Low Air Pollution Levels Linked To Longer Hospital Stays For Covid-19 Patients

A recent study found that exposure to low levels of air pollutants like nitrogen dioxide and black carbon could result in hospitalized Covid-19 patients spending four extra days in the hospital. The study was published in the European Respiratory Journal this month.

The study further proves that during multiple Covid-19 waves since the last three years when hospitals were overwhelmed with patients, air pollution was a major contributing factor to the crushing burden on health care systems globally.

“These results show how air pollution can compromise our immune system and leave us vulnerable to Covid-19 and other respiratory infections,” one of the study’s authors, Zorana Jovanovic Andersen from the University of Copenhagen, Denmark said in a press release.

“Reduction of air pollution should be in the heart of preventive measures for current and future pandemics, as well as a strategy for dealing with seasonal influenza pandemics. Cleaner air would make populations more resilient to respiratory infections, seasonal epidemics, and major pandemics in future,” Andersen added.

The researchers included 328 hospitalized patients in Belgium who tested positive for Covid-19 from May 2020 to March 2021. None of them were vaccinated while the study was being conducted. Their average age was 65.7 years. More than half of them were diagnosed with congestive heart failure. They simultaneously analyzed air pollution levels during that period and particularly focused on air pollutants like black carbon, fine particulate matter (PM2.5), and nitrogen dioxide. The team could access data from the Danish National Covid-19 Surveillance System. They took each patient’s blood samples to measure how much black carbon had infiltrated their bodies. They observed that patients who had black carbon or soot in their blood were at a 36% higher risk of ending up in the ICU than those who were not exposed to the air pollutant. Black carbon is also known to cause lung disease.

The average duration of the participants’ hospitalization was close to 17 days. They observed that men spent longer durations in the hospital (close to four days more) than women. Fine particles and nitrogen dioxide contributed the most to Covid-19 patients staying in the hospital for four days longer. “Inhalation of elevated concentrations of air pollutants results in inflammation processes of mucus membranes in the pulmonary tract and is a factor that could influence the process of SARS-cov-2-infection,” the researchers explained.

“Our findings show that exposure to air pollutants both recent and long-term exposures at relatively low levels has a significant impact on disease severity and progression for COVID-19 patients. The public health and clinical significance of our findings should not be understated,” they added. “Based on our observed effects of air pollution exposure on hospitalisation duration, it is clear that for relevant improvements in air quality, even at relatively low concentrations, health gains are in the order of 40 to 80% of the aforementioned proven novel therapies. These findings reinforce the existing call for action to reduce air pollution levels in order to limit the burden of COVID-19 and improve respiratory health worldwide.”