P-phenylenediamines (PPDs) and 6PPD-quinone in tunnel PM: From the perspective of characterization, emission factors, and health risks.

P-phenylenediamines (PPDs) and a quinone derivative (6PPD-Q), as antioxidants added to tires, can inevitably enter into the environment during tire wear emission, posing potential health and ecological risks. However, investigation on their pollution characteristics in PM is still lacking, especially for high-pollution scenarios, such as tunnels. Herein, we investigated the pollution characteristics and emission factors, as well as the correlation analysis and daily intakes of PM-bound PPDs and 6PPD-Q in tunnel.

p‑Phenylenediamine antioxidants in PM: New markers for traffic in positive matrix factorization source apportionment.

The extensive utilization of rubber-related products can lead to a substantial release of p-phenylenediamine (PPD) antioxidants into the environment. In recent years, studies mainly focus on the pollution characteristics and health risks of PM-bound PPDs. This study presents long-time scale data of PPDs and N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine quinone (6PPD-Q) in PM and proposes the innovative use of PPDs as new markers for vehicular emissions in the Positive Matrix Factorization (PMF) source apportionment.

[Changes in Secondary Inorganic Ions in PM at Different Pollution Stages Before and After COVID-19 Control].

To investigate the change characteristics of secondary inorganic ions in PM at different pollution stages before and after COVID-19, the online monitoring of winter meteorological and atmospheric pollutant concentrations in Zhengzhou from December 15, 2019 to February 15, 2020 was conducted using a high-resolution (1 h) online instrument. This study analyzed the causes of the haze process of COVID-19, the diurnal variation characteristics of air pollutants, and the distribution characteristics of air pollutants at different stages of haze.The results showed that Zhengzhou was mainly controlled by the high-pressure ridge during the haze process, and the weather situation was stable, which was conducive to the accumulation of air pollutants.