Impact of aerosol-radiation interaction and heterogeneous chemistry on the winter decreasing PM and increasing O in Eastern China 2014-2020.

In the context of the prevalent winter air quality issues in China marked by declining PM and rising O, this study employed a modified WRF-Chem model to examine the aerosol radiation interaction (ARI), heterogeneous chemistry (AHC), and their combined impact (ALL) on the variations in O and PM during the 2014-2020 in eastern China. Our analysis confirmed that ARI curtailed O while elevating PM. AHC reduced O through heterogeneous absorption of NO and hydroxides while notably fostering fine-grained sulfate, resulting in a PM increase.

Significantly underestimated traffic-related ammonia emissions in Chinese megacities: Evidence from satellite observations during COVID-19 lockdowns.

Ammonia (NH) plays an important role in the formation of atmospheric particulate matter, but the contribution of traffic-related emissions remains unclear, particularly in megacities with a large number of vehicles. Taking the opportunity of the stringent COVID-19 lockdowns implemented in Beijing and Shanghai in 2022, this study aims to estimate the traffic-related NH emissions in these two megacities based on satellite observations. Differences between urban and suburban areas during the lockdown and non-lockdown periods are compared.

Application of machine learning to analyze ozone sensitivity to influencing factors: A case study in Nanjing, China.

Ground-level ozone (O) has been an emerging concern in China. Due to its complicated formation mechanisms, understanding the effects of influencing factors is critical for making effective efforts on the pollution control. This study aims to present and demonstrate the practicality of a data-driven technique that applies a machine learning (ML) model coupled with the SHapley Additive exPlanations (SHAP) approach in O simulation and sensitivity analysis.

Multi-timescale variation characteristics of PM in different regions of China during 2014-2022.

Over the past decade, China has achieved a significant reduction in PM concentrations. Due to the diversity of natural and artificial factors, regional differences are remarkable in the variation characteristics and have not been well addressed in previous studies. Based on hourly observed PM concentrations from 2014 to 2022, this study conducted a comprehensive analysis of variation characteristics on annual, seasonal, and diurnal scales, with a special focus on differences across major regions.

[Pollution Characteristics and Source Apportionment of Volatile Organic Compounds in Lishui Area of Nanjing].

To understand the changes in the components of volatile organic compounds(VOCs), the contribution proportion of each component to ozone, and the VOCs sources, we monitored the VOCs for a year in Lishui. The results showed that the(TVOC) was 223.46 μg·m, (alkanes) was 49.

Size-resolved light-absorbing organic carbon and organic molecular markers in Nanjing, east China: Seasonal variations and sources.

Owing to the potential influence of light-absorbing organic carbon (OC), also termed "brown carbon" (BrC), on the planetary radiation budget, many studies have focused on its absorption in single-sized ranges of particulate matter (PM). However, the size distribution and organic tracer-based source apportionment of BrC absorption have not been extensively investigated. In this study, size-resolved PM samples were collected using multi-stage impactors from eastern Nanjing during each season in 2017.

[Seasonal Variations, Size Distributions, and Sources of Chemical Components of Submicron Particulate Matter in Nanjing].

Size-segregated particulate matter (PM) samples were collected in different seasons from 2016 to 2017 at the Xianlin Campus of Nanjing University. Mass concentrations of water-soluble inorganic ions, carbonaceous components, and elements were analyzed for PM with an aerodynamic diameter ≤ 1.1 μm (PM; <0.

[Evolution of PM Chemical Composition and Sources in Nanjing During the Implementation of the APPCAP].

To acquire a deeper understanding about the impact of the Air Pollution Prevention and Control Action Plan (APPCAP) on ambient fine particulate matter (PM), measurements of PM chemical components were conducted in the urban area of Nanjing during the implementation of the APPCAP. Evolution characteristics of several properties of the PM were studied, including the concentrations, proportions, and enrichment factors of major PM components and the acidity of the PM. In addition, the source apportion of the PM was analyzed using the positive matrix factorization (PMF) model.

Improved atmospheric mercury simulation using updated gas-particle partition and organic aerosol concentrations.

The gaseous or particulate forms of divalent mercury (Hg) significantly impact the spatial distribution of atmospheric mercury concentration and deposition flux (FLX). In the new nested-grid GEOS-Chem model, we try to modify the Hg gas-particle partitioning relationship with synchronous and hourly observations at four sites in China. Observations of gaseous oxidized Hg (GOM), particulate-bound Hg (PBM), and PM were used to derive an empirical gas-particle partitioning coefficient as a function of temperature (T) and organic aerosol (OA) concentrations under different relative humidity (RH).

Seasonal variations, temperature dependence, and sources of size-resolved PM components in Nanjing, east China.

Size-segregated ambient particulate matter (PM) samples were collected seasonally in suburban Nanjing of east China from 2016 to 2017 and chemically speciated. In both fine (< 2.1 µm, PM) and coarse (> 2.

Secondary organic aerosol formation and source contributions over east China in summertime.

Various precursor emissions and chemical mechanisms for secondary organic aerosol (SOA) formation were incorporated into a regional air quality model system (RAQMS) and applied to investigate the distribution, composition, and source contribution of SOA over east China in summer 2018. Model comparison against a variety of observations at a national scale demonstrated that the model was able to reasonably reproduce meteorological variables, O and PM concentrations, and the model simulated SOA concentration generally agreed with observations, with the overall NMB of 7.0% and R of 0.

Chemical composition, structures, and light absorption of N-containing aromatic compounds emitted from burning wood and charcoal in household cookstoves.

N-containing aromatic compounds (NACs) are an important group of light-absorbing molecules in the atmosphere. They are often observed in combustion emissions, but their chemical formulas and structural characteristics remain uncertain. In this study, red oak wood and charcoal fuels were burned in cookstoves using the standard water boiling test (WBT) procedure.

Inflammatory responses of urban air PM modulated by chemical composition and different air quality situations in Nanjing, China.

The health risks of air pollutants and ambient particulate matter (PM) are widely known. PM composition and toxicity have shown substantial spatiotemporal variability. Yet, the connections between PM composition and toxicological and health effects are vaguely understood.

High time-resolved PM composition and sources at an urban site in Yangtze River Delta, China after the implementation of the APPCAP.

In this study, hourly concentrations of PM water-soluble inorganic ions, bulk organic carbon (OC), and elemental carbon (EC) were monitored from 1/1/2017 to 12/31/2017 and validated using filter-based offline analysis at an urban site in Nanjing, China. Compared with 2013 or before, the annual average of PM concentration (36.5 ± 32.

Particulate matter exposure disturbs inflammatory cytokine homeostasis associated with changes in trace metal levels in mouse organs.

Few studies have focused on the impact of particulate matter (PM) exposure with respect to the relationship between PM-induced inflammation and the levels of trace metals in tissues and organs. In this study, C57BL/6 male mice were exposed to ambient air alongside control mice breathing air filtered through a high-efficiency particulate air (HEPA) filter. In both groups, mRNA levels of pro- and anti-inflammatory cytokines were measured after 4, 8 and 12 weeks together with the trace metal contents of the lungs, heart, liver, hippocampus and blood.

Air quality intervention during the Nanjing youth olympic games altered PM sources, chemical composition, and toxicological responses.

Ambient particulate matter (PM) is a leading global environmental health risk. Current air quality regulations are based on airborne mass concentration. However, PM from different sources have distinct chemical compositions and varied toxicity.

PM elements at an urban site in Yangtze River Delta, China: High time-resolved measurement and the application in source apportionment.

Elemental concentrations of ambient aerosols are commonly sampled over 12-24 h, and the low time resolution puts a great limit on current understanding about the temporal variations and source apportionment based on receptor models. In this work, hourly-resolved concentrations of eighteen elements in PM at an urban site in Nanjing, a megacity in Yangtze River Delta of east China, were obtained by using a Xact 625 ambient metals monitor from 12/12/2016 to 12/31/2017. The influence of traffic activities was clearly reflected by the spikes of crustal elements (e.

Emissions and atmospheric processes influence the chemical composition and toxicological properties of urban air particulate matter in Nanjing, China.

Ambient inhalable particulate matter (PM) is a serious health concern worldwide, but especially so in China where high PM concentrations affect huge populations. Atmospheric processes and emission sources cause spatial and temporal variations in PM concentration and chemical composition, but their influence on the toxicological characteristics of PM are still inadequately understood. In this study, we report an extensive chemical and toxicological characterization of size-segregated urban air inhalable PM collected in August and October 2013 from Nanjing, and assess the effects of atmospheric processes and likely emission sources.

Magnetic Properties as a Proxy for Predicting Fine-Particle-Bound Heavy Metals in a Support Vector Machine Approach.

The development of a reasonable statistical method of predicting the concentrations of fine-particle-bound heavy metals remains challenging. In this study, daily PM samples were collected within four different seasons from a Chinese mega-city. The annual average PM concentrations determined in industrial, city center, and suburban areas were 90, 81, and 85 μg m, respectively.

Prediction of size-fractionated airborne particle-bound metals using MLR, BP-ANN and SVM analyses.

Size-fractionated heavy metal concentrations were observed in airborne particulate matter (PM) samples collected from 2014 to 2015 (spanning all four seasons) from suburban (Xianlin) and industrial (Pukou) areas in Nanjing, a megacity of southeast China. Rapid prediction models of size-fractionated metals were established based on multiple linear regression (MLR), back propagation artificial neural network (BP-ANN) and support vector machine (SVM) by using meteorological factors and PM concentrations as input parameters. About 38% and 77% of PM concentrations in Xianlin and Pukou, respectively, were beyond the Chinese National Ambient Air Quality Standard limit of 75 μg/m.

Mortality effects assessment of ambient PM2.5 pollution in the 74 leading cities of China.

Background: Ambient fine particulate matter (PM2.5) pollution is currently a most severe and worrisome environmental problem in China. However, current knowledge of the health effects of this pollution is insufficient.

Fractionation of airborne particulate-bound elements in haze-fog episode and associated health risks in a megacity of southeast China.

Haze caused by high particulate matter loadings is an important environmental issue. PM2.5 was collected in Nanjing, China, during a severe haze-fog event and clear periods.