Aibo Li , Ziqing Zhao , Yuhao Yang , Kun Sun , Jilai Chen , Benzhi Zhou
{"title":"气温和颗粒物2.5是亚热带常绿阔叶林大气负离子动态的关键环境驱动因素","authors":"Aibo Li , Ziqing Zhao , Yuhao Yang , Kun Sun , Jilai Chen , Benzhi Zhou","doi":"10.1016/j.tfp.2025.100944","DOIUrl":null,"url":null,"abstract":"<div><div>Negative air ions (NAIs) are widely studied for their role in evaluating the therapeutic effects of forests on human health and mitigating air pollution through mechanisms such as neutralizing airborne particulate matter and reducing reactive gaseous pollutants via oxidative pathways. This study examined NAI temporal dynamics and key environmental drivers in forests. On-site monitoring (June 2021-May 2023) included NAIs, air temperature, relative humidity, wind speed, direct radiation, and particulate matter. We found that NAI concentrations in the forest generally met the World Health Organization's clean air threshold, averaging 1698 ± 347 ions·cm<sup>−3</sup>. NAI concentrations followed a single-peak diurnal pattern, peaking at 12:00–15:00 and reaching a minimum at 5:00–8:00. Seasonal variations in NAI concentrations were significant, with the highest levels in summer (1919 ± 260 ions·cm<sup>−3</sup>), followed by autumn (1734 ± 115 ions·cm<sup>−3</sup>), spring (1580 ± 338 ions·cm<sup>−3</sup>), and winter (1535 ± 226 ions·cm<sup>−3</sup>). Correlation analyses indicated significant positive correlations between NAI concentrations and air temperature, wind speed, and direct radiation, while relative humidity and particulate matter showed significant negative correlations. Multiple regression and random forest analyses identified air temperature and particulate matter 2.5 as the primary factors influencing NAI concentrations. A predictive model (NAIs = 18.4 × Ta–17.5 × WS–3.6 × RH–8.0 × PM<sub>2.5</sub> + 5.3 × PM<sub>10</sub> + 1.8 × 10<sup>3</sup>) was developed to estimate NAI concentrations in forest environments. Given these temporal patterns of NAI, the findings support scheduling forest therapy in summer and autumn afternoons to maximize exposure to NAI at peak concentrations. Additionally, the predictive model offers a practical tool for air quality management in forested areas, supporting evidence-based decisions in urban green space planning, forest therapy zone scheduling, and environmental health policy development. This study addresses a crucial knowledge gap regarding NAI dynamics and environmental drivers in forests, potentially informing evidence-based decision-making in forest-based health interventions and ecological planning.</div></div>","PeriodicalId":36104,"journal":{"name":"Trees, Forests and People","volume":"21 ","pages":"Article 100944"},"PeriodicalIF":2.7000,"publicationDate":"2025-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Air temperature and particulate matter 2.5 are key environmental drivers of negative air ion dynamics: Results from long-term monitoring in subtropical evergreen broad-leaved forest\",\"authors\":\"Aibo Li , Ziqing Zhao , Yuhao Yang , Kun Sun , Jilai Chen , Benzhi Zhou\",\"doi\":\"10.1016/j.tfp.2025.100944\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><div>Negative air ions (NAIs) are widely studied for their role in evaluating the therapeutic effects of forests on human health and mitigating air pollution through mechanisms such as neutralizing airborne particulate matter and reducing reactive gaseous pollutants via oxidative pathways. This study examined NAI temporal dynamics and key environmental drivers in forests. On-site monitoring (June 2021-May 2023) included NAIs, air temperature, relative humidity, wind speed, direct radiation, and particulate matter. We found that NAI concentrations in the forest generally met the World Health Organization's clean air threshold, averaging 1698 ± 347 ions·cm<sup>−3</sup>. NAI concentrations followed a single-peak diurnal pattern, peaking at 12:00–15:00 and reaching a minimum at 5:00–8:00. Seasonal variations in NAI concentrations were significant, with the highest levels in summer (1919 ± 260 ions·cm<sup>−3</sup>), followed by autumn (1734 ± 115 ions·cm<sup>−3</sup>), spring (1580 ± 338 ions·cm<sup>−3</sup>), and winter (1535 ± 226 ions·cm<sup>−3</sup>). Correlation analyses indicated significant positive correlations between NAI concentrations and air temperature, wind speed, and direct radiation, while relative humidity and particulate matter showed significant negative correlations. Multiple regression and random forest analyses identified air temperature and particulate matter 2.5 as the primary factors influencing NAI concentrations. A predictive model (NAIs = 18.4 × Ta–17.5 × WS–3.6 × RH–8.0 × PM<sub>2.5</sub> + 5.3 × PM<sub>10</sub> + 1.8 × 10<sup>3</sup>) was developed to estimate NAI concentrations in forest environments. Given these temporal patterns of NAI, the findings support scheduling forest therapy in summer and autumn afternoons to maximize exposure to NAI at peak concentrations. Additionally, the predictive model offers a practical tool for air quality management in forested areas, supporting evidence-based decisions in urban green space planning, forest therapy zone scheduling, and environmental health policy development. This study addresses a crucial knowledge gap regarding NAI dynamics and environmental drivers in forests, potentially informing evidence-based decision-making in forest-based health interventions and ecological planning.</div></div>\",\"PeriodicalId\":36104,\"journal\":{\"name\":\"Trees, Forests and People\",\"volume\":\"21 \",\"pages\":\"Article 100944\"},\"PeriodicalIF\":2.7000,\"publicationDate\":\"2025-07-12\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Trees, Forests and People\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S2666719325001700\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"FORESTRY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Trees, Forests and People","FirstCategoryId":"1085","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S2666719325001700","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"FORESTRY","Score":null,"Total":0}
Air temperature and particulate matter 2.5 are key environmental drivers of negative air ion dynamics: Results from long-term monitoring in subtropical evergreen broad-leaved forest
Negative air ions (NAIs) are widely studied for their role in evaluating the therapeutic effects of forests on human health and mitigating air pollution through mechanisms such as neutralizing airborne particulate matter and reducing reactive gaseous pollutants via oxidative pathways. This study examined NAI temporal dynamics and key environmental drivers in forests. On-site monitoring (June 2021-May 2023) included NAIs, air temperature, relative humidity, wind speed, direct radiation, and particulate matter. We found that NAI concentrations in the forest generally met the World Health Organization's clean air threshold, averaging 1698 ± 347 ions·cm−3. NAI concentrations followed a single-peak diurnal pattern, peaking at 12:00–15:00 and reaching a minimum at 5:00–8:00. Seasonal variations in NAI concentrations were significant, with the highest levels in summer (1919 ± 260 ions·cm−3), followed by autumn (1734 ± 115 ions·cm−3), spring (1580 ± 338 ions·cm−3), and winter (1535 ± 226 ions·cm−3). Correlation analyses indicated significant positive correlations between NAI concentrations and air temperature, wind speed, and direct radiation, while relative humidity and particulate matter showed significant negative correlations. Multiple regression and random forest analyses identified air temperature and particulate matter 2.5 as the primary factors influencing NAI concentrations. A predictive model (NAIs = 18.4 × Ta–17.5 × WS–3.6 × RH–8.0 × PM2.5 + 5.3 × PM10 + 1.8 × 103) was developed to estimate NAI concentrations in forest environments. Given these temporal patterns of NAI, the findings support scheduling forest therapy in summer and autumn afternoons to maximize exposure to NAI at peak concentrations. Additionally, the predictive model offers a practical tool for air quality management in forested areas, supporting evidence-based decisions in urban green space planning, forest therapy zone scheduling, and environmental health policy development. This study addresses a crucial knowledge gap regarding NAI dynamics and environmental drivers in forests, potentially informing evidence-based decision-making in forest-based health interventions and ecological planning.