Does Usage of a Room Air Freshener Affect the Nasal

Delivered by Publishing Technology to: Linda Hanai IP: 202.62.16.210 On: Thu, 11 Dec 2014 01:22:18Copyright (c) Oceanside Publications, Inc. All rights reserved.

For permission to copy go to https://www.oceansidepubl.com/permission.htm

Does usage of a room air freshener affect the nasalmucosa?

Mehmet Akdag, M.D.,1 Salih Bakir, M.D.,1 Ulas Alabalik, M.D.,2 Fazıl Emre Ozkurt, M.D.,1

and Ismail Topcu, M.D.1

ABSTRACTBackground: Effects of chemicals emitted from the room air freshener sprays (RAFSs) on nasal mucosa are still unclear. The purpose of this study was to

investigate effects of RAFSs on the nasal mucosa of rats for different time intervals.Methods: Twenty-eight rats were randomly divided into four experimental groups: group 1 (n � 7) was the control group and not exposed to RAFS or

other chemicals, group 2 (n � 7) was exposed to RAFS for 1 month, group 3 (n � 7) was exposed to RAFS for 2 months, and group 4 (n � 7) was exposedto RAFS for 3 months. Samples from the nasal septum were stained using hematoxylin and eosin solution, examined by a pathologist using a light microscope,and analyzed with Fisher’s exact test.

Results: We observed that distinct histopathological differences in the nasal mucosa of exposed rats depends on different time intervals (p � 0.05).Increased congestion was found after the 1st month of exposure (group 2). Although edema and mild inflammatory cell infiltration, including someeosinophils, was seen after the 2nd month (group 3), squamous metaplasia, numerous eosinophils, and intense inflammatory cell infiltration began after3 months of exposure (group 4).

Conclusion: Our results showed that continuous use of RAFS can cause inflammation and eosinophilic infiltration in rats, which begins after 2 monthsof exposure and may lead to metaplasia after 3 months. Because of differences in body size, geometry, and physiological responses of rats, the extrapolation ofthese results to humans is not straightforward. However, any such comparison should be made with caution. Finally, more performance is necessary to clarifythis subject.

(Am J Rhinol Allergy 28, e202–e208, 2014; doi: 10.2500/ajra.2014.28.4105)

The nasal mucosa performs many important functions, such astemperature regulation through the heating of air, olfaction,

respiration, and protection of the airway by filtering foreign bodies.1

Nasal mucosa, which is lined by respiratory epithelium, needs ahealthy mucociliary transport mechanism, cell structure, and anat-omy to perform these functions. A problem with cell structure oranatomy may disrupt the epithelial cells of the nasal mucosa andcause different nasal diseases such as rhinitis. Rhinitis is an inflam-matory condition of the nasal mucosa and can be caused by a varietyof different allergic and nonallergic (infectious, hormonal, drug in-duced, chemical agent induced, and occupational) conditions).2

Fragranced products including room air freshener sprays (RAFSs),laundry supplies, and personal care products are commonly used indaily life. Previous studies suggest that fragranced products cancreate adverse health effects, especially in sensitive individuals suchas asthmatic patients.3 RAFSs are volatile organic compounds (VOCs)composed of low–molecular-weight compounds with lower and up-per boiling points of 50–100°C and 240–260°C, respectively.4 All ofthese solvents are liquid at room temperature and have lipophilicproperties. Common household products that contain VOCs includeair fresheners, insect sprays, cleaners, polishes, and personal careproducts such as hair spray and deodorant.4 These chemical sub-stances are normally considered tolerable, but these substances maylead to multiple-chemical sensitivity, in which its symptoms includerespiratory problems such as rhinitis and anaphylaxis, as well asneurological, musculoskeletal, dermatological, gastrointestinal, car-diac, and endocrine effects.5,6

Different chemical agents are commonly used throughout our livesand we are exposed to them via nasal inhalation. The nasal mucosa islocated at the airway entrance and changes to its functional structureare likely responsible for the development of rhinitis. However, it isunclear how these chemical agents lead to histopathological changeswithin the nasal mucosa. Although the functional effects of RAFSs orgases have been examined with allergy susceptibility testing in ratsand humans, histochemical changes have not been studied. Impor-tantly, complete functional testing has not been conducted on theairway of rats exposed to chemical agents.7–9

The aim of this study was to investigate the short-term histopatho-logical effects that normal levels of air freshener sprays have on therat nasal mucosa.

MATERIALS AND METHODSThis study was approved by Dicle University Medical Institution

Ethical Committee (study number 2013/03) and was performed ac-cording to the Guide for the Care and Use of Laboratory Animals issuedby the National Institutes of Health, Commission on Life Sciences,and the National Research Council.10

Experimental DesignTwenty-eight male adult Wistar albino rats weighing between 225

and 320 g were used in this study. Animal weights were measured atthe beginning and end of the study. The rats were housed in accor-dance with standard guidelines in cages maintained under standardenvironmental conditions (room temperature between 22 and 24°C,50% relative humidity, and 12-hour light and dark cycles).11 The 28rats were randomly divided into four groups: group 1/control (n � 7)was a control group not exposed to RAFSs or other chemicals, group2/RAFS1 (n � 7) was exposed to RAFSs for 1 month, group 3/RAFS2(n � 7) was exposed to RAFSs for 2 months, and group 4/RAFS3 (n �7) was exposed to RAFSs for 3 months. Animals underwent anteriorrhinoscopy with a pediatric speculum and rigid pediatric nasal en-doscopy before the study began (1-mm; Karl Storz Hopkins AG,Tuttlingen, Germany). Animals were housed in a room with a volumeof 30 m3 (3 � 2.5 � 4 m). There was 3 m of distance between theanimals and the RAFSs. The control group was placed in a room

From the Departments of 1Otolaryngology and 2Pathology, Faculty of Medicine, DicleUniversity, Diyarbakir, TurkeyPresented at the 11th International Otolaryngology–Head and Neck surgical scientificmeeting, April 17–19, 2014, Ankara, TurkeyThe authors have no conflicts of interest to declare pertaining to this articleAddress correspondence to Mehmet Akdag, M.D, Department of Ear, Nose, and Throatand Head and Neck Surgery, Faculty of Medicine, Dicle University, Diyarbakir,TurkeyE-mail address: [email protected] online August 12, 2014Copyright © 2014, OceanSide Publications, Inc., U.S.A.

e202 November–December 2014, Vol. 28, No. 6

DO NOT C

OPY



without RAFSs. The air exchange rate within the rooms was main-tained at 0.670.1 air changes per hour, similar to typical residential airexchange rates.

Exclusion CriteriaAnimals that showed signs of nasal disease were excluded. Other

exclusion criteria were as follows: (1) runny nose, (2) detectableexternal nasal abnormalities on nasal endoscopy, and (3) signs ofnasal disease.

Drugs and AnesthesiaAnimals were anesthetized intraperitoneally with 30 mg/kg of

ketamine hydrochloride (Ketalar; Eczacibasi Ilac Sanayi ve TicaretA.S., Luleburgaz, Turkey) and 4 mg/kg of xylazine (Alfazyne 2%;Alfasan International B.V., Woerden, The Netherlands). An automaticpulse RAFS was used in this study, The RAFSs (Room Air Freshener;Reckitt Benckiser, Lane, Derby, England). We analyzed gases usingthe solid-phase microextraction technique with a gas chromatographmass spectrometer (GCMS-TQ8030 Triple Quadrupole; fiber, 75-�mCarboxen/Polydimethylsiloxane; extraction conditions, 50°C, 15 min-utes; volume, 50 �m; Kyoto, Japan). There were 97 samples (Fig. 1),and the majority of the chemical makeup included butane, isobutene,propane, water, ethyl alcohol, sodium tetraborate dehydrate, perfume(lavender shock), alpha methyl ionone, citral, citronerol, and li-monene. The total RAFS volume was 250 mL with an injection vol-ume of 0.1 mL. The spray was automatically injected every 33 minutesin the experimental room.

Histopathological ExaminationTissue Preparation. All surgical procedures were performed under

clean but nonsterile conditions. Animals were decapitated underanesthesia at the end of the 1st, 2nd, or 3rd month. The nose of eachrat was removed by microdissection and fixed in 10% formaldehydesolution for 24 hours followed by decalcification in 10% ethylenediamine tetraacetic acid solution for 3 weeks. Next, the nasal septawith mucosa were carefully dissected using scissors. The nasal septawere rinsed in tap water for 24 hours, dehydrated using a gradedalcohol series, rendered transparent, and blocked after infiltrationwith paraffin. The paraffin-embedded samples were sliced with amicrotome (Microm HM 360; Charleston, Walldorf, Germany) to athickness of 5 �m, and cross-sections were stained with hematoxylinand eosin (H&E) before examination with a Nikon ECLIPSE 80imicroscope (Nikon Instruments, Amstelveen, The Netherlands). Thesame pathologist, who was blinded to the study groups, evaluated allstained specimens.

For morphological analysis, parameters such as congestion, edema,inflammation, and squamous metaplasia were evaluated. These pa-rameters were scored as 0 (none), 1 (slight), 2 (moderate), and 3(severe; Table 1).

Statistical AnalysisStatistical analysis of categorical data were performed using the

SPSS 15.0 software package for Windows (SPSS, Inc., Chicago, IL).Because there were no severe histopathological scores, the slight andmoderate categories were combined. The categories were renamed“yes” or “no.” Fisher’s exact test was used to analyze 2 � 2 crosstabresults. Two-tailed hypotheses were considered, and a value of p �0.05 was accepted as significant.

RESULTSHematoxylin and eosin staining showed distinctive differences in

the nasal mucosa of the control group and the groups exposed toRAFSs. Significant differences between RAFS exposure times wereobserved during histopathological examination including edema,congestion, inflammation, and squamous metaplasia (p � 0.05; Table

2). The control group exhibited a normal nasal mucosal epithelium,covered by cilia, and subepithelial tissue (Fig. 2). Increased congestionwas observed in the subepithelial tissue after the 1st month of RAFSexposure (Fig. 3), and mild inflammatory cell infiltration, includingeosinophils, and edema were seen in the subepithelial tissue after the2nd month of exposure (Fig. 4). Squamous metaplasia was observedon the surface of the nasal mucosa after 3 months of RAFS exposure.Also, inflammatory cell infiltration with numerous eosinophils beganin the subepithelial tissue at the end of the 3rd month of exposure(Fig. 5). The rate of histopathological change by groups is shown inFig. 6. Also, Fig. 1 shows the analysis of 97 RAFS samples. Thehistopathological parameters were compared between the groups andthe rate of histopathological change is detailed in Tables 2 and 3. Themeasured volume of room spray was 0.145 cc/m3 in 24 hours. Thisdosage is commonly used by consumers.

DISCUSSIONRecently, fragranced products such as RAFSs are frequently used in

modern societies. For instance, the use of RAFS was reported to be�30.5% in the United States.11 However, RAFSs contain many ofchemicals such as butane, isobutene, propane, water, ethyl alcohol,sodium tetraborate dehydrate, perfume (lavender shock), alphamethyl ionone, citral, citronerol, and limonene. As it is known, rhi-nitis, allergic rhinitis, and asthma may occur when toxic or allergenicsubstances are inhaled.8–9 Carol et al.12 found that inhalant organicgases have adverse effects on pulmonary function in allergic patients.Therefore, this study was based on the widespread use of fragrancedproducts on nasal mucosa.

In this study, we showed that RAFS can cause deterioration of thenasal mucosa after 3 months of exposure. Increased nonallergic in-

Table 1 Evaluation of nasal mucosa score count

Score Description

0 No alteration in mucosa1 Slight edema, congestion, inflammation, and squamous

metaplasia2 Moderate edema, congestion, inflammation, and squamous

metaplasia3 Severe edema, congestion, inflammation, and squamous

metaplasia

Table 2 Statistical results of group comparison (Fisher’s exact�2�test)

Comparison ofGroups

p Value Comparison ofGroups

p Value

Edema InflammationControl/RAFS1 0.021 Control/RAFS1 0.462Control/RAFS2 0.021 Control/RAFS2 0.021Control/RAFS3 0.021 Control/RAFS3 0.001RAFS1/RAFS2 0.962 RAFS1/RAFS2 0.286RAFS1/RAFS3 0.984 RAFS1/RAFS3 0.021RAFS2/RAFS3 0.682 RAFS2/RAFS3 0.462Congestion Squamous metaplasiaControl/RAFS1 0.286 Control/RAFS1 1.000Control/RAFS2 0.021 Control/RAFS2 0.462Control/RAFS3 0.021 Control/RAFS3 0.001RAFS1/RAFS2 0.462 RAFS1/RAFS2 0.462RAFS1/RAFS3 0.462 RAFS1/RAFS3 0.001RAFS2/RAFS3 1.000 RAFS2/RAFS3 0.021

Distinct histopathological differences in the nasal mucosa of exposed ratsdepends on different time intervals (p � 0.05).RAFS � room air freshener spray.

American Journal of Rhinology & Allergy e203

DO NOT C

OPY



flammation with metaplastic changes was observed because of con-tinuous RAFS exposure. To the best of our knowledge, there have notbeen any animal studies that have specifically investigated the effectsof RAFS on the nasal mucosa of rats. Therefore, we believe this studyis the first to investigate the histopathological effects of RAFSs onnasal mucosa.

In this study, inflammation of the nasal mucosa was observed after2 months of RAFS exposure. Gibson et al.8 reported that many chem-

icals, such as those found in RAFSs or inhaled gases, have a negativeeffect on human health. These chemicals lead to the release of inflam-matory cytokines within the nasal mucosa, which result in inflamma-tion. However, the present study also found increased infiltration ofeosinophils that may mimic the pathology of nonallergic rhinitis.These inflammatory findings were more pronounced in the 3rdmonth of RAFS exposure. Anderson et al.9 investigated the functionaleffects of many chemical agents, such as RAFS, on the respiratory

Figure 1. Different rate of histopatholog-ical change is shown according to groups.


DO NOT C

OPY



systems of rats and found that chemical mixtures could cause sensoryirritation, pulmonary irritation, and airflow limitation. This report isconsistent with our result.

Volatile gases including butane, isobutane, limonene, and ethylalcohol are potentially toxic chemical substances. Many VOCs areclassified as known or possible carcinogens, irritants, and toxins.13 Inaddition, limonene is classified as a cyclic terpene. Chin et al.14 re-ported that limonene-including VOCs within homes could pose a

health risk. The same study found that limonene was the most com-monly used subgroup of VOCs in the home. In addition, Cooper etal.15 analyzed 31 fragranced products including perfumes, deodor-ants, soaps, fabric softeners, and air fresheners and identified �150unique VOCs. The most common VOCs, emitted from at least one-half of the products, were ethanol, limonene, linalool, ß-phenethylalcohol, and ß-myrcene. Limonene and ethanol-containing VOCs areconsidered dangerous air pollutants.16 These products may not be

Figure 1. Continued


DO NOT C

OPY



toxigenic in their primary form, but primary pollutants of fragranceVOCs (e.g., limonene) can readily react with ozone to produce sec-ondary pollutants such as formaldehyde, ultrafine particles, organicaerosols, and hydroxyl radicals.17

We investigated the histopathological effects of RAFSs on the nasalmucosa over time (3 months) and found significant (p � 0.001)histopathological changes in the nasal mucosa after the 1st, 2nd, and3rd month of RAFS exposure (Figs. 2–5). These results are importantbecause they were determined by histopathological examination, a

definitive method. It is also important to note that the effects of RAFSexposure changed as exposure time increased. The duration of RAFSexposure may be a determinative factor in the formation of cellularchanges. In our study, cellular changes such as squamous metaplasiabegan after 3 months of RAFS exposure (Fig. 5).

Metaplasia can be the result of stress and occurs when cells arereplaced by other cell types better equipped to survive in an adverseenvironment. Metaplasia is reversible cell injury that can occurthrough genetic “reprogramming” of stem cells rather than transdif-

Figure 1. Continued

Figure 2. Group 1/control shows a normal appearance of the nasal mucosalepithelium (arrows) and subepithelial tissue (stars; hematoxylin and eosin,�200).

Figure 3. Group 2/RAFS at 1 month shows nasal mucosal epithelium(arrows) and moderate subepithelial edema (stars; hematoxylin and eosin,�200).


DO NOT C

OPY



ferentiation of already differentiated cells. If injured or damaged cellsare removed from harmful exposure in the early stages of metaplasia,before severe membrane damage and nuclear dissolution, the effectscan be reversible. If chemical exposure continues, irreversible celldamage such as necrosis or malignant transformation can occur.18 Inthis study, metaplasia was observed in the nasal mucosa after 3months of RAFS exposure. Shusterman et al.19 reported that a neutro-philic inflammatory response can occur after acute exposure to eitherozone or VOCs and that metaplastic mucosal changes may emergeafter prolonged exposure to photochemical mixed-air pollutants. Thisstudy supports our results.

The presence of metaplastic changes in the nasal mucosa is critical.Although inflammatory processes can elevate the risk of cancer,prolonged exposure to chemicals can also be a risk factor for nasaland nasopharyngeal cancer. For instance, Chung et al.20 reported anassociation between allergic rhinitis and nasopharyngeal carcinoma.The present study does not allow us to make any allegations aboutmalignancy, and multicenter double-blind, controlled, comparative,long-term studies are needed to investigate the potential connection.

The majority of studies related to toxic substances have been per-formed with function testing.7–9 Functional tests usually can not re-veal any pathology. The present histopathological study observedinflammatory changes including congestion and edema in the 1st and2nd month of RAFS exposure, respectively.

VOCs in RAFS may be involved in the unknown etiology of rhini-tis. There were inflammatory changes in all forms of rhinitis. Eosin-ophilic infiltration was found on histopathology in the present study.This is an important pathological finding relevant to both allergic andnonallergic rhinitis. However, we could not measure IgE in this study,and these results may be related to nonallergic rhinitis. We observedeosinophilic infiltration after 2 months of RAFS exposure. Xu et al.21

observed the same eosinophilic infiltration with inflammation in ex-perimental allergy studies with ovalbumin. Also, Larsson et al.22

reported that fragranced substances such as perfume or RAFS couldcause �15% of rhinitis and asthma cases. In addition to cigarettesmoke, chemical substances may lead to rhinitis and asthma, consis-tent with our findings of eosinophilic infiltration with inflammationin the subepithelial tissue after 3 months of RAFS exposure. Edema,congestion, and inflammation mimic the histopathological view ofrhinosinusitis.23 Therefore, RAFSs may be predictive for rhinosinus-itis.

The present study is novel and could be the precursor to long-termmolecular studies that analyze the effects of the various individualchemicals in RAFSs. We are unable to compare histopathologicalchanges due to RAFSs between studies because there are no histo-pathological studies that have evaluated the effects of RAFSs on rat orhuman nasal mucosa in the literature. Although we obtained impor-tant and useful findings, there is still much to learn and we did notobtain these results by studying people. Because of differences inbody size, geometry, and physiological responses between rats andhumans, extrapolation of these results to humans is not straightfor-ward and any such comparison should be made with caution.

CONCLUSIONOur histopathological results show that continuous use of RAFSs

can cause nonallergic inflammation in rats, which begins after 2months of exposure and may lead to metaplasia after 3 months.Although we obtained important and useful findings, further inves-tigation is required to identify the causes of nonallergic disease andexamine different RAFS dosages. It is not possible to perform humanstudies because of ethical and practical concerns. Therefore, the ratwill continue to be a useful model for investigating the effects on

Figure 4. Group 3/RAFS at 2 months shows mild inflammatory cell infil-tration, including some eosinophils, and congestion of the vessels in thesubepithelial region (hematoxylin and eosin, �200).

Figure 5. Group 4/RAFS at 3 months shows nasal mucosal epithelium(arrows) covered by stratified squamous epithelium and numerous eosino-phils. Intense inflammatory cell infiltration and mild congestion in thevessels of the subepithelial region (hematoxylin and eosin, �200).

Table 3 Rate of histopathological change in score by group,which found increased congestion after the 1st mo of exposure

Rate of HistopathologicalChanges

% Rate of HistopathologicalChanges

%

Edema InflammationControl 28.6 Control 0.0RAFS1 100.0 RAFS1 28.6RAFS2 100.0 RAFS 2 71.4RAFS3 100.0 RAFS 3 100.0Congestion Squamous metaplasiaControl 28.6 Control 0.0RAFS1 71.4 RAFS1 0.0RAFS 2 100.0 RAFS 2 28.6RAFS 3 100.0 RAFS 3 100.0

Although edema and mild inflammatory cell infiltration, including someeosinophils, was seen after the 2nd mo, squamous metaplasia, numerouseosinophils, and intense inflammatory cell infiltration began after 3 mo ofexposure.RAFS � room air freshener spray.


DO NOT C

OPY



nasal mucosa. However, additional studies, especially on long-termtreatment with different RAFSs, should be conducted. These resultsare novel and the frequent use of these chemicals may have a signif-icant effect on human health.

ACKNOWLEDGMENTSThe authors thank Assistant Professor Yilmaz Palanci of the De-

partment of Public Health, Dicle University School of Medicine, forhis valuable statistical assistance; Mehmet Zulkuf Akdag from theDepartment of Biophysics for her valuable support; Nesrin Geniselfrom the Department of Pharmaceutical Chemistry, Faculty of Phar-macy, Dicle University; and DUBAP for their editing system.

REFERENCES1. Jeong GN, Jo GJ, Jo UB, and Yu IJ. Effects of repeated welding fumes

exposure on the histological structure and mucins of nasal respira-tory mucosa in rats. Toxicol Lett 167:19–26, 2006.

2. Uzzaman A, and Story R. Chapter 5: Allergic rhinitis. AllergyAsthma Proc 33:15–18, 2012.

3. Rumchev K, Spickett J, Bulsara M, et al. Association of domesticexposure to volatile organic compounds with asthma in young chil-dren. Thorax 59:746–751, 2004.

4. Heavener DL, Morgan WT, and Ogden MW. Determination of vol-atile organic compounds and ETS apportionment in 49 homes. Envi-ron Int 21:3–21, 1995.

5. Lax MB, and Henneberger PK. Patients with multiple chemical sen-sitivities in an occupational health clinic: Presentation and follow-up.Arch Environ Health 50:425–431, 1995.

6. Ashford NA, and Miller CS. In Chemical Exposures: Low Levels and HighStakes, 2nd ed. New York, NY: Van Nostrand Reinhold, 371–372, 1992.

7. Baldwin CM, Bell IR, and O’Rourke MK. Odor sensitivity and respi-ratory complaint profiles in a community-based sample with asthma,hay fever, and chemical odor intolerance. Toxicol Ind Health 15:403–409, 1999.

8. Gibson PR, and Vogel VM. Sickness-related dysfunction in personswith self-reported multiple chemical sensitivity at four levels ofseverity. J Clin Nurs 18:72–81, 2009.

9. Anderson RC, and Anderson JH. Sensory irritation and multiplechemical sensitivity. Toxicol Ind Health 15:339–345, 1999.

10. Institute of Laboratory Animal Research. Commission on Life Sci-ences. National Research Council. The guide for the care and use oflaboratory animals, 7th ed. Washington, D.C.: National Academy ofSciences, 1996.

11. Meggs WJ. RADS and RUDS—The toxic induction of asthma andrhinitis. J Toxicol Clin Toxicol 32:487–501, 1994.

12. Caress SM, and Steinemann AC. Prevalence of fragrance sensitivityin the American population. J Environ Health 71:46–50, 2009.

13. Bousquet J, Khaltaev N, Cruz AA, et al. Allergic Rhinitis and ItsImpact on Asthma (ARIA) 2008 update (in collaboration with theWorld Health Organization, GA (2)LEN and AllerGen). Allergy 63:8–160, 2008.

14. Chin JY, Godwin C, Parker E, et al. Levels and sources of volatileorganic compounds in homes of children with asthma. Indoor Air24:403–415, 2014. (DOI: 10.1111.ina. 12086.)

15. Cooper SD, Raymer JH, Pellizzari ED, and Thomas KW. The identi-fication of polar organic compounds found in consumer productsand their toxicological properties. J Expo Anal Environ Epidemiol5:57–75, 1995.

16. U.S. Environmental Protection Agency. The Clean Air Act Amend-ments of 1990 list of hazardous air pollutants. Available online atwww.epa.gov/ttn/atw/origl89.html; accessed November17, 2008.

17. Nazaroff WW, and Weschler CJ. Cleaning products and air freshen-ers: Exposure to primary and secondary air pollutants. AtmosphericEnviron 38:2841–2865, 2004.

18. Kumar V, Abbas K, and Aster JC. Cell injury, cell death, and adap-tations. In Robbins Basic Pathology, 9th ed., Chap. 1. Philadelphia,PA: Elsevier Saunders: 19103–2899, 5–6, 2013.

19. Shusterman D. Environmental nonallergic rhinitis. Clin Allergy Im-munol 19:249–266, 2007.

20. Chung SD, Wu CS, Lin HC, and Hung SH. Association betweenallergic rhinitis and nasopharyngeal carcinoma: A population-based study. Laryngoscope 124:1744–1749, 2013.

21. Xu YY, Liu X, Dai LB, and Zhou SH. Effect of Tong Qiao drops on theexpression of eotaxin, IL-13 in the nasal mucosa of rats with allergicrhinitis. J Chinese Med Assoc 75:524–529, 2012.

22. Larsson ML, Frisk M, Hallstrom J, et al. Environmental tobaccosmoke exposure during childhood is associated with increased prev-alence of asthma in adult.s Chest 120:711–777, 2001.

23. Cingi C, Eskiizmir G, Burukoglu D, et al. The histopathological effectof thymoquinone on experimentally induced rhinosinusitis in rats.Am J Rhinol Allergy 25:e268–e272, 2011. e

Figure 6. This diagram shows the analysis of 97 room air freshener spray(RAFS) samples.


DO NOT C

OPY

Does Usage of a Room Air Freshener Affect the Nasal

Documents

Transcript of Does Usage of a Room Air Freshener Affect the Nasal