Anthropogenic Dust as a Significant Source of Ice‐Nucleating Particles in the Urban Environment

Earth s Future, Journal Year: 2024, Volume and Issue: 12(1)

Published: Jan. 1, 2024

Abstract Anthropogenic dust is an important constituent of airborne particles in the urban environment but its ice nucleation activity remains poorly investigated. Here, we studied sources and nucleating properties size‐resolved atmosphere under mixed‐phase cloud conditions. The heat‐resistant (INPs) unexpectedly contributed ∼70% supermicron INPs at temperatures below −15°C. A detailed chemical composition analysis revealed that these were associated with anthropogenic dust, such as traffic‐influenced road dust. parameterization based on was developed to predict INP concentration, given their correlations concentration similarity compositions. Once integrated into global models, this holds potential assess contribution a scale. Given considerable presence significant role INPs, suggest it may be aerosol source influencing microphysics warrant further investigations.

Language: Английский

---

Simulated phase state and viscosity of secondary organic aerosols over China

Atmospheric chemistry and physics, Journal Year: 2024, Volume and Issue: 24(8), P. 4809 - 4826

Published: April 23, 2024

Abstract. Secondary organic aerosols (SOAs) can exist in liquid, semi-solid, or amorphous solid states. Chemical transport models (CTMs), however, usually assume that SOA particles are homogeneous and well-mixed liquids, with rapid establishment of gas–particle equilibrium for simulations formation partitioning. Missing the information phase state viscosity CTMs impedes accurate representation evolution, affecting predictions aerosol effects on air quality climate. We have previously developed a parameterization to estimate glass transition temperature (Tg) an compound based volatility predict SOA. In this study, we apply method over China summer 2018 using Weather Research Forecasting model coupled Chemistry (WRF-Chem). The simulated Tg dry (Tg,org) agrees well value estimated from ambient measurements at urban site Beijing. For spatial distributions Tg,org, show surface values Tg,org range ∼287 305 K, higher northwestern China, where larger mass fractions low-volatility compounds. Considering water uptake by particles, shows prominent geospatial gradient which highly viscous mainly predicted China. lowest highest both occur Qinghai–Tibet Plateau, is high-altitude areas liquid south plateau high relative humidity during monsoon season. Sensitivity that, including extremely compounds, percent time particle decreases up 12 % southeastern period. With assumption inorganic compounds internally mixed one phase, absorbed species significantly lower This indicates constraining uncertainties mixing would improve prediction multicomponent also calculate characteristic timescale molecules 200 m evaluate kinetic limitations Calculations period longer than 1 h >70 500 hPa most northern indicating partitioning considering bulk diffusion may be required more concentrations size these areas.

Language: Английский

---

The capacity of human interventions to regulate PM2.5 concentration has substantially improved in China

Environment International, Journal Year: 2025, Volume and Issue: 195, P. 109251 - 109251

Published: Jan. 1, 2025

The rapid urbanization in China has brought about serious air pollution problems, which are likely to persist for a considerable period as the process continues. In urban areas, spatial distribution of pollutants represented by PM

Language: Английский

---

How does greenness contribute to reducing lung cancer risks associated with particulate matter exposure?

Atmospheric Pollution Research, Journal Year: 2025, Volume and Issue: unknown, P. 102500 - 102500

Published: March 1, 2025

Language: Английский

---

Reduction in Organic Aerosol from Coal Combustion is Partially Offset by Enhanced Secondary Formation during the Beijing Coal Burning Ban

Environmental Science & Technology, Journal Year: 2025, Volume and Issue: unknown

Published: May 5, 2025

A coal ban policy in northern China during winter 2017 enforced a switch from to gas or electricity for residential heating, providing unique opportunity study the effect of reduced combustion emissions on organic aerosol (OA). This explores OA composition, sources, and atmospheric transformations Beijing before using online chemical speciation monitor (ACSM) offline 14C measurements. Four primary factors (hydrocarbon-like, cooking, biomass burning, OA) one secondary factor (oxygenated OA, OOA) were resolved ACSM. In response ban, concentrations generally decreased, but decreased most strongly, consistent with fossil carbon contributions (67 ± 3% vs 55 4% ban). Concurrently, OOA fraction increased 45 72%, due larger decrease (POA; 59-88%) compared (34%), highlighting enhanced formation period. aligns evidence higher water-soluble (which has mostly sources). During period, Ox doubled positively correlated fraction, strong photochemical production. The results show that reduction POA stringent clean air actions is partially offset by formation.

Language: Английский

---

Understanding the Driving Forces of Summer PM₁ Composition in Seoul, Korea, with Explainable Machine Learning

ACS ES&T Air, Journal Year: 2024, Volume and Issue: 1(9), P. 960 - 972

Published: July 10, 2024

This study leverages explainable machine learning, specifically XGBoost models with Shapley Additive Explanations (SHAP), to explore the chemical properties of atmospheric aerosols in Seoul, Korea, during summer 2019. Focusing on non-refractory particulate matter (NR-PM1) measured by high-resolution time-of-flight aerosol mass spectrometry (HR-ToF-AMS), research extends organic (OA) sources identified via positive matrix factorization MS data. The achieved good predictive accuracy (R2 > 0.90) for all species concentrations, except hydrocarbon-like OA (HOA) due frequent concentration fluctuations. model outcomes aligned well those previously using conventional methods (chemical transport and correlational analysis), confirming that relative humidity is associated nocturnal nitrate photochemistry sulfate summertime Seoul. Importantly, revealed mostly nonlinear relationships between factors, such as temperature (PM) components, thereby deepening understanding formation processes. Notably, different potential mechanisms were discerned more oxidized oxygenated (MO-OOA) primary (OPOA). For MO-OOA, SHAP analysis showed a plateau values at an Ox 0.085 ppm, which suggested fragmentation from further oxidation agreed previous chamber experiments. Conversely, lack OPOA implied ongoing oxidation, suggesting higher longer potential. approach offers rapid insights into complex It essential acknowledge do not establish causality, knowledge underlying physical processes was required conclude valid comprehensive interpretations ML results.

Language: Английский

---

Hygroscopic Growth and Activation Changed Submicron Aerosol Composition and Properties in North China Plain

Published: April 23, 2024

Abstract. Aerosol hygroscopic growth and activation under high relative humidity (RH) conditions significantly influence the physicochemical properties of submicron aerosols (PM1). However, this process remains poorly characterized due to limited measurements. To address gap, we deployed an advanced aerosol-fog sampling system that automatically switched between PM1, PM2.5, TSP inlets at a rural site in North China Plain cold season. The results revealed aerosol swelling water vapor uptake influenced RH by shifting cut-off size impactors. Under subsaturated (> 90 %), over 25 % mass with dry diameters below 1 μm resided supermicron ranges, while supersaturated foggy conditions, more than 70 migrated ranges. Hygroscopic particularly affected highly hydrophilic inorganic salts significant sulfate nitrate particles 27 – 33 95 ≤ 99 %, 65.5 conditions. Moreover, 10 biomass burning organic grew beyond 2.5 during fog events, fossil fuel-related OA (FFOA) remained dominantly suggesting inefficient aqueous conversion FFOA. two SOA factors (OOA1 OOA2) behaved differently OOA2 exhibiting higher activated fraction despite lower oxygen-to-carbon ratio. A substantial increase organosulfur concentrations droplets events suggested conversions formations brown carbon potential radiative impacts. Overall, our study highlights remarkably different processing primary secondary PM1 components distinct ambient

Language: Английский

---

Hygroscopic growth and activation changed submicron aerosol composition and properties in the North China Plain

Atmospheric chemistry and physics, Journal Year: 2024, Volume and Issue: 24(16), P. 9387 - 9399

Published: Aug. 28, 2024

Abstract. Aerosol hygroscopic growth and activation under high-relative-humidity (RH) conditions significantly influence the physicochemical properties of submicron aerosols (PM1). However, this process remains poorly characterized due to limited measurements. To address gap, we deployed an advanced aerosol–fog sampling system that automatically switched between PM1, PM2.5 total suspended particulate (TSP) inlets at a rural site in North China Plain cold season. The results revealed aerosol swelling water vapor uptake influenced high-RH by shifting cut-off size impactors. At subsaturated high RH (> 90 %), over 25 % mass with dry diameters below 1 µm resided supermicron ranges, while supersaturated foggy conditions, more than 70 migrated ranges. Hygroscopic particularly affected highly hydrophilic inorganic salts, significant number sulfate nitrate particles 27 %–33 95 ≤ 99 78 conditions. Moreover, 10 biomass burning organic grew beyond 2.5 during fog events, fossil-fuel-related (FFOA) remained dominantly suggesting inefficient aqueous conversion FFOA. two secondary (SOA) factors (OOA1 OOA2) behaved differently OOA2 exhibiting higher activated fraction despite lower oxygen / carbon ratio. A substantial increase organosulfur concentrations droplets events suggested conversions formations brown potential radiative impacts. Overall, our study highlights remarkably different cloud processing behaviors primary aerosols, which would benefit better understanding aerosol–cloud interactions distinct atmospheric

Language: Английский

---

Phase state and viscosity of secondary organic aerosols over China simulated by WRF-Chem

Published: Aug. 14, 2023

Abstract. Secondary organic aerosols (SOA) can exist in liquid, semi-solid or amorphous solid states, which are rarely accounted for current chemical transport models (CTMs). Missing the information of SOA phase state and viscosity CTMs impedes accurate representation formation evolution, affecting predictions aerosol effects on air quality climate. We have previously developed a method to estimate glass transition temperature (Tg) an compound based volatility. In this study, we apply predict particles over China summer 2018 using Weather Research Forecasting model coupled Chemistry (WRF-Chem). This is first time that spatial distributions investigated by regional CTM. Simulations show Tg values dry range from ~287 K 305 K, with higher northwestern where larger mass fractions low volatility compounds. Considering water uptake particles, also shows prominent geospatial gradient highly viscous mainly found China. The lowest highest both occur Qinghai-Tibet Plateau predicted high-altitude areas liquid south plateau high relative humidity during monsoon season. characteristic mixing timescale molecules 200 nm calculated simulated particle bulk diffusion coefficient molecules. Calculations period percent longer than 1 h > 70 % at surface 500 hPa most northern China, indicating kinetic partitioning considering may be required more prediction concentrations size these areas. Sensitivity simulations including extremely low-volatile compounds, decreases up 12 southeastern period. With assumption inorganic compounds always internally mixed one phase, absorbed species significantly lower indicates constraining uncertainties accurately predicting occurrence separation would improve multicomponent

Language: Английский

---

Reply on RC1

Published: Jan. 23, 2024

Abstract. Secondary organic aerosols (SOA) can exist in liquid, semi-solid or amorphous solid states, which are rarely accounted for current chemical transport models (CTMs). Missing the information of SOA phase state and viscosity CTMs impedes accurate representation formation evolution, affecting predictions aerosol effects on air quality climate. We have previously developed a method to estimate glass transition temperature (T_g) an compound based volatility. In this study, we apply predict particles over China summer 2018 using Weather Research Forecasting model coupled Chemistry (WRF-Chem). This is first time that spatial distributions investigated by regional CTM. Simulations show T_g values dry range from ~287 K 305 K, with higher northwestern where larger mass fractions low volatility compounds. Considering water uptake particles, also shows prominent geospatial gradient highly viscous mainly found China. The lowest highest both occur Qinghai-Tibet Plateau predicted high-altitude areas liquid south plateau high relative humidity during monsoon season. characteristic mixing timescale molecules 200 nm calculated simulated particle bulk diffusion coefficient molecules. Calculations period percent longer than 1 h > 70 % at surface 500 hPa most northern China, indicating kinetic partitioning considering may be required more prediction concentrations size these areas. Sensitivity simulations including extremely low-volatile compounds, decreases up 12 southeastern period. With assumption inorganic compounds always internally mixed one phase, absorbed species significantly lower indicates constraining uncertainties accurately predicting occurrence separation would improve multicomponent

Language: Английский

---