People who live and work near the U.S.-Mexico border have complained for years about the ill effects from the cross-border pollution: noxious odors, headaches, breathing difficulties, nausea, stomach ailments. They now will have a face-to-face opportunity to tell the nation’s public health agency how the toxic mix of sewage and other contaminants that spill into the Tijuana River Valley affects them. The effort kicks off Thursday with a large team from San Diego County and San Diego State University notifying more than 6,000 homes of an upcoming visit by the Centers for Disease Control and Prevention and the possibility that their household may be selected for an interview, county public health officials said Wednesday. In cooperation with the county and state, the CDC will conduct 210 door-to-door surveys with randomly selected households from 2-7 p.m. Oct. 17-19. Each survey, expected to last about 15 minutes, is in-person, voluntary and anonymous. The process is formally known as a Community Assessment for Public Health Emergency Response, or CASPER. These assessments are usually quick and produce data about what a community needs “so public health leaders and emergency managers can make informed decisions,” according to the CDC’s website. “This is our opportunity for our community to voice their concerns, their experiences,” said Seema Shah, the county’s interim deputy public health officer. “This is how we can share what’s going on. We can share the concerns, the impact that it’s had to their properties, their family’s mental health, all of their health outcomes.” It’s unclear the kinds of questions households will be asked, but the point of the CASPER is to quickly gather information from residents since they have been exposed to “worsening environmental contamination of the Tijuana River estuary,” according to an agreement Aaron Bernstein, director of the CDC’s National Center for Environmental Health, signed Sept. 11 confirming the public health survey. That agreement noted that “over 100 billion gallons of untreated sewage, urban runoff and industrial waste has been spilled into the Tijuana River over the past five years.” This summer, the county and state formally enlisted the help of the federal health agency to conduct an epidemiological investigation, otherwise known as an Epi-Aid. The agencies determined a CASPER could better identify what resources are needed and what additional actions public health can take. The agreement mentions two objectives for the Epi-Aid: Conduct the CASPER and assess how cross-border pollution has affected people, including water and air exposures, and what resources they may need. Identify transient, non-community water systems, such as those that serve campgrounds, and other water sources. Review these sources regulations and operations and recommend ways to improve them. To get a random assortment of participants, CASPERs involve selecting 30 census blocks and interviewing seven households within each block. The census tracts matched where most air pollution complaints the San Diego County Air Pollution Control District had received from people, Shah said. The CASPER is expected to produce the most comprehensive information, to date, by a government agency about the health impacts persistent pollution has on people in the county’s southwest region. And it will be one of the most visible, on-the-ground work from public health officials in response to numerous concerns raised by residents, elected officials and others. Besides reported illnesses connected to ocean water, residents have reported experiencing symptoms such as nausea, coughing and headaches after being regularly exposed to strong odors emanating from the Tijuana River. While the U.S. and Mexico work on repairing treatment plants, concerns have grown in recent years about the short- and long-term effects of living and working near the pollution. Shah said the goal is to deliver at least some data results to the public by the end of the year. Staff writer Paul Sisson contributed to this report.