Noise Impacts by Population needed

A discussion with a friend at Boston West Fair Skies makes me realize one of the areas that is missing from our EA is noise impact by population. The Boston population analysis is very impressive- and it’s only for one RNAV SID (Departure) Runway.

After having mapped the DOT 4(f) noise data I perform an analysis and answer the question “Is there a net noise increase or decrease with the proposed action?”

Answer: There is a net noise increase of .15dB DNL across the Study Area.

It would be nice to do this across the populated areas- but I already put in that request for the census block noise data.

For people on the ground there is no net improvement, it just gets worse all around.


Subject: Request for further information on Noise Impacts by Population
From: Stephen Murray

Mr Robert Henry & Mr Ryan Weller,

This comment is a request for data and analysis of results on noise impacts on population and communities that is not included within the Draft Environmental Assessment.

The Draft EA summarily states that the proposed action would cause no increase in DNL noise exposure according to the Noise Impact Criteria. This is not the same as saying that there will be no change in noise impacts. The general public desires to understand the changes in noise exposure that will occur from the profound changes in airspace. The questions that the EA needs to answer are of these types:

  1. “Of the 20,502,021 people in the study area, how many are positively or negatively effected by the proposed changes- and to what degree?”
  2. “Do the proposed changes result in a net positive or negative noise impact?”
  3. “Are there any population groups that are disproportionately impacted by the changes?”
  4. “What are the expected impacts on each Community or Census block?”
  5. “What expected noise change will occur at my home or business?”

To adequately answer these questions detailed and summary tables of the populations and communities exposed to noise impact changes at all DNL levels are needed.

Some information is available by interpreting data within the study:

  1. Table 4-1 in the Draft EA has a brief listing of Maximum population exposed to aircraft noise within the study area. The table lists 3,378,170 people as being exposed to DNL 45dB to DNL 60dB. This DNL range is so large, as are the number of people who very little information is actually be supplied. Contextualizing the population and noise data by using smaller DNL ranges and including population clusters would offer greater meaning.
  2. According to the DOT 4(f) data included in Appendix 2, Tables 2 & 3 from the Noise Technical Report, there is a net DNL noise increase of .15dB DNL across the study area. In addition, most of the noise increases are in areas that are already at or below 60 dB (DNL) with the largest change in noise in areas less than 40dB. I created this table to demonstrate:
Change in noise by DNL dB range
DNL Range (dB)Percentage of TotalAverage Change in Noise DNL (dB)Highest DNL (dB) Lowest DNL (dB)
Less than 40dB93%0.1610-7.1
40 to less than 454.3% -0.094.4-3.9
45 to less than 501.3% 04.5-1.8
50 to less than 550.01%0.061.5 -1
55 to less than 600.01%0.050.5 -0.4
60 to less than 650.01%00.20.2
65 to less than 700.01%00.1-0.1
Greater than or equal to 700.01%000

The 4(f) data represents primarily rural areas so results aren’t generalizable over the denser population centers in the study area. This means that Executive Order 13045 and U.S. DOT Order 5680.1- “Federal Actions to Address Environmental Justice in Minority Populations and Low-Income Populations” can not be accommodated with the current information.

A similar analysis using Census Block centroids and including affected population is likely to yield different results.

The FAA has released information of this type before.  The “Boston Logan International Airport Runway 33L RNAV SID EA” included tables that explain the noise difference.

See tables 4.3- 4.6 in the attached BOS_33l_RNAV_Final_EA_Noise_Reduction_Excerpt_06042013 and compare to Section 5-7 of the SoCal_Metroplex_Noise_Impact_Analysis_Results.pdf for the SoCal EA Boston 33L Final_EA_Noise_Reduction_Excerpt.

Due to the lack of data on noise impacts on population clusters I request disclosure of the following data and information that highlight the noise impacts for each community:

  1. Table summarizing the population exposed to aircraft noise impacts under the proposed action for various DNL ranges.
  2. Table summarizing the difference in exposure between the No Action and Proposed Action alternatives  for various DNL ranges.
  3. Table detailing noise exposure and change in noise exposure by community.
  4. Table detailing the range of population exposed to DNL levels above 40DNL under the No Action and Proposed Action Alternatives.
  5. Data of Census Block Centroid points containing geographic coordinates, population and noise data. An earlier request called “Request Full Results from NIRS Noise Modeling” asked for release of the noise data and geographic points of Census Block Centroid Points. This request add the column of population.

Disclosing data that can be used to inform these concerns will help our elected officials and the general public further understand and manage expectations of the noise impacts to specific neighborhoods.

By the FAA supplying additional clarifying information, I hope that the communities can better engage and understand the draft Environmental Assessment. This will allow the FAA to receive additional valuable information that will allow refinements to procedure design prior to implementation. This in turn will help the FAA achieve a higher level of success with the projects implementation.

Thank you for your consideration to this request.

Stephen Murray