This article discusses the importance of heating, ventilation, and air conditioning (HVAC) systems in the context of the COVID-19 pandemic, and offers recommendations on how to improve their design to prevent the spread of the virus.

- HVAC systems can play a role in reducing the spread of SARS-CoV-2. - Indoor air quality monitoring systems can be used to detect and mitigate the spread of SARS-CoV-2. - Ultraviolet germicidal irradiation can be used to disinfect air. - Air filtration systems can be used to remove SARS-CoV-2 particles from the air. - Centralized air conditioning systems may increase the risk of SARS-CoV-2 transmission. - Improved air quality due to COVID-19 lockdowns may have positive health effects. - Proper ventilation and air flow can help reduce the spread of SARS-CoV-2. - Building operators should follow guidance from organizations like ASHRAE to reduce the risk of SARS-CoV-2 transmission.

This is from Process Saf Environ Prot. in 2021 at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8450051/.

Higher ventilation rates and lower indoor PM2.5 concentrations in elementary school classrooms are associated with reduced illness-related absences, highlighting the importance of indoor environmental quality for student health and attendance.

- Higher classroom ventilation rates significantly reduced illness-related absences. - Higher concentrations of indoor long-term monitored PM2.5 were significantly associated with increased illness-related absences. - Although mechanically ventilated classrooms had relatively low indoor PM2.5, more rigorous control of indoor particles was still beneficial. - Reduced absence rates are expected to provide socioeconomic benefits and benefits for academic achievements. - Higher ventilation rates and reduced particle levels will contribute to reduced health risks, including those related to airborne respiratory pathogens.

This is from ScienceDirect in 2023 at https://www.sciencedirect.com/science/article/pii/S0160412023002179

Proper ventilation, air filtration, germicidal ultraviolet lights and air quality monitoring are recommended for public spaces to prevent COVID-19 infections from spreading through inhaling fine aerosol particles that can hang in the air for hours, with little data favoring droplets or contact with contaminated surfaces as the primary way the virus is spread.

- Indoor air ought to be regulated for infection control, much like food and water are, air experts propose in the May 14 Science. - Cleansing the air is mostly a matter of proper ventilation and filtration. - Increasing ventilation in one room may carry infectious viruses into connected rooms through HVAC vents. - Experts recommend filtering air through materials that can trap airborne particles containing the virus. - Germicidal ultraviolet light may zap the virus and kill it in the air. - Not all UV lights are created equal, though.

This is from Science News in 2023 at https://www.sciencenews.org/article/coronavirus-covid-air-spread-indoor-clean-ventilation-filtration.

This article provides information for the general public on how proper ventilation and air conditioning can help prevent the spread of COVID-19 in homes, offices, schools, and airplanes.

- Ventilation is an important factor in preventing the spread of COVID-19. - Natural ventilation is preferred over mechanical ventilation. - Air conditioning can be used safely with proper maintenance and regular cleaning. - High-efficiency particulate air (HEPA) filters can be used to improve air quality. - When traveling on airplanes, wearing a mask and following recommended ventilation measures can reduce the risk of COVID-19 transmission.

This is from WHO in 2023 at https://www.who.int/news-room/questions-and-answers/item/coronavirus-disease-covid-19-ventilation-and-air-conditioning.

Air filtration, avoidance of recirculation of air, enhanced particle filtration by suitable air filters, and air disinfection can control COVID-19 infection transmission in indoor spaces, and the use of HEPA filters, UVC light, and natural ventilation are effective methods for reducing the spread of the virus.

- Effective ventilation, avoidance of recirculation of air, enhanced particle filtration by suitable air filters and air disinfection can control COVID-19 transmission. - Opening windows can increase natural ventilation and dilute indoor air, reducing infection spread. - Indoor air purifiers with high efficiency particulate air (HEPA) filters can filter contaminated indoor air, but must be replaced regularly. - Far-UVC light is recommended for single rooms without air conditioning, while a combination of HEPA filter and UVC light can reduce bacterial and virus load significantly in air-conditioned rooms. - The supply or outdoor air should be filtered by a filter and then mixed with the recirculated air and supplied to the room through the HEPA filters. - The ASHRAE recommends HVAC systems with a minimum efficiency of Minimum Efficiency Reporting Value-13 (MERV-13) to filter even very small particles.

This is from BMC Infectious Diseases in 2021 at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8234247/.

This article discusses the importance of building ventilation in reducing the risk of indoor transmission of COVID-19, and explains how airflows can affect the spread of the virus. The authors suggest that high levels of CO2 can be used as an indicator of the potential presence of the virus in the air, and that poor ventilation can contribute to the transmission of other airborne diseases as well.

- COVID-19 can spread through the air indoors. - Proper ventilation can help reduce the spread of COVID-19. - Heavy breathing, coughing, and talking can expel droplets that contain the virus. - These droplets can travel farther than 6 feet and can remain in the air for several minutes. - The risk of transmission is higher in poorly ventilated indoor spaces. - CO2 sensors can be used to monitor ventilation. - The WHO recommends increasing ventilation and avoiding recirculation of air in public spaces.

This is from Journal of Fluid Mechanics in 2020 at https://www.cambridge.org/core/journals/journal-of-fluid-mechanics/article/effects-of-ventilation-on-the-indoor-spread-of-covid19/CF272DAD7C27DC44F6A9393B0519CAE3.

Indoor air quality can have significant impacts on health, and there are various steps individuals can take to improve it, including increasing ventilation, controlling sources of pollutants, and using air purifiers or upgrading heating, ventilation, and air conditioning systems.

- Poor indoor air quality can contribute to health problems. - Fresh air from outside is better than no fresh air from outside. - Certain gases can be dangerous too, such as carbon monoxide and radon. - Consumer goods and cleaning supplies can release pollutants like formaldehyde, benzene, and other volatile organic compounds. - Smoking or burning a fire indoors introduces smoke. - Poor indoor air quality can have health consequences that range from irritation of the eyes, nose and throat to headaches and dizziness to asthma attacks. It's also linked to respiratory and heart disease. - There may be cognitive risks to breathing polluted air as well. - A portable air purifier can be a good way to clean the air if outdoor air quality is poor. - The spread of airborne germs is a serious issue indoors. - Ventilation, source control, and filtration can help improve indoor air quality. - Schools, health care facilities, and group residential or care facilities are in the best position to benefit from air quality improvements.

This is from NPR in 2023 at https://www.npr.org/sections/health-shots/2023/08/18/1194323903/air-quality-filter-purifier-indoor-pollution.

Improving ventilation in your home by bringing in fresh air, filtering the air, and improving air flow can help reduce virus particles and prevent the spread of COVID-19.

- Ventilate your home by getting fresh air into your home, filtering the air that is there, and improving air flow. - Good ventilation, along with other preventive actions, can help prevent you and others from getting and spreading COVID-19 and other respiratory viruses. - Here are some ways you can improve ventilation in your home: bring as much fresh air into your home as possible, filter the air in your home, consider using a portable air cleaner, turn on the exhaust fan in your bathroom and kitchen, use fans to improve air flow, and limit the number of visitors in your home and the time spent inside.

This is from CDC in 2023 at https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/Improving-Ventilation-Home.html.

Increasing ventilation and filtration in indoor spaces can help reduce the risk of airborne transmission of infectious agents, including SARS-CoV-2, and should be considered as a fundamental part of risk reduction strategies.

- Increasing air changes per hour and air filtration can help reduce the risk of airborne transmission of respiratory infectious diseases like SARS-CoV-2. - Higher ventilation and enhanced filtration are often overlooked but fundamental parts of risk reduction strategies that could have benefits beyond the current pandemic.

This is from JAMA in 2021 at https://jamanetwork.com/journals/jama/fullarticle/2779062.

This article explores different physical interventions that can be used to interrupt or reduce the spread of respiratory viruses, such as wearing masks, social distancing, and improving ventilation.

- Physical interventions can help reduce the spread of respiratory viruses. - Examples of physical interventions include wearing masks, social distancing, and hand hygiene. - These interventions can be effective in reducing the transmission of respiratory viruses in both community and healthcare settings. - It is important to use a combination of interventions to achieve the greatest impact.

This is from PMC in 2023 at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9885521/

Proper ventilation is an essential preventive measure to reduce COVID-19 transmission indoors, and the required ventilation rate depends on the type of activity, with mechanical or natural ventilation, recirculation, and intermittent exhaust as options to achieve adequate ventilation volume.

- Improving ventilation is an important measure to reduce COVID-19 transmission. - Mechanical or natural ventilation, recirculation, and intermittent exhaust are effective ways to improve ventilation. - Portable HEPA filters and ceiling-mounted HEPA-UV air filters are recommended for recirculation. - The minimum efficiency reporting value (MERV) of the filtration system should be targeted to 13 or more. - The Wells-Riley model can be used to estimate the maximum number of occupants or the maximum residence time allowed in a specific indoor space in advance. - Administrative controls can be used to limit the number of occupants or residence time when it is entirely impossible to improve the ventilation of the indoor space with engineering controls.

This is from Environmental Science and Pollution Research International in 2021 at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8363431/.

This systematic review examines the effectiveness of ultraviolet germicidal irradiation (UVGI), a feature that can be incorporated into heating, ventilation, and air conditioning (HVAC) systems, in reducing virus transmission. The research found that UV radiation is effective in inactivating viruses and reducing disease transmission; however, practical implementation of UVGI in HVAC systems needs to consider airflow patterns, air changes per hour, and device location. Further field studies could provide important information on system performance in real-world situations, particularly in the context of the current COVID-19 pandemic.

- Ultraviolet radiation can be effective in reducing the transmission of viruses in indoor spaces. - Upper-room UVGI disinfection systems can be optimized for ventilated rooms. - UV radiation can destroy influenza virus suspended in air. - UV air sterilization can reduce the incidence of respiratory infections in children's institutions. - UV irradiation of classrooms can reduce the spread of measles, mumps, and chickenpox.

This is from PLoS ONE in 2022 at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8992995/.

Proper ventilation with outside air can help reduce the concentration of airborne contaminants, including viruses, indoors, but it should be used in combination with other best practices recommended by the CDC to protect people from COVID-19.

- Increasing ventilation can help reduce the concentration of airborne contaminants, including viruses, indoors. - Proper ventilation also reduces surface contamination by removing some virus particles before they can fall out of the air and land on surfaces. - When used along with other best practices recommended by the Centers for Disease Control and Prevention (CDC) and others, increasing ventilation can be part of a plan to protect people indoors. - Improving ventilation benefits indoor air quality by reducing exposure to products used for cleaning and disinfecting potentially contaminated surfaces. - Improving ventilation will also help control other airborne infectious diseases.

This is from EPA in 2023 at https://www.epa.gov/coronavirus/ventilation-and-coronavirus-covid-19.

This article discusses the importance of proper ventilation in indoor spaces to prevent the spread of COVID-19, and analyzes the current regulations and guidelines in Europe and Spain regarding indoor air quality. It concludes that the current criteria established in applicable regulations are insufficient to ensure health and avoid contagion by aerosols indoors.

- Ventilation is crucial in reducing the risk of COVID-19 transmission in residential buildings. - Standard ventilation requirements may not be sufficient in the pandemic context. - Improving ventilation can reduce the concentration of aerosols and other pollutants in indoor air. - Indoor air quality can have a significant impact on human health and well-being. - Passive ventilation strategies can be effective in improving indoor air quality.

This is from Frontiers in Built Environment in 2021 at https://www.frontiersin.org/articles/10.3389/fbuil.2021.656718/full.

Proper ventilation, including increasing outdoor air delivery, filtration, and air cleaning, can help reduce the concentration of viral particles in indoor spaces and lower the risk of exposure to COVID-19.

- Indoor air movement and dilution of viral particles through mechanical or nonmechanical means can reduce the airborne viral concentrations and the overall viral exposure to occupants. - Ventilation system upgrades or improvements can increase the delivery of clean air and dilute potential contaminants. - Implementing multiple building-level mitigation strategies at the same time is consistent with CDC’s layered approach and will increase overall effectiveness of ventilation interventions. - Ventilation interventions can reduce the spread of disease, but they will not eliminate risk completely. - Improving air circulation and cleanliness can help reduce viral particle concentration. - Aim for 5 or more air changes per hour (ACH) of clean air to help reduce the number of germs in the air. - The ventilation interventions listed above come with a range of initial costs and operating costs.

This is from CDC in 2023 at https://www.cdc.gov/coronavirus/2019-ncov/community/ventilation.html.

Proper ventilation is a crucial component in reducing the transmission of COVID-19 and other airborne viruses, yet it is often overlooked in control measures, and there needs to be greater awareness and action taken to improve indoor air quality.

- Ventilation is a key measure to reduce the risk of transmission of COVID-19. - Ventilation reduces the concentration of airborne virus that can cause infection. - Vaccines are not effective in preventing transmission. - Wearing a mask reduces the risk of spreading and acquiring an infection. - Sufficient and effective ventilation in buildings is necessary to reduce the risk of transmission. - Ventilation airflow rates must be controlled by the number of occupants in the space and their activity. - The cost to society of prevention through better designed buildings and gradual improvement of ventilation in existing buildings is much lower than the cost of infections. - We need a national regulatory group for clean indoor air to establish protection against indoor air hazards in relevant Australian legislation.

This is from The Conversation in 2021 at https://theconversation.com/ventilation-reduces-the-risk-of-covid-so-why-are-we-still-ignoring-it-194820.