Chung-Te Lee

Effects of Asian dust event particles on inflammation markers in peripheral blood and bronchoalveolar lavage in pulmonary hypertensive rats

The health impact of dust events from China has become a concern within China and in its neighboring countries. Previous epidemiological studies have demonstrated an association between particulate matter exposure and cardiopulmonary mortality. Here, we use pulmonary hypertensive rat models to examine inflammation markers in the lung and in peripheral blood after exposure to Asian dust storm particles. Using a nose-only inhalation system, eight pulmonary hypertensive rats were exposed to concentrated ambient particles (CAPs) from an actual Asian dust storm that took place between March 18 and 19, 2002; four control rats were also exposed to room air. Four rats exposed to CAPs of 315.6 g/m3 for 6 h were classified as the low-exposure group, and another four rats exposed to CAPs of 684.5 g/m3 for 4.5 h were classified as the high-exposure group. The animals were sacrificed 36 h after exposure. Inflammation markers in the peripheral blood and in the bronchoalveolar lavage (BAL) were analyzed, and IL-6 in BAL was also determined using ELISA. White blood cell counts in peripheral blood increased with increased CAP exposure levels (P<0.001, test for trend). In BAL analysis, total cell numbers and the proportion of neutrophil also increased with increased CAP levels (P<0.001, test for trend for both markers). Positive dose-response relationships between CAP exposure and total protein (P<0.05) and between CAPs and LDH activity (P<0.05) were also observed. Moreover, IL-6 protein in BAL increasing with CAP levels (P<0.05, test for trend) was demonstrated. Our results revealed that exposure to particulate matters during an Asian dust storm could increase lung inflammation and injury in pulmonary hypertensive rats. Further studies are needed to determine the components of dust storm particles that may contribute to the particle toxicity.

CONTRIBUTION OF ENDOTOXIN IN MACROPHAGE CYTOKINE RESPONSE TO AMBIENT PARTICLES IN VITRO

Ambient particles may cause pulmonary inflammation with ensuing morbidity. Particle-induced production of proinflammatory cytokines in vitro has been used as an indicator of particle toxicity. To identify particle components that were related to particle toxicity, Andersen dichotomous impactors were used to collect ambient fine (PM 2.5 ) and coarse (PM 2.5-10 ) particles in central Taiwan with extraction in endotoxin-free water. Mouse mono-cyte-macrophage cell line RAW 264.7 cells were exposed to particle extracts at 40 g/ml for 16 h, and tumor necrosis factor-alpha (TNF- f ) was measured in the medium by enzyme-linked immunosorbent assay (ELISA). Cell viabilities were all greater than 82%. Coarse particles stimulated higher TNF- f production than fine particles, and this was associated with greater particulate endotoxin content. Polymyxin B inhibited 42% of TNF- f production elicited by coarse particles and 32% of TNF- f production elicited by fine particles. In fine particles, TNF- f production was negatively correlated with Zn content, while no element in coarse particles correlated with TNF- f production. Results suggest that endotoxin and other components may be important factors for TNF- f production by macrophages in vitro.

Differences in PM10 concentrations measured by β-gauge monitor and hi-vol sampler

Abstract In this paper, differences between the 24-h average PM 10 concentrations of Wedding β -gauge monitor and Andersen or Wedding hi-vol sampler were studied. When the deliquescent point is not exceeded, PM 10 concentrations of the β -gauge are close to those of the manual samplers. The ratio of β -gauge PM 10 to Andersen PM 10 and Wedding PM 10 is 1.08±0.06 and 1.09±0.12, respectively. However, when the deliquescent point is exceeded, water absorption by the inorganics of aerosols leads to higher PM 10 concentrations of the β -gauge compared to those of the manual sampler. The ratio of β -gauge PM 10 to Andersen PM 10 and Wedding PM 10 is 1.21±0.22 and 1.27±0.15, respectively. However, due to evaporation of water from the aerosols collected on the filter tape of the β -gauge, differences in PM 10 concentrations are much less than theoretically calculated.

Enhanced insulin resistance in diet-induced obese rats exposed to fine particles by instillation.

Context: Epidemiological studies indicate that diabetes is a sub-population at risk for particulate matter (PM)-associated cardiovascular disease (CVD). Recent animal studies suggested PM might impair glucose tolerance, which may lead to CVD. However, the mechanism remains unclear. Objective: To investigate further the PM effect on insulin resistance (IR) in obese and healthy rats. Materials and methods: Male Sprague–Dawley rats were fed with either a high fat diet (HFD) or normal chow diet (NCD) for 6 weeks. Both groups were then further assigned to receive PM10, PM2.5 or normal saline (n = 6 per group) by intratracheal instillation (IT) once per week for 3 weeks. Fasting glucose and insulin were measured and homeostasis model assessment-insulin resistance (HOMA-IR) was used to assess IR. Biochemistry tests and lipids profile were examined at sacrifice. The markers of fibrinogen and [nitrate+nitrite], an indicator of nitric oxide (NO) production, C-reactive protein (CRP) and white blood counts (WBCs) in peripheral blood were also determined. Results: Body weight, insulin and HOMA-IR of HFD rats were significantly increased compared with a NCD after 6 weeks. In HFD rats, PM2.5 increased HOMA-IR after first IT and further increased HOMA-IR at the end of exposure. However, this increase was not observed in NCD rats and after PM10 exposure. Increased fibrinogen was also noted after chronic PM2.5 exposure in both HFD and NCD rats. Discussion and conclusion: Exposure to PM2.5 enhanced IR in HFD rats but not in NCD rats. Obese subjects with IR may be a susceptible population to particulate air pollution.

PCDD/F Measurement at a High-Altitude Station in Central Taiwan: Evaluation of Long-Range Transport of PCDD/Fs during the Southeast Asia Biomass Burning Event

Recent biomass burning in Southeast Asia has raised global concerns over its adverse effects on visibility, human health, and global climate. The concentrations of total suspended particles (TSPs) and other vapor-phase pollutants (CO and ozone) were monitored at Lulin, an atmospheric background station in central Taiwan in 2008. To evaluate the long-range transport of persistent organic pollutants (POPs) during the Southeast Asia biomass burning event, the atmospheric polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were also measured at Lulin station. The atmospheric PCDD/F and TSP concentrations measured at Lulin station ranged from 0.71-3.41 fg I-TEQ/m(3) and 5.32-55.6 microg/m(3), respectively, during the regular sampling periods. However, significantly higher concentrations of PCDD/Fs, TSPs, CO, and ozone were measured during the spring season. These high concentrations could be the result of long-range transport of the products of Southeast Asia biomass burning. During the Southeast Asia biomass burning event (March 18-24, 2008), an intensive observation program was also carried out at the same station. The results of this observation program indicated that the atmospheric PCDD/F concentration increased dramatically from 2.33 to 390 fg I-TEQ/m(3) (March 19, 2008). The trace gas (CO) of biomass burning also significantly increased to 232 ppb during the same period, while the particle-bound PCDD/Fs in the TSP increased from 28.7 to 109 pg I-TEQ/g-TSP at Lulin station during the burning event. We conclude that there was a significant increase in the PCDD/F concentration in ambient air at a high-altitude background station in central Taiwan during the Southeast Asia biomass burning event.

Simulation of long-range transport aerosols from the Asian Continent to Taiwan by a Southward Asian high-pressure system

Aerosol is frequently transported by a southward high-pressure system from the Asian Continent to Taiwan and had been recorded a 100% increase in mass level compared to non-event days from 2002 to 2005. During this time period, PM2.5 sulfate was found to increase as high as 155% on event days as compared to non-event days. In this study, Asian emission estimations, Taiwan Emission Database System (TEDS), and meteorological simulation results from the fifth-generation Mesoscale Model (MM5) were used as inputs for the Community Multiscale Air Quality (CMAQ) model to simulate a long-range transport of PM2.5 event in a southward high-pressure system from the Asian Continent to Taiwan. The simulation on aerosol mass level and the associated aerosol components were found within a reasonable accuracy. During the transport process, the percentage of semi-volatile PM2.5 organic carbon in PM2.5 plume only slightly decreased from 22-24% in Shanghai to 21% near Taiwan. However, the percentage of PM2.5 nitrate in PM2.5 decreased from 16-25% to 1%. In contrast, the percentage of PM2.5 sulfate in PM2.5 increased from 16-19% to 35%. It is interesting to note that the percentage of PM2.5 ammonium and PM2.5 elemental carbon in PM2.5 remained nearly constant. Simulation results revealed that transported pollutants dominate the air quality in Taipei when the southward high-pressure system moved to Taiwan. Such condition demonstrates the dynamic chemical transformation of pollutants during the transport process from continental origin over the sea area and to the downwind land.

Increasing emergency room visits for stroke by elevated levels of fine particulate constituents.

The associations between fine particulate matter (PM2.5) and stroke remain inconsistent. We conducted a time-series study to evaluate emergency room (ER) visits for ischemic and hemorrhagic strokes in relation to PM2.5 and its constituents. Generalized additive models were used to model the counts of daily ER visits for ischemic and hemorrhagic strokes among patients admitted to the National Taiwan University Hospital from 1 January 2004 to 31 August 2008. Exposure variables included PM2.5 and the four constituents, nitrate, sulfate, organic carbon (OC), and elemental carbon (EC). 12,982 ischemic stroke and 3362 hemorrhagic stroke cases were identified during the study period. For hemorrhagic stroke, the strongest relative risks (RRs) of ER visits were 1.19 [95% confidence interval (CI), 1.07-1.32] and 1.08 (95% CI, 1.02-1.15) for an interquartile range (IQR) increase in 3-day average nitrate and EC. For ischemic stroke, increased RRs of ER visits of 1.21 (95% CI, 1.07-1.36) and 1.18 (95% CI, 1.06-1.31) were observed in the warm season for an IQR increase in 3-day average of OC and EC, respectively. PM2.5 and OC were associated with increased RRs of ER visits for ischemic stroke among patients aged 65 years or older and female patients. In conclusion, PM2.5 constituents, rather than PM2.5 mass, are more closely related to ER visits for hemorrhagic stroke. Both PM2.5 mass and its chemical constituents are associated with ER visits for ischemic stroke in the warm season, among patients older than 65 years, and female patients.

The Association of Ambient Air Pollution With Airway Inflammation in Schoolchildren

The biologic mechanisms involved in airway inflammatory response to air pollution are not clearly understood. The authors conducted a longitudinal study to investigate whether exposure to ambient air pollutants affected inflammatory cells and mediators from nasal lavage in schoolchildren. Study participants were 100 elementary and middle-school students in New Taipei City, Taiwan. A structured respiratory health questionnaire was administered in September 2007, followed by monthly measurement of nasal inflammation from October 2007 to November 2009. During the study period, daily concentrations of air pollutants were obtained from the Environmental Protection Administration monitoring station and the Aerosol Supersite. Mixed-effects models were applied to examine the association between air pollution and nasal inflammatory cells and mediators, including percentages of neutrophils, eosinophils, and monocytes in lavaged cells and interleukin-8. A total of 824 measurements were obtained from 100 participants over a period of 10 months. The level of particulate matter with an aerodynamic diameter of 2.5 μm or less (PM(2.5)) was found to be associated with percentage of neutrophils (β = 3.45%, 95% confidence interval: 0.89, 6.01) and interleukin-8 level (β = 29.98 pg/mL, 95% confidence interval: 3.26, 56.69) in the nasal lavage on the day of exposure. In this longitudinal cohort study of schoolchildren, results indicated that exposure to PM(2.5) might induce nasal inflammation.

Quantification on the source/receptor relationship of primary pollutants and secondary aerosols by a Gaussian plume trajectory model: Part III—Asian dust-storm periods

Characteristics of pollutants at heights in the top of the Planetary Boundary Layer (PBL) are collected and used in a local-scale model. A subsidence mechanism is developed to quantify the concentration fraction from the top PBL to simulate PM concentration during Asian dust-storm (ADS) periods. The results show that using the data measured at a mountain station, which is very vulnerable to ADS, as the top boundary conditions for the air quality model can capture all the PM2.5 episodes due to local sources and ADS events, at a low-altitude urban station. The correlation coefficient (r2) of daily PM2.5−10 concentration has increased from 0.17 to 0.62 by incorporating the subsidence mechanism, and that of PM2.5 increases as well. The model results of nitrate, sulfate and ammonium aerosol in fine radii can be compared with observations. According to our analysis, five out of eight PM2.5 or PM10 episode days occurred on ADS days in the past 4 years (1999–2002). During ADS episodes in 2000, 12% of PM2.5 and 53% of PM2.5−10 were from ADS dust. In addition, two dry deposition algorithms are evaluated; the algorithm of Seinfeld and Pandis (Atmospheric Chemistry and Physics from Air Pollution to Climate Change, Wiley, New York, 1998, 1057pp.) is suggested in this case study.

Applying GC-TCD to investigate the hygroscopic characteristics of mixed aerosols

Aerosol deliquescence plays a significant role in atmospheric phenomena such as acidic precipitation, formation of clouds and fogs, and changes in visibility. Important factors including aerosol composition and atmospheric relative humidity govern the aerosol deliquescence. However, recent work has revealed that certain aerosols form a metastable composition, which cannot be elucidated by measuring the solubility of bulk-phase solution, nor can it be predicted by traditional thermodynamic theory. This composition, however, contributes to the difference between the predicted and measured deliquescence of atmospheric aerosol. This work applied the newly developed semi-automated GC-TCD (gas chromatograph equipped with thermal conductivity detector) aerosol water mass measurement system to measure the hygroscopic characteristics of aerosols of NaCl, Na2SO4, NH4NO3, NH4Cl and mixed aerosols of NaCl–Na2SO4 and NH4NO3–NH4Cl in various proportions. The measurements are compared with those in the literature to validate the GC-TCD method and investigate the metastable solid form of the Na2SO4 aerosol, which cannot be predicted by traditional thermodynamic theory. The comparisons confirm that measurements of the characteristics of single- and mixed-salt aerosols, obtained by GC-TCD, are satisfactorily accurate. Furthermore, the Na2SO4 aerosol is found to form an anhydrate other than the dehydrate predicted by traditional thermodynamic theory. This result may explain the difference between the measured and modeled results at the DRH of NaCl–Na2SO4 mixed aerosol.