Sick Building Syndrome: Prevalence and Risk Factors Among Medical Staff in Chinese Hospitals

Abstract

Sick building syndrome (SBS) poses a significant challenge in hospital settings, adversely affecting staff health, operational efficiency, and environmental quality. This study aims to investigate the prevalence and risk factors of SBS among medical staff in Chinese hospitals, advancing the literature by pinpointing actionable environmental and psychological factors tailored to this occupational group within China’s distinct regional context. A survey questionnaire was administered to 615 medical staff members across seven private hospitals located in the eastern coastal region of China. Data were collected using structured questionnaires. The survey encompassed 27 factors across four aspects, with respondents being asked to self-assess the severity of four types of SBS symptoms (never, rarely, occasionally, often). Multivariable binary logistic regression analysis was carried out to identify factors associated with SBS, based on odds ratios (OR) with a significance level of p < 0.05. The prevalence rates for skin symptoms, mucosal symptoms, and general symptoms were 32.8%, 61%, and 71.1%, respectively. Gender, psychological mood, visibility of water systems and greenery from the workspace, outdoor noise environment, indoor air quality, indoor natural lighting, department of occupancy, design of workspace, cleanliness, and control over the indoor environment (temperature, lighting) were identified as risk factors related to SBS symptoms. These findings underscore the critical role of modifiable building design and psychological factors in SBS occurrence, offering a novel perspective on hospital-specific risks in China compared to global studies. Enhancing indoor and outdoor environments—through increased greenery, noise reduction, improved air quality, better lighting, and greater environmental control—emerges as a vital strategy to mitigate SBS, with implications for hospital management and staff well-being.

1. Introduction

The World Health Organization defines health as a state of complete physical, mental, and social well-being, beyond merely the absence of disease or infirmity [1]. The sudden outbreak of COVID-19 in 2020 has once again highlighted the importance of creating healthy buildings [2,3,4]. Building a truly healthy building is a significant challenge for the construction industry. The indoor environment directly affects human health levels [5], and poor environments can easily lead to sick building syndrome [6]. SBS refers to a series of non-specific symptoms, including discomfort in the eyes, nose, and throat, mental fatigue, headaches, nausea, dizziness, and skin discomfort. These symptoms usually do not manifest as objective physiological abnormalities but can cause discomfort and reduced efficiency [7]. Research on SBS in hospitals is of profound significance in enhancing hospital environmental quality, ensuring personnel health, reducing operational costs, and fully leveraging the social functional role of hospitals.

Currently, there is no unified standard for the classification of SBS, and most existing studies focus on residential [8,9,10,11,12,13,14] and office buildings [15,16]. Research indicates that up to 30% of new and renovated buildings suffer from SBS [8]. Even when indoor environments meet current standard requirements, the occurrence of SBS cannot be effectively prevented. The classification of SBS varies across different regions and studies. Generally, SBS can be divided into general symptoms (GS), mucosal symptoms (MS), and skin symptoms (SS). The incidence rate of SBS varies widely across different regions, building types, and case studies [17,18,19,20,21].

Research on the influencing factors of sick building syndrome has always been a hot topic in domestic and international studies. Since the 1970s, the reporting frequency of sick building syndrome has been increasing, as older, naturally ventilated buildings have gradually been replaced by air-conditioned and sealed buildings [7]. Currently, no single environmental parameter has been identified as the sole cause of a specific type of sick building syndrome. Existing research indicates that sick building syndrome is the result of the combined effects of multiple factors and long-term exposure of users [22].

The influencing factors of sick building syndrome mainly include five aspects: indoor environmental factors (physical and non-physical) [23,24,25,26], biological factors [27], chemical factors [25], psychological factors [16,22], and individual differences [22]. Numerous studies have focused on common physical environmental parameters, such as sound, light, heat, and air quality, and pointed out that they are all directly related to the incidence of sick building syndrome and can affect the health and work efficiency of users [28,29,30,31,32]. However, in indoor environments, lower CO₂ concentrations, pollutant concentrations, and suitable temperature and humidity levels help reduce the occurrence of sick building syndrome.

In China, hospital medical staff face high personnel density and heavy workloads [33], rendering them particularly vulnerable to sick building syndrome (SBS). However, current hospital environmental design strategies in China prioritize basic comfort requirements, with insufficient attention to SBS prevention and control. Consequently, recurring SBS issues in hospital buildings remain inadequately analyzed and addressed. While most existing studies target residential and office environments, research on SBS in hospitals—especially in the Chinese context—remains scarce. Chinese hospitals are characterized by dense occupancy, intense workloads, and distinct architectural designs that differ markedly from those in other countries, necessitating region-specific investigations. Moreover, the influence of non-physical environmental factors on SBS, such as spatial layout, building orientation, landscape views, and greenery, has been largely overlooked.

This study aims to quantify the prevalence and risk factors of SBS among medical staff in Chinese hospitals, with a focus on both physical and non-physical environmental parameters, and to provide evidence-based recommendations for retrofitting hospital designs to enhance staff health and well-being. By addressing these gaps, this research offers a novel contribution to understanding SBS in an underexplored occupational and regional setting.

2. Materials and Methods

The research framework, depicted in Figure 1, integrates these environmental and occupational factors to assess their combined impact on SBS. By addressing these gaps, this research offers a novel contribution to understanding SBS in an underexplored occupational and regional setting of China.

2.1. Study Locations, Participants, and Questionnaire Design

This study was approved by the Ethics Committee of Hangzhou Integrative Medicine Hospital. A survey was conducted in seven private hospitals in Zhejiang Province during winter (refer to Figure 2 for locations). A total of 615 research subjects participated, primarily comprising hospital staff. Data were collected using structured questionnaires.

Table 1. The outdoor environment during the test.

Hospital	Location	Outdoor Air Temperature (°C)	Outdoor Relative Humidity (%)	Oudtdoor PM2.5 (μg/m3)
H1/H5	Hangzhou, Zhejiang	5.0 ± 3.6	53.6 ± 21.2	31.0 ± 11.8
H2/H6	Lishui, Zhejiang	6.3 ± 4.1	59.5 ± 22.8	25.2 ± 11.7
H3/H4	Taizhou, Zhejiang	7.2 ± 3.9	48.6 ± 20.1	26.5 ± 11.6
H7	Quzhou, Zhejiang	5.8 ± 4.1	55.9 ± 20.9	35.9 ± 17.4

presents the environmental conditions of the selected hospitals, including outdoor temperature, humidity, and PM_2.5 levels during the questionnaire survey, while

Table 2. Basic information about the selected hospitals.

Hospital	Position	Built Time	Floor Area (m2)	Beds	Number of Staff	Number of Participants
H1	Hangzhou, Zhejiang	2018	21,525	497	421	298
H2	Lishui, Zhejiang	2019	35,000	320	310	55
H3	Taizhou, Zhejiang	2004	21,000	350	550	120
H4	Taizhou, Zhejiang	2015	8500	120	162	69
H5	Hangzhou, Zhejiang	2016	6800	124	103	41
H6	Lishui, Zhejiang	2016	3000	80	32	7
H7	Quzhou, Zhejiang	2006	2500	60	70	25

provides their basic structural and operational details. The outdoor surface horizontal radiation of Hangzhou during the test were depicted in Figure 3.

The questionnaire was based on the internationally recognized SBS scale [7,34] and was adapted to the actual situation of domestic hospitals and the thinking habits of medical staff. The questionnaire was divided into six parts based on the existing studies [31,34]: personal characteristics of the respondents, such as age, gender, smoking status, job position, work environment, etc.; building environmental design, such as floor or wall color, presence of greenery in the workspace, outdoor noise, etc.; subjective indoor environmental quality, such as satisfaction with temperature, air quality, and indoor light environment; awareness of building energy efficiency and its impact on occupant health, such as satisfaction with the control of the indoor environment (convenience, intelligence, and effectiveness of temperature and lighting control); building service performance, such as satisfaction with the size and design of the space (relative positions of functional rooms, vertical and horizontal traffic), and satisfaction with the cleanliness of the indoor environment; SBS symptom status, such as eyes (dryness/itching/stinging/tearing), nose (dryness/itching/runny nose/nosebleed), throat (pain/dryness/mouth dryness), etc.

SBS was the primary outcome variable in this study, defined as the presence of at least one symptom related to hospital conditions on the day of the survey.

Respondents were asked whether they had experienced any of the following symptoms in the past winter season to assess SBS: general symptoms (dizziness/headache, inattention/errors, chest tightness/chest pain/shortness of breath, fatigue/sleepiness/lethargy, irritability/easy agitation/anxiety, nausea/appetite loss/digestive problems); mucosal irritation symptoms (eye dryness/itching/stinging/tearing, nose dryness/itching/runny nose/nosebleed, throat pain/dryness/mouth dryness, asthma/dry cough/bronchitis); skin symptoms (skin dampness/dryness/local itching). There are four options designed for each symptom (never, rarely, occasionally, often). For statistical convenience, symptoms marked as “never” and “rarely” were considered non-symptomatic, while “occasionally” and “often” were considered symptomatic. The satisfaction options are based on the Likert scale [35], divided into seven levels, representing: 1 = Very Dissatisfied, 2 = Dissatisfied, 3 = Somewhat Dissatisfied, 4 = Neutral, 5 = Somewhat Satisfied, 6 = Satisfied, 7 = Very Satisfied.

2.2. Statistical Analysis

The SPSS Statistics 29.0 software was utilized to perform contingency table chi-square tests and multivariate logistic regression analysis to investigate the relationships among questionnaire respondents’ characteristics, building environmental design, indoor environmental quality, building energy-saving health awareness, building service performance, and sick building syndrome (SBS). Multivariate logistic regression [36] is essentially an extension of binary logistic regression, designed to model the probability of the dependent variable occurring. The calculation formula is as follows:

$$\ln P/(1-P)={\beta }_0+{\beta }_1{x}_1+{\beta }_2{x}_2+\cdots +{\beta }_m{x}_m$$

(1)

where P represents the probability of SBS occurrence; β₀ is the constant term; and the partial regression coefficients β_j (where j = 1, 2, …, m_j = 1, 2, …, m_j) indicate the average change in the logit of (P) for a one-unit change in the (j)-th independent variable, holding all other independent variables constant.

The odds ratio (OR) [37] is defined as

$${\mathrm{OR}}_j=e^{{\beta }_j}$$

(2)

where OR_j represents the odds ratio for the j-th independent variable. It measures the change in the odds of SBS occurrence for a one-unit increase in X_j, with all other factors constant. When OR_j = 1, it suggests that the factor X_j has no effect on the occurrence of the disease. When OR_j > 1, it indicates that X_j is a risk factor. Conversely, when OR_j < 1, it implies that X_j is a protective factor.

3. Results

3.1. Prevalence of Various SBS Symptoms

This study surveyed seven hospitals, collecting a total of 615 questionnaires. The prevalence of various SBS symptoms was summarized in

Table 3. Prevalence of various SBS symptoms.

Symptoms		Frequency	Prevalence Percentage (%)
General symptoms		437	71.1
	Fatigue, sleepiness, and lethargy	245	39.8
	Irritability, excitability, and anxiety	244	39.7
	Dizziness and headache	244	39.7
	Nausea, lack of appetite, and indigestion	149	24.2
	Inattention and proneness to errors	172	28.0
	Chest tightness, chest pain, and shortness of breath	192	31.2
Mucosal symptoms		375	61.0
	Eye dryness, itching, stinging, and tearing	309	50.2
	Nose dryness, itching, runny nose, and nosebleed	217	35.3
	Throat pain, dryness, and mouth dryness	267	43.4
	Wheezing, dry cough, and bronchitis	167	27.2
Skin symptoms		202	32.8
	Skin flushing, dryness, and localized itching	202	32.8

. The prevalence rates for skin symptoms, mucosal symptoms, and general symptoms were 32.8%, 61%, and 71.1%. Regarding general symptoms, the most common included fatigue, sleepiness, and lethargy, with a total of 245 cases (39.8%); irritability, excitability, and anxiety affected 244 cases (39.7%), while dizziness and headaches were reported in 244 cases (39.7%). Additionally, 149 cases (24.2%) experienced nausea, lack of appetite, and indigestion. Inattention and proneness to errors were reported by 172 cases (28.0%), while chest tightness, chest pain, and shortness of breath were reported by 192 cases (31.2%). For mucosal symptoms, eye dryness, itching, stinging, and tearing occurred in 309 cases (50.2%). Nose dryness, itching, runny nose, and nosebleed affected 217 cases (35.3%); throat pain, dryness, and mouth dryness were reported by 267 cases (43.4%); Wheezing, dry cough, and bronchitis were observed in 167 cases (27.2%). Regarding skin symptoms, skin flushing, dryness, and localized itching were observed in 202 cases (32.8%). These findings indicate that general symptoms were the most prevalent, followed by mucosal symptoms, with skin symptoms being the least common among the surveyed population.

3.2. Relationship Between Medical Staff Background Information and SBS Symptoms

The background of the participants is detailed in

Table 4. Correlation between basic information variables and SBS symptoms.

		Frequency	Skin Symptoms			Mucosal Symptoms			General Symptoms
			Yes (%)	OR	p	Yes (%)	OR	p	Yes (%)	OR	p
Basic information variables
Gender
	Male	158	36 (22.8)	0.418 *	0.003	87 (55.1)	0.665	0.131	101 (63.9)	0.406 *	0.002
	Female	457	166 (36.3)			288 (63)			336 (73.5)
Age
	<30	226	69 (30.5)	3.53	0.62	113 (50)	0.17	0.51	156 (69)	0.30	0.74
	30–40	203	69 (34)	3.78		130 (64)	0.17		151 (74.4)	0.28
	41–50	150	51 (34)	3.31		92 (61.3)	0.21		107 (71.3)	0.29
	51–60	31	11 (35.5)	2.52		19 (61.2)	0.19		21 (67.7)	0.38
	>60	5	2 (40)			1 (20)			2 (40)
Psychological mood
	Poor	57	25 (43.9)	3.092 *	<0.001	36 (63.2)	1.968 *	<0.001	44 (77.2)	2.246 *	0.002
	Average	321	123 (38.3)	2.416 *		228 (71)	2.817 *		244 (76)	1.935 *
	Good	237	54 (22.8)			111 (46.8)			149 (62.9)
Occupation
	Doctor	182	53 (29.1)	1.145	0.543	111 (61)	1.014	0.890	129 (70.9)	0.630	0.062
	Nurse	272	89 (32.7)	0.849		165 (60.7)	0.786		189 (69.5)	0.359
	Administrative	68	26 (38.2)	1.991		41 (60.3)	0.667		48 (70.6)	0.175
	Service	69	27 (39.1)	1.525		42 (60.9)	0.703		51 (73.9)	0.326
	Others (Security, etc.)	24	7 (29.1)			16 (66.7)			20 (83.3)
Duration of Stay in Buildings per Week
	<10 h	148	42 (28.4)	0.611	0.213	90 (60.8)	0.919	0.491	109 (73.6)	1.228	0.548
	11–20 h	48	17 (35.4)	0.978		31 (64.6)	1.210		34 (70.8)	1.042
	20–40 h	89	29 (32.6)	0.870		49 (55.1)	0.702		67 (75.3)	1.474
	>40 h	330	114 (34.5)			205 (62.1)			227 (68.8)
Department
	Outpatient	151	55 (36.4)	1.365	0.566	101 (66.9)	0.607 *	0.025	101 (66.9)	0.623	0.091
	Inpatient	305	93 (30.5)	1.039		171 (56.1)	0.335 *		217 (71.1)	1.055
	Management	95	32 (33.7)	0.756		56 (58.9)	0.489 *		73 (76.8)	1.942
	Others (Service, etc.)	64	22 (34.4)			47 (73.4)			46 (71.9)
Common space type
	Medical office	130	38 (29.2)	0.990 *	0.006	80 (61.5)	1.162	0.332	95 (73.1)	0.860	0.432
	Ward	87	33 (37.9)	1.607 *		48 (55.2)	1.060		61 (70.1)	0.651
	Nurse station	153	45 (29.4)	1.005 *		93 (60.8)	1.161		106 (69.2)	0.624
	Waiting room	10	7 (70)	4.626 *		8 (80)	2.682		8 (80)	1.839
	Treatment room	35	8 (22.9)	0.526 *		24 (68.6)	1.061		20 (57.1)	0.399
	Examination room	46	10 (21.7)	0.431 *		23 (50)	0.427		29 (63.4)	0.543
	Registration area	24	11 (45.8)	1.222 *		16 (66.7)	0.957		17 (63)	0.619
	Operating room	22	11 (50)	3.582 *		13 (59.1)	0.954		17 (77.3)	1.200
	Others (spaces not specifically listed)	108	39 (36.1)			70 (64.8)			84 (77.8)

* and bold indicate that p is less than 0.05.

. Among the respondents, 456 were female (74.3%) and 158 were male (25.7%). Regarding age distribution, 226 respondents (36.8%) were under 30 years old, while 353 respondents (57.3%) were aged between 30 and 50 years, with 203 in the 30–40 age group and 150 in the 41–50 age group. A total of 36 respondents (5.9%) were over 50 years old. Regarding their self-reported mood, more than half of the respondents (321, 52.2%) described their mood as “average”, while 237 (38.5%) reported a positive state ranging from “good” to “very good”. In terms of smoking habits, the vast majority of respondents (569, 92.5%) were non-smokers, with only a small minority (42, 6.8%) indicating that they had a smoking habit.

Nurses and doctors were the predominant medical professions, with 272 nurses (44.2%) and 182 doctors (29.6%). Nearly half of the respondents (307, 49.8%) had worked in the hospital building for over three years, and 419 (68.1%) spent more than 20 h per week in the hospital building; the most respondents were from the inpatient department, totaling 305 (49.6%); the nurse’s station was the most frequently visited space by respondents, with 153 (24.9%), followed by medical offices and others, accounting for 21.1% and 17.6%, respectively.

The results indicated that job satisfaction, work environment, and work duration are the most important psychological factors leading to the prevalence of SBS. There is a strong correlation between the time spent by respondents in the building and its impact on their health.

The analysis in Table 4 demonstrates that the psychological mood of individuals is closely related to the presence of SBS symptoms, with p-values for all three categories of symptoms being less than 0.05. The probability of experiencing skin symptoms is 3.092 times higher for those in a poor mood and 2.416 times higher for those in an average mood compared to those in a good mood. For mucosal irritation symptoms, the probabilities are 1.968 times and 2.817 times higher, respectively, while for general symptoms, they are 2.246 times and 1.935 times higher, respectively, relative to those in a good mood. These results suggest that poorer mood may increase the likelihood of SBS symptoms. Moreover, extended work duration, which may contribute to reduced social support and poorer mood, is significantly associated with SBS symptoms [9].

Gender also has a significant impact on the symptoms, with skin symptoms (p = 0.003) and general symptoms (p = 0.002) showing particularly strong associations. Compared to females, males have lower odds of experiencing these symptoms, with odds ratios (ORs) of 0.418 for skin symptoms and 0.406 for general symptoms, indicating that males are less likely to be affected.

Furthermore, the department in which one works has a significant impact on the incidence of mucosal irritation symptoms (p = 0.025). The OR values for outpatient, inpatient, and logistics management departments are all below 1 compared to other departments. Workplace spatial type also significantly impacts skin symptoms (p = 0.006), with ORs of 1.607 (wards), 4.626 (waiting rooms), 1.222 (registration areas), and 3.582 (operating rooms), suggesting that staff in these areas are more susceptible to skin symptoms, whereas those in other departments are more prone to mucosal irritation symptoms. Collectively, these findings highlight the critical role of psychological factors, gender, and workplace environment in the prevalence of SBS symptoms among medical staff.

3.3. Relationship Between Building Environmental Design and SBS Symptoms

The results presented in

Table 5. Correlation between building environmental conditions and SBS symptoms.

		Frequency	Skin Symptoms			Mucosal Symptoms			General Symptoms
			Yes (%)	OR	p	Yes (%)	OR	p	Yes (%)	OR	p
Building environmental conditions variables
Window and view conditions
	Cannot see the ground vs. can see the ground	388	118 (30.4)	1.073	0.736	226 (58.2)	0.826	0.377	262 (67.5)	1.181	0.482
	Cannot see outdoor greenery (e.g., trees, grass), vs. can see outdoor greenery	326	90 (27.6)	1.122	0.568	167 (51.2)	1.862 *	0.002	205 (62.9)	2.053 *	<0.001
	Cannot see the sky vs. can see the sky	398	118 (29.6)	1.220	0.358	223 (58.5)	1.424	0.114	270 (67.8)	1.155	0.554
	Without interior windows vs. with interior windows	198	32 (16.1)	1.326	0.164	121 (61.1)	1.194	0.360	137 (69.2)	1.321	0.169
If you can observe the outdoor environment, how would you describe it?
	Noisy	302	121 (40)	1.685 *	0.006	212 (70.2)	1.642 *	0.007	233 (77.2)	1.346	0.134
	Quiet	313	81 (25.9)			212 (67.7)			198 (63.2)
What color are the indoor walls of the space where you often work?
	Warm	131	41 (31.3)	1.161	0.543	74 (56.5)	1.022	0.965	83 (63.3)	0.617	0.220
	Cool	276	99 (35.9)	0.859		183 (66.3)	0.957		207 (75)	0.892
	Neutral	208	62 (29.8)			118 (56.7)			147 (70.7)
What color is the indoor floor of the space where you often work?
	Warm	180	51 (28.3)	0.946	0.073	99 (55)	1.010 *	0.034	124 (68.9)	1.415	0.186
	Cool	177	76 (42.9)	1.628		131 (74)	1.821		139 (78.5)	1.515
	Neutral	258	75 (29.1)			145 (56.2)			174 (67.4)

* and bold indicate that p is less than 0.05.

highlight the significant impact of various environmental design factors on SBS symptoms. Specifically, the analysis focuses on the role of windows, outdoor views, noise levels, and indoor color schemes.

Of the 615 respondents, 521 (84.7%) reported that their workplaces had windows. Among those with windows, the majority had views of the ground, outdoor greenery or water systems, and the sky. However, 302 (49.1%) of the respondents considered the outdoor environment to be noisy. In the respondents’ workplaces, the absence of indoor greenery was notable, accounting for 44.7% of the responses. Wall colors were predominantly neutral colors (42.0%), followed by warm colors and cool tones.

The analysis reveals that windows with views of outdoor greenery or water systems significantly affect mucosal symptoms (p = 0.002) and general symptoms (p < 0.001), with respondents lacking such views being 1.862 times more likely to experience mucosal irritation symptoms.

Furthermore, outdoor noise significantly influences skin symptoms (p = 0.006) and mucosal symptoms (p = 0.007), with probabilities 1.685 times and 1.642 times higher, respectively, in noisy environments compared to quiet ones. Noise stands out as a key indoor environmental quality concern, consistent with data indicating increased SBS symptom prevalence in noisy settings.

Additionally, indoor floor color impacts mucosal irritation symptoms (p = 0.034), with cool-colored floors associated with an OR of 1.821 compared to neutral colors, while warm-colored floors have an OR near 1, indicating a higher likelihood of mucosal irritation with cool tones. These results underscore the importance of environmental design elements, such as window views, noise levels, and color schemes, in mitigating SBS symptoms.

3.4. Relationship Between Indoor Environmental Quality and SBS Symptoms

The results presented in

Table 6. Correlation between indoor environmental quality variables and SBS symptoms.

		Frequency	Skin Symptoms			Mucosal Symptoms			General Symptoms
			Yes (%)	OR	p	Yes (%)	OR	p	Yes (%)	OR	p
Indoor environmental quality variables
Current thermal sensation
	Cold	177	132 (74.6)	1.20	0.778	69 (39.0)	1.11	0.778	122 (68.9)	0.68	0.323
	Neutral	392	266 (67.9)	1.31		112 (28.6)	1.01		273 (69.6)	0.53
	Hot	46	39 (84.8)			21 (45.7)			34 (73.9)
Satisfaction with the current temperature environment
	Dissatisfied	76	60 (78.9)	1.21	0.793	39 (51.3)	0.80	0.793	61 (80.1)	0.33	0.092
	Neutral	232	175 (75.8)	1.22		96 (41.3)	0.97		165 (71.1)	0.67
	Satisfied	307	202 (65.8)			67 (21.80			149 (48.5)
Perception of indoor air
	Dry	91	77 (84.6)	0.49 *	<0.001	48 (52.7)	0.60 *	<0.001	48 (52.7)	0.54	0.426
	Moderate	458	310 (67.7)	0.25 *		115 (25.1)	0.43 *		249 (54.4)	0.59
	Humid	58	50 (86.2)			39 (67.2)			49 (84.4)
Satisfaction with current humidity
	Dissatisfied	78	66 (84.6)	1.43	0.324	46 (59.0)	1.62	0.324	68 (87.1)	0.91	0.981
	Neutral	263	197 (74.9)	1.65		103 (39.2)	0.92		181 (68.8)	1.01
	Satisfied	274	174 (63.5)			53 (19.3)			126 (46.0)
The indoor light environment
	Dark	389	302 (77.6)	0.18 *	0.003	154 (39.6)	0.79 *	0.003	271 (69.7)	1.07	0.078
	Moderate	195	117 (60.0)	0.10 *		37 (18.9)	0.47 *		89 (45.6)	0.64
	Bright	20	10 (50)	0.09 *		39 (15)	0.4 *		7 (35)	0.48
	No windows	11	8 (72.7)			8 (72.7)			8 (72.7)
Satisfaction with the overall indoor light environment
	Dissatisfied	82	68 (82.9)	0.62	0.112	40 (48.8)	0.83	0.112	63 (76.8)	0.69	0.483
	Neutral	270	207 (76.7)	1.48		109 (40.3)	1.79		198 (73.3)	1.24
	Satisfied	263	162 (61.6)			53 (20.2)			114 (43.3)

* and bold indicate that p is less than 0.05.

provide insights into the relationship between indoor environmental quality and SBS symptoms. The analysis examines various factors related to indoor air quality, lighting, and noise levels.

In terms of indoor air quality, while 268 respondents (43.6%) reported no noticeable odor, over half of the participants perceived varying degrees of odor in their indoor environments. The most common response regarding indoor air quality satisfaction was a neutral attitude, with 245 respondents (39.8%) indicating neither satisfaction nor dissatisfaction. A total of 213 respondents (34.6%) reported being “somewhat satisfied” or “satisfied” with the indoor air quality.

Regarding the sensation of drafts in the room, most respondents reported no draft or only a slight draft, with 292 people (47.5%) indicating no draft and 264 people (42.9%) reporting a slight draft.

In terms of room brightness, whether during the day (lights off) or during the day (lights on), most respondents considered the brightness to be moderate. For room brightness during the day (lights off), 117 people (19.0%) reported it as very dark, and 264 respondents (42.9%) reported it as somewhat dark. For room brightness during the day (lights on), the majority, 448 respondents (72.9%), reported it as moderate; regarding indoor light environment and sound environment satisfaction, the neutral attitude was also the most common, with 270 respondents (43.9%) and 266 respondents (43.3%), respectively, and a relatively high proportion also reported being “somewhat satisfied” or “satisfied”.

In terms of noise sources, buildings may be exposed to various noise sources, both internal and external. Internal sources include office equipment, footsteps, conversations, and other human activities. External sources may include traffic, construction, and other environmental noises. In this study, surrounding patients (talking, making phone calls, etc.) and external traffic were the main sources of noise, with 195 respondents (31.7%) and 113 respondents (18.4%), respectively; in terms of overall indoor environment satisfaction, 274 respondents (44.6%) had a neutral attitude, and a combined total of 115 and 106 respondents (35.9%) reported being “somewhat satisfied” or “satisfied”.

The analysis indicates that the perception of the indoor air has a very significant impact on mucosal symptoms (p < 0.001) and skin symptoms (p < 0.001). The probability of suffering from mucosal symptoms in dry and moderate humidity conditions is 0.60 times and 0.43 times that in damp conditions, respectively, while the probability of skin symptoms is 0.49 times and 0.25 times that in damp conditions. The probability of suffering from skin symptoms and mucosal symptoms increases with higher humidity.

Furthermore, the indoor light environment is closely related to mucosal symptoms (p = 0.003) and skin symptoms (p = 0.003).

3.5. Relationship Between Building Energy-Saving Health Awareness and SBS Symptoms (Concern for Indoor Environment)

The results presented in

Table 7. Correlation between building energy-saving awareness and SBS symptoms.

		Frequency	Skin Symptoms			Mucosal Symptoms			General Symptoms
			Yes (%)	OR	p	Yes (%)	OR	p	Yes (%)	OR	p
Building energy-saving health awareness variables
Are you willing to know the objective parameters of your surrounding environment?
	Unwilling	62	47 (75.8%)	1.102	0.861	40 (64.5%)	0.889	0.55	26 (41.9%)	1.437 *	0.032
	Indifferent	194	154 (79.4%)	0.92		137 (70.6%)	1.227		72 (37.1%)	1.884 *
	Willing	359	236 (65.7%)			198 (55.2%)			104 (29%)
Are you satisfied with the indoor environment control of this building (temperature, lighting, etc., in terms of convenience, intelligence, and effect)?
	Dissatisfied	69	68 (98.6%)	1.909	0.057	63 (91.3%)	2.881 *	<0.001	41 (59.4%)	2.253 *	0.012
	Neutral	274	210 (76.6%)	1.589		196 (71.5%)	2.411 *		105 (38.3%)	1.768 *
	Satisfied	256	159 (62.1%)			116 (45.3%)			56 (21.8%)
Will you control and adjust the building’s indoor environment (e.g., adjust aircon temp., open/close windows, draw curtains)?
	Often	264	195 (84.4%)	0.805 *	<0.001	175 (50.8%)	1.096	0.195	105 (50.8%)	0.587	0.221
	Sometimes	206	137 (74.7%)	0.342 *		111 (37.6%)	0.652		47 (37.6%)	0.409
	Occasionally	124	87 (60.9%)	0.556 *		74 (19.4%)	0.714		39 (41.1%)	0.45
	Never	21	18 (60.9%)			15 (19.4%)			11 (41.1%)

* and bold indicate that p is less than 0.05.

highlight the relationship between building energy-saving health awareness and sick building syndrome (SBS) symptoms, particularly focusing on the concern for the indoor environment.

Awareness of environmental parameters: Most respondents (359, 58.4%) expressed a willingness to understand the objective parameters of their surrounding environment. However, a significant portion were indifferent (194, 3.15%), while a smaller group (62, 10.1%) were unwilling to engage with this information.

Satisfaction with indoor environment control: Regarding satisfaction with the control of the indoor environment (convenience, intelligence, and effectiveness of temperature and lighting control), the majority of respondents (274, 45.7%) held a neutral attitude. However, more respondents were satisfied (256, 42.8%) than dissatisfied (69, 11.5%).

Convenience of controlling the indoor environment: The analysis revealed that poor control effectiveness and inconvenience in adjusting the indoor environment (e.g., air conditioning temperature, opening/closing windows, drawing curtains) were related to SBS symptoms.

The analysis demonstrates that awareness of environmental parameters, satisfaction with indoor environment control (convenience, intelligence, and effectiveness of temperature and lighting control), and the ease of adjusting the indoor environment (e.g., temperature and lighting) are significantly associated with specific SBS symptoms.

Willingness to understand environmental parameters significantly affects general symptoms (p = 0.032), with those unwilling to engage showing a 1.437 times higher probability of experiencing general symptoms compared to those who are willing. This suggests that lower awareness may elevate the risk of general symptoms.

Satisfaction with indoor environment control significantly influences mucosal irritation symptoms (p ≤ 0.001) and general symptoms (p = 0.012). Dissatisfied respondents have a 2.881 times higher probability of mucosal irritation symptoms and a 2.253 times higher probability of general symptoms compared to satisfied respondents, while those with a neutral attitude show probabilities 2.411 and 1.768 times higher, respectively.

3.6. Relationship Between Building Service Performance and SBS Symptoms

As shown in

Table 8. Correlation between building service performance and SBS symptoms.

		Frequency	Skin Symptoms			Mucosal Symptoms			General Symptoms
			Yes (%)	OR	p	Yes (%)	OR	p	Yes (%)	OR	p
Building service performance variables
Are you satisfied with your work efficiency/productivity under the overall environment of this building?
	Dissatisfied	71	37 (52.1)	4.68 *	0.001	52 (73.2)	2.01	0.21	55 (77.5)	0.79	0.89
	Neutral	277	114 (41.2)	2.84 *		200 (72.2)	1.58		213 (76.9)	0.98
	Satisfied	267	51 (19.1)			123 (46.1)			169 (63.3)
Are you satisfied with the size and design of your space?
	Dissatisfied	100	41 (41)	0.41 *	0.03	69 (69)	1.57 *	0.03	79 (79)	1.36	0.83
	Neutral	271	112 (41.3)	1.1 *		205 (75.6)	2.53 *		216 (79.7)	1.16
	Satisfied	234	49 (20.9)			101 (43.7)			142 (60.7)
Are you satisfied with the cleanliness of the indoor environment?
	Dissatisfied	95	56 (58.9)	3.06 *	0.001	80 (84.2)	3.6 *	0.001	79 (83.2)	2.42 *	0.04
	Neutral	187	67 (35.8)	1.31 *		129 (69)	1.33 *		146 (78.1)	1.51 *
	Satisfied	333	79 (23.7)			167 (50.2)			211 (63.3)
Are there the following issues in the indoor space?
	Moldy	43	16 (37.2)	0.81	0.69	28 (65.1)	1.18	0.76	29 (67.4)	1.36	0.57
	Damp	167	58 (34.7)	0.79	0.61	102 (61.1)	1.17	0.73	114 (68.3)	1.18	0.72
	Decoration damage	377	120 (31.8)	0.85	0.71	227 (60.2)	1.19	0.68	274 (72.7)	0.97	0.95
	Condensation	28	8 (28.6)			18 (64.3)			20 (71.4)

* and bold indicate that p is less than 0.05.

, the analysis explores the relationship between building service performance and SBS symptoms, focusing on various aspects of the Building Service Performance and their impact on occupants’ SBS Symptoms.

Regarding work efficiency and productivity under the overall environment of the building, 277 respondents (45.0%) held a neutral attitude, while 267 respondents (43.4%) reported being satisfied.

The respondents’ satisfaction with the size and design of the building space and its operation and maintenance was low, with neutral feedback accounting for nearly half. In contrast, 54.1% of the respondents expressed satisfaction to a high degree with the cleanliness of the building. According to the feedback, the most common indoor issue was decoration damage, accounting for 377 (61.3%), followed by humidity issues, accounting for 167 (27.2%). These results indicate that improving the environment around personnel is very important for effectively enhancing the perceived work efficiency of staff.

The analysis indicates that satisfaction with work efficiency and productivity in the building environment significantly affects skin symptoms (p = 0.011), with dissatisfied and neutral respondents showing probabilities 4.68 and 2.84 times higher, respectively, than satisfied respondents. Higher satisfaction is thus associated with a reduced likelihood of skin symptoms.

Satisfaction with the size and design of the space significantly influences mucosal symptoms (p = 0.03), with probabilities for dissatisfied and neutral respondents 1.57 and 2.53 times higher, respectively, than for satisfied respondents, suggesting a link between greater satisfaction and lower symptom prevalence.

Satisfaction with indoor cleanliness is significantly associated with all SBS symptoms. For skin symptoms (p = 0.001), dissatisfied and neutral respondents have probabilities 3.06 and 1.31 times higher, respectively, than satisfied respondents; for mucosal symptoms (p = 0.001), 3.6 and 1.33 times higher; and for general symptoms (p = 0.04), 2.42 and 1.51 times higher. Greater satisfaction with cleanliness thus correlates with reduced symptom likelihood.

4. Discussions

4.1. Prevalence of Various SBS Symptoms in Different Areas

The present study revealed a high prevalence of sick building syndrome (SBS) symptoms among medical staff in seven private hospitals in eastern coastal China, with rates of 32.8% for skin symptoms, 61.0% for mucosal symptoms, and 71.1% for general symptoms. Table 9 summarizes the prevalence rates of SBS from domestic and international studies, providing a comparative backdrop for these findings. These figures are notably higher than those reported in some international studies but align with findings from other hospital-based research in regions with similar environmental or occupational challenges. For instance, Babaoglu et al. (2019) [19] reported prevalence rates of 23.0–63.7% among Turkish hospital staff, while Surawat-tanasa-kul et al. [38] found a 10.7–25.3% prevalence among office workers at Thailand hospitals. Comparatively, residential studies, such as Wong et al. (2009) [8] in Hong Kong (34–72%) and Sun et al. [24] in China (40–73.4%), also indicate elevated SBS prevalence.

The predominance of general symptoms (71.1%), such as fatigue (39.8%), irritability (39.7%), and dizziness (39.7%). Mucosal symptoms, particularly eye dryness (50.2%) and throat dryness (43.4%), were also highly prevalent, likely exacerbated by poor indoor air quality and low humidity—factors consistently identified as SBS contributors [12,14,19,39]. Skin symptoms (32.8%), though less frequent, align with findings from the study in South Korean shopping malls [20] and another study in Gondar town, northwest Ethiopia [10].

Regarding specific functional spaces, other studies on the variable of frequently occupied space types have also shown the prevalence of SBS in hospital wards. The total prevalence of SBS among hospital staff was 65%, with the highest rate in the emergency ward (17.9%), followed by the internal ward (15.9%), ICU (12.8%), and CCU (11.8%) [40]. This indicates a significant relationship between SBS and cooperation among colleagues in work and infection control, which is like our conclusion.

The variation in symptom prevalence across studies underscores the role of regional climate, building design, and occupational factors. Our study emphasizes the unique susceptibility of hospital medical staff to SBS during winter in Zhejiang, China.

4.2. Risk Factors and Their Implications

Table 10 provides an overview of the risk factors associated with sick building syndrome (SBS), categorizing their characteristics and mechanisms of influence as identified in this and prior studies.

4.2.1. Individual and Psychological Factors

Gender emerged as a significant predictor of SBS symptoms, with females exhibiting higher odds of experiencing skin symptoms (OR = 0.418 for males vs. females, p = 0.003) and general symptoms (OR = 0.406, p = 0.002). This aligns with prior research [16,18,19,20,41,42,43]. We speculate that females may be more sensitive to the factors associated with SBS symptoms or more likely to report these symptoms. Mood also played a critical role, with individuals reporting poor or average mood showing significantly higher odds of all SBS symptom categories compared to those in a good mood (e.g., OR = 3.092 for skin symptoms in poor mood, p < 0.001). This finding corroborates the influence of psychological factors, such as stress and low social support, on SBS prevalence [15].

4.2.2. Environmental Design and Indoor Quality

Building environmental design factors, such as the visibility of outdoor greenery or water systems, significantly reduced the likelihood of mucosal (OR = 1.862, p = 0.002) and general symptoms (OR = 2.053, p < 0.001) when absent. This supports Dolling et al.’s [44] observation that natural views exert a positive psychological and physiological effect, potentially mitigating SBS through improved air quality and stress reduction. Outdoor noise, reported as a concern by 49.1% of respondents, increased the odds of skin (OR = 1.685, p = 0.006) and mucosal symptoms (OR = 1.642, p = 0.007). These findings align with a cross-sectional study in Slovenian hospitals [45], which identified noise as one of the key IEQ disruptor. Indoor air quality perceptions, particularly dryness (OR = 0.49 for skin, p < 0.001; OR = 0.60 for mucosal, p < 0.001), and lighting conditions further underscored the critical role of ventilation [46,47] and illumination in SBS etiology, echoing findings by Hoang et al. [48]

4.2.3. Control over Environment and Building Services

User control over the indoor environment emerged as a protective factor. Dissatisfaction with indoor environment control of this building increased the odds of mucosal (OR = 2.881, p < 0.001) and general symptoms (OR = 2.253, p = 0.012), while bad control effectiveness reduced mucosal symptom likelihood. This aligns with Rostron’s study [49], which noted that adjustable environments reduce absenteeism and SBS risk. Similarly, satisfaction with building service performance, particularly cleanliness, was inversely associated with all SBS symptom types (e.g., OR = 3.06 for skin in dissatisfied vs. satisfied, p = 0.001), reinforcing the importance of maintenance in mitigating biological and chemical triggers like mold and dust [48,50].

4.2.4. Occupational and Spatial Influences

The study identified department-specific risks, with staff in wards, waiting rooms, and operating rooms showing elevated odds of skin (OR = 1.607–4.626, p = 0.006), possibly due to prolonged exposure to irritants or poor ventilation. Mucosal symptoms were less prevalent in outpatient and inpatient departments (OR < 1, p = 0.025), speculating that spatial design and airflow differences modulate SBS risk. Despite these findings, research exploring how spatial environments differentially affect SBS remains limited. Notably, a strong link emerged between nasal symptoms and hospital ward type, with healthcare workers in the pediatric ward [45] reporting the majority of such complaints.

Table 9. Summary of domestic and international research on sick building syndrome.

Researchers	Year	Region	Building Type	Samples	Prevalence Rate (%)
Wong et al. [8]	2009	Hong Kong, China	Residential	881	34–72 (GS:34 MS:65 SS:52–59)
Kielb et al. [9]	2014	United States	School	501	0.8–16.8 (GS:15 MS:16.8 SS:14.8)
Shan et al. [21]	2016	Singapore	School	39	Unknown
Belachew et al. [10]	2018	Ethiopia	Residential	3405	21.7 (GS:54 MS:64 SS:10)
Lu et al. [15]	2018	Taiwan, China	Office	389	2.1–26.2 (GS:26.2 MS:39.1 SS:2.1)
Nakayama et al. [11]	2019	Japan	Residential	1500	20.7–31.8 (GS:8 MS:7.3–13.6 SS:Unknown)
Kim et al. [20]	2019	South Korea	Shopping mall	314	43.6–65.6 (GS:64.7 MS:65.6 SS:43.6)
Sun et al. [24]	2019	China	Residential	32	40–73.4 (GS:73.4 MS:66.7 SS:22.5)
Huo et al. [12]	2020	China	Residential	7865	9–14 (GS:14 MS:11 SS:9)
Mentese et al. [13]	2020	Turkey	Residential	121	32–72
Dhungana and Chalise [22]	2020	Nepal	Bank	234	8.1–47.6 (GS:47.6 MS:11.9 SS:8.1)
Babaoglu et al. [19]	2020	Turkey	Hospital	204	23.0–63.7 (GS:47.6 MS:36.3 SS:63.7)
Baloch et al. [50]	2020	Europe	School	5175	3.12–11.77 (GS:11.77 MS:18.71 SS:5.09)
Hou et al. [14]	2021	China	Residential	165	21–95 (GS:78.5 MS:65.8 SS:63.2)
Zuo et al. [23]	2021	China	Experimental cabin	24	Unknown
Sarkhosh et al. [16]	2021	Iran	Office	154	70.1 (GS:51.89 MS:20.33 SS:13.55)
Fu et al. [18]	2021	Malaysia	School	308	51 (GS:42.6 MS:36.7 SS:12)
Sayan and Dülger [17]	2021	Turkey	Hospital	890	23–40 (GS:40 MS:27.6 SS:26)
Akova et al. [51]	2022	Turkey	Hospital	300	64.7–74.1
Fan and Ding [52]	2022	China	Multi-type	29,785	9–29
Surawat-tanasa-kul [38]	2022	Thailand	Hospital	290	10.7–25.3 (GS:25.3 MS:10.7 SS:19.1)
Shim et al. [43]	2023	South Korea	Shopping mall	128	16.4–43.8 (GS:43.8 MS:28.9 SS:16.4)
Isman et al. [53]	2024	Malaysia	Food outlets	107	60.5–66.7

Notes: general symptoms (GS), mucosal symptoms (MS), skin symptoms (SS).

Table 9. Summary of domestic and international research on sick building syndrome.

Researchers	Year	Region	Building Type	Samples	Prevalence Rate (%)
Wong et al. [8]	2009	Hong Kong, China	Residential	881	34–72 (GS:34 MS:65 SS:52–59)
Kielb et al. [9]	2014	United States	School	501	0.8–16.8 (GS:15 MS:16.8 SS:14.8)
Shan et al. [21]	2016	Singapore	School	39	Unknown
Belachew et al. [10]	2018	Ethiopia	Residential	3405	21.7 (GS:54 MS:64 SS:10)
Lu et al. [15]	2018	Taiwan, China	Office	389	2.1–26.2 (GS:26.2 MS:39.1 SS:2.1)
Nakayama et al. [11]	2019	Japan	Residential	1500	20.7–31.8 (GS:8 MS:7.3–13.6 SS:Unknown)
Kim et al. [20]	2019	South Korea	Shopping mall	314	43.6–65.6 (GS:64.7 MS:65.6 SS:43.6)
Sun et al. [24]	2019	China	Residential	32	40–73.4 (GS:73.4 MS:66.7 SS:22.5)
Huo et al. [12]	2020	China	Residential	7865	9–14 (GS:14 MS:11 SS:9)
Mentese et al. [13]	2020	Turkey	Residential	121	32–72
Dhungana and Chalise [22]	2020	Nepal	Bank	234	8.1–47.6 (GS:47.6 MS:11.9 SS:8.1)
Babaoglu et al. [19]	2020	Turkey	Hospital	204	23.0–63.7 (GS:47.6 MS:36.3 SS:63.7)
Baloch et al. [50]	2020	Europe	School	5175	3.12–11.77 (GS:11.77 MS:18.71 SS:5.09)
Hou et al. [14]	2021	China	Residential	165	21–95 (GS:78.5 MS:65.8 SS:63.2)
Zuo et al. [23]	2021	China	Experimental cabin	24	Unknown
Sarkhosh et al. [16]	2021	Iran	Office	154	70.1 (GS:51.89 MS:20.33 SS:13.55)
Fu et al. [18]	2021	Malaysia	School	308	51 (GS:42.6 MS:36.7 SS:12)
Sayan and Dülger [17]	2021	Turkey	Hospital	890	23–40 (GS:40 MS:27.6 SS:26)
Akova et al. [51]	2022	Turkey	Hospital	300	64.7–74.1
Fan and Ding [52]	2022	China	Multi-type	29,785	9–29
Surawat-tanasa-kul [38]	2022	Thailand	Hospital	290	10.7–25.3 (GS:25.3 MS:10.7 SS:19.1)
Shim et al. [43]	2023	South Korea	Shopping mall	128	16.4–43.8 (GS:43.8 MS:28.9 SS:16.4)
Isman et al. [53]	2024	Malaysia	Food outlets	107	60.5–66.7

Notes: general symptoms (GS), mucosal symptoms (MS), skin symptoms (SS).

4.3. Limitations and Future Directions

This study provides valuable insights into SBS among Chinese medical staff but is limited to winter conditions in a specific coastal region. Given the significant climatic variations across seasons in eastern China, future research should explore seasonal differences to assess how temperature, humidity, and ventilation needs fluctuate. Longitudinal studies could further clarify causality between environmental factors and SBS symptoms, addressing the cross-sectional nature of this analysis. Additionally, incorporating objective IEQ measurements (e.g., CO₂ levels, PM_2.5 concentrations) alongside self-reported data would strengthen the evidence base. Expanding the sample to include public hospitals and diverse geographic areas could enhance generalizability, while investigating the efficacy of specific interventions (e.g., greenery installation, noise barriers) offers a pathway to practical solutions. We also acknowledge other potential factors (e.g., biological and chemical agents) and justify their exclusion due to scope and measurement constraints, with a note for future research. For example, chronic diseases should also be considered as a potential confounder in SBS symptom evaluation.

Table 10. Risk factors of sick building syndrome.

Risk Factors		Characterization Parameters	Mechanism of Influence
Indoor environmental parameters (physical)	Thermal environment	Air temperature	High temperature and humidity can easily cause discomfort [22,23]. The occurrence of SBS is positively correlated with temperature [52]. Indoor air humidity is the main influencing factor for the occurrence of mucosal irritation symptoms (p < 0.001), so improving indoor air quality can effectively reduce the probability of mucosal irritation symptoms (this study).
		Relative humidity	When relative humidity is high, the likelihood of mucosal and skin SBS symptoms in residents is lower [14].
	Air quality	CO2 concentration, ventilation rate	Higher CO2 concentration is significantly associated with a higher percentage of stuffy feelings [14]. Lower ventilation rates increase the probability of mucosal symptoms [24]. Poor air quality can cause SBS [54].
		Particulate matter concentration, dust	SBS in hospitals is related to PM1 and smoking [19]. High concentrations of PM2.5 are associated with a higher incidence of asthma [25].
	Light environment	Illuminance, color temperature	Dynamic lighting consistent with the natural light cycle can alleviate anger [55]. The occurrence of eye discomfort is related to the interaction between air quality and color temperature [56].
	Acoustic environment	Noise level	Noise is the most important factor affecting indoor environmental quality [8]. Indoor air humidity is the main influencing factor for the occurrence of mucosal irritation symptoms (p < 0.001), so improving indoor air quality can effectively reduce the probability of mucosal irritation symptoms. (this study)
Indoor environmental parameters (non-physical)		Cleaning frequency, building materials, building orientation, building layout, etc.	Green plants have an indirect, unconscious psychological effect on work efficiency, health, and stress [26]. Having windows with a view of outdoor greenery is the main influencing factor for general symptoms (p < 0.001) and mucosal symptoms (p = 0.002). Enhanced control over the indoor environment—such as adjustable temperature and lighting, lowering the odds of mucosal (p < 0.001) and general symptoms (p = 0.012). Satisfaction with building service performance, particularly work efficiency (p = 0.001 for skin) and cleanliness (p = 0.001 for skin, p = 0.001 for mucosal, p = 0.04 for general), also correlated with reduced SBS prevalence(this study).
Biological factors		Mold, dust mites, animal dander and excrement, pollen, viruses, fungi	Higher relative humidity is associated with a higher perception of moldy [14]. Condensation, dampness and moldy odors are significantly related to SBS [11]. Aspergillus versicolor and ergosterol may be risk factors for SBS [27].
Chemical factors		Formaldehyde, acetaldehyde, volatile organic compounds	High levels of acetaldehyde and volatile organic compounds are associated with a higher incidence of asthma [25].
Psychological factors		Satisfaction, stress	Psychological factors are the most important factors affecting SBS [16]. Work stress is related to general symptoms [22]. Among them, the current mood is the main influencing factor (p < 0.001), so improving one’s own mood is conducive to reducing the occurrence of SBS symptoms. Secondly, for work-related psychosocial factors, high work pressure, working more than 10 h a day, and staff with greater control are positively correlated with lower respiratory symptoms (this study).
Individual factors		Gender, age, region, education level, pre-existing diseases	Age is significantly related to general symptoms [22]. Females exhibit SBS symptoms at a rate 1.12 to 1.31 times higher than males [57]. Females are more susceptible, with an approximate ratio of 1:0.4 (this study).

Table 10. Risk factors of sick building syndrome.

Risk Factors		Characterization Parameters	Mechanism of Influence
Indoor environmental parameters (physical)	Thermal environment	Air temperature	High temperature and humidity can easily cause discomfort [22,23]. The occurrence of SBS is positively correlated with temperature [52]. Indoor air humidity is the main influencing factor for the occurrence of mucosal irritation symptoms (p < 0.001), so improving indoor air quality can effectively reduce the probability of mucosal irritation symptoms (this study).
		Relative humidity	When relative humidity is high, the likelihood of mucosal and skin SBS symptoms in residents is lower [14].
	Air quality	CO2 concentration, ventilation rate	Higher CO2 concentration is significantly associated with a higher percentage of stuffy feelings [14]. Lower ventilation rates increase the probability of mucosal symptoms [24]. Poor air quality can cause SBS [54].
		Particulate matter concentration, dust	SBS in hospitals is related to PM1 and smoking [19]. High concentrations of PM2.5 are associated with a higher incidence of asthma [25].
	Light environment	Illuminance, color temperature	Dynamic lighting consistent with the natural light cycle can alleviate anger [55]. The occurrence of eye discomfort is related to the interaction between air quality and color temperature [56].
	Acoustic environment	Noise level	Noise is the most important factor affecting indoor environmental quality [8]. Indoor air humidity is the main influencing factor for the occurrence of mucosal irritation symptoms (p < 0.001), so improving indoor air quality can effectively reduce the probability of mucosal irritation symptoms. (this study)
Indoor environmental parameters (non-physical)		Cleaning frequency, building materials, building orientation, building layout, etc.	Green plants have an indirect, unconscious psychological effect on work efficiency, health, and stress [26]. Having windows with a view of outdoor greenery is the main influencing factor for general symptoms (p < 0.001) and mucosal symptoms (p = 0.002). Enhanced control over the indoor environment—such as adjustable temperature and lighting, lowering the odds of mucosal (p < 0.001) and general symptoms (p = 0.012). Satisfaction with building service performance, particularly work efficiency (p = 0.001 for skin) and cleanliness (p = 0.001 for skin, p = 0.001 for mucosal, p = 0.04 for general), also correlated with reduced SBS prevalence(this study).
Biological factors		Mold, dust mites, animal dander and excrement, pollen, viruses, fungi	Higher relative humidity is associated with a higher perception of moldy [14]. Condensation, dampness and moldy odors are significantly related to SBS [11]. Aspergillus versicolor and ergosterol may be risk factors for SBS [27].
Chemical factors		Formaldehyde, acetaldehyde, volatile organic compounds	High levels of acetaldehyde and volatile organic compounds are associated with a higher incidence of asthma [25].
Psychological factors		Satisfaction, stress	Psychological factors are the most important factors affecting SBS [16]. Work stress is related to general symptoms [22]. Among them, the current mood is the main influencing factor (p < 0.001), so improving one’s own mood is conducive to reducing the occurrence of SBS symptoms. Secondly, for work-related psychosocial factors, high work pressure, working more than 10 h a day, and staff with greater control are positively correlated with lower respiratory symptoms (this study).
Individual factors		Gender, age, region, education level, pre-existing diseases	Age is significantly related to general symptoms [22]. Females exhibit SBS symptoms at a rate 1.12 to 1.31 times higher than males [57]. Females are more susceptible, with an approximate ratio of 1:0.4 (this study).

5. Conclusions

This study explored the prevalence and risk factors of sick building syndrome (SBS) among 615 medical staff across seven private hospitals in Zhejiang Province, China, during the winter season. The aim was to develop comprehensive, multifactorial strategies that integrate both psychosocial and physical measures to effectively prevent the occurrence of SBS symptoms. The findings revealed that the prevalence rates for skin symptoms, mucosal symptoms, and general symptoms were 32.8%, 61%, and 71.1%, respectively. Among individual and occupational factors, gender, mood, department type, and duration of time spent in the building significantly impacted symptom occurrence. Notably, poor or average mood emerged as a primary driver, substantially elevating the odds of experiencing SBS symptoms, while females showed higher susceptibility to skin and general symptoms compared to males. Department-specific risks were evident, with staff in wards, waiting rooms, and operating theaters facing increased odds of skin, likely due to prolonged irritant exposure or inadequate ventilation.

Building environmental design also played a pivotal role. Access to windows with views of outdoor greenery significantly reduced the likelihood of general and mucosal symptoms (p = 0.002), while noisy outdoor environments heightened the risk of skin (p = 0.006) and mucosal symptoms (p = 0.007). Indoor environmental quality factors, including air humidity and lighting, further influenced outcomes, with poor air quality strongly linked to mucosal irritation. Enhanced satisfaction with control of the indoor environment—such as adjustable temperature and lighting—served as a protective factor, lowering the odds of mucosal (p < 0.001) and general symptoms (p = 0.012). Satisfaction with building service performance, particularly work efficiency (p = 0.001 for skin) and cleanliness (p = 0.001 for skin, p = 0.001 for mucosal, p = 0.04 for general), also correlated with reduced SBS prevalence.

These findings underscore the interplay of modifiable environmental and psychological factors in SBS occurrence, offering actionable strategies for hospital management. Enhancing visibility of greenery, implementing soundproofing measures, improving ventilation systems, and empowering staff with greater control over their workspaces could substantially alleviate SBS symptoms. Additionally, maintaining high cleanliness standards not only boosts user satisfaction but also reduces symptom likelihood, providing a dual benefit for staff health and operational efficiency in Chinese hospitals.