Community Pesticide Monitoring

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This website provides information and guidance to communities interested in monitoring for the presence of pesticides in ambient air. The quality of the data collected influences the potential end use of the data. Following precise procedures is necessary to collect data that can be considered for use in future decision-making. Documents to provide guidance on study plan considerations and sample collection are available below.

Pesticide Use Report Data

In 1990, California established a comprehensive program for reporting agricultural use of pesticides. Under the program, pesticide applications to agricultural sites must be reported monthly to county agricultural commissioners, who in turn, report the data to the Department of Pesticide Regulation (DPR). Detailed reports are required for applications used to produce agricultural commodities, such as applications to grape vineyards and cotton fields. The pesticide use reports for production agricultural use include information for each individual application, including the product applied, the amount applied, crop/site treated, date applied, and location (within a 1 x 1 mile area). Summary pesticide use reports are required for non-production agricultural and some non-agricultural uses. Non-production agricultural uses include applications to approximately 20 sites, such as golf courses, cemeteries, and roadsides. Non-agricultural uses that must be reported include applications by structural pest control businesses and applications for vector control. Some industrial (e.g., fumigations of harvested commodities), institutional (e.g., schools), and veterinarian uses must be reported. Pesticide use reports for non-production agricultural and non-agricultural uses include the product applied, monthly total amount applied, month applied, and county of application. Uses by homeowners and consumers require no reporting.

Pesticide Sales Data

Pesticide manufacturers and distributors (registrants), pest control dealers and pesticide brokers are mandated to report the total dollar value and total pounds or gallons of each product they sell for use in California. These are the only estimates of home-use or consumer use of pesticides.

Pesticide Air Monitoring Data

DPR maintains a Pesticide Air Monitoring Results Database containing both preliminary and published data from pesticide air monitoring studies conducted throughout California. The database contains both preliminary and published results from seasonal and long-term ambient air monitoring studies conducted by DPR and the CARB. Intensive seasonal ambient monitoring studies are normally conducted in multiple high-use communities during the high-use season for individual pesticides and last anywhere from 4-16 weeks depending on the study. Long-term ambient air monitoring studies are conducted in a single or multiple communities on a year-round basis for one or more years. Both seasonal and long-term ambient air monitoring studies produce data that is used to estimate concentrations associated with subchronic, annual, and lifetime exposures. Additionally, data collected from these monitoring studies assists DPR in assessing potential health risks, developing measures to mitigate risks, and measuring the effectiveness of regulatory requirements.

Pesticide Air Sampling Procedures

Data generated from pesticide ambient air monitoring projects must meet stringent quality assurance/quality control standards if it is to be used for regulatory purposes. The entire process, from sampling design, sample quality assurance, chemical analysis, and reporting of results, must follow approved protocols in order to maintain the integrity of the collected sample data.

DPR has prepared the following documents intended to provide guidance for the development of effective community air monitoring programs. It also includes examples of the elements described in this guide.

Additionally, DPR and ARB have been conducting a variety of pesticide air monitoring studies since the 1980s. DPR maintains a list of published monitoring reports that can be used as guide during the development of future pesticide air monitoring studies.

How Communities were selected by DPR to be included in the Air Monitoring Network

As part of DPR’s Air Monitoring Network 2017 sampling plan, DPR evaluated pesticide use reports for applications of selected pesticides within five miles of 1,267 California communities (all communities, except those in Los Angeles, Orange, and San Francisco Counties). Eight communities were selected for inclusion in the Air Monitoring Network. Communities were selected based on objective data, using criteria that can be quantified, validated, and verified. DPR selected the monitored communities based on the following criteria:

  • Two sets of communities were selected (four communities per set):
    • One set was based on 2012-2014 use of 4 fumigants – 1,3-dichloropropene, chloropicrin, methyl bromide, and MITC-generators
    • One set was based on 2012-2014 use of 11 organophosphates – acephate, bensulide, chlorpyrifos, DDVP, diazinon, dimethoate, malathion, methidation, naled, oxydemeton-methyl, phosmet and S,S,S-tributyl phosphorotrithioate.
  • For all communities considered, reported pesticide use was calculated for 3 zones:
    • Use within the community boundary (community zone)
    • Use between the community boundary and 1 mile of community boundary (local zone)
    • Use between 1 mile of community boundary and 5 miles of community boundary (regional zone)
  • The use density (lbs/sq mi) was determined by pesticide, year, and zone for each community.
  • Using data from the nearest California Irrigation Management Information System (CIMIS) station, DPR used the average wind speed as a weighting factor.
  • Each community was ranked from highest to lowest community (1 to 1,267) for each zone and assigned a final ranking based on the average rank of the three zones
  • Highly ranked communities were grouped by geographic region, and one community was selected from the region.

Community Pesticide Use Rankings

Geographic boundaries of 1,267 communities were obtained from the US Census Bureau’s 2015 TIGER/Line Place shapefile ( Geographic information system (GIS) analysis calculated the amount of each pesticide applied to individual sections around the communities. Three zones were evaluated, as shown below: within the community boundary (the “community zone”); between the community boundary and 1 mile of the community boundary (the “local zone”); and within 1 to 5 miles of the community boundary (the “regional zone”).

To date, the smallest geographic unit for reporting pesticide use to DPR is the square-mile section. For sections that are only partially included within the zone boundary (see examples 15S18E03 and 15S18E04) including the entire amount of pesticide applied within those sections may result in considerable over counting. To adjust for this, the proportion of each section within a zone was calculated and the amount of pesticide included was reduced in proportion to the area of the section within the zone. The multiplication (or portion) factor assumes that pesticide use is distributed uniformly across the section in which it is reported.

A graphical representation of the community, local and regional zones around a community
      A graphical representation of the community, local and regional zones around a community.

To determine use density (lbs/sq mi), the amount of pesticide applied within each of these three “zones” was divided by the area of each zone (in square miles), and then expressed as amount of pesticide active ingredient per square mile by pesticide and zone for each community. GIS analysis was used to determine the closest CIMIS station to each community, and the use density of each community was then divided by the average annual wind speed from that CIMIS station. Communities were ranked independently for weighted fumigant and organophosphate use within the three zones, and a final ranking was assigned based on the average rank of the three zones.

The Community Use Rankings link below includes a complete community use rank for fumigants and organophosphates

For content questions, contact:
Edgar Vidrio
1001 I Street, P.O. Box 4015
Sacramento, CA 95812-4015
Phone: (916) 323-2778