The Almond Board of California has submitted a report to California air quality agencies, suggesting they can reduce the baseline PM-10 dust emission factor from almond harvest by about 30 percent. The report relies on data gleaned from seven years of PM-10 harvest dust research funded by the Almond Board.

The PM-10 emission factor is used to calculate baseline emissions from which improvements may be required. In 2002, the California Air Resources Board identified almond harvesting as the largest agricultural contributor to PM-10 emissions in the San Joaquin Valley. It based its determination on initial data from one limited 1994 study.

The research also assessed measures growers and custom harvesters can take to reduce dust emissions during harvest, as visible dust is a nuisance to neighbors and PM-10 is regulated in the San Joaquin Valley.

A few of those established techniques are:

  • Good orchard floor preparation;
  • Setting sweeper heads at the manufacturer’s factory level so that wire tines are 0.125 inch off the ground;
  • Adjusting blower spouts to match the unique conditions in the field;
  • Adding an optional berm brush to help minimize blower passes;
  • Reducing harvester ground speed based on field conditions;
  • Reducing suction fan speeds under clean orchard conditions; and
  • Blowing into the orchard at edges to use trees as a natural filter.