Introduction There is growing interest in the impact of greenness exposure on airway diseases, but the impact of greenness on lung function in children is limited. We aimed to investigate the associations between greenness surrounding schools and lung function in children and whether these associations are modified by air pollution exposure. Methods Between 2012 and 2013, a cross-sectional survey and spirometry were performed among 6740 school children. Lung function patterns were determined as obstructive forced expiratory volume 1 s/forced vital capacity (FEV1/FVC <0.8) or restrictive (FEV1/FVC ≥0.8 but FVC <80% of predicted). School greenness was defined by Normalized difference vegetation index (NDVI) and soil-adjusted vegetation index. Nitrogen dioxide, sulphur dioxide and particular matter concentrations were assessed using a spatiotemporal model and national monitoring data. Two-level generalised linear models were used to investigate associations and interactions. Results Overall, an IQR in NDVI within 500 m was associated with higher FEV1 (+57 mL 95% CI 44 to 70) and FVC (+58 mL 95% CI 43 to 73). NDVI was similarly associated with 25% reduced odds of spirometric restriction (OR: 0.75, 95% CI 0.65 to 0.86). However, among children exposed to the highest compared with the lowest quartile of particulate matter, increasing NDVI was paradoxically associated with lower −40 mL FVC (95% CI −47 to –33, p interaction <0.05). Discussion Our findings suggest that, in this study population, greening urban areas may promote lung health in low–moderate pollution areas but not in high air pollution areas. If the findings are replicated in other moderate-to-high pollution settings, this highlights a need to have a flexible green policy. Data are available upon reasonable request. See author contributions for specific data sets.

中文翻译：

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绿色可能会改善中低但不是高空气污染地区的肺部健康：东北七个城市的研究

引言 绿色暴露对气道疾病的影响越来越受到关注，但绿色对儿童肺功能的影响是有限的。我们旨在调查学校周围的绿化与儿童肺功能之间的关联，以及这些关联是否因空气污染暴露而改变。方法 2012-2013年对6740名学童进行横断面调查和肺活量测定。肺功能模式被确定为阻塞性用力呼气量 1 s/用力肺活量（FEV1/FVC <0.8）或限制性（FEV1/FVC ≥ 0.8 但 FVC <80% 的预测值）。学校绿度由归一化差异植被指数（NDVI）和土壤调整植被指数定义。二氧化氮，使用时空模型和国家监测数据评估二氧化硫和特定物质浓度。两级广义线性模型用于研究关联和相互作用。结果 总体而言，500 m 内 NDVI 的 IQR 与较高的 FEV1（+57 mL 95% CI 44 至 70）和 FVC（+58 mL 95% CI 43 至 73）相关。NDVI 与肺量测定受限的几率降低 25% 类似（OR：0.75，95% CI 0.65 至 0.86）。然而，在暴露于最高四分位数颗粒物与最低四分位数颗粒物的儿童中，增加 NDVI 与较低的 -40 mL FVC 矛盾地相关（95% CI -47 至 -33，p 相互作用 <0.05）。讨论 我们的研究结果表明，在本研究人群中，绿化城市地区可能会促进低中度污染地区的肺部健康，但不会促进高空气污染地区的肺部健康。如果这些发现在其他中度至重度污染环境中得到复制，这就凸显了制定灵活的绿色政策的必要性。可应合理要求提供数据。请参阅特定数据集的作者贡献。