|
Included on this list
of offenders are gases such as ammonia and hydrogen sulfide, which
can affect human health if they're at high levels. Because of the
risk, Funk said some states have established air quality standards
that limit emissions of hydrogen sulfide and ammonia from livestock
and poultry operations. However, he added that most states agree
there is not yet a sound scientific basis for determining fair and
effective standards.
Other gases, such as
ammonia, methane and carbon dioxide, can have implications for
global warming and acid rain as well, Funk said. Methane, for
example, can be produced by bacteria in liquid manure storages. It
is estimated that one-third of the methane produced each year comes
from agriculture -- primarily generated by animals and manure
storages or lagoons.
To keep these
offenders in check, experts offer a variety of tips on how to
control dust, odors and gases in key areas.
Livestock buildings
Dust in livestock
buildings originates from feed, bedding material, manure and the
animals themselves. The amount of dust depends on animal activity,
temperature, relative humidity, ventilation rate, stocking density
and feeding methods.
Because dust often
carries gases and odors, dust reduction in and around a building can
also reduce odors. Some effective methods to control dust include:
--Spraying a small
amount of vegetable oil inside confinement buildings (one gallon per
day in a 1,000-head swine finisher)
--Using windbreak
walls, biomass filters and biofilters
--Frequent cleaning
of outdoor feedlots
--Sprinkling water on
open earthen lots in arid and semi-arid areas (typically done in
late afternoons and evenings when animals are more active)
Manure treatment and storage
facilities
Lagoons have a large
surface, which increases gas emission and results in wide gas and
odor plumes. Manure storage basins contain more concentrated manure
than lagoons (for the same size operation) and produce less overall
odor than lagoons. Storages have a narrower odor plume because of
their small surface area. Covers can be very effective for outdoor
storages.
[to top of second column in
this article]
|
While under-floor
deep pits are better for outdoor air quality than outdoor storages,
they result in poorer air quality within the building and can
occasionally emit high levels of toxic hydrogen sulfide and other
gases during agitation.
Land application areas
Over half of all odor
complaints related to animal production occur when manure is applied
on the land. Manure is typically applied to an area up to 700 times
the surface area of the original storage, creating a large but
short-term downwind odor plume.
To significantly
reduce odors, directly inject manure or till it into the soil within
an hour after application.
Manure transport systems
Dust from truck and
tractor traffic is often cited as a nuisance caused by animal
operations. Sprinkling the roadbed of heavily traveled gravel or
unpaved roads with calcium chloride can reduce dust substantially.
Funk believes
producers must also consider the perception of neighbors in their
efforts to minimize the production of gases and dust at their
facilities.
"The public has an
increasing intolerance of odors," said Funk. "Maintaining general
cleanliness and upkeep are an important part of being a good
neighbor. Producers can't afford to ignore what others think of them
or their operations."
For a more detailed
description of procedures to measure and minimize a facility's
impact on air quality, Midwest Plan Service has developed the
publication "Outdoor Air Quality" (96 pages). Written for producers,
this book includes an air quality model to help estimate the
downwind odor impacts for a producer's operation.
"Outdoor Air Quality" is available for
$17 plus shipping and handling fees from MWPS, Iowa State
University, Ames, IA 50011-3080. To order, call (515) 294-4337 or go
to
http://www.mwpshq.org/.
[University
of Illinois news release]
|
