Dust A major component of particulate matter that is greater than 2.5 um, but less than 10 um in diameter –PM 10 Major PM 10 sources –Dust Livestock operations Construction Roads Agricultural fields Deserts –Soot EPA limit for PM 10 –24 average – 150 ug/m 3 –Annual average – 50 ug/m 3

Effects of PM 10 –Human health Settles in upper airways Aggravates respiratory diseases –Carries odors Extends distance of odor plume –Reduces visibility Clean air act states that it will provide protection for the visibility of natural parks and wilderness areas Extent of the problem Natural visibility Average visibility miles Eastern U.S Western U.S Dust contributes 5 – 20% of the reduction of visibility in the U.S.

Sources of dust from livestock –Feeds Wastes in buildings Damage during delivery Processing –Dry manure –Animal skin –Feathers –Bedding –Bacteria –Molds

Factors contributing for livestock dust –Building type Solid floor > slats –Animal activity –Temperature –Humidity –Ventilation –Stocking density Lower density > high density –Feeding method Results of these factors causes evening dust peak around outdoor cattle lots –Reasons Afternoon heat and wind dries manure Cattle become active in the evening –Moving to the feed bunk or waters or interacting socially Atmosphere becomes more stable in evening so suspended dust particles hang in air

Dust control –For swine and poultry in confinement buildings Feeding system –Feed pelleted feeds »May be improved by adding fat during cooling –Deliver feeds to feeders with drop tubes –Use liquid feeding systems »For swine Improve skin health –Improve dietary fat quality –Supplement with zinc to requirement Management –Frequent cleaning »Include ventilation fans and motors, louvers and shrouds »If animals are kept year-round, zone clean part of barn –Spray vegetable oil »Do not mist »Reduces respirable dust by 81% –Use wet scrubbers –Use Biofilters –Use Biomass filters –Use windbreak walls –Use vegetative shelter belts

–For cattle in an earthen lot Feeding system –Add up to 5% fat to the diet –Feed for the last time early in the afternoon »Minimizes late afternoon activity –Frequent cleaning »Also applies to concrete lots –Set manure scraping equipment to leave 1 to 2 inches of compacted manure on top of the soil »Prevent leaching of nutrients into ground water –Increase stocking rate during hot dry weather »Increased urine reduces dust –Sprinkle water over lot »Most effective in late afternoon when cattle are active »Need capacity for.25 inches/day »Sprinklers should have at least 50% overlap, but not run onto feed apron »Excessive moisture may increase odor –Topical application of crop residues on lot surface