郵差暴露之懸浮微粒來源及其對心血管功能之急性效應

Source Apportionment of Particulate Matter Exposure in Mail Carriers and the Short-Term Effects on Cardiovascular Function

黎雅如(Ya-Ru Li)

指導教授 ： 吳章甫

國立臺灣大學/公共衛生學院/環境衛生研究所/碩士(2008年)

https://doi.org/10.6342/NTU.2008.02828

摘要

目的：本研究從人體暴露的角度考慮，探討環境中大氣懸浮微粒的特性及其對人體健康的影響，包括：(1) 懸浮微粒的粒徑分布及成分；(2) 懸浮微粒的暴露來源；以及(3) 懸浮微粒的成分與來源對心血管功能的影響。

方法：本追蹤研究(Panel study)於台北縣新莊郵局徵募18位郵務人員為受試者。微粒採樣方面，每位受試者於外出投遞郵件的時段配戴一台微粒採樣器，展開為期五至六個工作天的個人懸浮微粒暴露採樣。另外，我們在新莊超級測站裝置一台同型的微粒採樣器，其採樣時段與個人暴露採樣時段同步。該微粒採樣器可將採集之懸浮微粒按照粒徑大小區分為五個階層(A層：>2.5 µm； B層：1.0-2.5 µm； C層：0.50-1.0 µm； D層：0.25- 0.50 µm；E層：< 0.25 µm)。健康指標量測方面，每位受試者於每天外出投遞時段接受心率監測，並且於星期一、四和五外出前及回來後分別接受血管特性量測。元素化學分析方面，我們利用微波消化以及感應偶合電漿質譜(ICP-MS)技術進行懸浮微粒微量元素成分分析。資料分析使用的數據方面，我們使用受試者外出投遞時段的懸浮微粒成分濃度與投遞結束後量測的心跳速率(HR)、五項心率變異性指標[HRV:正常心律間隔標準差(SDNN)、正常心律間隔差值均方根(r-MSSD)、高頻功率(HF)、低頻功率(LF)以及低頻功率：高頻功率比率(LF/HF)]及心-踝血管指數(CAVI)進行資料分析。資料分析方法方面，我們使用絕對主成分方法(APCA)來分析懸浮微粒汙染源的種類且量化污染源對懸浮微粒的貢獻度。接著，使用混合回歸模式(MERM)來評估懸浮微粒成分及來源對心血管功能的影響。

結果：絕對主成分分析結果指出，PM1.0-2.5的主要來源包括城市灰塵(urban dust)、車輛廢氣(vehicle exhaust)及煞車磨損(brake wear)等汙染源，其中城市灰塵對PM1.0-2.5質量濃度貢獻度達66.1 %；PM0.25的主要來源包括工業(industrial processing)及車輛廢氣(vehicle exhaust)等汙染源，其中工業對PM0.25質量濃度貢獻度達43.4 %。此外，交通相關之燃燒源(車輛廢氣)及非燃燒源(煞車磨損)對PM1.0-2.5的貢獻度相當(各佔約13 %)。混合回歸模式結果顯示，在校正其他因子後，每增加一四分位距(IQR; 1.9 μg/m3)來自車輛廢氣之PM1.0-2.5濃度，會導致郵差之心-踝血管指數上升2.84 % (95 %信賴區間, 1.37－4.39 %)；每增加一四分位距(1.4 μg/m3)來自煞車磨損之PM1.0-2.5濃度，會導致郵差之正常心律間隔標準差下降11.60 % (95 %信賴區間, -19.68－-2.70 %)；以及每增加一四分位距(10.9 μg/m3)來自工業活動之PM0.2.5濃度，會導致郵差之正常心律間隔標準差下降10.36 % (95 %信賴區間, -27.97－-1.67 %)。我們也發現來自煞車磨損之PM1.0-2.5濃度與心跳速率呈現正相關的趨勢；來自車輛廢氣之PM1.0-2.5濃度與低頻功率：高頻功率比率呈現正相關的趨勢。

結論：城市灰塵及工業是台北縣新莊市重要的懸浮微粒來源，而且交通(包括燃燒性及非燃燒性)及工業相關活動所排放之懸浮微粒會對健康受試者的心血管功能造成急性的不良影響。政府應制定相關管制策略來規範這些重要懸浮微粒污染源的排放。我們建議郵務人員於室外空氣污染嚴重時段(例如交通尖峰時段)儘量避免外出，或是避免在高交通流量地區從事一般性活動或郵件投遞工作。我們也發現不同的懸浮微粒成分會導致不同程度的心血管健康風險，因此直接使用懸浮微粒的總質量來評估懸浮微粒的心血管急性效應，可能無法真實反映懸浮微粒的組成分對心血管功能的影響程度。

關鍵字

懸浮微粒 ； 微量元素 ； 個人暴露 ； 環境量測 ； 來源分析 ； 心率變異性 ； 心-踝血管指數

並列摘要

Objectives: This study is intended to provide the scientific information, in aspect of personal exposure, on exposure to airborne particulate matter (PM) and its components, possible sources contributed to them, and their associations with short-term cardiovascular effects.

Methods: This panel study was conducted in Sin-Jhuang city, Taipei County, Taiwan. Eighteen mail carriers were recruited from the Sin-Jhuang Post Office. Each subject’s personal PM exposure and ambient PM concentrations were measured during working hours from Monday to Friday (or Saturday). PM samples were collected using a personal sampler, which classifies PM into five size ranges [>2.5 (A), 1.0-2.5 (B), 0.50-1.0 (C), 0.25- 0.50 (D), and < 0.25 (E) µm]. Heart rate variability (HRV) was monitored during working hours from Monday to Friday, and cardio-ankle vascular index (CAVI) was measured before and after working hours on Monday, Thursday, and Friday. Particle filters were digested in a microwave digestion system and the elemental concentrations were determined using the inductively coupled plasma mass spectrometry (ICP-MS) technique. The concentration of 21 elements, the right-side CAVI (r-CAVI), the heart rate (HR), and the 5-min segment of HRV data (SDNN, r-MSSD, HF, LF, and LF/HF) recorded immediately after the PM sampling session were used for data analysis. Absolute principal component analysis (APCA) was applied to PM elemental concentrations to identify sources and then quantify the source contributions. Mixed-effects regression model (MERM) was used to assess potential associations between source-specific PM and cardiovascular end points.

Results: Three significant PM1.0-2.5 source factors (urban dust, vehicle exhaust, and brake wear) and two significant PM0.25 source factors (industrial processing and vehicle exhaust) were identified. The urban dust source accounted for the majority of PM1.0-2.5 mass (66.1 %); the largest contributor to PM0.25 mass was industrial processing (43.4 %). We also found that traffic-derived combustion (vehicle exhaust) and noncombustion (brake wear) sources had equal contribution to PM1.0-2.5 in urban areas. In the health analysis, controlling for the covariates, an interquartile range (IQR; 1.9 μg/m3) increase in PM1.0-2.5 from vehicle exhaust accounted for a 2.84 % increase in CAVI [95 % confidence interval (CI), 1.37－4.39 %]; an IQR (1.4 μg/m3) increase in PM1.0-2.5 from brake wear accounted for a 11.60 % decrease in SDNN (CI, -19.68－-2.70 %); and an IQR (10.9 μg/m3) increase in PM0.25 from industrial processing accounted for a 10.36 % decrease in SDNN (CI, -27.97－-1.67 %). We also observed that PM1.0-2.5 attributable to brake wear was positively associated with heart rate, and PM1.0-2.5 attributable to vehicle exhaust had positive association with LF/HF.

Conclusions: Our findings indicate that urban dust and industrial sources are particularly important in Sin-Jhuang and suggest that PM derived from traffic (both combustion and noncombustion included) - and industrial-related sources probably trigger adverse cardiovascular effects in healthy subjects. The government should initiate pollution control strategies to reduce these urban PM emissions. We also suggest that mail carriers should stay indoors when air pollution levels are high (e.g., peak hours) or avoid all activity or working near high-traffic areas. In addition, we found that cardiovascular risks may vary among different PM components. Thus, using PM mass as exposure metrics may bias the health estimates of some of its specific components.

並列關鍵字

Particulate matter ； Trace element ； Personal exposure ； Ambient measurement ； Source apportionment ； Heart rate variability ； Cardio-ankle vascular index

參考文獻

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