新聞媒體與社群媒體間的跨媒體屬性議題設定效果：以臺灣的空污健康風險爲例

Intermedia Attribute Agenda-Setting Between the News Media and Social Media: The Case of Health Risks Related to Air Pollution in Taiwan

本研究探討臺灣空氣污染健康風險議題中，新聞媒體與社群媒體之間的跨媒體屬性議題設定效果。空污健康風險結合了不可見的環境威脅與高度情緒動員潛力，適合檢驗傳統媒體與社群媒體在持續性議題上的互動關係。本研究蒐集2017至2021年間《聯合報）丶《自由時報》、《蘋果日報》的新聞報導，及PTT八卦板的討論資料，透過電腦輔助內容分析，量化媒體文本中四個空污健康風險屬性（危害度、暴露度、脆弱度丶韌性）及情感屬性的日變化，並使用時間序列分析檢驗二者間的因果關係，控制每日PM2.5濃度作爲現實指標。研究結果顯示，社群媒體在四個風險屬性上對新聞媒體具有顯著的正向議題設定影響；新聞媒體僅在暴露度屬性上對社群媒體展現接近顯著的影響，兩者間在情感屬性上則無顯著互動。此外，現實空氣污染程度顯著影響新聞媒體對暴露度的報導量與社群媒體對脆弱度的討論量。整體而言，本研究發現相較於以往認爲新聞媒體主導社群媒體的模式，在臺灣空污健康風險議題上，社群媒體已展現出反向設定新聞媒體屬性議程的能力。此一結果對於理解持續性公共健康風險議題下的媒體互動模式、社群媒體的資訊建構角色，以及非西方社會中跨媒體議程設定動態，提供了重要的理論貢獻與實務啓示。

This study examines the intermedia attribute agenda-setting (IAAS) effects between the news media and social media in the context of air pollution health risks in Taiwan. Air pollution combines invisible environmental threats with the potential for significant emotional mobilization, making it a suitable topic for exploring media interactions on enduring public issues. We collected news reports on air pollution from the United Daily News, Liberty Times, and Apple Daily, as well as discussions from PTT’s Gossip Board between 2017 and 2021. Using computer-assisted content analysis, we measured the daily salience of four risk attributes—hazard, exposure, vulnerability, and resilience—and emotional tone across the different media types. Time series analysis was conducted to examine causal relationships while controlling for PM2.5 levels as an indicator of real-world pollution. The results show that social media significantly influenced the news media in all four risk attributes. The news media had a marginally significant influence on social media regarding exposure, but no significant reciprocal effects were found for emotional tone. Additionally, real-world air pollution levels significantly predicted an increase in news coverage on the exposure and heightened social media discussions on vulnerability. Overall, this study demonstrates that, contrary to the traditional media-dominant model, social media has exerted a reverse attribute agenda-setting influence on the news media in the context of environmental health risks. These findings contribute to a deeper understanding of intermedia agenda-setting dynamics in non-Western societies and offer practical implications for understanding media interactions, the role of social media in information construction, public health communication and environmental risk governance.