Environmental Engineering Reference
In-Depth Information
This study investigates methods to characterize the transport of ozone from the
Ohio River Valley (ORV) region, a major source area experiencing significant
emission reductions resulting from the NOx SIP Call, into a domain encompassing
New York State (NYS). Back-trajectories were performed from several sites within
this domain across eight summers (1999-2006) to identify predominant meteoro-
logical patterns. These meteorological patterns were investigated for associations
with ozone concentrations and respiratory-related hospital admissions. This paper
presents the preliminary results from this analysis.
2. Approach
Daily maximum 8-h ozone concentrations were calculated from hourly measure-
ments for the summers (June 1 through August 31) of 1999 through 2006 obtained
from the EPA's Air Quality System database (http://www.epa.gov/oar/data/aqsdb.
html) and the Clean Air Status and Trends Network (http://www.epa.gov/castnet/ ).
Daily 8-h maximum ozone concentrations were interpolated to provide estimates
for each county to coincide with the hospital admissions data. Back trajectories
from selected sites were computed using the HYSPLIT (HYbrid Single-Particle
Lagrangian Integrated Trajectory) model (Draxler and Hess, 1997) for 48 h back
in time, producing a total of 736 trajectories for each site. Health data for the
summers of 1999 through 2006 were obtained from the NYS Statewide Planning
and Research Cooperative (SPARCS). These data included daily hospital admissions
for respiratory-related diseases, including asthma, chronic bronchitis, chronic
obstructive pulmonary disease (COPD), emphysema, and pneumonia and influenza.
3. Discussion and Results
The transport of ozone into NYS was examined by performing back-trajectories
during the summers of 1999 through 2006 at selected sites in Albany
(Fig. 1
),
Buffalo, New York City (NYC) and southwestern NYS. Based on these back-
trajectories, each day was categorized as having a wind flow pattern originating
from the ORV or not originating from the ORV (
Fig. 2)
. These days were then
matched to the corresponding daily maximum 8-h ozone concentrations and daily
respiratory-related hospital admissions. In addition, ozone concentrations and
hospital admissions were examined before the implementation of the NOx SIP
Call (1999-2000) and after the implementation of the NOx SIP Call (2004-2006).
The results of this analysis indicate that the mean levels for ozone concentrations
and respiratory-related hospital admissions were significantly higher for those
days when the sites were downwind from the ORV versus those days that the sites
were not downwind from the ORV. In addition, the mean levels for ozone
concentrations were found to be significantly higher before the implementation of
