Ta-Chih Hsiao

National Taiwan University | NTU · Graduate Institute of Environmental Engineering

Black carbon, or soot, significantly contributes to atmospheric light absorption due to its low single scattering albedo (SSA). This study investigates the impact of soot's hygroscopic restructuring on satellite remote sensing, focusing on radiative forcing, top-of-atmosphere (TOA) reflectance, and aerosol optical depth (AOD) retrievals. We charact...

The aeration tanks in wastewater treatment plants (WWTPs) are important sources of airborne antibiotic resistance genes (ARGs) and antibiotic-resistant bacteria (ARB) due to bubble bursts at the air-liquid interface. This study employed an integrated metagenomic workflow, encompassing reference-based, assembly-based, and binning-based modules, to i...

Microplastics (MPs) are ubiquitous environmental pollutants extensively detected in atmospheric environments. Airborne MPs have raised concerns due to their transport and potential health risks of inhalation exposure. However, the factors influencing airborne MPs, particularly their concentrations and shapes suspended in urban air, remain unclear....

This study investigates the fabrication, optimization, and performance of submicron polyacrylonitrile (PAN) and nanofiber cellulose triacetate (CTA) air filters produced through electrospinning. PAN fibers with diameters ranging from 379 to 804 nm were generated from PAN/DMF solutions, while genuine CTA nanofibers (65-102 nm) were successfully prod...

The rapid global urbanization has transformed cityscapes, giving rise to iconic skyscrapers that define modern cities. However, alongside this urban evolution, a pressing concern arises –the air quality within these towering urban environments. Fine particulate matter, known as PM2.5, poses a grave threat to human health and the environment. These...

COVID-19 has been a significant global concern due to its contagious nature. In May 2021, Taiwan experienced a severe outbreak, leading the government to enforce strict Pandemic Alert Level 3 restrictions in order to curtail its spread. Although previous studies in Taiwan have examined the effects of these measures on air quality, further research...

During the unprecedented COVID-19 city lockdown, a unique opportunity arose to dissect the intricate dynamics of urban air quality, focusing on ultrafine particles (UFPs) and volatile organic compounds (VOCs). This study delves into the nuanced interplay between traffic patterns and UFP emissions in a subtropical urban setting during the spring-sum...

This study investigated the utilization of images collected from low-quality dash cameras on passenger vehicles for the estimation of traffic-related air pollution (TRAP). We conducted mobile monitoring along Taiwan Avenue, Taichung, Taiwan, and collected pollution concentration data including carbon dioxide (CO2), nitrogen oxides (NOx), black carb...

Single-particle inductively coupled plasma mass spectrometry (spICP-MS) has been used to characterize metallic nanoparticles (NPs) assuming that all NPs are spherical and composed of pure element. However, environmental NPs generally do not meet these criteria, suggesting that spICP-MS may underestimate their true sizes. This study employed a syste...

The motorcycle is a common mode of transport in many countries. Although there exist abundant studies on emissions from internal combustion engine motorcycles, little is known regarding the emissions from electric motorcycles (EMs). Methods commonly used in emissions analysis for internal combustion engine motorcycles are not suitable for non-exhau...

This review article delves into the multifaceted relationship between climate change, air quality, and respiratory health, placing a special focus on the process of particle deposition in the lungs. We discuss the capability of climate change to intensify air pollution and alter particulate matter physicochemical properties such as size, dispersion...

Positive Matrix Factorization (PMF) is a commonly used receptor model for source apportionment of PM2.5. However, PMF results often retrieve an individual factor mainly composed of secondary aerosols, making it difficult to link with primary emission sources and formulate effective air pollution control strategies. To overcome this limitation, we e...

Electronic cigarettes (ECs), considered a healthier alternative to traditional cigarettes (TCs), vaporize e-liquid, which may produce harmful by-products due to thermal decomposition and metal transfer. These by-products' deposition in the respiratory tract is largely determined by particle size distribution (PSD). We employ the Multiple-Path Parti...

In the quest to reconcile public perception of air pollution with scientific measurements, our study introduced a pioneering method involving a gradient boost-regression tree model integrating PM2.5 concentration, visibility, and image-based data. Traditional stationary monitoring often falls short of accurately capturing public air quality percept...

Taiwan is located downwind of a variety of regional sources of air pollutants transported particularly during the seasons of East Asian winter monsoon. In addition, western Taiwan is a highly populated and urbanized/industrialized area, where the air quality is subject to the influences of local air pollution. To mitigate the impacts of air polluti...

The air exchange rate (AER), defined as the number of times the air is fully replaced per hour in an indoor space, is an important parameter affecting indoor air quality (IAQ). Hospital operation rooms (ORs), one of the indoor environments with relatively high health risks, should maintain high AERs to quickly remove surgical smoke during surgery....

Fine particulate matter (PM2.5) is thought to exacerbate Parkinson's disease (PD) in the elderly, and early detection of PD progression may prevent further irreversible damage. Therefore, we used diffusion tensor imaging (DTI) for probing microstructural changes after late-life chronic traffic-related PM2.5 exposure. Herein, 1.5-year-old Fischer 34...

Volatility and effective density of aerosol particles are complicatedly linked properties, undergoing dynamic temporal evolution in the ambient environment. However, the simultaneous investigation of these physicochemical characteristics remains unexplored in roadside environments that exhibit a significant proportion of motorcycles in the vehicle...

Transportation emissions significantly affect human health, air quality, and climate in urban areas. This study conducted experiments in an urban tunnel in Taipei, Taiwan, to characterize vehicle emissions under real driving conditions, providing emission factors of PM2.5, eBC, CO, and CO2. By applying multiple linear regression, it derives individ...

Much attention has been found to the long-range transport (LRT) of air pollutants and their adverse effects on downwind air qualities resulting from the Chinese haze, which frequently occurs in association with winter monsoon. This study integrates ground-based measurements, unmanned aerial vehicles (UAVs), and model simulations to characterize the...

The Coronavirus Disease 2019 (COVID-19) pandemic provided an unprecedented natural experiment, that allowed us to investigate the impacts of different restrictive measures on personal exposure to specific volatile organic compounds (VOCs) and aldehydes and resulting health risks in the city. Ambient concentrations of the criteria air pollutants wer...

Satellite aerosol optical depth (AOD) provides an alternative way to depict the spatial distribution of near-surface PM2.5. In this study, a mathematical formulation of how PM2.5 is related to AOD is presented. When simplified to a linear equation, a functional dependence of the slope on the aerosol type, scattering enhancement factor f(RH), and bo...

Modeling is a cost-effective measure to estimate ultrafine particle (UFP) levels. Previous UFP estimates generally relied on land-use regression with insufficient temporal resolution. We carried out in-situ measurements for UFP in central Taiwan and developed a model incorporating satellite-based measurements, meteorological variables, and land-use...

Walking and other human activities resuspend deposited pathogens from surfaces into the air, potentially leading to infection through inhaling the bioaerosols. We performed experiments in a laboratory chamber to quantify the pathogen resuspension from a human stepping on pathogen-seeded flooring. Three common flooring materials were chosen: carpet,...

Taiwan is located downwind of a variety of regional sources of air pollutants transported particularly during the seasons of East Asian winter monsoon. In addition, western Taiwan is a highly populated and urbanized/industrialized area, where the air quality is subject to the influences of local air pollution. To mitigate the impacts of air polluti...

Air pollution has been linked to respiratory diseases, and urban air pollution can be attributed to a number of emission sources. The emitted particles and gases are the primary components of air pollution that enter the lungs during respiration. Particulate matter with an aerodynamic diameter of ≤ 2.5 µm (PM2.5) can deposit deep into the respirato...

Submicron and ultrafine particle (UFP) exposure may be epidemiologically and toxicologically linked to pulmonary, neurodegenerative, and cardiovascular diseases. This study explores UFP and fine particle sources using a positive matrix factorization (PMF) model based on PM2.5 chemical compositions and particle number size distributions (PNSDs). The...

We investigated the effects of antibiotics, drugs, and metals on lung and intestinal microbiomes after sub-chronic exposure of low-level air pollution in ageing rats. Male 1.5-year-old Fischer 344 ageing rats were exposed to low-level traffic-related air pollution via whole-body exposure system for 3 months with/without high-efficiency particulate...

Physicochemical properties of nanoparticles are important in regulating nanoparticle toxicity; however, the contribution of nanoparticle charge remains unclear. The objective of this study was to investigate the pulmonary effects of inhalation of charged soot nanoparticles. We established a stably charged nanoparticle generation system for whole-bo...

Acute exposure to fresh traffic-related air pollutants (TRAPs) can be high for road users, including motorbike drivers, cyclists, and pedestrians. However, evaluating the toxicity of fresh traffic emissions from on-road vehicles is challenging since pollution properties can change dynamically within a short distance and time. This study demonstrate...

Characterizing engineered nanoparticles (ENPs) in complex environmental matrices remains a challenging task. This work presents a two-dimensional size analysis method by combining differential mobility analyzer (DMA) and single-particle inductively coupled plasma-mass spectrometry (spICP-MS) with a new atomizer (ATM)-enabled sample introduction tha...

This study applied positive matrix factorization (PMF) to identify the sources of size-resolved submicrometer (10–1000 nm) particles and quantify their contributions to impaired visibility based on the particle number size distributions (PNSDs), aerosol light extinction (bp), air pollutants (PM10, PM2.5, SO2, O3, and NO), and meteorological paramet...

This study investigated the hourly inorganic aerosol chemistry and its impact on atmospheric visibility over an urban area in Central Taiwan, by relying on measurements of aerosol light extinction, inorganic gases, and PM2.5 water-soluble ions (WSIs), and simulations from a thermodynamic equilibrium model. On average, the sulfate (SO4²⁻), nitrate (...

Fine particulate matter (PM2.5) has been linked to cardiopulmonary disease and systemic effects in humans. However, few studies have investigated the particle bioreactivity in Chinese megacities during haze episodes. The objective of this study was to determine the contributions of chemical components in PM2.5 to particle bioreactivity in Chinese m...

The significance of this work is that ambient PM2.5 is a direct transmission mode for influenza virus infection to the human alveolar epithelium. The concentration of PM2.5 was 11.7 ± 5.5 μg/m³ in Taipei during 24 December 2019–13 January 2020. Approximately 79% of inhaled PM2.5 is able to reach the upper-to-lower airway, and 47% of PM2.5 is able t...

Adverse human health effects caused by fine particulate matter (PM2.5) were reported; however, source-specific PM2.5 and its bioreactivity need to be assessed to understand regional human impacts. The objective of this study was to investigate the contributions of PM2.5 to particle bioreactivity in Taichung City, an urban area of west-central Taiwa...

In recent years, many sample analyses have revealed that the proportion of nitrate (NO3-) in PM2.5 frequently exceeds that of other major PM2.5 species, such as SO42-, NH4+, and OC. This phenomenon has attracted considerable attention because it could change the direction of PM2.5 control policies. The present study analyzed the long-term trends of...

Source-apportioned particle concentrations are necessary to properly evaluate the health impacts of air pollution. In this study, a measurement station was established at an urban roadside in northern Taiwan to the investigate lung deposited surface area (LDSA) concentration, a relevant metric for the adverse health effects of aerosol exposure, alo...

Traffic-related air pollutants (TRAPs) pose a serious health hazard for residents and commuters in urban areas. In this study, a real-time mobile monitoring system was deployed in Taipei, a typical East Asian city with an overlap of high population density, traffic, and special structures (e.g., viaducts), to capture the on-road TRAPs at different...

The deterioration of visibility due to air pollutants and relative humidity has been a serious environmental problem in eastern Asia. In most previous studies, chemical compositions of atmospheric particles were provided using filter-based offline analyses, which were unable to provide long-term and in-situ measurements that resolve sufficient temp...

Air pollution has been linked to emphysema in chronic obstruction pulmonary disease (COPD). However, the underlying mechanisms in the development of emphysema due to air pollution remain unclear. The objective of this study was to investigate the role of components of the Hippo signaling pathway for E-cadherin-mediated contact inhibition of prolife...

In urban areas, traffic emission is a growing concern for ambient air quality and public health. Ultrafine particles (UFP) and black carbon (BC), a fraction of ambient particulate matter (PM), are both closely related to traffic emissions. Characterizing their physical and chemical properties is a crucial step in assessing health effects and air po...

Chlorine dioxide (ClO2) has proven its efficiency as a fumigant toward bacteria and viruses. However, it still has challenges on its portability and simplicity of ClO2 generation to meet the demand for disinfection in public and medical sectors. In this study, ClO2 stripping process via a rotating packed bed (RPB) from the commercial ClO2 solution...

Vehicle emissions are an important source of particulate matter (PM) in urban areas and have well-known adverse health effects on human health. Oxidative potential (OP) is used as a quantification metric for indexing PM toxicity. In this study, by using a liquid spot sampler (LSS) and the dithiothreitol (DTT) assay, the diurnal OP variation was ass...

Human umbilical cord-derived mesenchymal stem cells (hUC-MSCs) were shown to have potential for immunoregulation and tissue repair. The objective of this study was to investigate the effects of hUC-MSCs on emphysema in chronic obstructive pulmonary disease (COPD). The C57BL/6JNarl mice were exposed to cigarette smoke (CS) for 4 months followed by a...

Southeast Asia is a major biomass burning (BB) source area and BB has been identified as an important source of mercury (Hg) and aerosols to the atmosphere. Previous studies found correlations between atmospheric Hg and Delta-C (BC370–BC880) during the BB episodes in low-elevation BB source areas; however, whether this relationship persists during...

Epidemiological studies identified the relationship between air pollution and pulmonary tuberculosis. Effects of lung-deposited dose of particulate matter (PM) on culture-positive pulmonary tuberculosis remain unclear. This study investigates the association between lung-deposited dose of PM and pulmonary tuberculosis pleurisy. A case-control study...

Background: Air pollution has been linked to emphysema in chronic obstruction pulmonary disease (COPD). However, the underlying mechanisms in the development of emphysema due to air pollution remain unclear. The objective of this study was to investigate the role of components of the Hippo signaling pathway for E-cadherin-mediated contact inhibitio...

Exposure to road dust particulate matter (PM) causes adverse health impacts on the human airway. However, the effects of road dust on the upper airway epithelium in humans remain unclear. We investigated the involvement of the epidermal growth factor receptor (EGFR) after PM with an aerodynamic diameter of < 2.5 μm (PM2.5)-induced E-cadherin disrup...

Quantifying aerosol compositions (e.g., type, loading) from remotely sensed measurements by spaceborne, suborbital and ground-based platforms is a challenging task. In this study, the first and second-order spectral derivatives of aerosol optical depth (AOD) with respect to wavelength are explored to determine the partitions of the major components...

Inter-alpha-trypsin inhibitor heavy chain 4 (ITIH4) is a type II acute-phase protein; however, the role of pulmonary ITIH4 after exposure to air pollution remains unclear. In this study, we investigated the role of ITIH4 in the lungs in response to air pollution. ITIH4 expression in bronchoalveolar lavage fluid (BAL) of 47 healthy human subjects an...

Toxicological studies have demonstrated the associations between fine particle (PM2.5) components and various cytotoxic endpoints. However, few studies have investigated the toxicological effects of source-specific PM2.5 at the individual level. To investigate the potential impact of source-specific PM2.5 on cytotoxic effects, we performed repeated...

Particle morphology can affect the performance of an electrostatic precipitator air–liquid interface (ESP-ALI) cell exposure system and the resulting cell toxicity. In this study, three types of monodisperse aerosols – spherical sucrose particles, nonspherical align soot aggregates, and nanosilver aggregates/agglomerates – were selected to evaluate...

Background: Inter-alpha-trypsin inhibitor heavy chain 4 (ITIH4) is considered a type II acute-phase protein; however, the role of ITIH4 in the lungs after exposure to fine particulate matter (PM2.5) remains unclear. The objective of this study was to investigate the role of ITIH4 in the lungs in response to PM2.5 exposure. Results: ITIH4 expression...

Introduction: Angiotensin-converting enzyme 2 (ACE2) provides an adhesion site for SARS-CoV-2 infection. Patients with COPD could have severe outcomes after SARS-CoV-2 infection. The objective of this study was to investigate ACE2 regulation by air pollution during the development of COPD. Methods: Sprague Dawley rats were exposed to unconcentrated...

Cigarette smoke (CS) has been reported to induce oxidative stress and inflammatory process in the lungs. However, the role of human umbilical cord-derived mesenchymal stem cells (hUC-MSCs) in the regulation of pulmonary inflammation remains unclear. The objective of this study is to investigate the effects of hUC-MSCs on lung inflammation in the ac...

Coronavirus disease 2019 (COVID-19), an acute respiratory disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has rapidly developed into a pandemic throughout the world. This disease is a highly infectious novel coronavirus and can affect people of all ages. Previous reports observed that particulate matter (PM) prov...

The vertical distribution of aerosols is important for accurate surface PM2.5 retrieval and initial modeling forecasts of air pollution, but the observation of aerosol profiles on the regional scale is usually limited. Therefore, in this study, an approach to aerosol extinction profile fitting is proposed to improve surface PM2.5 retrieval from sat...

Epidemiological and toxicological evidence indicates that fine particulate matter (PM2.5, particulate matter < 2.5 µm in aerodynamic diameter) causes cardiopulmonary toxicity; however, its neurotoxic effects remain unclear. The objective of this study was to investigate the role of the neurofilament light (NEFL) serum polypeptide in neurotoxicity....

Removing submicron particles in the size range from 0.1 to 1.0 µm from gas streams is difficult because they cannot be efficiently captured neither through inertial separation nor by diffusion utilized in air pollution control devices. Electrostatic agglomeration is an effective and practical method for improving the removal efficiency of fine part...

Urban wastewater treatment plants (WWTPs) can be an emission source of aerosol particles to the air and this process has the potential to spread emerging pollutants into the air, where the particles can be widely transported over long distances to areas where this pollution is unexpected. This study demonstrates aeration tanks in WWTPs as a potenti...

Air-liquid exchange process could spread pathogens and pharmaceutical emerging pollutants into the air as aerosol particles in an Urban wastewater treatment plants (UWTPs). These particles can later be transported to places where such pollution is unforeseen. In this study, measurements were conducted in the aeration area of a UWTP in northern Taiw...

Neurotoxicity caused by particulate matter (PM) has been highlighted as being a potential risk factor for neurodegenerative diseases. However, the effects of brain inflammation in response to traffic-related PM remain unclear. The objective of this study was to investigate the effects of traffic-related PM on microglial responses. We determined the...

Electrospray-differential mobility analysis coupled to aerosol particle mass analyzer (ES-DMA/APM) was demonstrated for development of metal-organic framework (MOF) nanocarrier system. A successful quantification of ibuprofen loading in UiO-66-NH2 (i.e., the representative drug molecule and MOF, respectively) achieved based on the aerosol particle...

A custom-built steam-based aerosol collector (SBAC) was developed to improve the detection limits in aerosol chemical analysis. The SBAC was coupled with wet chemical analytical instruments to characterize the chemical composition of ambient particulate matter with high-time resolution. The particulate matter was mixed with a jet of steam and forme...

Virtual impactors can be used as aerosol concentrators as well as particle size classifiers. The flow field and particle trajectory inside a linear slit-type virtual impactor were investigated using a commercial computational fluid dynamics software package. Effects of flow and slit geometry, including the inlet flow (Q in ), the ratio of minor to...

Traffic emission is responsible for most small-sized particulate matter (PM) air pollution in urban areas. Several recent studies have indicated that traffic-related PM may aggravate kidney disease. Furthermore, exposure to particulate air pollution may be related to the risk of chronic kidney disease (CKD). However, the underlying molecular mechan...