Taiwan's indoor air quality standards (室內空氣品質標準) set the formaldehyde limit at 0.08 ppm as a 1-hour value, the number most often used to judge whether formaldehyde in a newly renovated home is high. Legally, however, the standard binds only the public places announced by the Ministry of Environment (schools, hospitals, stations, department stores and so on). Ordinary homes have no legal limit, and the authorities do not specify how many days to ventilate after renovation before moving in. To know the condition of your own home, rely on testing, not on smell or counting days.
Reminder: If a newly finished home smells sharp as soon as you walk in, or your eyes or throat feel uncomfortable, open the windows and leave first; do not shut the windows and run the air conditioner. If someone in the family is pregnant, is an infant or young child, or has asthma or a history of allergies, it is even more worthwhile to test before moving in. See a doctor if the discomfort continues. For the standards and testing rules, follow the Ministry of Environment's latest announcements.
What 0.08 ppm means: how to read the standard
Article 2 of the indoor air quality standards (Ministry of Environment, issued and in force on November 23, 2012) lists standard values for 9 pollutants. The unit ppm for formaldehyde is parts per million by volume. Under Article 3, a "1-hour value" means the arithmetic mean of the readings within one hour, or the reading from sampling accumulated over one hour. So a handheld meter jumping to 0.1 for a moment does not mean "over the limit"; what counts is the 1-hour average.
| Item | Standard value | How it is calculated |
|---|
| Formaldehyde (HCHO) | 0.08 ppm | 1-hour value |
| Total volatile organic compounds (TVOC, the sum of 12 substances) | 0.56 ppm | 1-hour value |
| Carbon dioxide (CO2) | 1,000 ppm | 8-hour value |
| Carbon monoxide (CO) | 9 ppm | 8-hour value |
| Bacteria | 1,500 CFU/m³ | Maximum value |
| Fungi | 1,000 CFU/m³ (not applicable where the indoor/outdoor ratio is ≤ 1.3) | Maximum value |
| PM10 | 75 μg/m³ | 24-hour value |
| PM2.5 | 35 μg/m³ | 24-hour value |
| Ozone (O3) | 0.06 ppm | 8-hour value |
If the report you have uses mg/m³: at 25°C and 1 atmosphere, 0.08 ppm of formaldehyde is about 0.098 mg/m³ (this article converts using formaldehyde's molecular weight of 30.03; the figure is not in the regulation text). Under Article 3, TVOC is the sum of the concentrations of 12 substances, including benzene, toluene, xylene, styrene and tetrachloroethylene, not all volatile organic compounds.
Does it apply to ordinary homes? Legally it is only a reference value
Article 3 of the indoor air quality management act (室內空氣品質管理法, promulgated November 23, 2011) defines "indoor" as the enclosed or semi-enclosed space of buildings used by the public, plus the passenger space of mass transit vehicles. Under Article 6, the Ministry of Environment announces the regulated places "batch by batch" based on factors such as how many people gather there, and Article 7 requires those announced places to meet the indoor air quality standards. A private home is not within the definition, so:
- If a home measures 0.08 ppm or above, there is no penalty, and you cannot ask the environmental protection bureau to impose a fine on that basis.
- 0.08 ppm is still the health reference value most often cited in Taiwan; in a purchase or handover inspection it can be used as a standard the two sides agree on (this article's suggestion: write it into the contract beforehand).
- Article 4 assigns "management of building renovation materials" to the building authority and "national standards for air pollutants released by renovation materials" to the economic affairs authority, so the formaldehyde rules for the materials themselves are found in the green building material label and national standards, not in this air quality standard.
Where formaldehyde comes from
The Ministry of Environment's indoor air quality information site (室內空氣品質資訊網) explains that the plywood commonly used for interior boards and furniture is bonded with a formaldehyde-containing resin (urea-formaldehyde resin adhesive), and the formaldehyde in the resin is released slowly. The same site lists plywood partitions (finished with wallpaper or plaster and paint), mineral-fiber ceilings, synthetic carpet, PVC floor tiles, gypsum ceilings, and also foam, insulation, adhesives, fabrics and carpets as possibly containing formaldehyde and other volatile organic compounds, which are released slowly after the renovation is finished.
On health effects, the indoor air quality information site says formaldehyde irritates the skin and mucous membranes, such as the throat, eyes and nasal cavity. The green building material label website states that formaldehyde is a human carcinogen evaluated by the International Agency for Research on Cancer (IARC) (Group 1). The Ministry of Environment advises that after moving into a new home or buying new furniture you must keep the air circulating, and open wardrobes and drawers often; when choosing furniture, consider solid-wood products or furniture that uses paint carrying the green building material label. For a comparison of material choices and budgets, see Low-VOC and eco-friendly materials: renovation budget; this article covers only standards and testing.
How to test: use a testing agency that holds a permit
The approach for announced places can serve as a reference. Article 10 of the indoor air quality management act requires announced places to commission a testing agency to test regularly, and Article 11 requires testing agencies to hold a permit issued by the Ministry of Environment; the testing methods and quality control are announced by the ministry. The website of the Ministry of Environment's national environmental research academy (國家環境研究院) has an "environmental testing agency lookup" (環境檢驗測定機構查詢) where you can check which agencies have permitted items related to indoor air, and then ask for quotes yourself. This article found no uniform rule on whether such agencies accept commissions from ordinary homes or what they charge; ask the agency directly.
The management measures for indoor air quality testing at announced places (公告場所室內空氣品質檢驗測定管理辦法, amended June 24, 2022) set position requirements for the inspection points at announced places: at least 0.5 meters from indoor structures or display fixtures, at least 3 meters from the door or elevator, and evenly distributed. For measuring at home yourself, this article suggests following the same principle: put the instrument in the middle of the room at the height where people spend a long time, and away from places just wiped with cleaner or just sprayed with perfume.
Handheld formaldehyde detectors are common on the market, but this article found no Ministry of Environment evaluation of the accuracy of such products. The reading can only show trends (for example before and after ventilation, or which rooms are relatively higher or lower) and should not be treated as proof of "pass" or "fail". When negotiating with the renovation contractor, a report from a qualified testing agency is more persuasive (this article's suggestion).
Reading the green building material label: formaldehyde grades of healthy green building materials
The green building material label is promoted by the architecture and building research institute (建築研究所) of the Ministry of the Interior and assessed by the Taiwan Architecture and Building Center foundation (財團法人台灣建築中心). Within it, "healthy green building materials" (also called low-emission green building materials) are assessed on the formaldehyde and TVOC emission rates. The categories covered are flooring, walls, ceilings, caulking and putty, paint, adhesives, wooden doors and windows made of a single material, and screens or cabinets taller than 1.2 meters that are fixed to the floor. The assessment criteria listed on the label website are a formaldehyde emission rate of ≤ 0.05 mg/m²·hr and TVOC of ≤ 0.19 mg/m²·hr, further divided into three grades:
| Emission grade | Formaldehyde emission rate (mg/m²·hr) | TVOC emission rate (mg/m²·hr) |
|---|
| Grade 1 | ≤ 0.005 | ≤ 0.005 |
| Grade 2 | 0.005 < formaldehyde ≤ 0.02 | 0.005 < TVOC ≤ 0.06 |
| Grade 3 | 0.02 < formaldehyde ≤ 0.05 | 0.06 < TVOC ≤ 0.19 |
A few points that are easy to misunderstand:
- The emission rate (how much a square meter of material releases per hour) and the indoor concentration (ppm) are two different things. Even with healthy green building materials, the indoor concentration can still be high if a large quantity is used and ventilation is poor.
- The test uses 48 hours as the assessment time point (green building material label website). It represents the properties of the material itself, not the air in your home after completion.
- An older article on the Ministry of Environment's indoor air quality information site still gives formaldehyde as 0.08 mg/m²·hr, which differs from the 0.05 on the assessing body's current website; this article uses the figure from the assessing body's website.
- Article 321 of the Building Technical Regulations (建築技術規則), Building Design and Construction part (amended February 23, 2026), requires the green building material usage rate for interior renovation materials, floor surface materials and windows to reach 60% or more of the total area. But Article 298 limits the scope to buildings used by the public and to non-public buildings that the Ministry of the Interior deems necessary, so an ordinary home renovation is not necessarily subject to this requirement.
For paint, the Ministry of Environment's advice is that "water-based paint is healthier". At handover, ask the contractor to provide label certificates or product data; label data can be looked up in the green building material database on the label website.
How long to ventilate? No official number of days; what you can do before moving in
This article found no figure from the Ministry of Environment or the Ministry of Health and Welfare specifying "how many days to ventilate after renovation". Claims commonly seen online, such as "ventilate for one month" and "3 to 15 years", have no official source that could be found and cannot be applied to every home. All that the authorities confirm is to keep the air circulating and open cabinets and drawers often. What follows is this article's suggestion:
- After completion, keep the windows open and run the exhaust fan continuously, with cabinet doors and drawers fully open.
- Test once before moving in: close the windows for several hours first and then test, which is closer to sleeping at night with the windows shut. If it fails, keep ventilating and test again after a few weeks.
- Test bedrooms and children's rooms first; rooms with a lot of newly built system cabinets or woodwork also need testing.
- For long-term ventilation you can consider a total heat exchange ventilator; for duct and condensation problems see A guide to avoiding pitfalls with total heat exchange ventilators in renovation. Before opening windows you can check the outdoor air quality; see AQI air quality index: the six color levels.
- Do not use an "ozone air purifier" to remove formaldehyde. The Ministry of Environment's indoor air quality information site, citing US EPA data, says that ozone at concentrations that do not exceed health standards has very limited effect on removing pollutants, and ozone itself irritates the respiratory tract. For how to choose an ordinary air purifier, see How to read air purifier CADR.
Frequently asked questions
Is it illegal if the formaldehyde in my home is above 0.08 ppm?
No. The indoor air quality management act covers only the public places announced by the Ministry of Environment, and homes are not within its definition of "indoor". 0.08 ppm can serve as a health reference value, or be agreed in the renovation contract as the handover standard.
Are formaldehyde detectors bought online accurate?
This article found no official evaluation of the accuracy of such products. The reading can show trends, for example before and after ventilation or between different rooms. To use it as evidence in a negotiation or handover, we suggest commissioning a testing agency that holds a Ministry of Environment permit.
Does a green building material label mean there is no formaldehyde?
No. Healthy green building materials are "low emission": a formaldehyde emission rate of ≤ 0.05 mg/m²·hr is required to obtain the label, and it is divided into Grades 1 to 3. When a large quantity is used and ventilation is poor, the indoor concentration can still be high, so you still need to test before moving in.
How long after renovation can I move in?
The authorities do not specify a number of days. This article suggests judging by test results: test formaldehyde after keeping the windows closed for several hours, and move in once the 1-hour average is below 0.08 ppm. Households with pregnant women, infants and young children, or people with asthma especially need to test first.
Last updated: 2026-10-31
This article was compiled by SOSfix editors from public information and is for general reference only. For your own case, contact the Ministry of Environment (indoor air quality regulation inquiries: 02-2311-7722 ext. 6801, 6804) or an environmental testing agency that holds a permit.
Sources
- National laws and regulations database (全國法規資料庫): indoor air quality standards (issued November 23, 2012; verified 2026-10-31, in Chinese): Article 2 lists the 9 standard values (formaldehyde 0.08 ppm as a 1-hour value, TVOC 0.56 ppm and so on), Article 3 defines the 1-hour value and the 12 TVOC substances, Article 5 gives November 23, 2012 as the date in force.
- National laws and regulations database (全國法規資料庫): indoor air quality management act (promulgated November 23, 2011; verified 2026-10-31, in Chinese): Article 3 defines indoor as buildings used by the public, Article 4 the duties of the building and economic affairs authorities, Article 6 batch-by-batch announcement of places, Article 7 announced places must meet the standards, Article 10 commissioned testing, Article 11 testing agency permits and announced methods.
- National laws and regulations database (全國法規資料庫): management measures for indoor air quality testing at announced places (amended June 24, 2022; verified 2026-10-31, in Chinese): inspection points 0.5 meters from structures or display fixtures and at least 3 meters from the door or elevator, evenly distributed; regular testing must be commissioned to a testing agency.
- Ministry of Environment indoor air quality information site: how to choose low-pollution furniture (site updated 2026/10/23; verified 2026-10-31, in Chinese): plywood bonded with formaldehyde-containing urea-formaldehyde resin, formaldehyde released slowly, keep the air circulating after moving into a new home or buying new furniture, open wardrobes and drawers often, solid-wood furniture.
- Ministry of Environment indoor air quality information site: how to choose low-pollution building materials (site updated 2026/10/23; verified 2026-10-31, in Chinese): plywood partitions, mineral-fiber ceilings, synthetic carpet, PVC floor tiles, gypsum ceilings and so on may contain formaldehyde and release it after renovation; the 0.08 mg figure for healthy green building material formaldehyde on this page is an old number, and this article uses the assessing body's website instead.
- Ministry of Environment indoor air quality information site: how to choose low-pollution paint (site updated 2026/10/23; verified 2026-10-31, in Chinese): the Ministry of Environment advises that water-based paint is healthier.
- Ministry of Environment indoor air quality information site: pollution sources you may not know about, office machines (site updated 2026/10/23; verified 2026-10-31, in Chinese): indoor ozone comes from photocopiers and ozone air purifiers; citing US EPA data, ozone has very limited effect on removing pollutants; ozone irritates the respiratory system.
- Ministry of Environment indoor air quality information site: pollutant descriptions on the home page (verified 2026-10-31, in Chinese): sources of formaldehyde and its irritation of the skin, mucous membranes, throat, eyes and nose; the indoor air quality regulation inquiry phone line.
- Green building material label of the architecture and building research institute, Ministry of the Interior (Taiwan Architecture and Building Center foundation): assessment items, healthy green building materials (verified 2026-10-31, page undated, in Chinese): categories covered by healthy green building materials, formaldehyde emission rate ≤ 0.05 mg/m²·hr, TVOC ≤ 0.19 mg/m²·hr, Grades 1 to 3, 48-hour assessment, formaldehyde is IARC Group 1.
- National laws and regulations database (全國法規資料庫): Building Technical Regulations (建築技術規則), Building Design and Construction part (amended February 23, 2026; verified 2026-10-31, in Chinese): Article 298, item 5, scope of green building materials is buildings used by the public and non-public buildings the Ministry of the Interior deems necessary; Article 321, green building material usage rate of 60% or more.
- Ministry of Environment national environmental research academy: environmental testing agency lookup (verified 2026-10-31, in Chinese): look up environmental testing agencies that hold a permit; the "testing methods" link on the indoor air quality information site points to this page.
