[Characteristics and Source Analysis of VOCs Pollution During Emergency Response in Tianjin].

To elucidate the characteristics of VOCs chemical components during heavy pollution episodes, hourly online VOCs data derived from 11 heavy pollution events in Tianjin from 2019 to 2020 were employed. The positive matrix factorization （PMF） and conditional bivariate probability function （CBPF） were employed to analyze the sources of VOCs during heavy pollution episodes. The results indicated that the average VOCs volume fraction during these episodes was recorded at 35.

Characteristics of number concentration, size distribution and components of particulate matter emitted from a typical large civil airport.

Civil airports are recognized as significant contributors to fine particulate matter, especially ultra-fine particulate matter (UFP). The pollutants from airport activities have a notable adverse impact on global climate, urban air quality, and public health. However, there is a lack of practical observational studies on the characterization of integrated pollutant emissions from large civil airports.

Quantification of NO sources contribution to ambient nitrate aerosol, uncertainty analysis and sensitivity analysis in a megacity.

Dual isotopes of nitrogen and oxygen of NO are crucial tools for quantifying the formation pathways and precursor NO sources contributing to atmospheric nitrate. However, further research is needed to reduce the uncertainty associated with NO proportional contributions. The acquisition of nitrogen isotopic composition from NO emission sources lacks regulation, and its impact on the accuracy of contribution results remains unexplored.

High aerosol loading over the Bohai Sea: Long-term trend, potential sources, and impacts on surrounding cities.

Air pollution over the oceans has received less attention compared to densely populated urban areas of continents. The Bohai Sea, a semi-enclosed sea in northern China, is surrounded by thirteen industrial cities that have experienced significant improvements in air quality over the past decade. However, the changes in air pollution over the Bohai Sea and its impacts on surrounding cities remain poorly understood.

The role of sources and meteorology in driving PM-bound chlorine.

The role of chloride in atmospheric chemistry received increased attention over recent years. Given the primary and chemical-active nature of PM-bound chlorine (p-Cl), it makes sense to get to know the sources and processes of p-Cl. The temporal behavior of observed p-Cl concentration based on 1-h high resolution exhibited seasonal variation of high in winter, low in summer and diurnal variation of high in the morning, low in afternoon.

Impact of sand and dust storms on the atmospheric environment and its source in Tianjin-China.

Sand and dust storms (SDS) frequently hit northern China and adversely impact both environment and health. The carbonaceous components, inorganic elements, water-soluble ions, and meteorological parameters of several severe SDS episodes have been measured in a supersite in Tianjin, which is a big and representative city located in SDS transmission pathway in northern China. Six SDS episodes were identified in Spring, 2021.

Estimating uncertainties of source contributions to PM using moving window evolving dispersion normalized PMF.

Conventional factor analyses can present problems in cases with changing numbers of sources and/or time-dependent source compositions. There is also lack of a reliable method to estimate uncertainties in the source contributions derived by positive matrix factorization (PMF). Applying a moving window evolving PMF to hourly PM composition dataset from a field campaign in Tianjin China that included the Spring and Lantern Festivals and the start of COVID-19 pandemic has substantially improved the apportionment compared to a conventional analysis using the entire data.