Pesticide air monitoring in California is an illusion of protection: It reassures the public but fails to measure the real danger

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California’s Department of Pesticide Regulation (DPR) wants credit for recently expanding its pesticide air monitoring network. And yes,10 monitoring stations are better than five, but it is still not enough to cover a whole state with diverse crops and widespread pesticide use. 

Let’s not confuse expansion with protection.

Right now, California’s pesticide air monitoring system functions less as a public health safeguard in communities like mine in Watsonville and more as a public relations shield — offering communities the appearance of oversight while leaving major gaps in what is actually measured, where it is measured and how the risks are communicated.

PESTICIDES IN THE PAJARO VALLEY: Read more Lookout news and Community Voices opinion coverage here

I attended a recent DPR Environmental Justice Advisory Committee meeting in Salinas, and saw frustration boil over before DPR had even reached the agenda item on air monitor expansion. Residents from agricultural communities across the state pushed back against a proposal that still continues to leave vast areas effectively unmonitored.

For example, our local pesticide monitor was recently moved from Ohlone Elementary School to Pajaro Middle School. DPR considers that monitor sufficient coverage for both Santa Cruz and Monterey counties, despite geographic divides and varied crop patterns. 

At the meeting, Salinas Valley residents vehemently disagreed – as did people from other agricultural communities, who also say their neighborhoods, schools and workers remain invisible to the state’s monitoring system. 

How do these monitors create a false sense of safety?

Some families understandably assume that if a school has an air monitor, someone is watching closely enough to keep children safe. But DPR’s monitoring system captures only fragments of exposure. Sampling happens over 24 hours one day a week. Only about 40 chemicals are tracked, even though hundreds of pesticides are used in California agriculture. 

Some chemicals being monitored are no longer even registered for use in the state, while other toxic pesticides currently applied are left out altogether. And air is only one of multiple exposure pathways, especially in communities like ours with large farmworker populations, and with homes, as well as schools, sited close to agricultural fields. 

These are snapshots, not a documentary.

The pesticide monitor locations themselves are rooted in a long history of delay and inadequate response. The original school-based monitors were installed after parents filed a 1999 federal complaint saying their children were disproportionately harmed by pesticide exposure, particularly from methyl bromide, a fumigant known for serious human and environmental toxicity. 

Yet the monitors did not arrive until 11 years later — long after the affected students had left those campuses. 

Now, after 15 years of collecting data, DPR continues to present the results as reassuring. But reassuring according to whose standards?

DPR repeatedly points out that pesticide levels generally remain below its own regulatory targets. The key phrase is “its own.” Those standards sometimes differ sharply from health-protective levels recommended by the Office of Environmental Health Hazard Assessment (OEHHA).

Take chloropicrin, a fumigant linked to respiratory and eye irritation. DPR’s air monitoring benchmark is reportedly 79 times higher than the level DPR and OEHHA agreed avoids eye and respiratory irritation in children. 

That’s not a technical discrepancy, it’s a policy choice.

And while public attention often focuses on cancer risks and neurological impacts, one of the most immediate realities in agricultural communities is often overlooked: asthma. Asthma is the most common chronic childhood disease. 

In the Pajaro and Salinas valleys, respiratory illness is widespread among children and adults, even with coastal winds helping disperse pollution. Many agricultural regions fare even worse, sitting in air basins already classified by the California Air Resources Board (CARB) as failing federal air quality standards.

Pesticides don’t exist in isolation. 

Communities may be exposed simultaneously to diesel exhaust, wildfire smoke, fine particulate matter, volatile organic compounds and industrial pollution. Yet DPR evaluates pesticides largely one chemical at a time, as though pesticides were separate not only from each other, but from other contaminants people inhale.

DPR’s modeling methods for siting the new monitors raise questions. For example, the agency reportedly factored in average wind speed — but not wind direction. That omission alone should undermine confidence in the precision of the system. And DPR’s air monitoring network has prior history of data errors, both in calculations and in how data was presented. 

Meanwhile, communities are trying to fill the gaps themselves. 

At the Salinas meeting, one teacher described how her principal leased an independent air monitor after receiving repeated spray day notifications near Edward Alvarez High School. But like most public and private air monitors in California, it cannot detect pesticides. 

That includes the over 250 in CARB’s system and the many home-use devices, some of which were distributed recently in the Pajaro Valley through a UCSC research program.

Still, as projects like the above demonstrate, those community monitors may end up revealing something DPR has not: how pollutants move through neighborhoods, how pesticide-related volatile compounds interact with other contaminants, and how time and weather conditions change potential for exposure.

The larger question is how cumulative exposure shapes public health over time. 

Workers and residents in ag communities are exposed to multiple toxic pesticides, sometimes over lifetimes, with very little known about combined and long-term effects. New science is uncovering genetic risks, risks from exposure during critical developmental periods and synergetic risks. 

The regulatory process for reevaluating pesticides when new risks are identified is glacially slow. Assessment and regulatory duties are parceled out to various state agencies that don’t appear to communicate effectively with each other, much less to the communities they are tasked to protect. 

Agencies like CARB and DPR need to collaborate when they have overlapping functions. Protection of public health must have priority over profits for the chemical and ag industries.

This is the conversation California should be having.

Pesticide air monitors should not exist primarily to reassure regulators that their models are working. They should exist to help communities reduce exposure and move toward safer agricultural practice – not just insufficient attempts at risk reduction. 

Which raises the obvious question: If pesticides are dangerous enough to require air monitoring at schools, why are we still allowing them to be applied so close to children in the first place?

Our Safe Ag Safe Schools and Californians for Pesticide Reform members continue calling for a 1-mile organic buffer around schools and residential neighborhoods, along with the phase-out of fumigants and organophosphates. That’s the kind of upstream prevention that could actually improve public health.

And when that day comes — when our schools are no longer surrounded by toxic pesticide drift — it will be a victory if those air monitors can finally be moved off school campuses and into the broader community.

Until then, California’s monitoring system remains an uneasy reminder of how slowly regulation moves, even when the dangers are already well known.

Here’s a final, sobering reminder. Consider methyl bromide. Forty years after the Montreal Protocol mandated methyl bromide’s elimination, and a decade after California’s supposed phase-out deadline, the chemical is still being used to fumigate shipping materials and export products. Researchers continue detecting it at troubling levels near urban schools in Southern California.

And in rural agricultural communities far from those industrial uses, DPR still cannot  explain why methyl bromide continues appearing on our school air monitors.

That should concern everyone far more than another reassuring report.

Kathleen Kilpatrick has been a midwife, done pediatric and geriatric home care, worked in a farmworkers clinic, taught nursing and worked in Pajaro Valley Unified School District from 2000 to 2017, where she served as team leader for district health services. She is committed to continuing work on public health issues as key aspects of social and environmental justice.