Taiwan Air Quality Monitoring Network Research Articles

Short-term impact of exposure to ambient air volatile organic compounds on daily clinic visits for urticaria in Kaohsiung, Taiwan.

Air volatile organic compounds (VOCs) cause allergic reaction mainly via the respiratory tract or skin. This study aimed to investigate the association between daily visits by patients with urticaria and short-term changes in exposure to ambient air VOCs. The dependent variable was information from patients with urticaria at a medical center in Kaohsiung, Taiwan, from 2014/01/01 to 2018/07/31. The multivariable model included one-day average 75th percentile values of air VOCs and meteorologic data retrieved from Taiwan Air Quality Monitoring Network database, and was analyzed using a case-crossover study design and conditional logistic regression. Total daily clinic visits for urticaria were significantly positively associated with higher levels of 4 VOCs (ethylbenzene, toluene, m-/p-xylene, and o-xylene (adjusted odds ratio (AOR: 1.03-1.28)) on the visit days, and 10 VOC levels on the fourth lag day (benzene, ethylbenzene, toluene, m-/p-xylene, o-xylene, 1,3,5-trimethylbenzene, n-hexane, methylcyclohexane, cyclohexane, and ethylene (AOR: 1.02-3.02)). Analyses of age and gender subgroups revealed that men showed resistance on the visit day, and women, older, and younger patients were more vulnerable. Men were influenced by higher benzene levels (AOR = 1.24) on the fourth lag day. Higher values of more than 6 VOCs on the fourth lag day significantly affected women, younger and older patients (AOR: 1.04-6.5). The most notable VOCs were methylcyclohexane (women AOR = 3.28, younger AOR = 3.82) and 1,3,5-trimethylbenzene (women AOR = 2.77, older AOR = 6.5) on the fourth lag day, which had the lowest concentrations but highest influence. The concentration of certain air VOCs significantly affected daily visits for urticaria.

Are associations of leisure-time physical activity with mortality attenuated by high levels of chronic ambient fine particulate matter (PM2.5) in older adults? A prospective cohort study

Background and purposeAlthough leisure-time physical activity (PA) has established health benefits in older adults, it is equivocal if exercising in environments with high levels of PM2.5 concentrations is equally beneficial for them. To explore the independent and joint associations of ambient PM2.5 and PA with all-cause mortality among adults aged 60 or older and to assess the modifying effect of age (60–74 years vs. 75+ years) on the joint associations. MethodsA prospective cohort study based on the MJ Cohort repeat examinations (2005–2016) and the Taiwan Air Quality Monitoring Network and death registry linkages (2005–2022). We included MJ Cohort participants aged 60 or more at baseline who attended the health check-ups at least twice (n = 21,760). Metabolic equivalent hours per week (MET-h/week) of leisure-time PA were computed. Multivariable adjusted associations were examined using time-varying Cox proportional hazard models. ResultsThere were 3539 all-cause deaths over a mean follow-up of 12.81 (SD = 3.67) years. Ambient PM2.5 and physical inactivity are both independently associated with all-cause mortality. The joint associations of PA and PM2.5 concentrations with all-cause mortality differed in the young-old (60–74 years) and the older-old (75+ years) (P for interaction = 0.01); Higher levels of long-term PM2.5 exposures (≥25 μg/m3) had little influence on the associations between PA and mortality in the young-old (HR = 0.68 (0.56–0.83) and HR = 0.72 (0.59–0.88) for participants with 7.5–<15 and 15+ MET-h/week respectively) but eliminated associations between exposure and outcome in the older-old (HR = 0.91 (0.69–01.21) and HR = 1.02 (0.76–1.38) for participants with 7.5–<15 and 15+ MET-h/week). ConclusionLong-term exposures to higher PM2.5 concentrations may eliminate the beneficial associations of PA with all-cause mortality among adults aged 75 and over.

Spatially adaptive calibrations of airbox PM2.5 data.

The Taiwan air quality monitoring network (TAQMN) and the AirBox network both monitor PM2.5 in Taiwan. The TAQMN, managed by Taiwan's Environmental Protection Administration (EPA), provides high-quality PM2.5 measurements at 77 monitoring stations. The AirBox network launched more recently consists of low-cost, small internet-of-things (IoT) microsensors (i.e., AirBoxes) at thousands of locations. While the AirBox network provides broad spatial coverage, its measurements are unreliable and require calibrations. However, applying a universal calibration procedure to all AirBoxes does not work well because the calibration line varies with local factors, including the chemical compositions of PM2.5 , which are not homogeneous in space. Therefore, different calibrations are needed at different locations to adapt to their local environments. Unfortunately, AirBoxes and EPA locations are misaligned, challenging the calibration task. In this paper, we propose a spatial model with spatially varying coefficients to account for the heterogeneity in the data. Our method gives spatially adaptive calibrations of AirBoxes and produces accurate PM2.5 concentration estimates with their error bars at any location, incorporating two types of measurements. In addition, the proposed method is robust to outliers, requires no colocated data, and provides calibration formulas for new AirBoxes once they are added to the network. We illustrate our approach using hourly PM2.5 data in 2020. After the calibration, the results show that the PM2.5 prediction improves by about 38%-68% in root-mean-squared prediction error. Once the calibration formulas are established, we can obtain reliable PM2.5 values even if we ignore EPAdata.

Air Pollution Effects to the Subtype and Severity of Lung Cancers.

The correlation between lung cancer incidence and air pollution has been established in previous research, but the other detail impact of air pollution to lung cancer is still under investigation. This study aimed to explore if air pollution affected the subtype and staging of lung cancer. At the same time, we investigated the effect of individual pollutant to subtypes and staging. Single center data were extracted from January 1, 2020 to June 30, 2020 using the search engine in the radiology reporting system of Shuang-Ho Hospital, New Taipei City, Taiwan. There were 169 patients finally included for analysis. The nationwide statistics data of lung cancer were extracted from the Taiwan Cancer Registry. The air quality data were extracted from the Taiwan air quality monitoring network. Comparison of the single center lung cancer characteristics with nationwide data was made using the chi-square test. Comparison of the air quality of the living space of the included cases with the average quality in Taiwan in 2020 was made using the Z-test. The result shows there was significant difference of cancer subtype and staging between the regional data and the nationwide data. The regional data demonstrated a tendency of higher incidence of adenocarcinoma and advanced stage disease. As for air quality, there was no significant difference. The regional PM10 level presented generally lower levels in regional data as compared to Taiwan in 2020 with near statistically significant P-value (0.052); the regional NO2 level presented generally higher levels in regional data as compared to Taiwan in 2020 with near statistically significant P-value (0.060). The results indicate that air pollution might be related to increase in adenocarcinoma ratio and advanced stage of lung cancer at initial presentation. The NO2 was probably the leading pollutant causing this trend.

Short-term impact of ambient air pollution exposure on daily clinic visits for patients with urticaria in Kaohsiung, Taiwan

The aim of this study was to investigate associations between daily visit count for patients with urticaria (DVCPU) and short-term changes in ambient air pollutant concentrations. Information of DVCPU with an ICD-9 diagnostic code 708 in out-patient clinic visits was retrieved from the medical records of Kaohsiung Veterans General Hospital from January 1, 2014, to July 31, 2018, as a dependent variable. Ambient air pollutant data were retrieved from the Taiwan Air Quality Monitoring Network database including carbon monoxide (CO), ground-level ozone (O3), particulate matter (PM)10, PM2.5, nitrogen dioxide (NO2), and nitric oxide (NO). Independent variables included one-day weighted 75th percentile values of one kind of air pollutant, meteorological factors (temperature, humidity, wind speed, and rainfall), and weekdays in the same model. Multivariable Poisson regression was used for analysis. DVCPU was significantly positively associated with an increasing level of NO2 on the 1st–3rd lag days (relative risk (RR): 1.02~1.03) and O3 on the 1st and 3rd lag days (RR = 1.002). Men were associated with CO on the visit day and 1st–5th lag days (RR: 1.65~2.06) and PM10 on the 1st (RR = 1.002) and 3rd lag days (RR = 1.003). Women were associated with CO on the 3rd–4th lag days (RR = 1.4) and O3 on the 1st (RR = 1.003) and 5th (RR = 1.004) lag days. The non-elderly (age < 65 years) was associated with O3 on the 1st (RR = 1.003) and 3rd (RR = 1.002) lag days. The elderly (age ≥ 65 years) was associated with CO on the visit day, 1st, 3rd, and 5th lag days (RR: 1.94~4.67), PM2.5, and PM10 on the visit day (RR = 1.01). Ambient air pollutants exposure was an important risk factor for patients with urticaria seeking treatment on certain days among the visit day and lag days.

Epidemiological Correlation of Pulmonary Aspergillus Infections with Ambient Pollutions and Influenza A (H1N1) in Southern Taiwan.

An increase in fungal spores in ambient air is reported during a spike in particulate matter (PM2.5 and PM10) aerosols generated during dust or smog events. However, little is known about the impact of ambient bioaerosols on fungal infections in humans. To identify the correlation between the incidence of pulmonary aspergillosis and PM-associated bioaerosols (PM2.5 and PM10), we retrospectively analyzed data between 2015 and 2018 (first stage) and prospectively analyzed data in 2019 (second stage). Patient data were collected from patients in three medical institutions in Tainan, a city with a population of 1.88 million, located in southern Taiwan. PM data were obtained from the Taiwan Air Quality Monitoring Network. Overall, 544 non-repeated aspergillosis patients (first stage, n = 340; second stage, n = 204) were identified and enrolled for analysis. The trend of aspergillosis significantly increased from 2015 to 2019. Influenza A (H1N1) and ambient PMs (PM2.5 and PM10) levels had significant effects on aspergillosis from 2015 to 2018. However, ambient PMs and influenza A (H1N1) in Tainan were correlated with the occurrence of aspergillosis in 2018 and 2019, respectively. Overall (2015–2019), aspergillosis was significantly correlated with influenza (p = 0.002), influenza A (H1N1) (p < 0.001), and PM2.5 (p = 0.040) in Tainan City. Using a stepwise regression model, influenza A (H1N1) (p < 0.0001) and Tainan PM10 (p = 0.016) could significantly predict the occurrence of aspergillosis in Tainan. PM-related bioaerosols and influenza A (H1N1) contribute to the incidence of pulmonary aspergillosis.

The Association between Ambient Fine Particulate Matter and Oral Neoplasm among Smokers and Betel Quids Chewers

The association between fine particulate matter < 2.5 µm (PM2.5) and oral neoplasm has barely been addressed. The purpose of this study is to elucidate the association between PM2.5 and oral neoplasm, including oral potentially malignant disorder (OPMD) and oral cancer (OC), taking into account the geographical heterogeneity. Data for analysis were derived from nationwide OC screening program, targeting Taiwanese cigarette smokers and/or betel quid chewers, and the Taiwan Air Quality Monitoring Network between 2006 and 2016. Totally 3,864,045 smokers and/or betel quids chewers were enrolled in this study. Among them, 154,030 OPMD cases and 23,286 oral cancers were found during the study period. Information on age, gender, living area, personal oral habits, and monthly PM2.5 concentration in average were collected. We used the Bayesian random-effect logistic regression model to assess the association between PM2.5 and OPMD/OC. After adjusting for sex, age, and behavior of betel quid chewing and cigarette smoking, we found that subjects from areas of higher levels of PM2.5 (≥ 35 µg m–3) had an increased risk of OPMD/OC and OC by 11% (aRR = 1.11; 95% CI: 1.09–1.13) and 55% (aRR = 1.55; 95% CI: 1.49–1.60) respectively, compared to those from areas of lower PM2.5 (< 35 µg m–3). Such effect was further demonstrated in a concentration-dependent manner. Subjects from areas of higher PM2.5 levels were found to have greater risk of OPMD/OC in Taiwan. Future studies are warranted to investigate the effect of personal PM2.5 exposure on OPMD/OC risk.

Association of ambient non-methane hydrocarbons exposure with respiratory hospitalizations: A time series study in Taipei, Taiwan

Ambient hydrocarbons are important precursors of ground-level ozone and secondary organic aerosol formation. However, few studies have assessed the health impact of airborne hydrocarbons. We conducted this time series ecological study to evaluate the association of short-term airborne hydrocarbons exposure with hospital admissions for respiratory diseases, while controlling for co-exposure to criteria pollutants. Taipei air pollution and weather data for the period spanning from January 2010 to December 2017 were obtained from Taiwan Air Quality Monitoring Network. Subsequently, daily pollutant concentrations were linked with daily hospital admission counts for respiratory diseases into a time series data frame. The standard generalized additive Poisson model adjusted for temporal trends, seasonal variations, weather conditions, and calendar effects, was applied to examine the short-term associations of acute airborne hydrocarbon exposure with respiratory hospital admissions. Next, the robustness of the associations was tested using two-pollutant models with further adjustment for fine particulate matter (PM2.5) and gaseous pollutants. The results demonstrated that an interquartile range increase in non-methane hydrocarbon (NMHC) exposure on lag0 day (0.15 ppm) was associated with a 0.86% (95% confidence interval: 0.37%–1.36%), 2.06% (0.77%–3.38%), and 1.25% (0.31%–2.20%) increment in all-respiratory-disease-, asthma-, and chronic-obstructive-pulmonary-disease-linked hospital admissions, respectively. The associations were robust with further adjustment for co-exposure to PM2.5 and ozone. The acute effect estimate of methane on each respiratory category was sensitive to the co-pollutant adjustment and lost statistical significance in the two-pollutant models. In conclusion, we confirmed that airborne NMHC exposure increased the risk of respiratory-disease-related hospital admissions in Taipei; this information may aid in the regulation of hydrocarbon pollution.

Spatiotemporal assessment of mortality attributable to ambient PM2.5 exposure in Taiwan during 2008–2015

In this study, we quantified the spatiotemporal burden of mortality attributable to ambient fine particulate matter (PM2.5, which is defined as a mass of particles with an aerodynamic dry diameter of ≤ 2.5 μm) in Taiwan during 2008–2015. Hourly concentrations of PM2.5 were obtained from the Taiwan Air Quality Monitoring Network. According to geographical and climatic characteristics, the Taiwan Environmental Protection Administration has divided Taiwan into seven air quality regions (AQRs): the North (four districts), Chu-Miao (two districts), Central (three districts), Yun-Chia-Nan (three districts), Kao-Ping (two districts), Yilan (one district), and Hua-Tung (two districts) regions. Demographic information and mortality data were acquired from the Department of Household Registration and National Death Registry of Taiwan, respectively. The World Health Organization’s (WHO) AirQ+ software was used to estimate the mortality attributable to exposure to PM2.5 for specific causes of deaths, specifically from ischemic heart disease (IHD), cerebrovascular disease (stroke), lung cancer (LC), and chronic obstructive pulmonary disease (COPD). The results indicated that nationally, the annual mean concentration of PM2.5 decreased from 2008 (30.75 μg m−3) to 2015 (20.07 μg m−3). Moreover, the population-attributable fraction (PAF) of cause-specific mortality due to PM2.5 exposure for IHD, stroke, LC, and COPD decreased from 21.72%, 30.31%, 15.97%, and 13.04%, respectively, in 2008 to 17.40%, 18.18%, 10.77%, and 9.09%, respectively, in 2015. Geographic variation was observed in the PM2.5 concentration and PAF. High PM2.5 levels and PAF of mortality due to PM2.5 were observed in southwestern and central Taiwan. Moreover, cardiovascular and cerebrovascular disease (IHD and stroke) accounted for the majority of the premature deaths related to PM2.5. Stroke was the largest contributor in PM2.5-related premature mortality; however, IHD instead of stroke became the largest contributor in the Yilan AQR in 2010, 2012, and 2014–2015 and in the Hua-Tung AQR in 2012–2015 with relatively low PM2.5 levels (less than 19 μg m−3). In Taiwan, ambient PM2.5 contributed substantially to the burden of disease. Our results could aid authorities in determining the effectiveness of current air pollution control strategies and plans.

Characteristics of patients with endometrial hyperplasia under different air quality index conditions

ObjectiveAir pollution has been widely recognized to pose a threat to health. Urban outdoor air pollution was listed as the 14th biggest risk factor for global deaths in 2004 in the Global Health Risks report published by the World Health Organization in 2009. Many past studies have indicated that exposure to environmental contaminants promotes changes in the internal mechanisms of diseases, including the infection of various systems in the body, hormonal changes, and vascular proliferation. These changes may be related to the severity of endometrial hyperplasia. Therefore, this study used the air quality monitoring data of the Environmental Protection Administration (EPA) to examine the effects of air pollutant concentration on patients with endometrial hyperplasia. Materials and methodsThis population-based nationwide study used data for 2002–2013 from the National Health Insurance Research Database of Taiwan. Patients who developed endometrial hyperplasia before 2002 were excluded. In total, 14,883 patients with endometrial hyperplasia were tracked. The exposure levels and air quality index (AQI) values in this study were based on the taiwan air quality monitoring network data collected by the EPA from 2000 to 2013. The data were further divided into the good air quality group (AQI ≤ 50) and poor air quality group (AQI > 50). The study used linear regression model to estimate the correlation linking air pollutant concentration with endometrial hyperplasia. ResultsThe results indicated that, in comparison to endometrial hyperplasia patients who were exposed to air with good quality, those exposed to air with poor quality had a higher average age (p < 0.001) and higher proportion of living in southern Taiwan (p < 0.001), as well as higher rates of diabetes (p < 0.001), hyperlipidemia (p < 0.001), hypertension, cerebrovascular diseases (p = 0.024), cerebral vascular accidents (p = 0.024), and chronic kidney disease (p < 0.001). ConclusionThe patients with endometrial hyperplasia in poor AQI area had severe comorbidity. Thus, attention must be paid to the improvement of air quality and the implementation of preventive measures against contaminants.

Association between exposures to air pollution and biomarkers of cardiovascular disease in Northern Taiwan

Exposure to air pollution has been associated with increased cardiovascular disease (CVD). Biological mechanism of oxidative stress and systemic inflammation link this association. Heart rate (HR), Systolic Blood Pressure (SBP), Diastolic blood pressure (DBP), White Blood Cell (WBC), Red Blood Cell (RBC), hematocrit (HCT), and hemoglobin (HB) are some biomarkers of oxidative stress and systemic inflammation related to CVD. However, study about effects of air pollution on biomarkers of CVD in specific group remains very limited. We conducted this study to measure the association between ambient air pollution and biomarkers of CVD in adult people in the urban area of northern Taiwan. We conducted this study using a cross-sectional design. We extracted biomarkers of CVD data from the daily hospital admissions of pulmonary department of Shuang-Ho Hospital in New Taipei City from 2014 to 2015. We averaged the 24 h concentrations of PM10, PM2.5, NO2, and SO2, and 8 h concentrations of O3 from the database of Taiwan Air Quality Monitoring Network. We analyzed the data using multiple linear regression. We used lag up to 5 previous days in the analysis to measure the delay effect of the air pollution. We controlled meteorological variables (temperature and relative humidity) and individual characteristics (sex, age, smoking status, and alcohol consumption) in the analysis. We use the beta coefficients (β) and 95% CI to express the association. We considered P-value < 0.05 as statistically significant. We found statistically significant positive associations between air pollutants and HR, SBP, and RBC concentrations and statistically significant negative associations between air pollutants and HCT concentrations. On the other hand, we found no significant association between air pollutants and DBP, WBC, and HB concentration.

Associations of PM2.5 and aspergillosis: ambient fine particulate air pollution and population-based big data linkage analyses

A substantial amount of reports has been published on the association between the environment Aspergillus conidia and fine particulates, while limited studies have focused on the association between invasive aspergillosis and ambient fine particulate air pollution. The aim of this study is to explore the population-level association between ambient fine particulate PM2.5 air pollution and invasive aspergillosis. We designed multiple powerful systems applied to a unique collection of long-term and nationwide database of daily ambient PM2.5 levels and invasive aspergillosis incidence in Taiwan. Two data sets were leveraged for this study; the National Health Insurance Research Database and the Taiwan air quality monitoring network. The National Health Insurance Research Database was used to define invasive aspergillosis while the Taiwan air quality monitoring network was used to profile the PM2.5 concentration in Taiwan. We adopted the cases of invasive aspergillosis infection from the system with PM2.5 levels. A total of 1,000,000 patients during the study period (1999–2009) were included in the data set.The findings of this study suggest positive association between PM2.5 concentration and incidence of aspergillosis. Furthermore, monthly-wise invasive aspergillosis case number potentially demonstrated lagged pattern following peaking of PM2.5 concentration.

Burden of disease attributable to ambient fine particulate matter exposure in Taiwan.

There is compelling epidemiological evidence that links air pollution to increased risk of mortality from cardiopulmonary disease and lung cancer. We quantified the burden of mortality attributable to ambient fine particulate matter (PM2.5) among the Taiwanese population in 2014 at the national and subnational levels. Subnational PM2.5 exposure levels were obtained from Taiwan Air Quality Monitoring Network. Relative risks were derived from a previously developed exposure-response model. Population attributable fraction for cause-specific mortality was estimated at the county level using the estimated ambient PM2.5 concentrations and the relative risk functions. In 2014, PM2.5 accounted for 6282 deaths [95% confidence interval (CI), 5716-6847], from ischemic heart disease (2244 deaths; 95% CI, 2015-2473), stroke (2140 deaths; 95% CI, 1760-2520), lung cancer (1252 deaths; 95% CI, 995-1509), and chronic obstructive pulmonary disease (645 deaths; 95% CI, 418-872). Nationally, the population attributable mortality fraction of PM2.5 for the four disease causes was 18.6% (95% CI, 16.9-20.3%). Substantial geographic variation in PM2.5 attributable mortality fraction was found; the percentage of deaths attributable to PM2.5 ranged from 8.7% in Hualian County to 21.8% in Yunlin County. In terms of absolute number of deaths, New Taipei and Kaohsiung cities had the largest number of deaths associated with PM2.5 (874 and 829 deaths, respectively) among all cities and counties. Ambient PM2.5 pollution is a major mortality risk factor in Taiwan. Aggressive and multisectorial intervention strategies are urgently needed to bring down the impact of air pollution on environment and health.

Influence of Sea-Land Breezes on the Tempospatial Distribution of Atmospheric Aerosols over Coastal Region

ABSTRACT The influence of sea-land breezes (SLBs) on the spatial distribution and temporal variation of particulate matter (PM) in the atmosphere was investigated over coastal Taiwan. PM was simultaneously sampled at inland and offshore locations during three intensive sampling periods. The intensive PM sampling protocol was continuously conducted over a 48-hr period. During this time, PM2.5 and PM2.5–10 (PM with aerodynamic diameters ≤2.5 μm and between 2.5 and 10 μm, respectively) were simultaneously measured with dichotomous samplers at four sites (two inland and two offshore sites) and PM10 (PM with aerodynamic diameters ≤10 μm) was measured with β-ray monitors at these same 4 sites and at 10 sites of the Taiwan Air Quality Monitoring Network. PM sampling on a mobile air quality monitoring boat was further conducted along the coastline to collect offshore PM using a β-ray monitor and a dichotomous sampler. Data obtained from the inland sites (n = 12) and offshore sites (n = 2) were applied to plot the PM10 concentration contour using Surfer software. This study also used a three-dimensional meteorological model (Pennsylvania State University/National Center for Atmospheric Research Meteorological Model 5) and the Comprehensive Air Quality Model with Extensions to simulate surface wind fields and spatial distribution of PM10 over the coastal region during the intensive sampling periods. Spatial distribution of PM10 concentration was further used in investigating the influence of SLBs on the transport of PM10 over the coastal region. Field measurement and model simulation results showed that PM10 was trans ported back and forth across the coastline. In particular, a high PM10 concentration was observed at the inland sites during the day because of sea breezes, whereas a high PM10 concentration was detected offshore at night because of land breezes. This study revealed that the accumulation of PM in the near-ocean region because of SLBs influenced the tempospatial distribution of PM10 over the coastal region. IMPLICATIONS Model simulation and field measurements show that PM was transported back and forth across the coastline because of SLBs and that this regularly influenced the tempospatial distribution of PM10 over the coastal region. A high PM10 concentration was observed at the inland sites because of daytime onshore breezes, whereas a high PM10concentration was detected over the ocean because of nighttime offshore breezes. The implications of these results suggest that relevant authorities should work to prevent pollution episodes by reducing regional PM emissions that lead to stagnant or recirculating air under specific weather conditions.

Long-term spatial distributions and trends of ambient CO concentrations in the central Taiwan Basin

Long-term spatial distributions and trends of atmospheric carbon monoxide (CO) concentrations in the central Taiwan Basin were investigated by analysis of CO data obtained from the Taiwan Air Quality Monitoring Network (TAQMN). The influence of meteorological conditions on the CO patterns was also analyzed in this paper. The results showed the highest CO concentrations were found in the vicinity of urban areas with a 13-yr mean value of 0.79±0.16ppm. This was associated with the most intensive anthropogenic CO emissions at the urban sites. For all sites, lower CO levels were consistently observed during the summer season. This was explained by favorable conditions for dispersion and loss of CO via photochemical reactions. Analysis of wind fields and backward trajectories revealed that two types of synoptic sea breezes directly influenced the CO spatial distributions in the basin. During autumn to spring, northerly flow accompanied by pollutants traveled to inland areas, resulting in higher CO concentrations in the remote areas. During summer, breezes coming from the sea or areas to the south with lower CO emissions, resulted in more uniform spatial distributions of CO in the study region. While CO concentrations exhibited decreasing trends, the average CO mixing ratio from 1994 through 2006 decreased at a rate of approximately 0.02ppmyr−1 in the central Taiwan Basin.

Measurements of Sulfur Dioxide and Formaldehyde in Taipei Using a Differential Optical Absorption Spectrometer

ABSTRACT Taipei, the capital city of Taiwan, lies in a basin, and its topography prevents the dispersion of pollutants in the city. As a continuation of our air quality study, from February 1999 through June 1999, we measured the concentrations of SO2 at six different locations and of formaldehyde at five locations using a differential optical absorption spectrometer (DOAS). The average concentration of SO2 varied from 3.5 to 6.6 ppb. The average concentration was highest at Toucheng because of its proximity to point sources. The level in Hsientien was close to that in Toucheng, with Hsinyu showing the lowest concentrations. The DOAS and the Taiwan Air Quality Monitoring Network (TAQMN) measurements for SO2 were highly correlated (r2 > 0.9) for Toucheng, Panchiao, and Hsientien. However, DOAS SO2 concentrations were 2 times higher for Hsientien and slightly lower for Panchiao than the TAQMN concentrations were. The average concentration of formaldehyde varied from 7 to 10 ppb. Diurnal variation of formaldehyde closely followed the variation of ozone, especially when the 1-hr peak ozone concentration was >60 ppb. Photochemical formation accounted for the ambient levels of formaldehyde in Taipei. Concentration of formaldehyde became significant on days when O3 concentration was high. Our results indicate that DOAS can replace conventional measurement techniques.

Short-Term Effect of Ozone on the Pulmonary Function of Children in Primary School

The objective of this study was to evaluate the short-term effect of ambient air pollution on the pulmonary function of schoolchildren. We sampled 941 children in primary school in three communities in Taiwan (Sanchun, Taihsi, and Linyuan). The nearby stations of the Taiwan air quality monitoring network provided the hourly ambient concentrations of sulfur dioxide, carbon monoxide, ozone, particulate matter &lt; or = to 10 microm in aerodynamic diameter, and nitrogen dioxide. Spirometry was performed once for each sampled child. We also obtained the status of indoor air pollution and chronic respiratory disease history by using a structured questionnaire. Multivariate linear model analysis was used to evaluate pulmonary function effects of each pollutant in addition to determinants of indoor air pollution and meteorologic conditions. We found a significantly negative association of peak O(3) concentration on the day before spirometry with individual forced vital capacity and forced expiratory volume in 1 sec. The decrease in children's lung function can occur at peak hourly O(3) concentrations &lt; 80 ppb. The slope of lung function decrease for Taiwanese children is approximately 1 mL/ppb for peak hourly O(3) exposure.

Short-term effect of ozone on the pulmonary function of children in primary school.

The objective of this study was to evaluate the short-term effect of ambient air pollution on the pulmonary function of schoolchildren. We sampled 941 children in primary school in three communities in Taiwan (Sanchun, Taihsi, and Linyuan). The nearby stations of the Taiwan air quality monitoring network provided the hourly ambient concentrations of sulfur dioxide, carbon monoxide, ozone, particulate matter < or = to 10 microm in aerodynamic diameter, and nitrogen dioxide. Spirometry was performed once for each sampled child. We also obtained the status of indoor air pollution and chronic respiratory disease history by using a structured questionnaire. Multivariate linear model analysis was used to evaluate pulmonary function effects of each pollutant in addition to determinants of indoor air pollution and meteorologic conditions. We found a significantly negative association of peak O(3) concentration on the day before spirometry with individual forced vital capacity and forced expiratory volume in 1 sec. The decrease in children's lung function can occur at peak hourly O(3) concentrations < 80 ppb. The slope of lung function decrease for Taiwanese children is approximately 1 mL/ppb for peak hourly O(3) exposure.