Effects of Indoor Air Purifiers on Children with Asthma

PURPOSE: To evaluate the effects of air purifiers on the concentrations of indoor air pollutants and on asthma control in children.MATERIALS AND METHODS: In this randomized crossover trial, daily use of an air purifier filter was compared with a matched placebo with the filter off. Thirty elementary school students who had asthma were enrolled and randomly allocated to one of two groups. The primary endpoints were changes in indoor air quality, asthma severity, lung function, airway inflammatory, urine microbiome, and phthalate after the installation of air purifiers. PM(2.5) and CO₂ were measured as indoor air pollutants. Asthma severity was assessed in terms of both symptom and medication scores acquired using a daily questionnaire. The higher the score, the better the symptom or the less frequent the use of medication. Peak expiratory flow rate and fractional exhaled nitric oxide were also measured.RESULTS: The mean age of the enrolled patients was 9.2±1.98 years. The mean concentration of PM2.5 was 17.0 µg/m³ in the filter-off condition, but significantly lower at 9.26 µg/m³ in the filter-on condition. Medication scores were 6.9 for the filter-off and 7.12 for the filter-on conditions, reflecting a statistically significant decrease in the frequency of medications used during air purifier operation. Bacterial richness, as determined using the Chao 1 index, was markedly lower in the filter-on than the filter-off condition.CONCLUSION: This study suggests that air purifiers benefit medication burden in children with asthma by reducing PM(2.5) levels.

Effect of human activities and air purifier on airborne microorganisms and particulate matter in a bronchoscopy room / 中国感染控制杂志

Objective To evaluate the effect of personnel activities and air purifiers on airborne microorganisms and particulate matter in bronchoscopy room.Methods According to whether there was personal activity and air purifier in the bronchoscopy room,the experiment was divided into four groups:dynamic non-purification group,dynamic purification group,static non-purification group,and static purification group,indoor air samples were collected and analyzed at five different time points (0,0.5,1,2,4 h),microorganisms in the air were collected by planktonic method,then cultured and counted,concentration of particulate matter was determined by DT-9881M laser dust particle counter,variance analysis of factorial design was used for statistical analysis.Results Colony count/concentration of airborne bacteria,fungi,total microorganisms (bacteria + fungi),PM2.5,and PM2.5-10.0 in dynamic non purification group were (113.53 ± 7.78) CFU/m3,(89.67 ± 7.17) CFU/m3,(203.20 ± 10.92) CFU/m3,(86 557.20 ±4 158.29) counts/m3,and (659.69 ± 38.91) counts/m3 respectively,in static non-purification group were (84.33 ± 3.65) CFU/m3,(65.00 ± 2.65)CFU/m3,(149.33 ± 4.98) CFU/m3,(45 812.64 ±1 279.61) counts/m3,and (189.15 ± 4.64) counts/m3 respectively,in dynamic purification group were (84.80 ±8.08) CFU/m3,(90.40 ± 5.50) CFU/m3,(175.20 ± 9.22) CFU/m3,(49 336.38 ± 2 039.16) counts/m3,and (218.36 ± 7.02) counts/m3 respectively,in static purification group were (67.80 ± 5.63) CFU/m3,(38.27 ± 3.70)CFU/m3,(106.07 ± 6.76) CFU/m3,(29 772.53 ± 2 212.93) counts/m3,and (124.80 ± 7.16) counts/m3 respectively.Colony count/concentration of airborne bacteria,total microorganisms,PM2.5,and PM2.s 10.0 in dynamic group were all higher than those in static group,non-purification group were higher than purification group(both P ＜0.05),colony count of fungi in dynamic non-purification group was higher than static non-purification group,in static purification group was lower than static non-purification group(both P＜0.05),there was no significant difference between dynamic purification group and dynamic non-purification group (P =0.936).Conclusion Personal activities can increase colony count/concentration of microorganisms and particulate matter in bronchoscopy room,air purifier can reduce the bacteria,total microbial count,and particulate matter in the air of bronchoscopy room.

The study on effects of indoor air filtration on radon exposure to residents / 中华放射医学与防护杂志

Objective To evaluate the influence of indoor air filtration by air purifier on the behavior of indoor radon progeny and estimate its effects on indoor radon exposure to residents.Methods The concentrations of indoor radon progeny with and without the air filtration were calculated by the theoretical model developed in this study.Based on the dose conversion factors of attached and unattached radon progeny,the mitigation effects of indoor radon exposure due to the air filtration were estimated.Verification experiments were conducted in an airtight room.Results With the air filtration rate increased,the removal efficiency of indoor radon progeny would appear more obvious.For an airtight room with its initial aerosol concentration of 10 000 cm-3,the concentration of total radon progeny would decrease by more than 90％ when the air filtration rate exceeded 10 h-1.But the concentrations of indoor unattached radon progeny would increase by using the air purifier in different extents.The variations of radon progeny concentrations and the decrease of internal doses were closely related to the filtration rate of air purifier.With the air filtration rates increased,the mitigation effects would be better and faster.The internal dose would reduce by more than 70％ when the filtration rate exceeded 5 h-1.Conclusions Although the indoor concentration of unattached radon progeny will increase by using the air purifier,it is still effective in reducing the exposure dose to residents due to the inhalation of radon progeny.

Effect of air purifier on indoor air quality and atopic dermatitis

PURPOSE: High level of indoor air pollutant may cause aggravation of atopic diseases long with various allergic respiratory diseases especially in people who spend mostly of their lives indoors. The aim of this study was to evaluate the effect of air purifier on the reduction of relevant hazards in indoors and the improvement of atopic dermatitis (AD). METHODS: A total of 24 families, consisted of 18 AD families and 6 normal control families, were enrolled in this study. We examined air quality and AD severity before the installation of air purifiers and after twenty-four weeeks. The assessment of air quality included fine particles (particulate matter, PM2.5 and PM10), gaseous contaminants (CO, CO2, volatile organic compounds [VOCs], formaldehyde, NO2) and density of offloating microorganisms. Severity of AD was assessed by SCORing atopic dermatitis (SCORAD) index and transepidermal water loss (TEWL). RESULTS: At the end of study, particular air pollutants and VOCs of gaseous air pollutants decreased in both groups (P<0.01). In AD group, SCORAD index decreased from 23.45+/-4.34 to 15.42+/-6.53 (-18.5%) and TEWL decreased from 33.78+/-5.16 to 26.89+/-5.66 (-18.7%) (P<0.01 and P<0.01, respectively). However, the value of total immunoglobulin E and eosinophil did not show significant changes in both groups compared with baseline. CONCLUSION: These results suggested that air purifier may improve severity of AD by reducing air pollutants like fine particles and VOCs. Our preliminary study could provide a basis for using air purifier to prevent aggravation of AD.

Testing and Analysis of Air Purifier's Adsorptive Performance to Formaldehyde in Indoor Air / 环境与健康杂志

Objective To verify whether the X brand air purifier could adsorb the formaldehyde in indoor air. Method An purifying test was carried out in a purified laboratory that had a volume of 30 m3, with an air leakage rate less than 0.05 m3/h, and was equipped with medium and high effective filters, air circulating ventilation system, gas sample generating system,etc. Results Significanly negative correlation was observed between the values of natural logarithm of formaldehyde concentration (lnCt) and time variables with a correlation coefficient r values of-0.995 0 ～-0.999 7. After the running of the air purifiers, the concentrations of formaldehyde in air significantly decreased with the prolongation of the running duration of air purifiers compared with its original concentration (P0.05). Conclusion This kind of air purifier could effectively adsorb formaldehyde in indoor air.