United States District Court, E.D. North Carolina, Southern Division
EARL BRITT SENIOR U.S. DISTRICT JUDGE.
matter is before the court on plaintiffs' motion to
exclude or limit the expert testimony of Pamela Dalton, Ph.D.
pursuant to Federal Rules of Evidence 104 and 702 and in
accordance with Daubert v. Merrell Dow Pharms.,
Inc., 509 U.S. 579 (1993). (DE # 95.) Defendant has
filed a response in opposition to the motion. (DE # 113.)
Dalton is defendant's designated odor expert. During a
period in the Fall of 2016, she oversaw an odor monitoring
study regarding the hog farm operations at Kinlaw Farm, the
hog operation at issue in this action. Persons serving as
monitors used a field olfactometer, the Nasal Ranger,
monitor for odor frequency and intensity. Using the Nasal
Ranger, if the monitor perceived any odor, s/he recorded it
as a dilution to threshold ratio. According to Dr. Dalton,
[i]n states where odor regulations exist based on the use of
a Nasal Ranger™ or similar device, the threshold for
flagging an elevated or objectionable odor (along with other
temporal requirements) has been commonly determined to be 7:1
or above. It is generally agreed that unless an odor can be
detected at ¶ 7:1 dilution or higher, it is not an
(DE # 96-1, at 4.) Based on this 7:1 standard and the data
collected during odor monitoring, Dr. Dalton opines “to
a reasonable degree of scientific certainty,  that the
normal operating activities at the farm do not produce odors
that travel offsite at an intensity, frequency or duration
that would be considered a nuisance level at the
Plaintiffs' properties.” (Id. at 5.) Dr.
Dalton also oversaw odor monitoring studies at other farms in
related cases and states “the entirety of the data
collected represent a very small number of potential
objectionable odor events.” (Id. at 9.)
Finally, Dr. Dalton details the biology of olfaction and
factors that influence individual perception of and response
to odor and explains why self-report of odors is often
Rule 104(a), “[t]he court must decide any preliminary
question about whether a witness is qualified . . . or
evidence is admissible.” Further, the court operates as
a gatekeeper under Rule 702 and Daubert in regards
to expert testimony.
[A] district court's gatekeeping responsibility [is] to
“ensur[e] that an expert's testimony both rests on
a reliable foundation and is relevant to
the task at hand.”
Relevant evidence, of course, is evidence that helps
“the trier of fact to understand the evidence or to
determine a fact in issue.” To be relevant under
Daubert, the proposed expert testimony must have
“a valid scientific connection to the pertinent inquiry
as a precondition to admissibility.”
Nease v. Ford Motor Co., 848 F.3d 219, 229 (4th
Cir.), cert. denied, 137 S.Ct. 2250, 198 L.Ed.2d 680
(2017) (citations omitted) (most alterations in original).
argue that Dr. Dalton's opinion that the farm does not
produce odors that would be a nuisance at plaintiffs'
properties should be excluded because it embraces the
ultimate issue and is not based on the proper legal standard
in North Carolina. Plaintiffs also take issue with Dr.
Dalton's odor study results based on the use of the Nasal
Ranger and the 7:1 standard. As for Dr. Dalton's opinion
about the unreliability of self-report of odors, plaintiffs
contend she is impermissibly opining on plaintiffs'
credibility. For the most part, the court agrees with
plaintiffs that Dr. Dalton's testimony on these issues
should be excluded.
Dalton recognizes, “[t]he perception of odors is a
highly subjective experience . . . . .” (DE # 96-1, at
6 (citation omitted).) Even though the use of the Nasal
Ranger enables one to quantify odor, the intensity of the
odor still derives from the monitor's perception of the
odor. Given that fact along with the fact that North Carolina
(unlike some other jurisdictions) has not adopted a dilution
to threshold ratio or any other objective standard for
assessing whether an odor is objectionable, Dr. Dalton's
testimony about her odor monitoring study of Kinlaw Farm and
its results would not be helpful to the jury. In fact, such
testimony would have a strong likelihood of confusing or
misleading the jury. It follows that Dr. Dalton's opinion
based on the data collected from that study would not be
helpful to the jury and would be confusing. Accordingly, the
court excludes Dr. Dalton's testimony about the odor
monitoring study and her opinion regarding the lack of odor
nuisance emanating from Kinlaw Farm.
court agrees with plaintiffs that Dr. Dalton cannot opine on
plaintiffs' credibility. See United States v.
Lespier, 725 F.3d 437, 449 (4th Cir. 2013) (“[I]in
the absence of unusual circumstances, Rule 702 renders
inadmissible expert testimony on issues of witness
credibility.”). However, her opinion about the
unreliability of self-report of odor does not invade the
jury's province to assess plaintiffs' credibility,
and the court will not exclude this opinion
foregoing reasons, plaintiffs' motion to exclude or limit
the expert testimony of Dr. Dalton is ...