San Joaquin Valley almond growers have until Jan. 1, 2009, to meet new emissions requirements for gas-powered irrigation pump engines.

A new rule by the San Joaquin Valley Air Pollution Control District establishes new thresholds for spark-ignited internal combustion engines in agricultural operations as part of its effort to reduce agricultural emissions of NOx, CO and VOCs in the Central Valley.

Under District Rule 4702, growers with irrigation pumps or other engines powered by gasoline, natural gas, propane/LPG, biogas or other fossil fuels must retrofit engines that do not meet those thresholds with an emission control device, such as an exhaust catalyst, or replace them with a more efficient lean-burn, electric or diesel engine that meets the limit.

Rich burn engines, which comprise about 99 percent of most agricultural spark-ignited engines in the Valley, must meet NOx emissions requirements of less than 90 ppm, CO emissions below 2000 ppm and VOC emissions below 250 ppm.

Growers must also install and maintain a monthly time meter and use logs on new or modified engines as part of the rule requirements.

Brian Clements, senior air quality engineer with the District, said installing a three-way catalyst that controls all three pollutants is probably the easiest way to comply with District Rule 4702.

“If you install a certified control system you can avoid ongoing testing and monitoring requirements which makes choosing this method a little less cumbersome,” Clements said.

Growers may also replace rich burn gas engines with a lean burn engine that meets emissions requirements of 150 ppm NOx, 2000 ppm CO, and 750 ppm VOC.

Another option for growers is to replace the spark-ignited engine with an electric pump motor or new latest-tier certified diesel engine that meets emissions thresholds.

Replacing the gas engines with Tier-3 or better diesel engines, however, requires more extensive paperwork and growers should check first with the District before considering this option, Clements added.

Electric pump engines provide the easiest route in terms of District compliance, but growers may have other issues, such as waiting for PG&E to extend power lines to the pump.

To modify existing permits on those engines, growers will need to submit an Authority to Construct immediately with the district and complete the modification by Jan. 1, 2009. Smaller operations or others with a permit-exempt engine must submit a Permit-Exempt Equipment Registration (PEER) by Oct. 1, 2008.

For information or technical assistance about how to comply with District Rule 4702 call the Air Pollution Control District Office's small business assistance line in your region.

Modesto (209) 557-6446

Fresno (559) 230-5888

Bakersfield (661) 326-6969