06 New Harmony Project - City Council - City of Davis

New Harmony Apartments – PA#61-07
project. This number takes into account actual meteorological data, actual truck percentages and
other project specific details. It results in a significant difference and a much lower risk. The
HRA results are based on a very conservative scenario that assumes 70-year, 24-hour-a-day
outdoor exposure to pollutants. It is also conservative from a location standpoint and calculates
the risk level at the fence line of the office parcel north of Cowell Boulevard at the point closest
to the freeway. When adjusted for location, the risk level from exposure where the residences are
actually proposed falls to about 8.6 in one million. The risk falls even further to 3.1 in one
million when calculated on a more realistic 30-year exposure period. Additional analysis was
conducted on the cancer health risk levels for children at the project site and included additional
parameters specific to children. The results show a carcinogenic risk level of 1.9 in one million
for a 9-year exposure period.
The HRA also assessed exposure risk levels for long-term chronic impacts and short-term acute
impacts that include all non-carcinogenic health effects to people including asthma. The chronic
risk of 0.010 and acute risk of 0.00026 for the project are well below the YSAQMD threshold of
1.0 for stationary sources. The Southern California health study which found detrimental effects
on the lung development of children living near freeways highlights the importance of detailed
site analysis. The applicant’s air quality consultant provided additional information and analysis
of the study (Attachment 7).
The air quality consultant pointed out that the health study generalizes the health effects as
related to distance from a freeway. Southern California freeways have much higher traffic
volumes, over 300,000 vehicles per day, and a much higher percentage of diesel-powered trucks,
as high as 50%, compared to I-80 through Davis with 126,000 vehicles per day and about 6%
diesel-powered. Specific conditions and exposure levels can vary dramatically. It is not intended
to minimize the health risks of living near freeways. It is already known that exposure to
particulate matter has adverse health effects. Children, the elderly, and those with existing
conditions are most at risk. The HRA results do not directly address the effect on lung
development which is difficult to quantify. It does address asthma and other respiratory
problems. The modeling software used in the HRA is made available by the California Air
Resources Board and is the preferred methodology for evaluating health risks from air pollution.
It incorporates site specific information and calculates quantifiable risk levels and comparable
information. It indicates that chronic and acute impacts for the project from exposure to freeway
traffic would be less than significant.
Additional Expert Input
The City solicited additional independent analysis from Dr. Thomas Cahill, a nationallyrecognized
air quality expert who has also conducted numerous studies in the Davis and
Sacramento region. His analysis and understanding of local conditions indicated that the air
quality at the project site would not be expected to be substantially worse than other locations in
the city. The conclusion was based on two main points: 1) prevailing wind conditions favor the
New Harmony site and would disperse highway pollutants away from the project; and 2) studies
including measurements of air quality at the USFS Nursery site in Davis which has a similar
distance and location on the south side of I-80 as the New Harmony site indicate relatively good
overall air quality. Dr. Cahill also recommended measures to mitigate impacts and improve
indoor air quality that have been incorporated. The Cahill analysis is included in the Planning
Commission staff report attachments.
10/07/2008 City Council Meeting 06 - 8