Indoor air pollution is a common problem for every home and in some cases is two to five times worse than outdoors. This includes various indoor pollutants that can cause respiratory diseases. The quick spread of the highly infectious respiratory disease caused by COVID-19 raised concern about the efficient indoor ventilation and sanitation measures.
Our homes should protect the indoor environment to create a healthy indoor environment for the health and comfort of our family. The HVAC systems and other advanced technologies for air purification can help to clean the indoor environment from contagious microbial contaminants.
Indoor Air Pollution and Health Problems
Indoor air quality is one of the five major environmental risks to public health. Indoor air is important because most people spend a substantial time in buildings.
About 2 million deaths per year and 3 percent of the global disease burden are associated with indoor air pollution. These contaminants can cause various diseases such as chronic (allergies, asthma), respiratory infections, and even cancers.
Typical indoor air pollutants and allergens are biological contaminants, dust, volatile organic compounds, gases, fine particulate matter (PM2.5), etc. Common biological pollutants include mold, pollen, dust mites, pet dander, bacteria, and viruses.
Particles of 5 microns or smaller 5 can pass through the lungs and are harmful to your health. These are biological particles, dust, and gases. The smaller the particles, the more harmful they are. Therefore, particles of 2.5 microns are classified as respirable suspended particles and considered very hazardous.
How to Improve Indoor Air Quality?
ASHRAE has developed proactive guidance to prevent the spread of coronavirus pandemic (COVID-19) with respect to the operation and maintenance of heating, ventilating and air-conditioning (HVAC) systems.
ASHRAE recommends the following strategies to prevent disease transmission:
- dilution ventilation
- laminar and other in-room flow regimes
- differential room pressurization
- personalized ventilation
- source capture ventilation
- filtration (central or unitary),
- UVGI (upper room, in-room, and in the airstream).
ASHRAE’s Indoor Air Quality Guide is aimed to protect your home from exposure to airborne particles that might be circulated by HVAC systems.
You can improve the ventilation and filtering in your home with a ventilation and air conditioning system. Controlling airflow from clean to dirty areas to avoid the spread of polluted air around the house is critical.
HVAC systems are very important to maintain fresh indoor air quality. Many infectious particles are known to be transmitted by air. Therefore, proper ventilation can provide health and public safety.
The most efficient filters such as HEPA filters are able to remove up to 99.97 percent of particles as small as 0.3 microns. HEPA filters can remove dust, dust mites, pet dander, pollens, mold, some bacteria, and other common indoor allergens. Maintaining the relative humidity between 30 and 60 percent will help control mold and dust mites.
In crowded conditions with poor ventilation like in hospital waiting rooms and other public places, even particles with controversial airborne transmission capacity can cause explosive outbreaks.
For instance, the influenza virus can spread in a plane with poor ventilation. In some cases, the infection can be propagated at a significant distance away from the source by ventilation-induced airflows.
The Best Appliances Against Biological Contaminants
In addition to HVAC systems, the best technologies for anti-microbial protection against biological contaminants include:
- Antibacterial (Ultraviolet) Lamps can effectively destroy viral, bacterial, and fungal organisms such as Mycobacterium tuberculosis (TB), influenza viruses, mold, and other agents in air and surface, so they are unable to spread and cause disease.
- Whole House In-Duct Air Purifiers can help to eliminate indoor air pollutants of dust, dander, and pollen from your entire home.
- Whole-house air filtration systems with HEPA filters can trap 99.97 percent of dust, biological contaminants, and other common indoor allergens.
- Whole-house humidifiers and dehumidifiers to properly adjust the amount of moisture in your home.
- Energy Recovery Ventilators (ERVs) that exhaust the stale indoor air and bring in fresh, preconditioned air from the outdoors.
- Air ionizer removes particles as small as 0.01 microns as well as neutralize chemical fumes, cigarette smoke, viruses, and bacteria.
The proper HVAC system and appliances can improve the indoor air quality in your home and remove air-born pollutants including microbes.
How is Coronavirus Transmitted?
Airborne particles can be of various origins: viral (chickenpox, smallpox, measles, influenza), and bacterial (tuberculosis). Coronaviruses include seasonal and common cold viruses. Two more virulent coronaviruses caused epidemics: severe acute respiratory syndrome (SARS), in 2003 and Middle-East Respiratory Syndrome (MERS) in 2012.
It is known that coronavirus infection can be transmitted (1) through the air by large droplets as well as small particles in the air (droplet nuclei), (2) through a fecal-oral route and (3) by touching an infected surface.
The infected individuals produce infectious droplets of varying sizes by breathing, coughing or sneezing, transmitting them to others by both short-range large droplets and airborne small droplet nuclei, depending on the distance from them.
Aerosols are small droplets in the air, therefore called airborne agents with a diameter of < 10 μm. Airborn agents are highly contagious because of aerosols small size (< 5–10 μm) and their properties to follow air flows. The ‘intermediate particles’ of 10–20 μm will share some properties of both small and large droplets.
Personal Protection Against Air-born Agents
PPE for or aerosol-transmissible agents requires a better filtering capacity and a tight seal around the airways than for those that are only transmitted by large droplets or direct contact.
For personal protection against aerosol transmission of infectious agents the PPE such as N95 masks should be used, rather than surgical ones.
Surgical masks are effective as a physical barrier to large droplets (> 20 μm) as they are too large to be inhaled into the respiratory tract around the sides of the mask.
A recent study showed that under certain conditions, liquid droplets can travel more than 26 feet. CDC now recommends wearing non-surgical masks in public.
4 Simple Rules against COVID-19
Dr. Dave Price from Weill Cornel Medical Center in New York City suggests 4 simple rules to protect yourself from COVID-19 infection:
1. Keep your hands clean. Use a disinfectant or wash your hands every time you touch any surface.
2. Do not touch your face. People unknowingly touch their face about 90 times a day. Wearing a mask can help you stop touching your face.
3. You do not need a respirator. it’s required only for doctors when performing special procedures to sick patients.
4. Social distancing. Keep a distance of 6-6.5 feet (1.5-2 meters) from other people.
Knowing these simples rules can save you from unnecessary anxiety and help protect yourself and your family from this coronavirus disease.
Strengthen Your Immune System
Remember that there are about 40 trillion microbes including bacteria, viruses, fungi, and other microorganisms in the human body (so-called microbiome). Healthy people contain a broad range of viruses including pathogenic and potentially harmful such as papillomaviruses, hepatitis B, hepatitis, herpes, HIV and influenza viruses.
Our immune system is able to protect us from pathogenic viruses and even tumor cells that form in our bodies. Their effect on human health depends on the state of your immune system. Keep a healthy immune system by maintaining personal hygiene, a healthy diet, good sleep, and an active lifestyle. Add to your diet vitamins A, C, and D as well as minerals supplements including zinc.
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