Improving photochemical indicators for attributing ozone sensitivities in source apportionment analysis.

Comprehensive Air Quality Model with extensions (CAMx)-Decoupled Direct Method (DDM) simulations of first-order ozone (O) sensitivity to nitrogen oxides (NO) and volatile organic compounds (VOCs) emissions were performed and combined with modelled [Formula: see text] ratios to obtain a range of thresholds for determining O-sensitivity regimes for different areas of China. Utilising the new threshold ranges for photochemical indicators, the method for determining O formation in the Ozone Source Apportionment Technology (OSAT) module within CAMx was improved by a dynamically varied threshold of [Formula: see text] ratio. The O concentration contributions in the newly added transition regime were apportioned to NO and VOCs emissions in proportion to the relationship between the [Formula: see text] ratio and first-order O sensitivity.

A Study of CeSnO and Pd/CeSnO as Low-Temperature NO Adsorbers with Excellent Hydrothermal Stability.

In the present work, we report on two passive NO adsorber (PNA) material candidates: the novel support CeSnO with and without Pd loading. The NO adsorption and storage capacities of fresh and hydrothermally aged CeSnO and Pd/CeSnO were investigated. The results show that CeSnO exhibits a rather large NO uptake and storage capacity (28.

Comprehensive evaluation method of urban air quality statistics based on environmental monitoring data and its application.

Air quality monitoring is effective for timely understanding of the current air quality status of a region or city. Currently, the huge volume of environmental monitoring data, which has reasonable real-time performance, provides strong support for in-depth analysis of air pollution characteristics and causes. However, in the era of big data, to meet current demands for fine management of the atmospheric environment, it is important to explore the characteristics and causes of air pollution from multiple aspects for comprehensive and scientific evaluation of air quality.

The long-term trend of PM-related mortality in China: The effects of source data selection.

Quantification of PM exposure and associated mortality is critical to inform policy making. Previous studies estimated varying PM-related mortality in China due to the usage of different source data, but rarely justify the data selection. To quantify the sensitivity of mortality assessment to source data, we first constructed state-of-the-art PM predictions during 2000-2018 at a 1-km resolution with an ensemble machine learning model that filled missing data explicitly.

Vertical profiles of biogenic volatile organic compounds as observed online at a tower in Beijing.

Vertical profiles of isoprene and monoterpenes were measured by a proton transfer reaction-time of flight-mass spectrometry (PTR-ToF-MS) at heights of 3, 15, 32, 64, and 102 m above the ground on the Institute of Atmospheric Physics (IAP) tower in central Beijing during the winter of 2016 and the summer of 2017. Isoprene mixing ratios were larger in summer due to much stronger local emissions whereas monoterpenes were lower in summer due largely to their consumption by much higher levels of ozone. Isoprene mixing ratios were the highest at the 32 m in summer (1.

Six sources mainly contributing to the haze episodes and health risk assessment of PM at Beijing suburb in winter 2016.

Aiming to a better understanding sources contributions and regional sources of fine particles, a total of 273 filter samples (159 of PM and 114 of PM) were collected per 8 h during the winter 2016 at a southwest suburb of Beijing. Chemical compositions, including water soluble ions, organic carbon (OC), and elemental carbon (EC), as well as secondary organic carbon (SOC), were systematically analyzed and estimated. The total ions concentrations (TIC), OC, and SOC of PM were with the following order: 16:00-24:00 > 08:00-16:00 > 00:00-08:00.

A Simple Method for Peak Alignment Using Relative Retention Time Related to an Inherent Peak in Liquid Chromatography-Mass Spectrometry-Based Metabolomics.

Retention time (RT) shifts are inevitable in liquid chromatography-mass spectrometry (LC-MS)-based metabolomics studies. RT alignment, aligning peaks originating from the same feature to an identical RT, is a necessary step prior to multivariate data analysis. Many RT alignment software packages and various algorithms have been developed.

Refined source apportionment of coal combustion sources by using single particle mass spectrometry.

In this study, samples of three typical coal combustion source types, including Domestic bulk coal combustion (DBCC), Heat supply station (HSS), and Power plant (PP) were sampled and large sets of their mass spectra were obtained and analyzed by SPAMS during winter in a megacity in China. A primary goal of this study involves determining representative size-resolved single particle mass spectral signatures of three source types that can be used in source apportionment activities. Chemical types describe the majority of the particles of each source type were extracted by ART-2a algorithm with distinct size characteristics, and the corresponding tracer signals were identified.

Mass spectra features of biomass burning boiler and coal burning boiler emitted particles by single particle aerosol mass spectrometer.

In this study, single particle mass spectra signatures of both coal burning boiler and biomass burning boiler emitted particles were studied. Particle samples were suspended in clean Resuspension Chamber, and analyzed by ELPI and SPAMS simultaneously. The size distribution of BBB (biomass burning boiler sample) and CBB (coal burning boiler sample) are different, as BBB peaks at smaller size, and CBB peaks at larger size.

Single particle mass spectral signatures from vehicle exhaust particles and the source apportionment of on-line PM by single particle aerosol mass spectrometry.

In order to accurately apportion the many distinct types of individual particles observed, it is necessary to characterize fingerprints of individual particles emitted directly from known sources. In this study, single particle mass spectral signatures from vehicle exhaust particles in a tunnel were performed. These data were used to evaluate particle signatures in a real-world PM apportionment study.

Comparison of biological HS removal characteristics between a composite packing material with and without functional microorganisms.

The performances of two identical biofilters, filled with a new composite packing material (named CM-5) embedded with functional microorganisms or sterilized CM-5 without microorganisms, were investigated for HS treatment. Running parameters in terms of microbial counts, pressure drops, and inlet and outlet HS concentrations were measured. The results show that the microbial count of the CM-5 was approximately ×10 CFU/g before being filled into the biofilter, while that of the sterilized CM-5 was negligible.

[Acidity and acid buffering capacity of aerosols during sand-dust storm weather in Beijing].

In the spring of 2000, there were 12 sand-dust storms in Beijing. 2 sand-dust storms were experienced in time and mass concentrations, elementary concentrations acidity and acidic buffering capacity of TSP(Total Suspended Particulate, < 100 microns) and PM10(Inhalable particulate, < 10 microns) were sampled and analyzed. Results showed that pollution level of aerosols was extremely high.