The initiative, which will involve the collaboration of international specialists, will elucidate whether atmospheric particulate matter, such as PM2.5, can be a vehicle for the spread of SARS-CoV-2 and its relationship with the increase in mortality due to COVID-19. Currently, there is sufficient evidence and scientific consensus to affirm that airborne pollutants can penetrate the cardio-respiratory system and generate serious acute and chronic diseases, including premature death and cancer, respectively. According to studies issued by the World Health Organization (WHO) last 2019, nine out of ten people worldwide breathe polluted air daily, this situation being one of the major global concerns in the midst of the climate crisis. In the national context, the figures are no more encouraging. According to analysis of the Ministry of Environment, in Chile about 4,000 people die every year due to exposure to air pollution, with significant differences in cases of mortality and morbidity in people according to their socioeconomic, geographic and demographic situation. Given this background, it is urgent to know the progress of research on the characteristics of SARS-CoV-2, a virus that causes the disease COVID-19, which to date reports more than 4,000 infected people in the country, increasing daily. The highest incidence rates (number of cases per 100,000 inhabitants) for COVID-19 are located in the regions of Magallanes, Ñuble and La Araucanía. To learn more about the behavior of this new coronavirus in conditions of atmospheric contamination, scientists Francisco Cereceda, expert in atmospheric chemistry, director of the Center for Environmental Technologies (CETAM) and academic of the Universidad Técnica Federico Santa María (USM), together with Michael Seeger, also an academic of the USM, Director of the GAMBIO Ring and specialist in environmental microbiology; and Luis Alonso Díaz, an academic from the University of Santiago de Chile (USACH), an expert in air quality modeling and health risk assessment, will lead an air pollution monitoring campaign in collaboration with international specialists to determine whether atmospheric particulate matter -such as PM2.5- can be a vehicle for the spread of SARS-CoV-2 and its relationship with the increase in mortality due to COVID-19. With this concern, the experts point out that, although the WHO confirmed that the virus is not transmitted through the air but by direct contact with an infected person -who can expel particles (droplets) of between 5 to 10 micrometers and thus infect another person within a range of less than one meter away-, the specialists argue that these droplets are not transmitted by air but by direct contact with an infected person, specialists argue that these droplets could reach much smaller sizes and behave as aerosols, with sizes similar to ultrafine particles, and could be part of the fine particulate matter in polluted air, functioning as a carrier vehicle for many pollutants, including viruses such as SARS-CoV-2. “If we consider the virus as ultrafine particles, which in the case of SARS-CoV-2 it is indeed, with a diameter of 0.12 to 0.16 µm, it could behave like any other ultrafine particle, that is, it follows the laws of physics in terms of its movement and distribution in the air”, describes Francisco Cereceda, who will expand on these conclusions in an academic publication soon to be published.
Dr. Cereceda, how will the atmospheric contamination produced in the central-southern zone of Chile during the winter season affect the population, with the spread of the coronavirus? Could it have an impact by increasing the contagion curve? -Today we can affirm that air pollutants cause the death of more than 7 million people prematurely every year due to diseases such as cancer, stroke, heart and lung diseases. Poor air quality conditions stimulate the appearance and exacerbation of cardio-respiratory diseases, which are aggravated by the appearance of outbreaks of seasonal and cyclical infectious diseases such as influenza, syncytial virus, adenovirus and nowadays most probably the same with SARS-CoV-2. According to this logic -argues Cereceda- with winter conditions of low temperatures and the existence of particulate matter in the polluted air, “the virus would find a more propitious environment to prolong its half-life and propagation. “In addition, social isolation measures will cause people to stay much longer in closed places with poor ventilation and even greater need for heating. Added to this situation is the fact that the heating equipment used by Chilean families in the center-south zone of the country is often not the most adequate, which added to an evident economic problem in the making, will produce a natural tendency to use cheaper fuels such as kerosene and firewood, fuels that precisely generate an abundance of PUF and the toxic pollutants mentioned above”. Due to these conditions, the director of Centro de Tecnologías Ambientales affirmed that we are in front of an “explosive cocktail”, which could favor the duration and the use of the most pollutant pollutants. which could favor the duration and entry of the virus into our organism, generating a more negative scenario than the one that has been estimated, especially if the peak of the curve coincides with the air pollution problems in the coming months. “This takes on greater relevance in the cities of southern Chile, where the poor combustion of firewood is already an endemic problem and where there are a series of decontamination plans underway, which the government will most likely have to accelerate to try to minimize the aforementioned effects”, he adds. In the same line of argument, the specialist in environmental microbiology, Michael Seeger, reiterates that this emerging pathogen (SARS-CoV-2) is a highly contagious virus among humans and emphasizes that in only two months, SARS-CoV-2 has infected a greater number of people than SARS-COV (China, 2003) for many months. This relationship is particularly important because “one must consider that SARS (2003) mortality doubled in those places in China that had poor air quality relative to clean air areas, which increased by 84% in those places of moderate air quality relative to those of clean air.” “Atmospheric particles act as a carrier vehicle for many chemical and biological pollutants, including viruses,” says air quality modeling and health risk assessment expert Luis Alonso Díaz.
“In addition to being a carrier, atmospheric particulate matter constitutes a substrate that can allow the virus to remain in the air under vital conditions for a certain period of time, in the order of hours to days. There is scientific research that indicates that the inactivation rate of viruses in atmospheric particles depends on environmental conditions such as an increase in temperatures and solar radiation that favors this inactivation rate, but high relative humidity can favor a higher virus diffusion rate”, says Díaz. What no one disputes today, both in the medical, scientific and political areas, is that the best prevention is social isolation measures such as preventive quarantines, since they allow controlling the rate of contagion and additionally reducing contamination levels. “It is true,” says Cereceda. “We have seen in Asia, Europe and now in America, these actions as a strategy to minimize the impacts of the virus. Collaterally, we have observed a localized improvement in air quality and in emissions of greenhouse gases such as CO2, an aspect that clearly illustrates the importance of anthropogenic activities on air quality, which are concentrated in the large cities of our planet. For example, Chin showed a 25% reduction in carbon emissions, and in general the measures to contain the coronavirus involved reductions of between 15% and 40% of production in key industrial sectors in this country. A 25% reduction in China’s emissions is equivalent to a 6% reduction in global air pollutant emissions (analysis by Carbon Brief). Michael Seeger adds that social isolation is key, as we know, to slowing down the distribution of the coronavirus in the population. “This method was used in the Wuhan region of China where the virus emerged, which made it possible to control the spread of the coronavirus in that region. Countries such as Italy and Spain and the cities of New York and Guayaquil, applied this quarantine measure only when the coronavirus had infected a large number of people, which explains the explosive growth of infected people and then of deaths in these regions. -Dr. Cereceda, if social isolation measures have been effective in controlling contagion where they have been applied in a timely manner and, in addition, contamination is reduced, why should we not expect similar results in Chile? -In Spain, France or China, this can be considered good news, especially because in these countries they are coming out of winter and entering spring. However, in Chile it is just the opposite, we are transitioning to a winter condition, where poor ventilation conditions are exacerbated, generating poor air quality and therefore a negative impact on the health of the population. Recent data observed in the cities where this phenomenon has occurred -he explains- show that these effects are not long-lasting, that is to say, they have a fairly rapid dynamic.
“Once the city’s activity is reactivated again, the air quality worsens again. We must not forget that, with quarantine, we not only move pollution into homes from the point of view of outdoor pollution, associated with heating and cooking systems, but we also install it inside homes, associated precisely with the same sources mentioned above”. According to this expert, homes act as real pollutant concentration systems. “In addition to the external pollutants, there are the so-called “intramural” pollutants associated with food preparation processes (frying, roasting, toasting, etc.), aerosols generated by cleaning and disinfection products, VOCs and COSVs, as well as the pollutants that are produced in the home; VOCs and COSVs emitted by construction materials (paints, varnishes, carpets, thermal insulation and house coverings), electronic equipment (printers, computers, televisions, household appliances), aerosol air fresheners and aromatizers, among many other typical household products. Whether these pollutants will act synergistically or antagonistically with the virus will have to be studied.” The European Federation of European Heating, Ventilation and Air Conditioning Associations recently issued formal guidance to buildings to prevent transmission of the virus. Increasing airflow and ventilation is a key part of their advice. This aspect will be essential in the case of our country, since in a winter condition normally ventilation rates in houses ostensibly decrease due to the reasonable intention of people to maintain thermal insulation conditions and save on heating. Under these conditions, the spread and greater impact of the SARS-CoV-2 coronavirus would be favored. Unfortunately -he adds- “in cities polluted with wood smoke, the level of indoor air quality is quite high, in some places even worse than atmospheric air. This level of chronic exposure to these high levels of ambient and intramural air pollution for more than 20 years, causes the inhabitants of these cities to have a weaker immune system, with significant cardio-respiratory diseases, which make them more vulnerable to infectious diseases, such as influenza, bronchitis, pneumonia and now COVID-19.” “Indeed, when analyzing the incidence rate by COVID-19 as of April 04, 2020, we can observe that one of the highest is the one occurring in the region of La Araucanía, with a rate of 47 cases per 100,000 inhabitants, almost doubling that of the RM of Santiago, which has a rate of 24.1. But at the same date, the number of fatalities in La Araucanía due to COVID-19 (9 cases) equals those of the Metropolitan Region. Unfortunately, the Araucanía region, in addition to having highly contaminated areas, is one of the regions with the highest rates of poverty and low human development, generating serious disadvantages to face this SARS-CoV-2 pandemic”. In 2015, Diaz and other scientists published a study that found that the risk of cardio-respiratory mortality and morbidity due to acute exposure to air pollution was much higher in Temuco than in Santiago.
“The excess risk was greater in Temuco than in Pudahuel, both for cardio-respiratory mortality in the elderly population (47%) and for hospital admissions for COPD (104.1%). These results show that there is a greater risk when people are exposed to air polluted with wood smoke. One of the reasons is that wood smoke has potent and abundant toxic compounds, such as Polycyclic Aromatic Hydrocarbons, aldehydes and ketones, etc., which weaken the human immune system and irritate the respiratory tract, in addition to the fact that the greatest number of particles from residential wood combustion emissions are smaller than 0.5 µm (size in the order of magnitude of SARS-CoV-2), entering more deeply into the respiratory and cardiovascular system”, he synthesizes. Internationally, Diaz adds, air pollution has been found to exacerbate severe cases of viral attacks, such as SARS. “In 2003, a scientific study was published that showed that the risk of mortality from SARS doubled in those areas of China that had bad air compared to good air quality, and increased by 84% when the air quality was moderate compared to clean air. This evidence allows us to suppose that those cities in Chile with high air pollution could have a greater impact from severe cases of COVID-19 this autumn-winter, especially in the cities of central-southern Chile.” Due to the delicate situation in the south-central zone of the country, the scientists together with their respective teams of researchers are coordinating an aerosol monitoring campaign for this winter. The monitoring -explains Cereceda- “will focus on the collection of atmospheric aerosol samples from the air of cities such as Santiago or Temuco, in order to obtain PM2.5 atmospheric particulate matter collected in filters that allow at the same time a chemical speciation of PM2.5 and at the same time evaluate the microbial community that has accumulated in the same filters, that is, that which has been transported by the aerosols, which has been used as a vehicle for the propagation of these infectious microorganisms”. “The SARS-CoV-2 coronavirus has a fairly large diameter, in the order of 0.12-0.16 um, so it can be trapped in the PM2.5 collected in the filters mentioned above. The idea then is to be able to analyze the microbial community and analyze the correlations that could exist between the presence of the SARS-CoV-2 coronavirus and the atmospheric pollutants present in the PM2.5 particulate matter”, says the expert in atmospheric chemistry of the Federico Santa María University. Luis Alonso Díaz adds that “the air quality monitoring data can be correlated with severe cases of COVID-19 with epidemiological models, with the objective of determining the level of risk due to acute exposure to particulate matter concentrations in different areas of Chile. These risk levels could be very useful in advanced air quality modeling platforms that allow generating information for better decision making by the authority and to help generate better public policies in health and environmental matters”.
