COVID-19: A New Challenge for IEQ/IAQ
Dr. Rajiv R Sahay, FIAS, CIAQP
The term “COVID-19”, is an abbreviated term used for coronavirus disease(in this word ‘CO’ is corona, ‘VI’ for virus and ‘D’ refers to disease, often it is suffixed with ‘19’ because it was first reported in the year 2019). However, the World Health Organization previously referred to it as “2019 novel coronavirus”. The International Committee on Taxonomy of Viruses (ICTV) is the nomenclature agency for viruses. They name a virus based on their genetic/molecular structures and other biochemical characteristics. These details often facilitate the development of diagnostics tests, vaccines, and medicines. The World Heath Organization (WHO) plays a pivotal role in naming diseases through the International Classification of Diseases (ICD). Disease classification is an essential and integral part in the understanding of its prevention, spread, transmissibility, severity, preparedness, and response.
Coronaviruses and SARS CoV-2
Coronaviruses are a large family of viruses that are classified together due to its crown (Latin word for crown is corona) like appearance. The structure of this virus is spherical or pleomorphic in shape and contains a single-stranded Ribonucleic Acid (RNA- a biochemically active genetic material) associated with a nucleoprotein (molecule made from nucleic acid and protein) and a capsid. This bears club-shaped glycoprotein projections that make a crown shaped entity. This virus is reported in avian and mammalian species. It may be zoonotic, meaning it can be transmitted by animals. Usually, this family of viruses can cause mild to moderate respiratory illnesses that give symptoms of a common cold, including nasal obstruction, sneezing, runny nose, fever, loss of & smell, cough, occasionally or rarely gastrointestinal infection and neurological diseases besides others. The respiratory illness caused by coronaviruses is commonly known as severe acute respiratory syndrome (SARS). As per the US CDC, SARS was first reported in Asia in February 2003 and the illness spread to more than two dozen countries in Asia, Europe, North America, and South America before it became a global outbreak in 2003.
The WHO first learned of a new virus on December 31, 2019, following a report of a cluster of cases of ‘viral pneumonia’ in Wuhan, People’s Republic of China. Subsequently, it was declared as an outbreak of public health emergency of international concern on January 30, 2020 and a pandemic on March 11, 2020. Coronavirus Study Group (CSG) of the International Committee on Taxonomy of Viruses, names this novel pathogen 2019 novel coronavirus (2019-nCov). Now currently it is designated as the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). A paper published in July 2020, (Maciej et al., Nature Microbiology volume 5, pages 1408–1417) traced the origins of SARS-CoV-2. The researchers concluded that it came from a virus circulating in horseshoe bats.
Transmission of COVID-19
SARS-CoV-2 is primary transmitted through respiratory secretions and contaminated surfaces and air.
Contact and droplet transmission: When an infected person discharges respiratory secretions or respiratory droplets through coughs, sneezes, talking or singing, these secretions or droplets can transmit the virus through direct, indirect, or close contact of the contaminated nuclei or aerosols. As a matter of fact, the infectious viruses can reach the mouth, nose, or eyes of the persons who are exposed which can cause infection. Also, indirect contact transmission involving contact with a susceptible host with a contaminated object or surface (fomite transmission) where these contaminated particles are settled may be possible.
Airborne transmission: This mode of transmission refers to the infection caused by the dissemination of droplet nuclei that remain infectious when suspended in air over long distances and time. Airborne transmission of SARS CoV-2 is possible due to aerosolization of virus infested particulates. Although, nosocomial transmission is not commonly reported when contact and droplet precautions were appropriately used, including the wearing of medical masks as a component of the personal protective equipment (PPE), but some studies concluded that SARS-CoV-2 virus RNA remained in air samples within aerosols for up to 3 hours in one study (Fears et al. 2020: Emerg Infect Dis 2020;26(9)) and 16 hours in another (Chia et al. 2020: Nat Comm. 2020;11(1)), which also found viable replication-competent viruses under the laboratory conditions.
Fomite transmission: Infected individuals can contaminate surfaces and objects, creating fomites (contaminated surfaces) with their respiratory secretions or droplets expelled into the environment. The duration of the viability of these infectious droplets may vary from few hours to days depending on the ambient environmental conditions (temperature, relative humidity, etc.) and nature of the surface. Therefore, transmission may also occur indirectly through touching surfaces in the immediate environment or objects contaminated with viral particles from an infected person, followed by touching the mouth, nose, or eyes.
Other modes of transmission: Infection of SARS CoV-2 may be acquired through urine and feces of infected person. Some other studies suggest that since this virus can multiply in plasma or serum, therefore blood borne transmission may also be possible. Even though viral RNA fragments have been found by RT-PCR testing in a few breast milk samples of mothers infected with SARS-CoV-2, viable virus was not able to be isolated. There is no evidence for intrauterine transmission from infected pregnant women to their fetus, although data remains limited. Current evidence suggests that humans infected with SARS-CoV-2 can infect other mammals, including dogs, cats, and farmed mink. However, it remains unclear if these infected mammals pose a significant risk for transmission to humans, though evidence to date shows that SARS-CoV-2 is most closely related to known betacoronaviruses in bats; the role of an intermediate host in facilitating transmission in the earliest known human cases remains unclear.
COVID-19 and Indoor Air/Environment Quality
People spend approximately 90% time indoors. In the ongoing situation of COVID-19 pandemic stay-at-home orders, remote working/learning and other activities have become the new normal worldwide, which only increases the attention on indoor air/environment quality (IAQ/IEQ). The health and hygiene of an occupied space has been linked with IAQ/IEQ. The management of IAQ/IEQ greatly depends on regular maintenance, opening and closing of windows & doors, Heating Ventilation Air Conditioning (HVAC) systems as well as other attributes of the closed/built environments. A number of a-biogenic and biogenic mass such respirable particulates (PM2.5, PM5, PM10, etc.), VOC’s (volatile organic compounds), fibers (asbestos, cellulose, fiberglass, plant trichomes/fiber and other manmade synthetic fibers, etc.), viruses, bacteria, actinomycetes, fungi/mold, myxomycetes, algal filaments, bryophytic/moss spores, pollen grains, protozoa, cysts, insect or insect bio-detritus, human skin cells, dust mites, indoor allergens beside other particulates of organic or inorganic in nature can influence the indoor living. A lack or absence of information of SARS-CoV-2 in IEQ/IAQ context can jeopardize public health and well-being. Current evidence suggests that transmission of SARS-CoV-2 primarily between people occurs through direct, indirect, or close contact with infected people through their respiratory droplets, which are expelled when an infected person coughs, sneezes, talks or sings. It has been also noticed that even an infected person may never develop symptoms, but they can pass the virus to others. As discussed earlier the spread of COVID-19 from person to person is mainly through contaminated surfaces and air. The typical incubation period for COVID-19 is up to 14 days from the time of exposure, with a median incubation period of 4 to 5 days. During this critical period, the building can be tested to minimize the risk of exposure to others. Also, the transmission chain can be broken by ascertaining the presence of SARS-CoV-2 in and around the building of your workplace or dwelling by undertaking a corrective action. A few simple tests including RT-qPCR on environmental samples (surface/air) collected from frequently touched or high traffic areas within a building can be helpful in the mitigation of COVID-19 risk.
Current Status of COVID-19
The COVID-19 weekly epidemiological update from WHO published on December 7, 2020 reveals that there have been over 65.8 million cases and over 1.5 million deaths reported since the start of the pandemic. In the past week, the five countries reporting the highest number of cases were the United States of America (reporting over 1.2 million cases, a 9% increase from the previous week), Brazil (over 295,000 new cases, a 35% increase), India (over 251,000 cases, a 15% decrease), Russian Federation (over 191,000 new cases, a 6% increase) and Italy (over 145,000 new cases, a 21% decrease).
A worldwide list of countries and territories has been compiled and linked below to present the status of COVID-19 since the first case was reported from those regions.
Environmental Management of COVID-19
The Infectious Diseases Society of America Guideline on Treatment and Management of Patients with COVID-19 was published on April 11, 2020 and last updated on December 2, 2020. The WHO has also published an interim guidance on May 27, 2020 for clinical management of COVID-19. The COVID-19 vaccines are soon going to be a reality, but even after that, it is hard to control the disease spreads and several imminent challenges are pertinent for a yet unknown period. A proper environmental management of SARS-CoV-2 is helpful in stopping the spread of COVID-19 through environment. A multifold approach like engineering controls, administrative controls, and utilization of personal protective equipment (PPE), besides other precautionary steps are an important and integral part in combating this pandemic. PPE has become an integral part of the defense mechanism to prevent the exposure of SARS-CoV-2 in healthcare workers. PPE includes at a minimum a pair of goggles or disposable full-face shield, N95 filtering face piece respirator (NIOSH-approved), gown, open pairs of clean, non-sterile gloves. Enhanced personal hygiene such as frequently washing hands with soap and water, use of hand sanitizer, wearing a mask, avoiding touching the face after touching fomites, maintaining social distancing, self isolation, etc. are some good and common beneficial practices in fighting this COVID-19 episode.
Some good examples of engineering control for managing COVID-19 in an indoor environment includes increased ventilation, use of HVAC system with good filtration for air conveyance system in houses or buildings, use of air purifier devices or cleaners to minimize the risk of viral spread within closed environments. Evaporative coolers are also helpful in enhancing the ventilation and thus controlling the coronavirus within an indoor space. Filtration UVGI (Ultraviolet Germicidal Irradiation), bipolar ionization and use of HEPA are some good practices recommended by various agencies though out the world to minimize the COVID-19 impact. Periodical indoor environmental or air quality assessment including SARS-CoV-2 tests on environmental matrices is of high importance during this challenging time to enhance the environmental health and hygiene or air quality and minimize the risk of COVID-19. The management healthcare and bio-genic waste is also crucial in reducing the transmission of these pathogenic agents.
Dr. Rajiv R Sahay, FIAS, CIAQP
Environmental Diagnostics Laboratory at Pure Air Control Services, Inc.
4911-C, Creekside Drive, Clearwater, Fl 33760
1-800-422-7872 ext. 304