Impact of microbial air quality in preschools on paediatric respiratory health

Comprehensive health risk assessment of microbial indoor air quality in microenvironments

The higher airborne microbial concentration in indoor areas might be responsible for the adverse indoor air quality, which relates well with poor respiratory and general health effects in the form of Sick building syndromes. The current study aimed to isolate and characterize the seasonal (winter and spring) levels of culturable bio-aerosols from indoor air, implicating human health by using an epidemiological health survey. Microorganisms were identified by standard macro and microbiological methods, followed by biochemical testing and molecular techniques. Sampling results revealed the bacterial and fungal aerosol concentrations ranging between (300–3650 CFU/m³) and (300–4150 CFU/m³) respectively, in different microenvironments during the winter season (December-February). However, in spring (March-May), bacterial and fungal aerosol concentrations were monitored, ranging between (450–5150 CFU/m³) and (350–5070 CFU/m³) respectively. Interestingly, Aspergillus and Cladosporium were the majorly recorded fungi whereas, Staphylococcus, Streptobacillus, and Micrococcus found predominant bacterial genera among all the sites. Taken together, the elevated levels of bioaerosols are the foremost risk factor that can lead to various respiratory and general health issues in additional analysis, the questionnaire survey indicated the headache (28%) and allergy (20%) were significant indoor health concerns. This type of approach will serve as a foundation for assisting residents in taking preventative measures to avoid exposure to dangerous bioaerosols.

Temporal Variation and Factors Associated with Allergic Rhinitis in a Cohort of Rural Preschool Children from Sri Lanka

BACKGROUND

Allergic rhinitis is a common chronic childhood disease with a low diagnosis rate, causing poor quality of life, absenteeism, decreased school performance and significant healthcare cost. However, data on the prevalence of allergic rhinitis is sparse in preschoolers of rural geography, especially in developing countries.

AIM

To describe the epidemiology of allergic rhinitis in preschoolers from a rural geography of a developing country.

METHODS

A population-based cross-sectional study was conducted in Anuradhapura district, Sri Lanka using the WHO-30 cluster methodology with probability proportionate to size sampling. The International Study of Asthma and Allergy in Childhood questionnaire was used to assess symptomatology.

RESULTS

The response rate was 91.8%, with 548 (51.7%) male and 512 (48.3%) female participants. The mean age was 4.4 (± 0.7) years. Allergic rhinitis was reported in 123 (11.6%; 95% CI 9.7-13.5), and eye symptoms were reported in 41 (3.9%; 95% CI 2.8-5.2) children. Activities of daily living were disturbed due to nasal symptoms in 113 (10.7%; 95% CI 8.8-12.5). Allergic rhinitis was independently associated with severe asthma (OR 6.26; 95% CI 3.54-11.06), sleeping on the floor (OR 4.79; 95% CI 1.33-17.25) and having cats in the households (OR 1.86; 95% CI 1.18-2.91). Nasal symptoms were more common in January and August to October months. The standardized local highest monthly temperature, lowest monthly temperature, highest monthly humidity and dew point strongly predicted allergic rhinitis symptom exacerbation (F=4.8, p=0.036, adjusted R square=57.8%, VIF≤2.259, DW=2.1).

CONCLUSIONS

Allergic rhinitis affects 1 in 10 preschool children of rural Sri Lanka. The factors associated and environmental factor model developed to predict symptom exacerbation could be used to prevent allergic rhinitis exacerbations.

Seasonal variation and size distribution in the airborne indoor microbial concentration of residential houses in Delhi and its impact on health

Exposure of microbial agents in the air of indoor dwellings is associated with effects on respiratory and general health. The current study was conducted in the urban area of Delhi Metropolis for the seasonal quantitative assessment of viable microbial indoor air quality. Bioaerosol measurement was conducted by using Anderson six stage impactor with cut-off diameters of 7.0, 4.7, 3.3, 2.1, 1.1, and 0.65 µm) throughout the all the seasons (April 2019 to March 2020). Meteorological parameters such as temperature and relative humidity were measured to check their effect on microbial survival. Air quality index data of the sampling area were recorded by DPCC air quality monitoring system, Ashok Vihar, Delhi. The highest (1654 ± 876.87 CFU/m3) and lowest (738 ± 443.59 CFU/m3) mean bacterial concentration in houses was recorded in August and December, respectively. Similarly, the highest fungal concentration (1275 ± 645.22 CFU/m3) was found in August and the lowest in (776 ± 462.46 CFU/m3) in January. Bacterial respirable fraction shows an irregular pattern in different seasons. In the case of fungi, the respirable fraction of 2.1 and 1.1 contributes more than 60% of total culturable bioaerosols in all seasons. Bacterial genera including Staphylococcus, Micrococcus, and Streptobacillus were most dominant, and Cladosporium, Aspergillus, Penicillium, and Alternaria were the most dominant fungal genera observed indoors. The results of this study suggest that higher respirable fungal fraction might penetrate deeper into the lungs and cause various health effects. A higher concentration of bioaerosols in outdoor areas than indoor shows that the source of indoor bioaerosols is outdoor air.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s10453-021-09718-3.

Impact of haze events on airborne bacterial consortia–a case study

Transboundary haze events received a noticeable attention recently, due to their frequent occurrences. They are mainly, consequences of anthropogenic activities. Sri Lanka experienced a haze event parallel to India in November 2019, the first air pollution event in Sri Lanka linked to a haze event in India. Due to the limited availability of information on haze-related microorganisms, we conducted this study in Kandy, Sri Lanka, aiming to explore the airborne bacterial consortia during a haze event. The natural sedimentation method was used for air sampling. Bacterial identification and the total bacterial load were determined using Sanger sequencing and qPCR. Notably, the total bacterial load was elevated by ~ 40% with the haze and decreased with decreasing haze intensity. The highest bacterial load was reported during the day time of the most intense hazy day (1.89 × 106 cells/µl) compared to non-hazy days (lowest; 1.12 × 105 cells/µl). Twelve bacterial species were identified and the most abundant phylum was Proteobacteria. The most common species observed during haze was Acinetobacter modestus. The percentage of culturable bacterial species was also high during the haze event (75% during day time of the most intense hazy day compared to 25% on the control). Two human pathogenic bacteria Burkholderia multivorans and Chryseobacterium gleum were found only during the haze event. Therefore, haze events could be hazardous to humans by means of the presence and fluctuating amounts of pathogenic bacteria. Thus, these findings are important in developing policies and guidelines to monitor and minimize the negative impact of haze events.