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Ambient air pollution and COVID-19 in California

Principal Investigator: 

University of California, Davis

This study will investigate the chronic and acute effects of air pollution exposure on COVID-19 incidence, mortality, and long-term complications, including onset of disease formation. Long- (2017−2018) and short- (2020) term exposures will be linked to a large medical records database in Southern California, with assessments at both the neighborhood and individual level.

Funded under

The COVID-19 outbreak and associated mitigation responses have exposed new public health challenges that will likely persist for decades as further coronavirus outbreaks occur (SARS 2003, MERS 2012, COVID-19 2020). With HEI support, we will study the chronic and acute effects of air pollution exposure on COVID-19 incidence, mortality, and long-term complications, including onset disease formation.

Aim 1: Develop Chronic and Acute Air Pollution Exposure Fields During COVID-19. Chronic (years 2017-2018) and acute daily (year 2020) air pollution exposure fields across California will be developed with 24km, 4km, 1km, and 30m resolutions using a combination of chemical transport models (CTMS) and land use regression models (LURs).

Aim 2: High Resolution Spatial Analysis. The strength of the association between air pollution and COVID-19 outcomes can be artificially weakened by incomplete exposure estimates and inconsistent reporting of health outcomes across the U.S. A more focused analysis within a smaller geographical area that has a large population, consistent health reporting practices, and accurate pollution exposure estimates will more accurately detect the association between air pollution and COVID-19 incidence or death. In this project, we will analyze 432 health neighborhoods of Los Angeles County with high spatiotemporal resolution (i.e., 30m resolution of daily and chronic exposures) for approximately 10 million residents. Some 244,999 laboratory-confirmed cases and 5,932 deaths were reported and attributed to COVID-19 across 432 neighborhoods between March 16th and September 4, 2020. Thus we have large samples, which is likely to be even larger by the initiation of our study, to quantify associations between air pollution and COVID-19 incidence and mortality in small areas of Los Angeles.

Aim 3: Long-term COVID-19 Complications. Patients who recover from the acute effects of COVID-19 infections may experience long-term complications including asthma and chronic obstructive pulmonary disease (COPD) exacerbations, strokes, immune-mediated inflammatory diseases (IMIDs) such as Chrones disease, colitis, and rheumatoid arthritis [1], and mental health conditions including anxiety and depression. In the proposed research, the relationship between acute or chronic air pollution exposure and increase in complications in COVID-19 patients (including exacerbation of existing comorbid conditions) will be studied for a period of 18 months after initial infection.

Aim 4: Multi-state Effects of Chronic and Acute Air Pollution: COVID-19 patients may progress through a number of potential disease states including admission to hospital, admission to ICU, invasive ICU procedure, recovery, chronic health issues, death, and long-term complications. Here we will test how exposure to both chronic and acute air pollution impacts the degree to which and the rates at which patients transition between these states.

Methods: Exposures will be linked to health data obtained from administrative records and from Kaiser Permanente Southern California (KPSC). Associations will be studied between air pollution, COVID-19 death rates, and long-term morbidity using Poisson, change score, and multi-state models. Long-term Objectives: The results will contribute to evidence of the associations between air pollution and COVID-19 outcomes. These results may suggest that reduced air pollution standards are necessary to protect public health by reducing COVID-19 incidence, mortality, severity and new onset disease.