室內環境空氣品質及溫濕度對於心血管健康的影響-關注夏季與冬季

Abstract

研究背景 過去研究表明PM2.5以及TVOC是高血壓顯著的危險因子之一，且室內環境空氣品質與疾病發生率以及死亡率的相關性較室外溫度更為顯著。不同季節居家空氣汙染物以及溫溼度對於健康之影響可能不同，人們在家中暴露到的環境因素對於其影響更為重要，因此本研究旨在探討夏天與冬天居家室內環境空氣品質以及溫溼度對於心血管健康之相關性，並區分為四種不同時序變化，包含即時、早晚變化、逐日早上變化以及逐日晚上變化，評估不同時序室內空氣品質以及溫溼度與相對應健康效應之相關性分析。亦將家中燒香頻率分組，探討不同燒香頻率之家戶，其空氣品質有無差異。

研究方法 本研究以臺灣北部某醫學中心心血管風險高之受試者及其家人為對象，不同季節各進行一週居家客廳室內空氣品質監測，共447人（392戶）參與2023年6至9月間進行的夏季監測，共372人（327戶）參與2023年11月底至2024年2月間進行的冬季監測。監測項目包含PM2.5濃度、TVOC濃度、CO2濃度、溫度以及相對濕度，每分鐘監測一筆，並收集受試者一週早晚量測之生理數值及量測時間點，生理數值包含兩手收縮壓、舒張壓、心跳、血氧飽和濃度以及兩耳的耳溫。

結果 夏天室內溫度以及相對濕度顯著高於冬天，而夏天室內PM2.5濃度以及TVOC濃度和冬天相比則顯著較低。本研究結果顯示冬天即時室內TVOC濃度與HR呈正相關。夏天與冬天即時室內溫度、早晚室內溫度變化以及逐日室內溫度變化皆與SBP以及DBP有顯著負相關，並與HR以及體溫有顯著正相關，且冬天室內溫度變化對於血壓以及HR之影響更為顯著。冬天即時室內溫度每降低1°C，SBP顯著上升0.74 mmHg、DBP顯著上升0.50 mmHg、HR顯著下降約0.17 bpm以及體溫顯著降低0.013°C。冬天晚上室內溫度和早上室內溫度相比，晚上每下降1°C，SBP增加0.837 mmHg、DBP增加0.546 mmHg、HR下降0.307 bpm以及體溫下降0.016°C。 夏天與冬天室內溫度對於SpO2的影響不同，夏天即時溫度以及逐日晚上溫度上升，SpO2顯著上升；冬天所有時序中，不論是即時室內溫度、早晚室內溫度變化以及逐日室內溫度變化，室內溫度上升，SpO2則顯著下降。另外，冬天室內CO2濃度變化與SpO2呈現顯著負相關，即時以及早晚變化皆有明顯之關係。 夏天與冬天逐日室內相對濕度變化與HR以及體溫有顯著正相關。夏天與冬天室內相對濕度對於血壓之影響不同；夏天SBP以及DBP隨著逐日早上室內相對濕度上升而有上升趨勢；冬天SBP以及DBP隨著即時室內相對濕度以及逐日室內相對濕度上升而下降趨勢。 關於家中燒香頻率之室內空氣品質差異，每天燒香至少一次之室內PM2.5濃度顯著較高，然而室內TVOC濃度、CO2濃度、溫度以及相對濕度和燒香頻率較少之家戶相比則無顯著差異。

結論 本研究的結果顯示冬天與夏天之室內溫度對於收縮壓以及舒張壓呈顯著負相關，且對於心跳速率以及體溫有顯著正關聯，且不論季節，夏天室內早晚溫差以及逐日溫差對於血壓以及心跳速率變化之影響與冬天室內溫差同樣重要。因此夏天與冬天，皆須將家中室內溫度以及室內相對濕度維持穩定，並降低室內相對濕度，以降低其對於血壓以及心跳速率變化幅度之影響。

Background Previous studies have showed that PM2.5 and TVOC is one of the significant risk factors for hypertension, and the correlation between indoor air quality and the incidence and mortality rates of diseases is more significant than that of outdoor temperature. The impact of indoor air pollutants, temperature and relative humidity levels on health may vary across different seasons. Additionally, the environmental factors to which individuals are exposed indoors play a crucial role in influencing their health. Therefore, this study aims to investigate the relationship between indoor air quality, temperature and relative humidity levels on cardiovascular health during summer and winter. The analysis is categorized into four temporal variations, including real-time, diurnal differences, and day-by-day fluctuations, assessing the correlation between indoor air quality, temperature and relative humidity levels, and corresponding health effects. Furthermore, the study examines the differences in air quality among households with varying frequencies of incense burning.

Methods The study involved participants with high cardiovascular risk and their family members from the medical center in northern Taiwan. Indoor air quality monitoring was conducted in living rooms for one week during different seasons. A total of 447 participants (392 households) were recruited for the summer survey from June to September in 2023, and 372 participants (327 households) were recruited for the winter survey from November in 2023 to February in 2024. Indoor air quality monitoring included PM2.5 concentration, TVOC concentration, CO2 concentration, temperature, and relative humidity, with data collected every minute. Additionally, measurements of blood pressure, heart rate, body temperature, and SpO2 from both sides were recorded by participants twice daily for one week, after awakening in the morning and before night sleep.

Results Indoor temperature and relative humidity were significantly higher in summer compared to winter, while indoor PM2.5 and TVOC concentrations were notably lower in summer than in winter. The results showed a positive correlation between real-time indoor TVOC concentration and heart rate (HR) in winter. There were significant negative correlations between real-time indoor temperature, diurnal indoor temperature differences, daily indoor temperature fluctuations, and both systolic blood pressure (SBP) and diastolic blood pressure (DBP) in both summer and winter. Additionally, indoor temperature was positively correlated with HR and body temperature, with more pronounced effects observed in winter. A 1°C decrease in real-time indoor temperature during winter resulted in a significant increase in SBP by 0.74 mmHg, DBP by 0.50 mmHg, HR decreased by approximately 0.17 bpm, and a decrease in body temperature by 0.013°C. Compared with the indoor temperature in the morning in winter, for every 1°C decrease in indoor temperature at night, SBP increased by 0.837 mmHg, DBP increased by 0.546 mmHg, HR decreased by 0.307 bpm, and body temperature decreased by 0.016°C. The impact of indoor temperature on SpO2 varied between summer and winter. In summer, increases in real-time temperature and nightly temperature were associated with significant increases in SpO2. Conversely, in winter, indoor temperature increases across all temporal variations led to significant decreases in SpO2. In addition, indoor CO2 concentration changes in winter showed a significant negative correlation with SpO2, with a noticeable relationship between real-time and diurnal differences. Daily indoor relative humidity fluctuations were positively correlated with HR and body temperature in both summer and winter. However, the impact of relative humidity on blood pressure differed; in summer, there was a trend of increasing SBP and DBP with rising day-by-day indoor relative humidity in the morning, while in winter, SBP and DBP showed a decreasing trend with increasing real-time and day-by-day indoor relative humidity fluctuations. Regarding differences in indoor air quality based on the frequency of incense burning, households that burned incense at least once daily had significantly higher indoor PM2.5 concentrations. However, no significant differences were observed in indoor TVOC concentration, CO2 concentration, temperature, and relative humidity compared to households with lower incense burning frequencies.

Conclusions The results of this study indicate a significant negative correlation between indoor temperature and both systolic and diastolic blood pressure during winter and summer, as well as a significant positive correlation with heart rate and body temperature. Regardless of the season, the impact of daily and diurnal temperature variations on blood pressure and heart rate is equally important. Therefore, it is essential to maintain stable indoor temperature and relative humidity levels during both summer and winter to minimize their effects on blood pressure and heart rate variations.