Long haul COVID is a pervasive and pernicious COVID-19 sequelae and affects every organ system, including the central nervous system. Neurological symptoms can last over a year, and include brain fog, chronic fatigue, dyspnea, mood dysregulation and headaches. Anosmia, for example, is the loss of partial or total smell and is a common symptom cited in acute and post COVID-19 infection. Current research surrounding the etiology of anosmia in COVID-19 cites olfactory epithelium damage, leading to neuronal death of olfactory receptors. Such damage is theorized to allow the virus to cross the blood-brain barrier (BBB) and lead to reduced cerebral spinal fluid (CSF) drainage via the cribriform plate. Reduced efficiency of cerebrospinal fluid is speculated to result in a decrease in CSF production and turnover in order to maintain appropriate intracranial pressure (ICP). This compensatory response can have a cascading effect on the entire central nervous system, particularly the meninges. Such etiology would allow for persistent neurological impairments, even in the absence of virus detection. Current research of anosmia also cites a relation between air pollution with olfactory impairment and neurodegenerative disease pathology. Although the mechanisms are unclear, the theorized etiology of Covid-19-induced anosmia is remarkably similar to the etiology of anosmia in relation with air pollution. Following IRB approval, we will analyze existing data from approximately 40 patients who completed neurological symptom questionnaires at a health clinic. Historical Air Quality Index (hAQI) of patient hometowns, collected by AirNow.gov and IQAir, will be tested for associations with self-report symptoms. Data analysis is planned for early January. We hypothesize that patients from areas of lower air quality will report more severe symptoms of long-haul Covid. Findings may provide insight into long Covid and other neurological pathology.