Indoor air quality in long-term care facilities: A scoping review of particulate matter, volatile organic compounds, and mitigation strategies

Abstract

Indoor air pollution is an environmental health concern in long-term care (LTC) facilities, where residents have prolonged exposure and may be particularly vulnerable. This scoping review mapped particulate matter (PM), volatile organic compound (VOC), formaldehyde, and complementary indoor air quality (IAQ) evidence, together with reported determinants, activity-related peaks, and mitigation strategies. Following PRISMA-ScR, PubMed, Scopus, and Web of Science were searched for English- or German-language peer-reviewed research published from 2000 to the family-specific final search dates in July and August 2026. Seventy-five publications were included: 41 informed observational IAQ evidence and 36 informed mitigation evidence, with two contributing to both evidence families. The 36 mitigation reports represented 32 distinct studies or campaigns; 28 were classified as core LTC-specific evidence and eight as supportive evidence. PM2.5 concentrations were commonly 5–30 ug/m3, whereas higher concentrations and short-term peaks occurred during traffic or wildfire episodes, cooking, occupancy, movement, or ventilation-related conditions. PM10, total VOCs, formaldehyde, and complementary indicators also varied by facility, room, season, activity, and measurement approach. Mitigation evidence covered filtration and air purification, natural and mechanical ventilation, fresh-air and pressure-control retrofits, germicidal ultraviolet and air-sterilization technologies, physical barriers, green infrastructure, and LTC-specific modelling. Particle-focused filtration generally reduced measured particle concentrations in the settings studied, while ventilation interventions increased air exchange or improved CO2-related and modelled outcomes under specific conditions. Evidence was heterogeneous, several studies were short-term or model-based, and VOC-targeted mitigation remained sparse. Standardized, activity-resolved monitoring and real-world evaluations integrating IAQ, thermal comfort, energy, humidity, and acceptability are needed. https://osf.io/jgxeu/overview?view_only=6f34df7604d54964a2369f1b39b622dc. No new primary measurement data were generated for this study.