Indoor/outdoor relationships of particulate matter in domestic homes with roadside, urban and rural locations

Particulate matter was measured inside and outside seven homes within Birmi ngham, UK, and two homes in rural locations during a 12 month period. Two o f the urban homes were on the 10th and 13th floor of a multi-storey block o f hats in the city centre; others were at ground level. Direct reading TEOM instruments provided near real-time data for PM10, PM2.5, and PM1 mass con centrations. Particulate chemical composition was determined by the analysi s of PTFE filters positioned in the bypass Row line of the TEOM, and QMA fi lters in modified Andersen cascade impactors. TEOM data were used in conjun ction with information gained from activity diaries completed by occupants to identify the sources of episodic elevated particle concentrations within the home. Whilst the results indicated an important background contributio n to indoor particulate matter from penetration of outdoor particles, indoo r sources such as cooking, smoking, cleaning and general activity contribut ed substantially to indoor concentrations of PM10 and were the dominant sou rce of episodic peaks in PM10. Cooking and smoking were determined to be ma jor indoor sources of PM2.5 and PM1, whilst cleaning and general activity h ad little influence on concentrations within this size range. Chemical anal ysis of the particles collected was used to identify those particles with m ainly indoor sources, such as organic carbon from cooking and those with ou tdoor sources, such as lead and sulphate. Sulphate proved a useful marker f or demonstrating the greater ingress and/or indoor air lifetime of fine par ticles from outside the home (I/O ratio 0.8 for PM1.1) compared to coarse p articles (I/O ratio 0.6 for PM10). I/O ratios for components such as zinc a cid elemental carbon were more site-specific. (C) 2000 Elsevier Science Ltd . All rights reserved.