Like many people in South County, Analy Hayes of Imperial Beach said nauseating odors stemming from raw sewage flowing into the Tijuana River Valley have affected her family, including her three young children. “The smell’s so potent it wakes us up at night,” she said Wednesday. “My oldest kid would have coughs, my other kid breathing issues and a runny nose. We need this to get fixed now.” Hayes said she is ready to share that information with the nation’s top public health agency should they knock at her door in the coming days. On Thursday, the Centers for Disease Control and Prevention will launch a face-to-face survey with 210 randomly selected households near where sewage and other pollutants spill into the Tijuana River Valley from Mexico. More than 80 people from the CDC, San Diego County and local universities will visit homes sometime between 2-7 p.m. from Thursday to Saturday. Each survey, expected to last about 15 minutes, will be voluntary and anonymous. Though it’s not known what specific questions will be asked, officials said the survey, formally known as a Community Assessment for Public Health Emergency Response (CASPER), will focus on changes in health, mental health and daily activities people may have experienced as a result of being exposed to polluted air and water. Nearly 7,000 South County households were notified two weeks ago about the CDC’s visit, which marks the first meaningful presence of a federal public health agency responding to growing public calls for a stronger focus on sewage-related health concerns tied to the cross-border pollution. Residents have reported experiencing symptoms such as chronic coughs, watery eyes, headaches, nausea and diarrhea after being regularly exposed to strong odors emanating from the river or after heavy rains that bring more polluted flows across the U.S.-Mexico border. Local public health officials have repeatedly said that they have not seen an increase in reportable illnesses in South County. That’s due, in part, to the fact that the county only tracks certain illnesses, leaving gaps that fail to show the full extent of the problem. The information collected from the CASPER will help the government better assess those gaps and the next steps “to bring more help to this community,” Ankita Kadakia, the county’s interim public health officer, said in a statement. “It is important for the selected households to answer the CDC survey questions completely and honestly to best capture what is happening in the community at the height of this crisis,” she added. CASPERs have been used many times in California and across the nation to find out what people need, usually following disasters and environmental health concerns. For example, one assessment produced public health statistics after a widespread methane leak in Aliso Canyon in Los Angeles County. From October 2015 to February 2016, the Aliso Canyon Natural Gas storage facility released 109,000 metric tons of methane, presenting a risk to residents’ health and safety, according to the CASPER. Residents had reported complaints of symptoms, such as nausea, abdominal discomfort and headaches, associated with odors from the gas leak. Thousands of people temporarily evacuated and businesses had to shut down. The assessment recommended conducting indoor testing of residential homes and preparing specific ways to air out and clean homes, among other suggestions. L.A. County officials then tested indoor air and dust in some homes and pushed for better safety and environmental review of the Aliso Canyon facility. In 2018, the county and other local and state agencies reached a nearly $120 million settlement with the gas company to fund a long-term health study, air monitoring, electric school buses and air filtration systems at schools, among other efforts. In South County, residents said they noticed that the noxious sewer gas odors improved after Mexican officials began diverting some flows away from the Tijuana River recently, but that the stench still re-emerges. A spokesperson for the San Diego County Air Pollution Control District said Wednesday that the agency is still receiving complaints about odors, but they have decreased over the past weeks. Wastewater infrastructure on both sides of the border are undergoing repairs and expansions after years of underinvestment, though completion will likely take years. Reports of Tijuana sewage leaking over the border into the San Diego region stretch back at least to the 1930s. While significant improvements were made in the 1990s, the city’s plumbing hasn’t kept pace with population growth. Sewage pollution has led to repeated beach closures as far north as Coronado and the relocation of Navy Seal and lifeguard training. Calls continue from local, state and federal elected officials, and most recently the California Coastal Commission, requesting President Joe Biden declare a state of emergency. Local leaders are also exploring petitioning the U.S. Environmental Protection Agency to investigate whether the Tijuana River Valley qualifies as a superfund site. County officials said the goal is to share at least some data results from the CASPER with the public by the end of the year. San Diego State University’s School of Public Health is also conducting its own survey to better understand “how pollution in the Tijuana River and Estuary affects the air, water and health of nearby communities.” The survey, which launched this month, is open for one year.