Universität zu Köln

Morfeld, Peter, Groneberg, David A. and Spallek, Michael F. (2014). Effectiveness of Low Emission Zones: Large Scale Analysis of Changes in Environmental NO2, NO and NOx Concentrations in 17 German Cities. PLoS One, 9 (8). SAN FRANCISCO: PUBLIC LIBRARY SCIENCE. ISSN 1932-6203

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Abstract

Background: Low Emission Zones (LEZs) are areas where the most polluting vehicles are restricted from entering. The effectiveness of LEZs to lower ambient exposures is under debate. This study focused on LEZs that restricted cars of Euro 1 standard without appropriate retrofitting systems from entering and estimated LEZ effects on NO2, NO, and NOx (= NO2 + NO). Methods: Continuous half-hour and diffuse sampler 4-week average NO2, NO, and NOx concentrations measured inside and outside LEZs in 17 German cities of 6 federal states (2005-2009) were analysed as matched quadruplets (two pairs of simultaneously measured index values inside LEZ and reference values outside LEZ, one pair measured before and one after introducing LEZs with time differences that equal multiples of 364 days) by multiple linear and log-linear fixed-effects regression modelling (covariables: e.g., wind velocity, amount of precipitation, height of inversion base, school holidays, truck-free periods). Additionally, the continuous half-hour data was collapsed into 4-week averages and pooled with the diffuse sampler data to perform joint analysis. Results: More than 3,000,000 quadruplets of continuous measurements (half-hour averages) were identified at 38 index and 45 reference stations. Pooling with diffuse sampler data from 15 index and 10 reference stations lead to more than 4,000 quadruplets for joint analyses of 4-week averages. Mean LEZ effects on NO2, NO, and NOx concentrations (reductions) were estimated to be at most -2 mu g/m(3) (or -4%). The 4-week averages of NO2 concentrations at index stations after LEZ introduction were 55 mu g/m(3) (median and mean values) or 82 mu g/m(3) (95th percentile). Conclusions: This is the first study investigating comprehensively the effectiveness of LEZs to reduce NO2, NO, and NOx concentrations controlling for most relevant potential confounders. Our analyses indicate that there is a statistically significant, but rather small reduction of NO2, NO, and NOx concentrations associated with LEZs.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Morfeld, Peter UNSPECIFIED UNSPECIFIED UNSPECIFIED Groneberg, David A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Spallek, Michael F. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-432044
DOI:	10.1371/journal.pone.0102999
Journal or Publication Title:	PLoS One
Volume:	9
Number:	8
Date:	2014
Publisher:	PUBLIC LIBRARY SCIENCE
Place of Publication:	SAN FRANCISCO
ISSN:	1932-6203
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language AIR-POLLUTION; NITROGEN-DIOXIDE; LUNG-CANCER; DIFFUSIVE SAMPLERS; STATISTICS NOTES; PM10; REGRESSION; EXPOSURE; IMPACT; REDUCTION Multiple languages Multidisciplinary Sciences Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/43204