Environmental Engineering Reference
In-Depth Information
O
3
with Cl
2
is also greater than that with HOCl. When an equal amount of chlorine
is present on a mass basis (300 pptv of Cl
2
vs. 600 pptv of HOCl), then the largest
increase in O
3
obtained with HOCl is greater than that with Cl
2
. However, the
initial rate of increase of O
3
with Cl
2
is still greater than that with HOCl. Similar
results were also obtained for rural conditions described in Gao et al. (1996).
4. Summary
These findings have important implications. First, it suggests that only a fraction
of chlorine that is added to cooling tower water can be emitted into the atmosphere.
Second, chlorine emissions from cooling towers are primarily emitted as HOCl,
not as Cl
2
. The chemical form of chlorine emissions is important since it affect O
3
differently. We plan to combine these estimates with other available estimates of
chlorine emissions and evaluate their impacts on O
3
in the U.S. by using the
Community Multiscale Air Quality (CMAQ) model (Byun and Schere, 2006).
Disclaimer
Although this paper has been reviewed by EPA and approved for publication, it does
not necessarily reflect EPA's policies or views.
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