Impact of air pollution on morbidity and mortality from COVID-19

Air pollution increases the risk of various chronic diseases, including diseases of the cardiovascular system and lungs, and this leads to a more severe course of the new coronavirus infection. These health conditions significantly increase the risk of hospitalizations and death for COVID-19 patients. This means that millions of people who have already suffered from chronic illnesses from exposure to air pollution are more vulnerable to this illness.

Air pollution weakens the immune system and makes it harder for the body to defend itself against viruses.

Undoubtedly, the frequency of contacts between people primarily affects the spread of the incidence of COVID-19, which was confirmed by the effectiveness of lockdowns. At the same time, environmental factors were not taken into account, which also contribute to the preservation of viruses in the surrounding air and their transfer over much greater distances than 1.5 meters of social distance.

Respiratory infections result from the transmission of the virus in droplets of moisture (particle size 5 to 10 μm) and aerosols (particle size ≤ 5 μm) excreted by infected persons during breathing, talking, coughing and sneezing. Aerosols can accumulate remain infectious in the air for several hours and easily penetrate deep into the lungs when inhaled.

Drops of exhaled moisture are deposited by gravity faster than they evaporate, contaminating surfaces and leading to contact transmission of the pathogen.

Smaller aerosols (≤ 5 μm) evaporate faster than they settle, and when suspended in air can be exposed to air currents and transported over long distances. Dust in the air interacts with aerosol, and the heterogeneity of its structure slows down the evaporation of the moist membrane of viral particles. Airborne dust transmission occurs when we inhale viruses or bacteria on dust particles that can remain in the air for several hours.

Thus, there are two main mechanisms of transmission of the respiratory virus: airborne droplets and airborne dust.

This project is being implemented to determine the dependences of the regional morbidity of COVID-19 on the factors of ambient air quality in the region and the possible impact on the morbidity and course of the disease.

In January - April 2021, our team conducted a series of studies aimed at assessing the impact of airborne dust pollution PM10 on morbidity and mortality from COVID-19 in Spain.

Average monthly PM10 concentrations and morbidity of COVID-19 are shown in Figures 1-4.

Fig.1

Fig.2

Fig.3

Fig.4

For the analysis, there were selected the provinces in which, according to the results from January to April 2021, there were recorded the largest number of deaths from COVID-19.

Evaluating the dynamics of morbidity in 10 selected provinces, there was established uniformity of growth and decrease in morbidity. Fig.5

Such a development in the incidence indicates a significant influence of factors common to all provinces, for example, the seasonal development of colds and weakening of the immune system.

Fig.5

The behavior of data on changes in the number of deaths is reflected in dynamics similar to morbidity. Fig.6

Fig.6

Considering the mortality rate as a percentage of deaths to the number of COVID-19 cases demonstrates a different behavior. We can observe that the survival rate of COVID-19 patients was higher in January and April and worse in February and March in all provinces. Fig.7.

Fig.7

Assessing the effect of air pollution on the condition of patients with COVID-19, we estimated the average monthly concentration of air pollution of PM10 in the studied provinces. Fig.8.

Fig.8

Comparing the last two graphs, we can see that they demonstrate the uniformity and direct dependence of the mortality rate on the concentration of PM10.

To assess the level of such interaction, we plotted a graph in Fig. 9 with a regression line, which confirmed the positive trend of an increase in the mortality rate of patients with COVID-19 from the level of concentration of air pollution PM10.

Fig.9

This assessment is preliminary and requires the continuation of the project to obtain more reliable data, take into account the influence of other factors and form reliable models to predict the spread of viral diseases like COVID-19.

ASMProjects / Data source Spanish Ministry of Health

Impact of air pollution on morbidity and mortality from COVID-19

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