Washington: A study has found that air pollution is associated with a higher risk of developing severe disease, admission to a hospital or an intensive care unit (ICU) and death by COVID-19. The study was published in the journal, ‘Nature Communications’. The study was based on a large cohort of 4,660,502 adults resident in Catalonia in 2020, the year the Spanish autonomous community had a high incidence of COVID-19.
The researchers determined the mean annual levels of fine particulate matter (PM2.5, particles with an aerodynamic diameter of <=2.5 um), nitrogen dioxide (NO2), black carbon (BC) and ozone (O3) at the residential address of each participant. They also collected data on severe cases of COVID-19 in 2020, including the number of hospital and ICU admissions, length of hospital stay, and COVID-19-related deaths.
An analysis of this data revealed the following associations:
– An increase in exposure to PM2.5 of 3.2 ug/m3 was associated with a 19 per cent increase in hospital admissions.
– An increase in exposure to NO2 of 16.1 ug/m3 was associated with a 42 per cent increase in ICU admissions.
– An increase in exposure to BC of 0.7 ug/m3 was associated with a 6 per cent increase in mortality.
“Our findings add further compelling evidence on the importance of reducing levels of air pollution to improve the health of the population in general and, in particular, to reduce the incidence of severe acute respiratory infections,” concludes Otavio Ranzani, ISGlobal researcher and first author of the study.
Possible Explanations for the Association
There are several biological mechanisms that may explain why long-term exposure to air pollution increases the risk of severe COVID-19.
1. One hypothesis is that exposure to air pollution increases the individual’s risk of developing chronic comorbidities associated with severe COVID-19, such as hypertension.
2. Another hypothesis is that air pollution may facilitate the infection, as there is published evidence that exposure to fine particulate matter increases the expression of the receptors the SARS-CoV-2 virus binds to, particularly in the lung.
3. Exposure to air pollution has also been associated in another study with changes in the immune defences key to mitigating SARS-CoV-2, such as a decrease in the type II interferon response to SARS-CoV-2 and the antibody response.
Nonetheless, the study authors believe that more research is needed to gain a better understanding of the main biological pathways involved.
How the Study was Carried Out
The COVAIR-CAT cohort is based on data from the Catalan public health system covering primary care, emergency care and the discharge from hospitals of patients with acute conditions. It also includes data from a SARS-CoV-2 surveillance system (SUVEC), which gathered information on PCR and rapid antigen test results in cohort participants in Catalonia.
According to the data analysed in this study, 340,608 people were diagnosed with COVID-19 in Catalonia in 2020. Of these, 14 per cent (47,174) were admitted to a hospital and 1.4 per cent (4,699) to an intensive care unit. In total, taking into account inpatients and outpatients, 10,001 COVID-19-related deaths (3 per cent) were recorded.
The meteorological and air pollution data was obtained from the pertinent Catalan and Spanish monitoring networks. These data were cross-checked with the place of residence of the 4,660,502 people in the study cohort.
Study Strengths Cathryn Tonne, an ISGlobal researcher and final author of the study explains,
One of the strengths of our analysis is that the population is very well represented. The study covers both large urban conglomerations and rural areas and we were able to obtain detailed individual-level data on the participants’ exposure to ambient air pollution in a country heavily affected by the pandemic in 2020
While many studies have been published on the effects of short- and long-term exposure to air pollution on chronic respiratory diseases, there is less data available on the effects of long-term exposure on the incidence and severity of acute respiratory infections. Otavio Ranzani concludes,
Our study provides robust evidence that long-term exposure to ambient air pollution is associated with severe COVID-19
(This story has not been edited by NDTV staff and is published from a syndicated feed.)
NDTV – Dettol have been working towards a clean and healthy India since 2014 via the Banega Swachh India initiative, which is helmed by Campaign Ambassador Amitabh Bachchan. The campaign aims to highlight the inter-dependency of humans and the environment, and of humans on one another with the focus on One Health, One Planet, One Future – Leaving No One Behind. It stresses on the need to take care of, and consider, everyone’s health in India – especially vulnerable communities – the LGBTQ population, indigenous people, India’s different tribes, ethnic and linguistic minorities, people with disabilities, migrants, geographically remote populations, gender and sexual minorities. In wake of the current COVID-19 pandemic, the need for WASH (Water, Sanitation and Hygiene) is reaffirmed as handwashing is one of the ways to prevent Coronavirus infection and other diseases. The campaign will continue to raise awareness on the same along with focussing on the importance of nutrition and healthcare for women and children, fight malnutrition, mental wellbeing, self care, science and health, adolescent health & gender awareness. Along with the health of people, the campaign has realised the need to also take care of the health of the eco-system. Our environment is fragile due to human activity, which is not only over-exploiting available resources, but also generating immense pollution as a result of using and extracting those resources. The imbalance has also led to immense biodiversity loss that has caused one of the biggest threats to human survival – climate change. It has now been described as a “code red for humanity.” The campaign will continue to cover issues like air pollution, waste management, plastic ban, manual scavenging and sanitation workers and menstrual hygiene. Banega Swasth India will also be taking forward the dream of Swasth Bharat, the campaign feels that only a Swachh or clean India where toilets are used and open defecation free (ODF) status achieved as part of the Swachh Bharat Abhiyan launched by Prime Minister Narendra Modi in 2014, can eradicate diseases like diahorrea and the country can become a Swasth or healthy India.