The study consists of two parts:
Determination of the indoor/outdoor relationship for PM10, PM2.5 and total particle number counts
Determination of the relationship between indoor and outdoor particle exposures with respiratory health of sensitive subjects.
A key feature of the study is the comparison of the indoor/outdoor relationship of PM10, PM2.5 and total particle number counts. This is important for the interpretation of epidemiological studies which have measured both. The reason is that if the I/O relationship is much weaker for one pollutant than for the other, associations with health effects will be much harder to find for that pollutant when it is being measured at only one outdoor location.
[Aim]
The objectives of the study are to improve exposure assessment for ultrafine particles and assess the effect of improved exposure characterization on estimated health effects by investigating:
1. The relationship between outdoor and indoor particle number counts on timescales relevant for epidemiological studies
2. The relative strength of the association between outdoor and indoor exposure to airborne particles characterized by particle number counts, PM10 and PM2.5 concentrations and respiratory health of sensitive subjects
[Methods]
A panel study will be conducted in which 35 non-working, non-smoking patients with asthma or chronic obstructive pulmonary disease (COPD) will be followed for six months in four cities in Greece, Finland, the Netherlands and the United Kingdom. During this six-month period, subjects will complete a daily diary. In the diary questions about respiratory symptoms, medication use and factors related to indoor sources of particles and penetration of particles indoors will be included. At a central site, PM2.5, PM10 and total particle number counts using a CNC will be measured in outdoor air. For each subject, more intensive measurements will be conducted during one week of this period (total study period approximately one year). Exposure will be characterized more intensively by PM2.5, PM10 and particle number counts using a CNC inside the home and directly outside the home. A time activity diary will be kept to elicit time that the subject is at home, ventilation patterns and use of indoor sources of particles. Respiratory health will be recorded by measurement of lung function, respiratory symptoms and medication use three times a day and urine collection in the morning for determination of CC16 (a marker of lung damage). |
