Environmental air pollution is a major risk factor for morbidity and mortality worldwide. Environmental air pollution has a direct impact on human health, being responsible for an increase in the incidence of and number of deaths due to cardiopulmonary, neoplastic, and metabolic diseases; it also contributes to global warming and the consequent climate change associated with extreme events and environmental imbalances. In this review, we present articles that show the impact that exposure to different sources and types of air pollutants has on the respiratory system; we present the acute effects-such as increases in symptoms and in the number of emergency room visits, hospitalizations, and deaths-and the chronic effects-such as increases in the incidence of asthma, COPD, and lung cancer, as well as a rapid decline in lung function. The effects of air pollution in more susceptible populations and the effects associated with physical exercise in polluted environments are also presented and discussed. Finally, we present the major studies on the subject conducted in Brazil. Health care and disease prevention services should be aware of this important risk factor in order to counsel more susceptible individuals about protective measures that can facilitate their treatment, as well as promoting the adoption of environmental measures that contribute to the reduction of such emissions.

Keywords: Air pollution; Particulate matter; Respiratory tract diseases; Pulmonary disease, chronic obstructive; Asthma; Respiratory tract infections; Lung neoplasms.

Over the past 250 years-since the Industrial Revolution accelerated the process of pollutant emission, which, until then, had been limited to the domestic use of fuels (mineral and vegetal) and intermittent volcanic emissions-air pollution has been present in various scenarios. Today, approximately 50% of the people in the world live in cities and urban areas and are exposed to progressively higher levels of air pollutants. This is a non-systematic review on the different types and sources of air pollutants, as well as on the respiratory effects attributed to exposure to such contaminants. Aggravation of the symptoms of disease, together with increases in the demand for emergency treatment, the number of hospitalizations, and the number of deaths, can be attributed to particulate and gaseous pollutants, emitted by various sources. Chronic exposure to air pollutants not only causes decompensation of pre-existing diseases but also increases the number of new cases of asthma, COPD, and lung cancer, even in rural areas. Air pollutants now rival tobacco smoke as the leading risk factor for these diseases. We hope that we can impress upon pulmonologists and clinicians the relevance of investigating exposure to air pollutants and of recognizing this as a risk factor that should be taken into account in the adoption of best practices for the control of the acute decompensation of respiratory diseases and for maintenance treatment between exacerbations.

Keywords: Respiratory System; Air pollution; Pregnancy; Pulmonary disease, chronic obstructive; Asthma; Respiratory tract Infections.

Air pollution is a major public health problem in the Amazon forest and in large Brazilian cities. During September of 2005, high concentrations of smoke from biomass burning were observed in the city of Rio Branco. An ecological study was conducted to evaluate the relationship between daily concentrations of particulate matter < 2.5 μm (PM2.5) and the number of respiratory disease (RD)-related emergency room visits. Daily PM2.5 concentrations exceeded recommended air quality limits on 23 days. The incidence of RDs was higher among children < 10 years of age. There was a significant positive correlation between PM2.5 concentrations and asthma emergency room visits.

Keywords: Air pollution/adverse effects; Fires; Respiratory tract diseases/epidemiology; Asthma; Space-time clustering.

Coronavirus disease 2019 (COVID-19), caused by the highly contagious severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is probably systemic, has a major respiratory component, and is transmitted by person-to-person contact, via airborne droplets or aerosols. In the respiratory tract, the virus begins to replicate within cells, after which the host starts shedding the virus. The individuals recognized as being at risk for an unfavorable COVID-19 outcome are those > 60 years of age, those with chronic diseases such as diabetes mellitus, those with hypertension, and those with chronic lung diseases, as well as those using chemotherapy, corticosteroids, or biological agents. Some studies have suggested that infection with SARS-CoV-2 is associated with other risk factors, such as smoking, external environmental pollution, and certain climatic conditions. The purpose of this narrative review was to perform a critical assessment of the relationship between COVID-19 and these potential risk factors.

Keywords: Coronavirus infections; COVID-19; Air pollution; Smoking; Tobacco use disorder.

Climate change is a huge and present threat to human health. This article aims to deepen the knowledge about the environmental impact of inhaler devices on their carbon footprint for patients and health professionals, providing information that allows a better choice of the type of device to be prescribed for the treatment of asthma and COPD. This narrative and nonsystematic review was carried out by searching databases (PubMed, Google Scholar, SciELO, and EMBASE) for articles published between 2017 and 2022, written in Portuguese or in English, using the search words "inhalation device" OR "environmental." The review showed that global warming cannot be addressed by focusing only on inhaler devices. However, the devices that we use to treat respiratory diseases such as asthma and COPD, which are diseases that are aggravated by climate change, are also causing that change. Therefore, health professionals, patient organizations, and industries should take a lead in health policies to offer affordable alternatives to inhalers containing hydrofluoroalkane.

Keywords: Asthma; Pulmonary disease, chronic obstructive; Environmental health; Nebulizers and vaporizers.

Objective: Respiratory complications are the main causes of morbidity and mortality in patients with neuromuscular disease (NMD). The objectives of this study were to determine the effects that routine daily home air-stacking maneuvers have on pulmonary function in patients with spinal muscular atrophy (SMA) and in patients with congenital muscular dystrophy (CMD), as well as to identify associations between spinal deformities and the effects of the maneuvers. Methods: Eighteen NMD patients (ten with CMD and eight with SMA) were submitted to routine daily air-stacking maneuvers at home with manual resuscitators for four to six months, undergoing pulmonary function tests before and after that period. The pulmonary function tests included measurements of FVC; PEF; maximum insufflation capacity (MIC); and assisted and unassisted peak cough flow (APCF and UPCF, respectively) with insufflations. Results: After the use of home air-stacking maneuvers, there were improvements in the APCF and UPCF. In the patients without scoliosis, there was also a significant increase in FVC. When comparing patients with and without scoliosis, the increases in APCF and UPCF were more pronounced in those without scoliosis. Conclusions: Routine daily air-stacking maneuvers with a manual resuscitator appear to increase UPCF and APCF in patients with NMD, especially in those without scoliosis.

Keywords: Neuromuscular diseases; Cough; Respiratory function tests; Respiratory therapy.

Objective: To evaluate the association between the risk of death from COPD and air temperature events in ten major Brazilian microregions. Methods: This was a time series analysis of daily COPD deaths and daily mean air temperatures between 1996 and 2017. Using distributed nonlinear lag models, we estimated the cumulative relative risks of COPD mortality for four temperature percentiles (representing moderate and extreme cold and heat events) in relation to a minimum mortality temperature, with a lag of 21 days, in each microregion. Results: Significant associations were found between extreme air temperature events and the risk of death from COPD in the southern and southeastern microregions in Brazil. There was an association of extreme cold and an increased mortality risk in the following microregions: 36% (95% CI, 1.12-1.65), in Porto Alegre; 27% (95% CI, 1.03-1.58), in Curitiba; and 34% (95% CI, 1.19-1.52), in São Paulo; whereas moderate cold was associated with an increased risk of 20% (95% CI, 1.01-1.41), 33% (95% CI, 1.09-1.62), and 24% (95% CI, 1.12-1.38) in the same microregions, respectively. There was an increased COPD mortality risk in the São Paulo and Rio de Janeiro microregions: 17% (95% CI, 1.05-1.31) and 12% (95% CI, 1,02-1,23), respectively, due to moderate heat, and 23% (95% CI, 1,09-1,38) and 32% (95% CI, 1,15-1,50) due to extreme heat. Conclusions: Non-optimal air temperature events were associated with an increased risk of death from COPD in tropical and subtropical areas of Brazil.

Keywords: Pulmonary disease, chronic obstructive/mortality; Temperature; Climate.

Objective: To create a mechanical model that could be regulated to simulate the conditioning of inspired and expired air with the same normal values of temperature, pressure, and relative humidity as those of the respiratory system of a healthy young man on mechanical ventilation. Methods: Using several types of materials, a mechanical device was built and regulated using normal values of vital capacity, tidal volume, maximal inspiratory pressure, positive end-expiratory pressure, and gas temperature in the system. The device was submitted to mechanical ventilation for a period of 29.8 min. The changes in the temperature of the air circulating in the system were recorded every two seconds. Results: The statistical analysis of the data collected revealed that the device was approximately as efficient in the conditioning of air as is the respiratory system of a human being. Conclusion: By the study endpoint, we had developed a mechanical device capable of simulating the conditioning of air in the respiratory tract. The device mimics the conditions of temperature, pressure, and relative humidity seen in the respiratory system of healthy individuals.

Keywords: Thermodynamics; Respiration, artificial; Temperature.

Objective: Manually assisted coughing (MAC) consists of a vigorous thrust applied to the chest at the beginning of a spontaneous expiration or of the expiratory phase of mechanical ventilation. Due to routine use of MAC in intensive care units, the objective of this study was to assess the effects of MAC on respiratory system mechanics in patients requiring full ventilatory support. Methods: We assessed 16 sedated patients on full ventilatory support (no active participation in ventilation). Respiratory system mechanics and oxyhemoglobin saturation were measured before and after MAC, as well as after endotracheal aspiration. Bilateral MAC was performed ten times on each patient, with three respiratory cycle intervals between each application. Results: Data analysis demonstrated a decrease in resistive pressure and respiratory system resistance, together with an increase in oxyhemoglobin saturation, after MAC combined with endotracheal aspiration. No evidence of alterations in peak pressures, plateau pressures or respiratory system compliance change was observed after MAC. Conclusions: The use of MAC alters respiratory system mechanics, increasing resistive forces by removing secretions. The technique is considered safe and efficacious for postoperative patients. Using MAC in conjunction with endotracheal aspiration provided benefits, achieving the proposed objective: the displacement and removal of airway secretions.

Keywords: Cough; Sputum; Respiratory mechanics; Respiration, artificial.

Objective: To evaluate submaximal exercise tolerance and respiratory muscle strength in relation to forward head posture (FHP) and respiratory mode in children, comparing mouth-breathing (MB) children with nasal-breathing (NB) children. Methods: This was a controlled, analytical cross-sectional study involving children in the 8-12 year age bracket with a clinical otorhinolaryngology diagnosis of MB, recruited between October of 2010 and January of 2011 from the Mouth Breather Clinic at the State University of Campinas Hospital de Clínicas, located in the city of Campinas, Brazil. The exclusion criteria were obesity, asthma, chronic respiratory diseases, heart disease, and neurological or orthopedic disorders. All of the participants underwent postural assessment and the six-minute walk test (6MWT), together with determination of MIP and MEP. Results: Of the 92 children in the study, 30 presented with MB and 62 presented with NB. In the MB group, the differences between those with moderate or severe FHP and those with normal head posture, in terms of the mean MIP, MEP and six-minute walk distance (6MWD), were not significant (p = 0.079, p = 0.622, and p = 0.957, respectively). In the NB group, the mean values of MIP and MEP were higher in the children with moderate FHP than in those with normal head posture (p = 0.003 and p = 0.004, respectively). The mean MIP, MEP, and 6MWD were lower in the MB group than in the NB group. Values of MIP and MEP were highest in the children with moderate FHP. Conclusions: Respiratory biomechanics and exercise capacity were negatively affected by MB. The presence of moderate FHP acted as a compensatory mechanism in order to improve respiratory muscle function.

Keywords: Mouth breathing; Posture; Exercise tolerance; Respiratory mechanics.

Objective: Respiratory muscle weakness is a functional repercussion of chronic lung disease (CLD). The objective of this study was to assess the effects of home-based respiratory muscle training (RMT) in children and adolescents with CLD or neuromuscular disease (NMD). Methods: This was a quasi-experimental study involving children and adolescents with CLD or NMD. Before and after 6 months of home-based RMT, we measured respiratory muscle strength (MIP and MEP), PEF, and peak cough flow (PCF). We made statistical comparisons between the pre-RMT and post-RMT values, as well as evaluating the correlation between the duration and effect of RMT. Results: The study included 29 patients, with a mean age of 12 years (range, 5-17 years), of whom 18 (62.1%) were male. The CLD group comprised 11 patients (37.9%), and the NMD group comprised 18 (62.1%). The mean duration of the RMT was 60 weeks (range, 46-90 weeks) in the CLD group and 39 weeks (range, 24-89 weeks) in the NMD group. In comparison with the pre-RMT values, the post-RMT values for MIP and MEP were significantly higher in both groups, whereas those for PEF and PCF were significantly higher only in the NMD group. We found no correlation between the duration and the effect of RMT. Conclusions: Home-based RMT appears to be an effective strategy for increasing respiratory muscle strength in children and adolescents with CLD or NMD, although it increased the ability to cough effectively only in those with NMD.

Keywords: Breathing exercises; Cystic fibrosis; Bronchiolitis obliterans; Neuromuscular diseases; Cough.

Objective: To evaluate a 24-month supervised, community-based maintenance exercise program after 3 months of pulmonary rehabilitation (PR) in comparison with a 27-month physical activity counseling program, in terms of the effects on maximal muscle strength, muscle power output, and exercise capacity, in individuals with COPD. Methods: Sixty-three men with moderate-to-severe COPD were recruited from two previous studies. Of those 63 participants, 31 were offered 3 months of PR followed by a 24-month supervised maintenance exercise program (24MME group) and 32 were offered a 27-month physical activity counseling program (27MPAC group). Measurements at 3 months and at the end of the study period included maximal strength of the upper and lower limbs, power output of the lower limbs, six-minute walk distance (6MWD), and quality of life. Results: At 27 months, the improvements in maximal strength of the upper and lower limbs were greater in the 24MME group than in the 27MPAC group (37.6 ± 28.3% and 28.4 ± 13.3%, respectively, vs. 8.8 ± 16% and 13.6 ± 16.4%, respectively; p < 0.05), as was the improvement in power output of the lower limbs (24.6 ± 18.4% vs. −2.3 ± 28.5%; p < 0.01). The increase in the 6MWD after 3 months was also greater in the 24MME group than in the 27MPAC group (33.2 ± 36.6 m vs. 2.9 ± 34.7 m; p < 0.05), although there were no differences between the two groups in terms of the Δ6MWD at 27 months (vs. baseline). Conclusions: A supervised, community-based maintenance program is a successful long-term strategy to preserve the benefits of PR on peripheral muscle function and exercise capacity in individuals with COPD. However, physical activity counseling can maintain maximal muscle strength and exercise capacity in such individuals.

Keywords: Pulmonary disease, chronic obstructive; Muscle strength; Leg/physiology, Muscle, skeletal/physiology; Physical fitness; Exercise therapy/methods.

Objective: To evaluate the effects of passive inhalation of cigarette smoke on the respiratory system of guinea pigs. Methods: Male guinea pigs were divided into two groups: control and passive smoking, the latter being exposed to the smoke of ten cigarettes for 20 min in the morning, afternoon and evening (30 cigarettes/day) for five days. After that period, inflammatory parameters were studied by quantifying mesenteric mast cell degranulation, as well as oxidative stress, in BAL fluid. In addition, we determined MIP, MEP, and mucociliary transport (in vivo), as well as tracheal contractility response (in vitro). Results: In comparison with the control group, the passive smoking group showed a significant increase in mast cell degranulation (19.75 ± 3.77% vs. 42.53 ± 0.42%; p < 0.001) and in the levels of reduced glutathione (293.9 ± 19.21 vs. 723.7 ± 67.43 nM/g of tissue; p < 0.05); as well as a significant reduction in mucociliary clearance (p < 0.05), which caused significant changes in pulmonary function (in MIP and MEP; p < 0.05 for both) and airway hyperreactivity. Conclusions: Passive inhalation of cigarette smoke caused significant increases in mast cell degranulation and oxidative stress. This inflammatory process seems to influence the decrease in mucociliary transport and to cause changes in pulmonary function, leading to tracheal hyperreactivity.

Keywords: Inflammation; Inhalation exposure; Tobacco smoke pollution.

Objective: To investigate the effects of airway obstruction on albuterol-mediated variations in the resistive and elastic properties of the respiratory system of adult patients with asthma. Methods: This study comprised 24 healthy controls and 69 patients with asthma, all of whom were nonsmokers. The patients were divided into three groups according to the severity of airway obstruction (mild, moderate or severe). Each of the three groups was divided into two subgroups according to the bronchodilator response (BR): positive (BR+) or negative (BR−). These measurements were conducted before and after albuterol use (300 µg). Airway obstruction was determined by means of spirometry, and the resistive and elastic properties were determined by means of the forced oscillation technique. Results: The resistance at the intercept (R0) presented greater reductions in the groups with higher obstruction. This reduction was more evident in the BR+ subgroups than in the BR− subgroups (p < 0.02 and p < 0.03, respectively). There was a significant difference between the control group and the BR+ subgroup with severe obstruction (p < 0.002). The reductions in dynamic elastance (Edyn) were significantly greater in proportion to the degree of obstruction, in the BR− subgroups (p < 0.03), and in the BR+ subgroups (p < 0.003). The reductions in Edyn were significantly greater in the BR− subgroup with moderate obstruction (p < 0.008) and in the BR+ subgroup with severe obstruction (p < 0.0005) than in the control group. Conclusions: In patients with asthma, increased airway obstruction results in greater reductions in R0 and Edyn after albuterol use. These reductions are greater among BR+ patients than among BR− patients.

Keywords: Asthma; Bronchodilator agents; Respiratory mechanics; Spirometry; Albuterol.