Indoor Environment Guidelines for Childcare: Essential for Health

The National Centre for Hygiene and Safety (LCHV), part of the RIVM (National Institute for Public Health and the Environment), has developed these guidelines for the indoor and outdoor environments in childcare centers, preschools, and after-school care facilities (hereinafter "childcare centers"). The aim is to reduce the risk of spreading infectious diseases among children and staff. The guidelines, dating from 2016, outline the most important standards, with an emphasis on air circulation, temperature control, and minimizing harmful substances.

Part 1: The Crucial Role of Air Circulation and Monitoring

A healthy indoor environment provides clean air, a pleasant temperature, and a comfortable noise level. Insufficient attention to this can lead to health problems, stress, and accelerated spread of pathogens. The air can be polluted by materials in the building, cleaning products, clothing, pets, and people themselves.

People exhale carbon dioxide CO2, the amount of which is easily measured. A low CO2 level indicates that the room is well-ventilated. A high CO2 level can cause symptoms such as headaches, irritation of the eyes and mucous membranes, difficulty concentrating, and coughing, sneezing, or asthma symptoms.

Ventilation versus Airing

Pathogens linger longer in poorly ventilated spaces, increasing the risk of illness.

Ventilation is the continuous replacement of air. The outside air replaces a portion of the indoor air that is polluted with moisture, gases, and pathogens (such as particulate matter). This must occur continuously.
Airing (for approximately 15 minutes) is the short-term replacement of all polluted indoor air by opening windows and/or exterior doors wide. Airing is not a replacement for ventilation.

Advice for Air Freshening and Mechanical Systems:

1. All rooms must have windows, vents, or a mechanical ventilation system.
2. All rooms must be ventilated day and night, in both hot and cold weather.
3. Open windows (or operate mechanical ventilation systems at their highest setting) and air the room during cleaning, after using strong-smelling items, and early in the morning if there has been no ventilation overnight.
4. Ventilation grilles and gaps under doors must be open and not covered.
5. For mechanical systems, capacity decreases rapidly due to contamination. Filters must be cleaned or replaced according to the manufacturer's instructions.
6. The system must be cleaned by the supplier at least once a year. The inside of the ducts must be cleaned every 5-7 years.
7. Every five years, the airflow of the system must be measured in each room and re-adjusted if necessary.

The Standard for CO2 Monitoring

To check whether ventilation is effective, the amount of CO2 must be measured. The guideline stipulates the following requirements for monitoring:

1. Provide an easily readable CO2 meter that displays good/moderate/poor with light and stores the data.
2. Place the CO2 meter in a location with no windows or doors and therefore no direct ventilation.
3. The CO2 level must be less than 1000ppm, and preferably below 800ppm.
4. Reset the settings every two weeks for correct values; leave the meter outside or in an open window for a while. 5. Keep a log of the measurements taken (room name, date, highest value of the week, calibration time) and store the data for at least 12 months.

The Room You sensor is ideal for this monitoring, with a clear display and data storage function for the logbook.

Dustness and Chemicals

To maintain healthy indoor air, limiting dust, allergens, and chemical fumes is also crucial.

Dust and Allergens: Use washable stuffed animals and textiles. Wash covers, pillows, and blankets at 60°C or at 40°C-60°C with a tumble dryer. Avoid flowers with a strong scent or plants with hairy leaves. Vacuuming, sweeping, or dry-cleaning should be done when children are not present and the room is well-ventilated.
Chemical Fumes: Do not use cleaning products or air fresheners with strong or irritating odors. Water-based paints and glues are recommended for crafts. The use of products containing solvents and chemicals is prohibited in the presence of children. After painting, the room must be ventilated for several weeks, even with water-based paint.
Combustion products: Burning incense, candles, tealight, oil, or gel is prohibited, as this releases combustion gases and particulate matter. Gas cooking appliances are only permitted in a lockable kitchen with mechanical ventilation and an adequate supply of fresh air. Water heaters and gas stoves must be inspected annually.

Carbon monoxide detectors are recommended near combustion appliances.

Part 2: Comfort, Heat, and Humidity Control

Temperature and Humidity Balance

Good ventilation combined with heating is the best way to remove moisture and prevent mold growth. Mold develops at a humidity above 70%. Air that is too dry (below 30%) can irritate the mucous membranes.

Temperature: The temperature in communal areas should be between 20°C (68°F) during cold periods, and between 15°C (59°F) and 18°C (64°F) in bedrooms. The temperature should be kept as constant as possible.
Humidity: The humidity should be maintained between 30% (30%) and 70% (70%). In the event of persistently high humidity (>70% in winter), a qualified professional must investigate the cause. Leaks must be repaired immediately. * **Thermometers** should be placed in every room where children are staying to monitor the temperature.

Heat in and around the Building

Hot weather can lead to fatigue, difficulty concentrating, and skin problems in children. Measures are necessary if the indoor temperature exceeds 25C.

Sunshades should be installed on windows facing the sun and lowered before the sun shines in.
Turn on as few lights or appliances as possible.
Provide extra ventilation at night when it is cooler outside than inside.
Use a fan in the rooms when the temperature exceeds 25C.
Outdoor play is good when it is cooler outside than inside, but direct exposure to sunlight between 12:00 and 15:00 should be avoided.

Jille Kuipers, Innovation Manager at LuxBalance, on the broad requirements for monitoring:

"The LCHV and the Municipal Health Service (GGD) set the standard. It is clear that a CO2 meter is no longer an optional luxury, but an operational necessity to prove compliance with the 1000 ppm standard and to achieve the 800 ppm target. What is often overlooked is the requirement for constant temperature and humidity monitoring to prevent mold growth and health problems. Modern CO2 monitors must offer an integrated solution that measures and logs all these crucial parameters—CO2, temperature, and humidity—for the mandatory logbook. This enables professionals to respond quickly and effectively to all climate factors, which is essential for the safety and well-being of children."

Other Environmental Advice

Asbestos: Have an inventory carried out for buildings built before 1994. Do not drill or saw into materials containing asbestos.
Mercury: Remove old mercury thermometers and barometers. In the event of a mercury spill, everyone must leave the room, open windows and exterior doors, and close doors to other rooms. Do not use a vacuum cleaner to remove mercury.
Plants: Prevent poisonous plants (such as hogweed) or plants that release large amounts of pollen (such as birch or ragweed) in or around childcare centers.

This guideline emphasizes that a proactive, measurable approach to the indoor environment, using instruments that monitor CO2, temperature, and humidity, is the key to healthy childcare.

Reference:
National Institute for Public Health and the Environment, and National Centre for Hygiene and Safety. (2016, May). Indoor and outdoor environment for daycare centers, playgroups, and out-of-school care.