transition of TOCF suspensions has been investigated using rheology to unveil the roles of ultrasonic pretreatment and temperature at various concentration. It was found that TOCF extracted with or without ultrasonic pretreatment exhibit similar functional groups in FTIR.