Leaffer Douglas J, Suh Helen, Durant John L, Tracey Brian, Roof Christopher, Gute David M
Civil & Environmental Engineering, Tufts University, Medford, MA, USA.
Electrical & Computer Engineering, Tufts University, Medford, MA, USA.
J Expo Sci Environ Epidemiol. 2025 Jan;35(1):37-49. doi: 10.1038/s41370-023-00599-x. Epub 2023 Sep 11.
Environmental low frequency noise (LFN < 125 Hz), ubiquitous in urban areas, is an understudied area of exposure science and an overlooked threat to population health. Environmental noise has historically been measured and regulated by A-weighted decibel (dBA) metrics, which more heavily weight frequencies between 2000 and 5000 Hz. Limited research has been conducted to measure and characterize the LFN components of urban environmental noise.
We characterized LFN noise at two urban sites in Greater Boston, Massachusetts (USA) using dBA and full spectrum noise measurements with aims to (1.) analyze spatio-temporal differences in the two datasets; (2.) compare and contrast LFN metrics with dBA noise metrics in the two sites; and (3.) assess meteorological covariate contributions to LFN in the dataset.
We measured A- and C-weighted, and flat, unweighted noise levels and 1/3-octave band continuously for 5 months using sound level meters sampling at f = 1 Hz and we recorded sound samples at 44.1 kHz. Our measurement sites were located in two urban, densely populated communities, burdened by close proximity to bus, rail, and aircraft routes.
We found that (1.) LFN does not follow the same seasonal trends as A-weighted dBA loudness; there are spatial differences in LFN and its very low frequency noise components (VLFN) between two urban sites; (2.) VLFN and LFN are statistically significant drivers of LCeq (nearly independent of frequency) minus LAeq, (LCeq-LAeq) >10 dB, an accepted LFN metric; and (3.) LFN was minimally affected by high wind speeds at either Site.
Environmental low-frequency noise (LFN < 125 Hz), ubiquitous in urban areas, is an understudied area of exposure science and an overlooked risk to population health. We measured environmental noise across the full spectrum of frequencies continuously for five months at two urban sites located in Environmental Justice communities. We found that LFN did not follow the same seasonal trends as A-weighted (dBA) loudness, and we observed spatial differences in LFN and very low frequency noise (VLFN < 20 Hz) at the two sites. Not characterizing LFN and basing noise regulations only on A-weightings, a poor predictor of LFN, may expose populations to LFN levels of concern.
环境低频噪声（LFN < 125Hz）在城市地区普遍存在，是暴露科学中一个研究不足的领域，也是对公众健康的一个被忽视的威胁。环境噪声历史上一直通过A加权分贝（dBA）指标进行测量和监管，该指标对2000至5000Hz之间的频率加权更重。关于测量和表征城市环境噪声中的LFN成分的研究有限。
我们在美国马萨诸塞州大波士顿地区的两个城市地点，使用dBA和全频谱噪声测量对LFN噪声进行了表征，旨在（1）分析两个数据集的时空差异；（2）比较和对比两个地点的LFN指标与dBA噪声指标；（3）评估数据集中气象协变量对LFN的贡献。
我们使用声级计以f = 1Hz的采样频率连续5个月测量了A加权、C加权和平坦、未加权的噪声水平以及1/3倍频程带，并以44.1kHz记录了声音样本。我们的测量地点位于两个城市人口密集社区，这些社区因靠近公交、铁路和飞机航线而负担较重。
我们发现（1）LFN与A加权dBA响度的季节性趋势不同；两个城市地点之间的LFN及其超低频噪声成分（VLFN）存在空间差异；（2）VLFN和LFN是LCeq（几乎与频率无关）减去LAeq的统计学显著驱动因素，（LCeq - LAeq）>10dB，这是一个公认的LFN指标；（3）两个地点的LFN受高风速的影响最小。
环境低频噪声（LFN < 125Hz）在城市地区普遍存在，是暴露科学中一个研究不足的领域，也是对公众健康的一个被忽视的风险。我们在位于环境正义社区的两个城市地点连续五个月对全频谱频率的环境噪声进行了测量。我们发现LFN与A加权（dBA）响度的季节性趋势不同，并且我们观察到两个地点的LFN和超低频噪声（VLFN < 20Hz）存在空间差异。不表征LFN并仅基于A加权（LFN的不良预测指标）制定噪声法规，可能会使人群暴露于令人担忧的LFN水平。
