Correction to: Recalibration and validation of the Swiss lichen bioindication methods for air quality assessment.

The correct fig. 2 is presented in this paper.

Recalibration and validation of the Swiss lichen bioindication methods for air quality assessment.

The aim of this study was to recalibrate the Swiss lichen bioindication methods, developed and calibrated with air pollution data 30 years ago. Since then, levels of air pollution have considerably decreased, and the mix of pollutants has changed due to successful emission control in Switzerland and neighboring countries. In particular, there has been a change from a sulfur- and acid-dominated to a more nitrogen-dominated pollution mix of NH3/NOx and ozone, resulting in increased pH levels. This allowed a recolonization and change in abundance and composition of the epiphytic lichen vegetation, indicating an improved air quality in Switzerland. The existing indices of atmospheric pollution or purity IAP18 and IAPBR developed 30 years ago showed good longitudinal correlations with air pollutant levels until the end of the last century, but a growing drift was observed in some regions over the last 15 years. This called for a method recalibration with more recent air pollution data. Data from a total of 7178 trees from 22 Swiss regions grouped into 1331 homogenous plots and covering the period 1994 to 2017 were averaged by year within plots. Three pollutant-specific lichen indices were newly established, one for primary pollutants (NO2, PM10, SO2), one for ozone (AOT40f), and one for ammonia (NH3). These pollutant-specific lichen indices were derived from linear regression models with lichen variables and a linear time trend variable as predictors, using time-dependent coefficients. Parameters were selected using the Lasso method. The primary pollutant lichen index showed a coefficient of determination R2 of 0.86 in the model with NO2, PM10, and SO2 as predictor variables, whereas corresponding models with other predictor variables (i.e., NH3, AOT40f, and meteorological variables) were of considerably lower fit. Regionalized lichen models for three larger Swiss regions revealed even better results, compared with the unified Swiss models. The best regionalized ozone and ammonia lichen indices reached an R2 of 0.88 and 0.71, respectively.

Aircraft noise: accounting for changes in air traffic with time of day.

Aircraft noise contours are estimated using model calculations and, due to their impact on land use planning, they need to be highly accurate. During night time, not only the number and dominant types of aircraft may differ from daytime but also the flight paths flown may differ. To determine to which detail these variations in flight paths need to be considered, calculations were performed exemplarily for two airports using all available radar data over 1 year, taking into account their changes over the day. The results of this approach were compared with results of a simpler approach which does not consider such changes. While both calculations yielded similar results for the day and close to the airport, differences increased with distance as well as with the period of day (day

Annoyance responses to stable and changing aircraft noise exposure.

This article reports the two extensive aircraft noise annoyance surveys subsequently carried out among residents in the vicinity of Zurich Airport in 2001 and 2003 in order to update and validate existing exposure-effect relationships for aircraft noise and annoyance in Switzerland. Logistic and polynomial approximations of the exposure-annoyance relationships for both the years 2001 and 2003 are presented for the L(dn), L(den), and L(A,eq24) noise metrics. The results confirm other recently published international research and provide further evidence that community annoyance due to aircraft noise has increased over the past decades. Between the two survey years, a considerable amount of early morning and late evening flight operations have been relocated to use an other runway than before; thus both the effects of a recent step decrease and recent step increase on the exposure-annoyance relationship could be investigated. Residents that experienced a step increase elicited a quite pronounced over-reaction of annoyance which correlated with the magnitude of the change. Two logistic regression models are provided to forecast the effects of changes in exposure during shoulder hours in the early morning and the late evening.