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It is our goal to provide as much information as possible 

Rest assured that the safety and well-being of our students and staff is the top priority for the Office of Facilities Management (OFM). We continue to work diligently to ensure our facilities are healthy places to learn and work.

If, after reading the answers to the frequently asked questions below, school administrators still believe that additional air purifiers should be installed in their school to supplement their HVAC systems, they may use this Google Form to make a request. To ask a question that isn't addressed here or to get assistance with completing the request form, please call 240-740-2338. 

Please note that this web page contains links to pages that are outside MCPS. MCPS does not control the content or relevancy of those pages.





How are schools being cleaned and disinfected to protect students and staff from COVID-19?

To help reduce the spread of germs, our building service staff regularly clean and disinfect all high-touch areas in Montgomery County Public Schools (MCPS) facilities using EPA-approved List N chemicals. Special attention is given to door handles, light switches, sink handles, and other surfaces that are touched frequently. Restrooms in common areas are cleaned and disinfected more frequently throughout the day.

Click here to view the general tasks that our building service staff members perform on a daily basis.

What are the cleaning procedures for my school?

  • Building service staff are cleaning and disinfecting building and room surfaces in all MCPS schools and facilities using EPA-approved List N chemicals that are effective for inactivating the COVID-19 virus. Click here to view the Safety Data Sheets for all of the products approved for use in our schools.
  • Special attention is given to surfaces that are touched frequently, such as door handles, light switches, handrails, faucet handles, water bottle filling stations, and elevator buttons.
  • Restrooms in common areas are also cleaned and disinfected more frequently throughout the day.
  • To assist in ensuring clean and healthy buildings, all MCPS employees are provided with cleaning and disinfecting products that they may use for their classrooms and workstations. 
  • Your building service manager can provide specifics about scheduled cleaning activities and the specific cleaning products being used in your facility.

Will building services clean and disinfect my classroom during the school day?

No. For the safety and well-being of students and staff, building service staff do not enter instructional spaces during the school day unless an incident has occurred that requires their special attention. Building services will not clean/disinfect classrooms between class periods or during student lunch breaks.

Will building services clean and disinfect Chromebooks?

No. Building service staff do not provide this level of detailed cleaning and disinfection. Teaching staff need to care for the tools used for instruction in their own classrooms and their own personal workspaces.

How should I prepare my classroom or workspace to be cleaned and disinfected?

As the last step in the daily disinfection process, building service staff will use chemical cleaners that you wouldn't necessarily want to have sprayed near certain items. For example, any items you would keep in your kitchen cabinets at home (coffee cups, eating utensils, water bottles, etc.) should be put away. Medical supplies kept in health rooms (cotton balls, Q-tips, tongue depressors, etc.) should be safely stored as a general practice.

Should I be worried about the toxicity of the chemicals being used by building service staff?

No. MCPS remains committed to maintaining a safe and healthy environment for all. This has been (and continues to be) accomplished by using cleaning products that reduce the adverse impacts on public health and the environment. Third-party organizations such as Green Seal have evaluated and certified all cleaning supplies. Internally-developed criteria and standards include the following: 

  • Products equipped with dispensing/portion-control systems, 
  • Non-caustic chemicals that prevent exposure, allergic reactions, and splatter accidents, and 
  • Products with reduced effluent wastewater contaminants like corrosives, heavy metals, and phosphates.

The chemical product review process includes an evaluation of product literature that provides safety and health information, recommended PPE for users (those who are typically most highly exposed to the products), and precautions related to using the chemical in school and office environments, and recommended product use and storage procedures. Additional information about product selection can be found in our Green Cleaning Brochure.

I've heard that MCPS has "sanitizing machines." How do these work?

The electrostatic sprayers used by building service staff apply a positive charge to liquid disinfectants as the liquid passes through the nozzle. The positively charged disinfectant is attracted to negatively charged surfaces. This allows the chemicals to coat hard, non-porous surfaces efficiently. In a nutshell, these units spray a super fine mist that coats all hard surfaces. Building services will use electrostatic sprayers to disinfect hard surfaces like desks, chairs, doors, etc. Building services will continue their practice of only cleaning and disinfecting rooms that are not occupied. This means the electrostatic sprayers cannot be used while students or staff are in the room. For safety reasons, anyone with a pacemaker or defibrillator must not use the electrostatic sprayer or stand close to anyone using it. Only trained building service personnel are allowed to operate the electrostatic sprayers.

Will the chemicals used in the electrostatic sprayer ruin the books in my library?

The nozzles of our electrostatic sprayers are set to 110 microns. This setting produces a very fine mist that dries quickly. To put that size droplet into perspective, a strand of human hair is approximately 100 microns thick. When using the electrostatic sprayer, building service staff will point it toward hard surfaces such as doors, chairs, desks, restroom stalls, walls, and sinks. They will not spray chemicals directly onto paper, cloth, or other soft, porous surfaces. However, if you prefer that the hard surfaces in your space not be disinfected, please post a sign on the door.



What is MCPS doing to improve air ventilation in response to the coronavirus?

As part of our return-to-school action plan, OFM has taken the following steps to improve ventilation and ensure the health and safety of students and staff:

  1. Assessed all existing systems and equipment and categorized schools by risk mitigation approach,
  2. Scheduled the replacement of all HVAC filters, upgrading them to the highest MERV efficiency possible for improved air filtration,
  3. Increased fresh air ventilation in buildings,
  4. Purchased portable air cleaners for installation in identified classrooms, multi-occupant offices, health rooms, and areas that will be used as isolation rooms for those experiencing symptoms while at school, and
  5. Modified HVAC system operations to include an extended run time that will allow the air in buildings to be "flushed" before and after the facility is occupied.

What sources of information is MCPS using to make decisions about indoor air quality (IAQ)?

Throughout the pandemic, MCPS relied on the expert recommendations of government and public health organizations to help guide our actions. The American Society of Heating, Refrigeration and Air-Conditioning Engineers (ASHRAE), the Centers for Disease Control and Prevention (CDC), and the U.S. Environmental Protection Agency (EPA) continue to be our primary resources for information and guidance during the COVID-19 pandemic.

In 2020, ASHRAE published a position document that discussed various approaches for mitigating airborne transmission of infectious aerosols. MCPS is following ASHRAE's suggestion that the following modifications be considered for HVAC systems in non-healthcare facilities:

  1. Increase ventilation,
  2. Improve central air and other HVAC filtration to MERV-13 or the highest level achievable, and
  3. Add portable air cleaners with HEPA or high-MERV filters with due consideration to the clean air delivery rate. 

What is MCPS doing to address the question of IAQ?


As suggested by experts in the field, increased outdoor ventilation and increased filter efficiency are the primary goals that guide our process for maintaining optimum air quality. Our facilities represent four primary scenarios with regard to our HVAC systems, and schools have been categorized as follows:

⧫⧫⧫⧫ = Schools with enhanced ventilation systems that require minimal modifications (filter upgrades and control adjustments are all that is needed)

⧫⧫⧫ = Schools with recently replaced systems that have enhanced ventilation (limited spaces require air cleaners)

⧫⧫ = Schools with older systems that can be modified (air cleaners are required to meet new COVID-19 IAQ requirements)

 = Schools with systems that require more extensive mechanical attention as well as air cleaners

While students have been learning remotely, our maintenance and operations teams have visited every school to assess HVAC systems and the air filters in use. Staff are involved in a continuous process of cleaning in and around HVAC units, washing reusable filters, and replacing filters with the highest MERV-rated filters the system can accommodate. Units are checked each day to ensure that they are operating properly; repairs are made as needed. Air purifiers are being installed in the facilities that require supplemental support. 

Click here to view the real-time status of our upgraded filter/air cleaner installation project.

I've been hearing the term "MERV filters." What does that mean?

The Minimum Efficiency Reporting Value (MERV) is a rating scale developed by ASHRAE. MERV ratings indicate the percentage and sizes of particles that air filters can remove from the air as it passes through the filter. Filters with higher MERV ratings are able to remove higher percentages of particles and more effectively remove small particles than those with lower MERV ratings. 

I'm concerned about IAQ. Can I get an air quality report for my classroom?

We have performed the work necessary to meet ASHRAE guidelines as they relate to the indoor environments within our schools. Our facility information is technical in nature and has long been considered to be confidential as it provides details of our school buildings. In the era of heightened school security, these building plans and engineering details are not published on pubic domain. Therefore, we will not provide technical details relating to maintenance logs, equipment data sheets, building plans, commissioning reports, or other related technical information.

It is important to note that indoor air quality (IAQ) testing and reporting relates to topics such as mold, radon, indoor pollutants, and overall temperature and humidity controls. The focus of our IAQ program is on continual testing and reporting for items such as radon, lead, and asbestos, but also focusing on investigations of concerns related to mold, moisture, and odors. There is a significant distinction between IAQ testing and reporting and that of the COVID-19 ventilation and filtration mitigation strategies. If you are requesting an air quality report in the context of COVID-19 mitigation, this report will not provide the information you are requesting and/or seeking. Click here for our COVID-19 ventilation and filtration mitigation information.

What is MCPS doing to increase the levels of fresh air in buildings?

Bringing in additional fresh outdoor air dilutes and flushes airborne particles - including viruses - out of the building. MCPS has increased the amount of time that HVAC systems operate to help "flush" the building prior to and after occupancy. For example, systems at an elementary school that were previously scheduled to be "ON" from 7:00 a.m. to 5:00 p.m. are now ventilated from 5:00 a.m. (two hours earlier) until 5:00 p.m.  

How many air changes per hour (ACH) will classrooms have?

Industry experts state that increasing air change rates can decrease the in-room concentration of air particles. The optimum target for our school buildings has been identified as four to six air changes per hour (ACH). It is important to note that ACH is defined as how many times the air in a room is replaced by air passing through a filtering device or by the introduction of outside air. 

Should students and staff open the windows in their classrooms?

It is the intent for all classrooms to have a sufficient air exchange without opening classroom windows. However, it has been calculated that opening windows can have a significant impact on overall air exchange rates. During times of appropriate outdoor temperatures and humidity, it may be recommended to open windows to supplement current strategies. 

Should I be worried that my classroom doesn't have a window or that the windows in my classroom don't open?

No. The ability to open a window does not necessarily benefit you or your students. While an open window does increase ventilation, it can also cause problems by allowing dust, pollen, and other irritants to enter the room. Your school's HVAC system filters outside air and provides enough fresh air for your room. Even in the cases where supplemental air purifiers have been installed, opening windows is not necessary. Keep in mind that windows that don't have screens should not be opened. Another thing to consider is the fact that steps have been taken to facilitate appropriate airflow and ventilation in your classroom. We have met and in most cases, exceeded the industry standards for proper ventilation and airflow.

Should we shut down the building ventilation system if someone in our building is suspected of having COVID-19?

No, you should not. According to ASHRAE standards, when operating properly, HVAC systems are designed to move, mix, and exhaust air in a way that dilutes and filters indoor air contaminants, including viruses. Shutting off HVAC systems disrupts this intentional dilution and filtering process and may actually increase the building occupants' risk of exposure to infectious contaminants like the coronavirus.

Does building air filtration protect me from getting COVID-19?

The air filtration in an HVAC system can be part of an overall risk mitigation approach, along with increasing ventilation, but it is not generally regarded as a solution by itself. 


How was the decision made to place or not place an air purifier in a particular room? 

The decision was based primarily on whether instructional rooms utilized by students and staff have sufficient mechanical ventilation. The rooms served by dedicated outdoor air systems (DOAS) and energy recovery units (ERUs) do not need air purifiers, whereas rooms served only by unit ventilators or fan coil units may need supplemental ventilation that air purifiers can provide.  

What should we do if we have staff scheduled to utilize spaces in our school where an air purifier has not been installed?

At this time, air purifiers have been designated for use only in instructional classrooms, main offices, health rooms, and isolation areas. 

Will air purifiers be provided for portables?

Yes and no - it depends on how the portable is being used and its mechanical systems. Portables have been assessed, and air purifiers have been placed where needed. Principals should alert OFM if they feel that a portable requires another assessment.     

I don't see an air purifier in my workspace. Is it okay for me to bring one from home? 

It is not recommended that staff members bring appliances, including air purifiers, from home.  

Our school's restrooms don't have any visible ventilation units. Should I be worried about these spaces? 

No. Restrooms, by code, have exhaust fans and some form of makeup air from adjacent spaces, so they do not require air purifiers.

Will opening a classroom window increase or decrease the air purifier's effectiveness?

An open window means that the air purifier has to work longer to clean the air. When you limit the amount of air that the unit has to clean, you decrease the amount of time it takes to clean the air in the room. Opening a window during favorable weather conditions will increase ventilation in the space, but it is not necessary and may present other issues (dust, pollen, etc.). 

Where should the unit be placed in the room for best filtering during instruction? 

Depending on the room's configuration, the air purifier should be placed in the back or the side of a classroom. This will allow the unit to work efficiently while minimizing noise levels and disruption during instruction. Air purifiers should always be placed so that its air intake and discharge vents are not obstructed. To allow for proper air circulation around the machine, keep materials and furnishings at least two feet away from the unit. Never place the unit near furniture or behind curtains! Also, be aware that moving the unit could pose a potential tripping hazard on the electrical cord.

If our students are moving to another room for lunch, should I move the air purifier with us?

No. All air purifiers have been strategically placed in your school and should remain in the same room where they were originally placed. 

Students will take off their masks to eat, so we're planning to have them leave the classroom for 30 minutes after lunch. Is that enough time for the air purifier to sufficiently clean the classroom's air, or should I change the setting from medium to high?

While adjusting the unit to the high setting will indeed clean the air at a faster rate, the medium setting is sufficient. Remember that your school's HVAC system will already be cleaning the air. The in-room units are there to supplement the HVAC system. 

How long should the air purifier run? Should we keep it running 24-7 or only when students are in the classroom?

It is not necessary to operate air purifiers overnight. To supplement your school's HVAC system, air purifiers should be operated during the day when your school is occupied. Your school's building services staff will turn the units on two hours before occupancy and turn them off two hours after occupancy.

What is the air filtering exchange rate for the smaller units compared to the large white ones? 

Air filtering exchange rates are typically measured in cubic feet per minute (CFM). Both units have multiple CFM ranges based on where they are set. Classrooms are being set between 300-400 CFM. The large Price units have a higher capacity that allows them to be used in larger spaces.

Will MCPS be using any air cleaners that generate ozone to help clean the air?

No. Based on guidance from the EPA, MCPS will not be using ozone-generating air cleaners. Ozone is a substance that irritates the lungs, and that type of unit can result in ozone levels that are above safe exposure limits.

I noticed that the Austin Air units have three settings. Which is the proper setting for my classroom?

The Austin Air Healthmate Plus units should be set on medium. Settings on the larger Price Room Air Purifier units are set by the service technicians. It is not recommended that staff change the settings on the air purifiers, particularly the Price units.

How will I know when the unit's filter needs to be changed?

Some air purifier models (BlueDri, Husqvarna, and XPower) have "change filter" lights that indicate when filters need to be changed. As a general rule, filter life is variable based on the air purifier model, airflow settings (low, medium, or high), the duration of operation (8 hours vs. 24/7), occupancy, and indoor air quality. The Austin Air units are unique in that the manufacturer recommends replacing the 4-stage HEPA/carbon combination filter once every five years under "typical" use. According to the manufacturer of the Price RAP units, the recommended life for pre-filters is 4,000 hours. Regardless of the model, your building service manager will visually check the air filters every other month and replace the filters when necessary. 

What should I do about troubleshooting?

Here are links to the user manuals for the air purifier units that MCPS has provided. If you cannot find adequate troubleshooting answers here, please ask your building service manager to submit a work order. 


Click here to view the status of the water bottle filling station project.

School buildings have been closed since last March. Should I be worried about the water that's been sitting in the pipes?

No. Our building service staff has been flushing the water in the schools regularly, even while students and teaching staff were not present. As a proactive measure, we implemented a school reopening flushing strategy before schools returned to in-person instruction. This flushing protocol is in accordance with recommendations from the Maryland Department of the Environment

What about drinking water? Will the water fountains in schools be turned on?

Effective June 27, 2021, hallway water fountains were returned to service on a school-by-school basis. As with all other frequent touchpoints, water fountains will continue to be cleaned regularly. Facilities that did not have water bottle filling stations were provided with a centrally-located portable 5-gallon water dispenser. As water bottle filling stations are installed in more schools, these supplementary water dispensers will be removed from service. 

As an added safety measure, hallway water fountains were not available for drinking while schools were closed for in-person learning. Facilities that did not have water bottle filling stations were provided with a centrally-located bottled water dispenser.

What about bubblers and faucets in the classrooms?

Faucets for hand washing continue to remain turned on for use by students and staff. Classroom bubblers, which had been previously turned off as an added safety measure, were returned to service on June 27, 2021. They continue to remain in service and are included in the frequent flushing plans implemented in each school. 


Will MCPS be using ultraviolet light or bipolar ionization to help clean the air?

No, MCPS does not currently have any HVAC systems that use ultraviolet germicidal irradiation or bipolar ionization.

Why haven't you installed plexiglass or sneeze guards in my classroom?

There are four very important reasons why we will not install plexiglass in our facilities:

  1. Plexiglass can obstruct ventilation airflow, especially when used in large quantities or installed near people's breathing zones. This is the opposite of what we want to happen. Improved ventilation is the goal.
  2. Plexiglass can create a fire safety hazard by impeding the water flow of sprinkler heads. Plexiglass is also a combustible material.
  3. Adding plexiglass will further stretch the already-increased workload on building service staff by adding more surfaces that would need to be regularly cleaned and disinfected.

Who is managing the PPE inventory levels for my school?"

School administrators are responsible for maintaining PPE supplies that will be used for students and staff. This includes face masks, hand sanitizer, and basic cleaning supplies that may be used only by teaching staff. Building service managers are, as they have always been, responsible for maintaining the PPE and cleaning supplies that are designated for use by their staff.

Should I keep my classroom door open?

No. The security challenges that arise when classroom doors are open are greater than the benefit of having that additional hallway air enter a room. Leaving your door open is not an added benefit.

Please note that this Web page may contain links to one or more pages that are outside MCPS. MCPS does not control the content or relevancy of these pages.