Estimation of long-term average exposure to outdoor air pollution for a cohort study on mortality

Abstract

Recent prospective cohort studies have suggested that long -term exposure to low levels of particulate matter ( PM ) air pollution is associated with increased mortality due to, especially, cardio -pulmonary disease. Exposure to ambient air pollution was estimated mostly as city average concentrations, assuming homogenous exposure within the city. We used an ongoing cohort study -The Netherlands Cohort Study ( NLCS ) on diet and cancer -to investigate the relationship between traffic -related air pollution and mortality. The baseline data collection took place in 1986. A study was conducted to develop methods for exposure assessment and evaluate the contrast in exposure to air pollution within the cohort. Assessment of long -term exposure to two traffic -related air pollutants, Black Smoke ( BS ) and Nitrogen Dioxide ( NO 2 ) , consisted of separate estimation of regional background, urban background, and local traffic contributions at the home address. Interpolation of concentration data from a routine monitoring network was used to estimate the regional background concentration. A regression model relating degree of urbanization to air pollution was used to allow for differences between different towns / neighborhoods of cities. Distance to major roads was calculated to characterize local traffic contributions, using a Geographic Information System ( GIS ) . Interpolation resulted in reasonably precise regional background estimation when distant sites were not used and distance squared was used as the weight. Cross -validation showed that prediction errors were about 15% of the range in regional background concentration. Urban and local scales contributed significantly to the contrast within the cohort. Prediction errors for estimating the urban background were about 25% of the range in background concentrations. When the developed model was applied to the study cohort, there was substantial contrast in estimated exposure to BS and NO 2 . About 90% of the study population lived 10 years or more at its 1986 home address -supporting the use of the estimated concentration at the 1986 address as a relevant exposure variable.

Air pollution and risk of lung cancer in a prospective study in Europe

“…In a study in Amsterdam, we observed that roads that were part of the main road network had approximately twice higher concentrations of soot, benzene and PAHs than those simultaneously measured in minor streets. 16 Also Nafstad et al 7 and Nyberg et al 15 found that the risk of lung cancer was mainly associated with levels of exposure greater than 30 lg/m 3 . This is lower than the guideline level of 40 lg/m 3 set by the World Health Organization for annual average NO 2 concentration 17 (see also http://www.euro.…”

Retrospective assessment of exposure to traffic air pollution using the ExTra index in the VESTA French epidemiological study

“…Only four teams Pikhart et al, 2000;Hoek et al, 2001;Brauer et al, 2002;Gehring et al, 2002;Hoek et al, 2002;Brauer et al, 2003) had recourse to statistical regression models to estimate exposure to traffic air pollutants (TAP). Moreover, pollutant dispersion models have been developed to improve the estimate of exposure levels (Hertel and Berkowicz, 1989;Benson, 1992;Eerhens et al, 1993;Berkowicz et al, 1994), but they have rarely been used in epidemiology (Larssen et al, 1993;Pershagen et al, 1995;Bartonova et al, 1999;Clench-Aas et al, 1999a, b;Briggs et al, 2000;Clench-Aas et al, 2000;Nyberg et al, 2000;Pikhart et al, 2000;Raaschou-Nielsen et al, 2000;Bellander et al, 2001;Raaschou-Nielsen et al, 2001;Zmirou et al, 2002).…”

On exposure and response relationships for health effects associated with exposure to vehicular traffic

“…For categorical exposure classification studies, the relative risks (RRs) of ''living near a major roadway'' are usually reported. For example, Hoek et al (2002) reported a RR of 1.41 for all-cause mortality and 1.95 for cardiopulmonary mortality for those residential locations, but only 5% of the cohort met this high-exposure definition (Hoek et al, 2001). These results would thus imply much more modest risks (1.02 to 1.03) when averaged over the whole cohort, as is usually the case with continuous measures of exposure.…”

“…Hoek et al (2001) report a minimum of 0.1 m, which clearly does not apply to limited-access freeways. Similarly, Fernandez (2006) describes New York City apartments that are only 10-15 m from the entrance to the Holland Tunnel to New Jersey.…”