[Indoor air pollution by fine particulate matter in the homes of newborns]

Spirometry parameter alterations due to exposure to indoor air pollutants in rural homes in Bogotá, Colombia

The aim of this study was to determine the association between the concentrations of intradomiciliary PM_2.5, CO, and BC and alterations in respiratory function parameters in a population living in rural dwellings in Bogotá, Colombia. For this cross-sectional study, people were recruited from the rural areas of the localities of Usme and Sumapaz in Bogotá. In total, 68 participants were recruited by means of nonrandom sampling. Indoor air monitoring of PM_2.5, BC, and CO was carried out. Additionally, evaluations of pulmonary function were performed using spirometry. The variables of pulmonary function were included in a multiple linear regression by successive steps and adjusted by the main variables described as modifiers of spirometry parameters, which are age, height, sex, disability, and a history of tobacco use. Assumptions of multicollinearity and the randomization of variances in the residuals were evaluated. Negative associations were found between spirometry parameters and the concentrations of indoor air pollutants. For FEV1/FVC and theoretical FEV1, there was a statistically significant association with the concentration of carbon monoxide (p = 0.003 and 0.019, respectively). The environmental concentrations were higher in homes where biomass was used for cooking, but these differences were statistically significant only for BC and CO (p = 0.008 and 0.03, respectively). The concentrations of carbon monoxide in rural homes were associated with alterations in respiratory function parameters.

Exposure levels to PM2.5 and black carbon for people with disabilities in rural homes of Colombia

Indoor exposure to air pollutants emitted by solid fuels used for cooking or heating homes remains as a problem to solve. The most affected people are newborns, mothers, children, and people with disabilities, due to the time they spend at home. This study is the first in a rural area of South America, which measures indoor air pollutants (PM_2.5 and black carbon) in different environments, inhabited by people with disabilities. The research was supported through a sociodemographic characterization, a methodology useful for future studies, continuous monitoring for 72 h of pollutants, and emission sources, cooking habits, and pre-existing diseases were identified. The primary sources of emissions are improved wood-burning stoves and their chimney. In households where firewood is used, the average concentrations of PM_2.5 were the highest (between 10.9 and 3302.5 μg/m³), as were the average concentrations of BC (average 72 h between 2.6 and 51.2 μg/m³) compared with the houses that use gas (average 72 h between 2.6 and 6 μg/m³). In 57% of the households visited, the World Health Organization (WHO) guidelines for PM_2.5 (25 μg/m³ for 24 h) were exceeded. The results reveal that rural concentrations of BC can be up to 2.5 times higher than those of an urban area with high vehicular traffic and high population density and could be used to establish a baseline that allows the implementation of control mechanisms to reduce pollution of indoor air.

Indoor PM2.5 from coal combustion aggravates ovalbumin-induced asthma-like airway inflammation in BALB/c mice

We hypothesized that indoor PM_2.5 exposure from coal combustion exaggerates airway inflammation in the lung tissue of asthmatic mice induced with ovalbumin (OVA). Forty BALB/c mice, randomly divided into four groups (n = 10 per group), were intratracheally instilled with normal saline alone, PM_2.5 (2.5 mg/ml PM_2.5 alone), OVA (15 μg/ml OVA alone), and PM_2.5+OVA (2.5 mg/ml PM_2.5 and 15 μg/ml OVA), respectively, four times at 2-wk intervals. Daily mean concentration of PM_2.5 from indoor coal combustion was 156.95 μg/m³. The highest metal composition in PM_2.5 was Zn (34.81 ± 1.8 μg/m³). Exposure to PM_2.5+OVA significantly elevated IL-4 and decreased IFN-γ production in mice compared with the control (P < 0.05). Exposure to PM_2.5+OVA showed a significant increase in the protein levels of granulocyte-macrophage colony-stimulating factor and IL-8 and a decrease in the protein level of transforming growth factor-β1 in bronchoalveolar lavage fluid of mice compared with the control (P < 0.05). The expression of IL-4 mRNA was significantly increased, whereas the expression of IFN-γ mRNA was decreased in lung tissue of the PM_2.5+OVA group (P < 0.05). The expression level of Foxp3 mRNA in the PM_2.5+OVA group was significantly lower than that in the control group in lung tissue (P < 0.05). Treatment with PM_2.5+OVA promoted a prominent neutrophil sequestration into the lung parenchyma, goblet cell proliferation, and severe inflammatory cell infiltration in the airways. Exposure to PM_2.5 from indoor coal combustion might induce airway inflammatory immune responses and exacerbate peribronchiolar inflammation due to infiltration of inflammatory cells into the airway submucosa and airway structural pathological changes.

Source Apportionment and Influencing Factor Analysis of Residential Indoor PM2.5 in Beijing

In order to identify the sources of indoor PM2.5 and to check which factors influence the concentration of indoor PM2.5 and chemical elements, indoor concentrations of PM2.5 and its related elements in residential houses in Beijing were explored. Indoor and outdoor PM2.5 samples that were monitored continuously for one week were collected. Indoor and outdoor concentrations of PM2.5 and 15 elements (Al, As, Ca, Cd, Cu, Fe, K, Mg, Mn, Na, Pb, Se, Tl, V, Zn) were calculated and compared. The median indoor concentration of PM2.5 was 57.64 μg/m³. For elements in indoor PM2.5, Cd and As may be sensitive to indoor smoking, Zn, Ca and Al may be related to indoor sources other than smoking, Pb, V and Se may mainly come from outdoor. Five factors were extracted for indoor PM2.5 by factor analysis, explained 76.8% of total variance, outdoor sources contributed more than indoor sources. Multiple linear regression analysis for indoor PM2.5, Cd and Pb was performed. Indoor PM2.5 was influenced by factors including outdoor PM2.5, smoking during sampling, outdoor temperature and time of air conditioner use. Indoor Cd was affected by factors including smoking during sampling, outdoor Cd and building age. Indoor Pb concentration was associated with factors including outdoor Pb and time of window open per day, building age and RH. In conclusion, indoor PM2.5 mainly comes from outdoor sources, and the contributions of indoor sources also cannot be ignored. Factors associated indoor and outdoor air exchange can influence the concentrations of indoor PM2.5 and its constituents.