Dose-response relationships for traffic noise and annoyance

Short-term annoyance from nocturnal aircraft noise exposure: results of the NORAH and STRAIN sleep studies

PURPOSE

The German Aerospace Center (DLR) investigated in the NORAH sleep study the association between a distinct change in nocturnal aircraft noise exposure due to the introduction of a night curfew (11:00 p.m.-5:00 a.m.) at Frankfurt Airport and short-term annoyance reactions of residents in the surrounding community. Exposure-response curves were calculated by random effects logistic regression to evaluate the aircraft noise-related parameters (1) number of overflights and (2) energy equivalent noise level L_ASeq for the prediction of short-term annoyance. Data of the NORAH sleep study were compared with the STRAIN sleep study which was conducted by DLR near Cologne-Bonn Airport in 2001/2002 (N = 64), representing a steady-state/low-rate change.

METHODS

The NORAH sleep study was based on questionnaire surveys with 187 residents living in the vicinity of Frankfurt Airport. Noise-induced short-term annoyance and related non-acoustical variables were assessed. Nocturnal aircraft noise exposure was measured inside the residents' home.

RESULTS

A statistically significant rise in the portion of annoyed residents with increasing number of overflights was found. Similarly, the portion of annoyed subjects increased with rising L_ASeq. Importance of the frequency of fly-overs for the prediction of annoyance reactions was emphasized. The annoyance probability was significantly higher in the NORAH than in the STRAIN sleep study.

CONCLUSIONS

Results confirm the importance of both acoustical parameters for the prediction of short-term annoyance due to nocturnal aircraft noise. Quantitative annoyance models that were derived at steady-state/low-rate change airports cannot be directly applied to airports that underwent a distinct change in operational and noise exposure patterns.

Air pollution exposure potentiates hypertension through reactive oxygen species-mediated activation of Rho/ROCK

OBJECTIVE

Fine particulate matter <2.5 microm (PM(2.5)) has been implicated in vasoconstriction and potentiation of hypertension in humans. We investigated the effects of short-term exposure to PM(2.5) in the angiotensin II (AII) infusion model.

METHODS AND RESULTS

Sprague-Dawley rats were exposed to PM(2.5) or filtered air (FA) for 10 weeks. At week 9, minipumps containing AII were implanted and the responses studied over a week. Mean concentration of PM(2.5) inside the chamber was 79.1+/-7.4 microg/m(3). After AII infusion, mean arterial pressure was significantly higher in PM(2.5)-AII versus FA-AII group. Aortic vasoconstriction to phenylephrine was potentiated with exaggerated relaxation to the Rho-kinase (ROCK) inhibitor Y-27632 and increase in ROCK-1 mRNA levels in the PM(2.5)-AII group. Superoxide (O(2).(-)) production in aorta was increased in the PM(2.5)-AII compared to the FA group, inhibitable by apocynin and L-NAME with coordinate upregulation of NAD(P)H oxidase subunits p22(phox) and p47(phox) and depletion of tetrahydrobiopterin. In vitro exposure to ultrafine particles (UFP) and PM(2.5) was associated with an increase in ROCK activity, phosphorylation of myosin light chain, and myosin phosphatase target subunit (MYPT1). Pretreatment with the nonspecific antioxidant N-acetylcysteine and the Rho kinase inhibitors (Fasudil and Y-27632) prevented MLC and MYPT-1 phosphorylation by UFP suggesting a O(2)(.-)-mediated mechanism for PM(2.5) and UFP effects.

CONCLUSIONS

Short-term air pollution exaggerates hypertension through O(2)(.-)-mediated upregulation of the Rho/ROCK pathway.

Traffic noise and cardiovascular risk: the Caerphilly and Speedwell studies, third phase--10-year follow up

The authors tested the hypothesis that prolonged exposure to road traffic noise causes ischemic heart disease in a 10-y follow-up cohort study of middle-aged men. In the Caerphilly and Speedwell studies, 2512 and 2348 men, respectively, who were 45-59 y of age were seen in the initial cross-sectional phase and at follow-up intervals of 10 y. Adjusted odds ratios of 1.1 (95% confidence interval = 0.6, 1.9) and 0.9 (95% confidence interval = 0.6, 1.4) were found in the total cohorts. However, the relative risk was 1.3 (95% confidence interval = 0.8, 2.2) in the pooled reconstructed cohort of men who were followed for 6 y (i.e., from phase 2 to phase 3) and for whom room orientation and window-opening habits could be considered. Furthermore, the relative risk increased to 1.6 (95% confidence interval = 0.9, 3.0) in the subsample of men who had lived at least 15 y in their present homes at the time of recruitment. Living adjacent to streets with high traffic noise levels was associated with an adjusted (for covariates) increase in relative risk of 1.01-1.02/y in residence--a result that was only borderline significant (p < .10).

Aircraft noise, hearing ability, and annoyance

The relationship between aircraft noise, loss of hearing, and annoyance was explored in a study in two schools located near an international airport in Taiwan. Sixth-grade students (N = 242) were recruited from two schools and were classified into high- and low-noise-exposure groups, based on environmental noise measurements. Personal-equivalent 24-h noise exposure was measured to determine noise exposure at the individual level, and it was compared with hearing threshold level and with aircraft noise measured at the environmental level. Individual hearing threshold levels did not differ between environmental high- and low-noise-exposure groups, as evidenced by the lack of difference between the two groups for noise exposure measured at the individual level. However, the proportion of students who were annoyed by aircraft noise was higher in the environmental high-noise-exposure group, although personal 24-h noise exposure was not a factor for annoyance. The results indicated that environmental noise measurement was not an appropriate criterion for assessment of auditory damage (or noise-induced hearing loss) in Taiwan. As well, aircraft-noise exposure in Taiwan did not appear to affect the hearing threshold but nonetheless annoyed schoolchildren near the airport.

Pleasantness and Unpleasantness of Environmental Sounds

The present study was done to identify environmental sounds as pleasant or unpleasant for use as stimuli. On a questionnaire of 138 pleasant and 150 unpleasant environmental sounds, students estimated the frequency of pleasant and unpleasant experiences for each sound item. More than half of the students rated 25 environmental sounds “always” or “often” pleasant and that 26 sound sources were rated as “always” or “often” unpleasant. Factor analyses (Promax) yielded 20 factors with eigenvalues greater than 1.0 for pleasant sounds and 27 for unpleasant sounds. Some of natural and musical sounds were pleasant for most subjects. Sounds of alarm, excretion, and scratching were unpleasant for most subjects. Some environmental sounds may be estimated as pleasant for some but unpleasant for others.