Indoor Air Quality + Health

The primary source for the Selected Results from Five Product Emissions Studies, Five Product-Emissions Studies Summarized in the table below, Adverse Health Effects Reported statistics, Most Frequently Reported Health-Effects categories, and the Reported Access Effects on this page is reference 5 below. Product-emissions testing also draws on the related Steinemann and Nematollahi studies (2015–2020) summarized within that entry.

Certain percentages shown on the page above are rounded to the nearest whole number. Exact values from each study appear in the references below.

1. Horvat, T., Pehnec, G., & Jakovljević, I. (2025). "Volatile Organic Compounds in Indoor Air: Sampling, Determination, Sources, Health Risk, and Regulatory Insights." Toxics, 13, Article 344. https://doi.org/10.3390/toxics13050344. Open access under a Creative Commons Attribution license. "Monoterpenes readily undergo chemical reactions with airborne oxidative agents, such as OH•, NO3, or ozone, producing dangerous secondary pollutants such as organic acids, formaldehyde, and SOA [129]." (p. 14 of 36) "Terpenes are used as active solvents in some cleaning products and perfumed agents in consumer products. These substances produce formaldehyde, hydrogen peroxide, hydroxyl radical and SOA in reaction with ozone [185–187]. According to Bello et al. [188], ten-minute cleaning sessions with glass and bathroom cleaners raised overall VOC concentrations for up to 20 min after the cleaning operation ended. Singer et al. [189] investigated concentrations of limonene and showed that it can be found in 10 to hundreds of milligrams per cubic meter in air and persist for many hours after cleaning." (p. 22 of 36) "Indoor air ventilation systems can significantly affect air quality. Several studies have highlighted increased levels of VOC concentrations in areas with inadequate ventilation." (p. 22 of 36) "Terpenes (α-pinene, camphene, limonene) represent the most prevalent group of compounds found in schools and kindergartens due to the frequency of their use as cleaning agents in these settings [218]." (p. 24 of 36) ↩
2. National Toxicology Program (NTP), U.S. Department of Health and Human Services. "Report on Carcinogens, Fifteenth Edition, Formaldehyde CAS No. 50-00-0" For table of contents: https://ntp.niehs.nih.gov/research/assessments/cancer/roc Accessed August 2026."Formaldehyde is known to be a human carcinogen based on sufficient evidence of carcinogenicity from studies in humans and supporting data on mechanisms of carcinogenesis." ↩
3. Patra, S. S., et al. (2024). "Rapid Nucleation and Growth of Indoor Atmospheric Nanocluster Aerosol during the Use of Scented Volatile Chemical Products in Residential Buildings." ACS EST Air, 1(10), 1276–1293. https://doi.org/10.1021/acsestair.4c00118. PMID: 39417158; PMCID: PMC11474976. Scented volatile chemical products (sVCPs) release terpenes indoors that react with ozone to trigger new particle formation—producing nanoparticle concentrations and growth rates orders of magnitude higher than outdoor events. These tiny particles penetrate deep into the lungs, delivering respiratory doses comparable to or exceeding those from gas stoves and diesel engines. ↩
4. California Air Resources Board (CARB). "Board Tightens Regulations on Smog-Forming Compounds for Household Products". March 25, 2021; and "Consumer products — including personal care products such as hair spray and perfumes, household cleaners, air fresheners, and even household pesticides — emit smog-forming volatile organic compound emissions (VOCs). VOCs are a precursor to smog. Consumer products are the second largest source of VOC emissions, behind the collective VOC emissions from all off-road mobile sources." "Personal fragrance, including perfumes, aftershaves, lotions, powders, and body mists and sprays, is the second largest source of consumer product VOC emissions."
   California Air Resources Board (CARB). "Fragrance Use in Consumer Products". "Over the past three decades, CARB has set VOC limits for numerous consumer product categories resulting in reduced fragrance use. For example, VOC limits on cleaning products capped the amount of monoterpenes (which have fragrance as well as solvency properties) in those products." "CARB also set new and lower VOC limits in 2021 for personal fragrance products (perfumes/colognes) and several types of “air freshener” products including automatic aerosol air fresheners, manual aerosol air fresheners, concentrated aerosol air fresheners, and total release aerosol air freshener products." ↩
5. Steinemann, A. (2021). Adapted and summarized from "The Fragranced Products Phenomenon: Air Quality and Health, Science and Policy." Air Quality, Atmosphere & Health, 14, 235–243. https://doi.org/10.1007/s11869-020-00928-1. Licensed under Creative Commons Attribution 4.0 International (CC BY 4.0): https://creativecommons.org/licenses/by/4.0/. "Across four countries, adults reported health effects from fragranced products" and "Loss of societal access" survey findings obtained from this source come from nationally representative cross-sectional surveys of adults ages 18–65 in the U.S., Australia, the U.K., and Sweden. The surveys were performed in June 2016 (US, AU, UK) and June 2017 (SE). Each country sample included approximately 1,100 respondents and was representative by age, gender, and region, with a 95% confidence level and 3% margin of error. ↩

   Full citations for product-emissions studies referenced by this source: (Steinemann 2015; Nematollahi et al. 2019, 2018a, b; Steinemann et al. 2020):

   • Steinemann, A., doi.org/10.1007/s11869-015-0327-6, "Volatile Emissions from Common Consumer Products" Air Quality, Atmosphere & Health 8, 273–281 (2015).
   • Nematollahi N, Kolev SD, Steinemann A., doi.org/10.1007/s11869-019-00754-0, "Volatile Chemical Emissions from 134 Common Consumer Products" Air Quality, Atmosphere & Health, 12, 1259–1265 (2019).
   • Nematollahi N, Doronila A, Mornane PJ, Duan A, Kolev SD, Steinemann A. "Volatile Chemical Emissions from Fragranced Baby Products". Air Quality, Atmosphere & Health,. 2018;11(7):785-790. doi: 10.1007/s11869-018-0593-1. Epub 2018 Jun 22. PMID: 30147808; PMCID: PMC6097056.
   • Nematollahi, N., Kolev, S.D. & Steinemann, A., doi.org/10.1007/s11869-018-0606-0, "Volatile Chemical Emissions from Essential Oils." Air Quality, Atmosphere & Health, 11, 949–954 (2018).
   • Steinemann, A., Nematollahi, N., Weinberg, J.L. et al., doi.org/10.1007/s11869-020-00886-8, "Volatile Chemical Emissions from Car Air Fresheners." Air Quality, Atmosphere & Health, 13, 1329–1334 (2020).

   Five product-emissions studies summarized (Steinemann 2015; Nematollahi et al. 2019, 2018a, b; Steinemann et al. 2020)

   Products studied	VOCs found	Potentially hazardous VOCs	Disclosure finding
   37 common products: air fresheners, laundry, cleaning, personal care	559 occurrences / 156 identities	230 occurrences / 42 identities; all products emitted potentially hazardous VOCs	Fewer than 3% of VOCs and fewer than 6% of potentially hazardous VOCs disclosed
   134 common products: air fresheners, laundry, cleaning, personal care, sunscreens	1,538 occurrences / 338 identities	517 occurrences / 69 identities; 99% of products emitted potentially hazardous VOCs	Fewer than 10% of VOCs and fewer than 4% of potentially hazardous VOCs disclosed
   42 fragranced baby products	684 occurrences / 228 identities	207 occurrences / 43 identities	Fewer than 5% of VOCs and fewer than 13% of potentially hazardous VOCs disclosed
   24 commercial essential oils	589 occurrences / 188 identities	124 occurrences / 33 identities	No ingredients disclosed on essential-oil labels in the study
   12 car air fresheners	546 occurrences / 275 identities	30 occurrences / 9 identities	Fewer than 2% of VOCs and none of the potentially hazardous VOCs disclosed

   PH VOC = potentially hazardous VOC, following the article’s terminology. The page paraphrases the article’s summary of the five studies.

6. Perinelli, D. R., et al. (2020). “Encapsulation of Flavours and Fragrances into Polymeric Capsules and Cyclodextrins Inclusion Complexes: An Update.” Molecules, 25(24), 5878. "Through encapsulation, the compounds are protected by a shell of a different nature (e.g., polymeric, inorganic, lipid or mixed), which acts as a diffusion barrier, thereby enhancing their retention, controlling the release and prolonging the chemical stability [10]. Encapsulation can be achieved using several techniques depending on the nature of the wall material and the fragrance itself, leading to the formation of micro/nano cargoes such as capsules, spheres or vesicles." ↩
7. Nakamura, E. “Thousands call for end to aroma capsules, citing ‘scent pollution’,” The Asahi Shimbun, March 22, 2024. Source note: The Japan case study on this page draws substantially from reporting in this article. The petition figures and parties involved, government and hospital responses, school-survey figure, and the experiences and observations of petition signers, municipal assembly member Sanae Teramoto, and respiratory physician Akio Yamazaki are summarized or quoted from the article. Direct quotations are attributed to the speakers as reported by The Asahi Shimbun; the remaining article-derived material is paraphrased. The individual experiences are reported personal accounts, not findings from a clinical study. ↩
8. Steinemann, A. (2016). “Fragranced Consumer Products: Exposures and Effects from Emissions.” Air Quality, Atmosphere & Health. "Scented laundry products vented outdoors: 12.5 % reported health problems from the scent of laundry products coming from a dryer vent (4.2 % mucosal symptoms, 4.0 % respiratory problems, 3.6 % skin problems, 3.3 % migraine headaches, 2.6 % gastrointestinal problems, 2.5 % asthma attacks, and others). This compares to previous studies (Caress and Steinemann 2009) that found 10.9 % of the population (in 2005–2006) reported headaches, breathing difficulties, or other health problems when exposed to the scent of laundry products vented outside." ↩
9. Steinemann, A., et al. (2013). “Chemical Emissions from Residential Dryer Vents During Use of Fragranced Laundry Products.” Air Quality, Atmosphere & Health. "Our analyses found more than 25 VOCs emitted from dryer vents, with the highest concentrations of acetaldehyde, acetone, and ethanol. Seven of these VOCs are classified as hazardous air pollutants (HAPs) and two as carcinogenic HAPs (acetaldehyde and benzene) with no safe exposure level, according to the US Environmental Protection Agency. As context for significance, the acetaldehyde emissions during use of one brand of laundry detergent would represent 3% of total acetaldehyde emissions from automobiles in the study area. Our study points to the need for additional research on this source of emissions and the potential impacts on human and environmental health." ↩
10. European Union, EUR-Lex. Access to European Union law. Document 32021R1902. Commission Regulation (EU) 2021/1902, amending Annex II to Regulation (EC) No 1223/2009. Accessed August 2026. Added 2-(4-tert-butylbenzyl) propionaldehyde (lilial, CAS 80-54-6) to the substances prohibited in cosmetics, effective 1 March 2022, following its harmonised classification as a Category 1B reproductive toxicant under the CLP Regulation. ↩
11. French Agency for Food, Environmental and Occupational Health & Safety (ANSES). "ANSES proposes classifying galaxolide as toxic for reproduction in the European CLP Regulation." March 4, 2025. ANSES proposed classifying galaxolide (HHCB) as a Category 1B reproductive toxicant under the CLP Regulation, citing potential effects on fertility and development. ECHA opened the scientific dossier for public consultation on January 27, 2025.
    European Chemicals Agency (ECHA). "Harmonised Classification and Labelling Process—Galaxolide (HHCB/hexamethylindanopyran)." CAS 1222-05-5; EC 214-946-9; Index 603-212-00-7. RAC adopted its final opinion in December 2025 and published it in March 2026, recommending classification as Repr. 1B, H360D (“May damage the unborn child”), based on developmental toxicity. As of July 2026, the recommendation has not been incorporated into CLP Annex VI. Commission adoption and application of an Annex VI entry remain necessary. Once applicable, the classification would generally prohibit the use of HHCB in EU cosmetic products under Article 15, subject to applicable exemptions and transition provisions. The ECHA record provides access to the RAC opinion and supporting background document. ↩
12. Weaver, J. A., et al. (2020). "Hazards of diethyl phthalate (DEP) exposure: A systematic review of animal toxicology studies." Environment International, 145, 105848. "Conclusions: These results suggest that DEP exposure may induce androgen-independent male reproductive toxicity (i.e., sperm effects) as well as developmental toxicity and hepatic effects, with some evidence of female reproductive toxicity. More research is warranted to fully evaluate these outcomes and strengthen confidence in this database." ↩
13. Ashcroft, S., Dosoky, N. S., Setzer, W. N., & Satyal, P. (2024). "Synthetic Endocrine Disruptors in Fragranced Products." Endocrines, 5(3), 366–381. https://doi.org/10.3390/endocrines5030027 Reviews fragrance-relevant endocrine-active chemicals, including the polycyclic musks galaxolide (HHCB) and tonalide (AHTN) and the nitro musks, describing the hormone-receptor and steroid-signalling activity reported for these compounds in laboratory studies. ↩
14. European Commission, Internal Market, Industry, Entrepreneurship and SMEs. "Endocrine disruptors" (cosmetics). Accessed August 2026. Sets out the Commission's priority list of potential endocrine disruptors in cosmetics and the SCCS-assessment process; the priority substances include the fragrance-relevant benzophenone, benzyl salicylate, and BHT. ↩
15. International Agency for Research on Cancer (IARC), World Health Organization (WHO). Last update: 3 July 2026. "IARC Monographs — List of Classifications." Classifies formaldehyde as carcinogenic to humans (Group 1); methyleugenol as probably carcinogenic (Group 2A, upgraded in 2023; IARC Monographs Vol. 134, published 2024); and benzophenone, β-myrcene, and safrole as possibly carcinogenic (Group 2B), the latter three based on sufficient evidence in experimental animals. "Agents Classified by the IARC Monographs, Volumes 1–142." ↩
16. State of California, Office of Environmental Health Hazard Assessment (OEHHA). The Proposition 65 List. Accessed August 2026. Lists β-myrcene, benzophenone, methyleugenol, pyridine, safrole, and formaldehyde as chemicals known to the State of California to cause cancer; the β-myrcene and pyridine entries rest on NTP animal-carcinogenicity findings via the authoritative-bodies mechanism. ↩
17. Imai, S., et al. (2002). "An onion enzyme that makes the eyes water." Nature, 419, 685. https://doi.org/10.1038/419685a The study identified lachrymatory-factor synthase and explains that chopping onion tissue releases an irritating lachrymatory factor responsible for tearing. ↩
18. Miller, C. S., Palmer, R. F., Kattari, D., et al. (2023). "What Initiates Chemical Intolerance? Findings from a Large Population-Based Survey of U.S. Adults." Environmental Sciences Europe, 35, Article 65. https://doi.org/10.1186/s12302-023-00772-x A population-based survey (10,981 U.S. adults recruited; about 7,997 in the census-weighted analytic sample) assessed Chemical Intolerance (CI) using the validated Quick Environmental Exposure and Sensitivity Inventory (QEESI). Twenty percent met QEESI criteria for Toxicant-Induced Loss of Tolerance (TILT), and about half of those identified one or more initiating exposures. The most commonly reported initiators were mold (15.6%), pesticides (11.5%), medical/surgical procedures (11.3%), remodeling/new construction (10.7%), fires/combustion products (6.4%), and implants (1.6%). Protracted antibiotic use for prostate, skin, tonsil, gastrointestinal, and sinus infections was strongly associated with TILT/CI (OR > 2). ↩
19. Miller, C. S., Palmer, R. F., Dempsey, T. T., et al. (2021). "Mast Cell Activation May Explain Many Cases of Chemical Intolerance." Environmental Sciences Europe, 33, Article 129. https://doi.org/10.1186/s12302-021-00570-3 "Mast cell activation and mediator release appear capable of explaining the increasingly frequent observations by physicians and their patients of chronic multi-system symptoms and new-onset chemical, food and drug intolerances following exposure to a wide variety of xenobiotics. Our logistic regression model demonstrated that as the likelihood of patients having MCAS increases, their likelihood of having CI/TILT similarly increases, to a near-perfect correspondence at the high ends of these scales." "The most problematic triggers for many MCAS patients are fragrances (VOCs at extraordinarily low exposure levels), which also pose major problems for CI individuals" ↩
20. American Medical Association (AMA). Fragrance Regulation H-135.902. AMA PolicyFinder, adopted 2025. Recognizes fragrance sensitivity and encourages healthcare facilities, government agencies, and nonprofits to adopt fragrance-free policies, addressing accessibility, healthcare settings, research needs, and ingredient disclosure. ↩
21. Wagner, H., & Klaschka, U. (2026). "Forced isolation by invisible barriers: international survey on the effects of fragrances on the quality of life." Environmental Sciences Europe, 38, 2. https://doi.org/10.1186/s12302-025-01259-7 The paper references previous cross-sectional surveys that showed 20 - 35% of the adult population reports health effects from fragrances. This international survey of 3,152 people with self-reported fragrance sensitivity examined symptoms, underlying conditions, coping strategies, social participation, and quality of life. "The survey was executed using the cloud-based software provided by the service company LimeSurvey. The anonymous survey was run in five languages: English, French, German, Italian, Spanish. The survey was piloted with 11 individuals. Full implementation started 23rd August 2024 and ended 28th February 2025." "Around three quarters (76.84%) of survey participants state that fragrance exposure affects their quality of life strongly or takes away any quality of life completely." "Fragrance exposure is an invisible barrier that leads to isolation of fragrance sensitive persons in society." ↩
22. Yu J, Lakey PSJ, Ditto JC, et al. VOC injection into a house reveals large surface reservoir sizes in an indoor environment. Proceedings of the National Academy of Sciences, 2025. View study. ↩
23. Warburton T, et al. The impact of plug-in fragrance diffusers on residential indoor VOC concentrations. Environmental Science: Processes & Impacts, 2023. View study. ↩
24. Gherghel S. Analysis of transferred fragrance and its forensic implications. University College London, 2019. View research. ↩
25. Teixeira CSNR, Martins IMD, Mata VLG, Barreiro MFF, Rodrigues AE. Characterization and evaluation of commercial fragrance microcapsules for textile application. Journal of The Textile Institute, 2012;103(3):269–282. View study. ↩

Additional Sources — background & further reading (not directly cited above)

• National Institute of Environmental Health Sciences, (NIEHS). "Endocrine Disruptors." Describes endocrine-disrupting chemicals as substances that can mimic, block, or interfere with the body's hormones, and notes that because the endocrine system operates through very small hormone concentrations, both low-level exposures and the timing of exposure can matter.
• Patra SS, Jiang J, Liu J, Steiner G, Jung N, Boor BE. "Flame-Free Candles Are Not Pollution-Free: Scented Wax Melts as a Significant Source of Atmospheric Nanoparticles." Environmental Science & Technology Letters 12(2), 175–182 (2025). doi: 10.1021/acs.estlett.4c00986. PMID: 39957788; PMCID: PMC11823451. "Our findings reveal that terpenes released from scented wax melts react with indoor atmospheric ozone (O3) to initiate new particle formation (NPF) events, resulting in significant indoor atmospheric nanoparticle concentrations (>106 cm–3) comparable to those emitted by combustion-based scented candles, gas stoves, diesel engines, and natural gas engines. We show that scented wax melt-initiated NPF events can result in significant respiratory exposures, with nanoparticle respiratory tract deposited dose rates similar to those determined for combustion-based sources. Our results challenge the perception of scented wax melts as a safer alternative to combustion-based aromatherapy, highlighting the need for further research on the toxicological properties of the newly formed nanoparticles to better understand their environmental health implications."
• Palmer RF, Dempsey TT, Afrin LB, et al. (2023) "Chemical Intolerance and Mast Cell Activation: A Suspicious Synchronicity." J Xenobiot. 2023 Nov 12;13(4):704-718. PMID: 37987446; PMCID: PMC10660865. https://doi.org/10.3390/jox13040045 "This paper confirms the strong likelihood—given the known biological behaviors of mast cells, the known clinical behaviors of MCAS, and prevalent findings of clinical issues of CI in a sizable cohort of MCAS patients—that MCAS may be a key biomechanism for a disease which underlies a host of "medically unexplained symptoms" and syndromes triggered by xenobiotics. MCAS doctors explain these adverse reactions as being due to altered MCs sensitizing and degranulating when provoked by previously tolerated chemicals or physical stimuli [8,12]." "From a public health standpoint, improved regulation of environmental initiators such as pesticides and combustion products and triggers such as fragranced consumer products and food additives may help reduce the impact of CI and MCAS."
• U.S. Environmental Protection Agency, (EPA). "What Are Volatile Organic Compounds (VOCs)?" Concentrations of many VOCs are consistently higher indoors (up to ten times higher) than outdoors.
  "Volatile Organic Compounds’ Impact on Indoor Air Quality". The U.S. EPA's overview of how indoor chemicals affect indoor air.
• National Oceanic and Atmospheric Administration, (NOAA)."Those Scented Products You Love? NOAA Study Finds They Can Cause Air Pollution." 15 Feb. 2018
• Lawrence Berkeley National Laboratory, "Introduction to VOCs." A national lab’s primer on what VOCs are — and why a single “total VOC” number can be misleading.
• Wells JR, Schoemaecker C, Carslaw N, Waring MS, Ham JE, Nelissen I, Wolkoff P., "Reactive indoor air chemistry and health - A workshop summary." International Journal of Hygiene and Environmental Health. 2017 Nov; 220(8):1222-1229. doi: 10.1016/j.ijheh.2017.09.009. Epub 2017 Sep 23. PMID: 28964679; PMCID: PMC6388628.
• Wu Y, et al., (2024), "Indoor Emission, Oxidation, and New Particle Formation of Fragranced Personal Care Products." "...The tested PCPs include a perfume, a roll-on deodorant, a body spray, a hair spray, and a hand lotion. Indoor use of these PCPs emitted over 200 VOCs and resulted in indoor VOC mixing ratios of several parts per million. The VOC emission factors for the PCPs varied from 2 to 964 mg g–1. We identified strong emissions of terpenes and their derivatives, which are likely used as fragrant additives in the PCPs. When using the PCPs in the presence of indoor ozone, these reactive VOCs underwent oxidation reactions to form a variety of gas-phase oxidized vapors and led to rapid new particle formation (NPF) events with particle growth rates up to ten times higher than outdoor atmospheric NPF events. The resulting ultrafine particle concentrations reach ∼34000 to ∼200000 cm–3 during the NPF events."
• Yeoman AM, Shaw M, Ward M, Ives L, Andrews SJ, Lewis AC. (2023), "Gas Phase Emissions of Volatile Organic Compounds Arising from the Application of Sunscreens.", International Journal of Environmental Research and Public Health. 2023 May 24;20(11):5944. doi: 10.3390/ijerph20115944. PMID: 37297548; PMCID: PMC10252547. "Fragrance compounds, such as monoterpenes, can induce adverse effects when inhaled in high concentrations [23] and have the potential to react with ozone and hydroxyl radials to form secondary organic aerosols (SOAs) [24] and small carbonyls such as formaldehyde."
• Kim S, Hong SH, Bong CK, Cho MH. "Characterization of air freshener emission: the potential health effects." Journal of Toxicological Sciences, 2015;40(5):535-50. doi: 10.2131/jts.40.535. PMID: 26354370. Research on what air fresheners release and how those chemicals — and their reaction products — can affect health.
  Lawrence Berkeley National Laboratory. "Secondary Pollutants from Cleaning Products and Air Freshener Use in the Presence of Ozone". "This study investigated secondary air pollutants formed from reactions between constituents of terpene-containing household products and ozone."
• Destiny Tiburcio, Makenna Parsell, Hannah Shapiro, Sarah Adolphe, Oandy Naranjo, Sophia George, Michal Toborek, "Endocrine Disruption to Metastasis: How Phthalates Promote Breast Carcinogenesis". Ecotoxicology and Environmental Safety, Vol. 303, (2025). 118874, ISSN 0147-6513,(https://www.sciencedirect.com/science/article/pii/S0147651325012199). Open access under a Creative Commons Attribution license CC BY 4.0 A 2025 review in Ecotoxicology and Environmental Safety examines the evidence linking phthalates — endocrine-disrupting chemicals used in plastics, cosmetics, and food packaging — to breast cancer. Noting that hereditary factors account for only 5–10% of cases, the authors describe mechanisms by which phthalate exposure could promote the disease, including effects on estrogen receptor signaling, activation of cancer-driving pathways, and induction of treatment resistance. The authors characterize the evidence as emerging; the review sets out biological plausibility and directions for research rather than establishing that phthalate exposure causes breast cancer in humans.
• Masri S, Miller CS, Palmer RF, et al. "Toxicant-Induced Loss of Tolerance for Chemicals, Foods, and Drugs". Environmental Sciences Europe 33:65 (2021).
• Suzuki K, Okamura M, Haruyama Y, Suzuki S, Shiina T, Kobashi G, Hirata K., "Exploring the Contributing Factors to Multiple Chemical Sensitivity in Patients with Migraine". Journal of Occupational Health, 2022 Jan;64(1):e12328. doi: 10.1002/1348-9585.12328. PMID: 35363938; PMCID: PMC9176718. "We showed that MCS was observed in 20% of patients with migraine, and our study results may indicate a possible association of MCS with central sensitization and hypersensitivity‐related symptoms in patients with migraine."