Cold Dry Air Research Articles

Performance Improvement Plan of Air Circulation-Type Solar Heat-Storage System Using Ventilated Cavity of Roof

Indoor solar-heating systems that use ventilated roofs have drawn attention in recent years. The effectiveness and efficiency of such air-heating systems vary depending on the design and operation methods. In Japan, by introducing outside air into a ventilated roof cavity and circulating the air indoors, systems that simultaneously obtain ventilation, solar heating, and heat-storage effects have been actively developed. The conventional systems intake a large volume of outside air to increase the solar heat collection effect. However, there is a risk of heat loss and over-drying when a large amount of cold dry air during winter is introduced. In this paper, plans are presented for improving these solar heating and heat-storage effects by preventing over-drying using indoor air circulation via ventilated cavities in the roof and indoor wall. By comparing the results of the proposed system with those of the conventional system via numerical simulation, the heating load is found to be reduced by 50% or more by circulating indoor air to the ventilated roof and storing the heat in the indoor wall. Moreover, an increased relative humidity of approximately 10% was confirmed by reducing the intrusion of the outside air and keeping the moisture indoors.

Vitamin D: A Boon to Respiratory Health in COVID-19

COVID-19 has errupted not only as a pandemic but as challenge to mankind. Life has come to a stand still. All spheres of life are affected not only in terms of jobs and economy but importantly health and well being. In Indian scenario this is of particular significance as autumn coincides with festivities, wedding season and mass gatherings. Outbreaks of respiratory viral infections, such as those caused by influenza A and Respiratory Synctial Virus have long been associated with changing season reaching a peak in winter season and nadir in summer months. Various factors could be attributed to this pattern like increased virus survival at low temperature, tendency of close gatherings in winter months and cold dry air reducing mucus in nasal passages. Clinically Vitamin D deficiency has been shown to associate with increased risk of diverse acute respiratory tract infections. It has been proposed that vitamin D, diminishes production of respiratory cytokines, which appear to play a central part in pathogenesis of severe COVID-19.

The Effect of Whole-Body Cryostimulation in Healthy Adults : Whole-Body Cryostimulation According to Gender and Smoking Status.

Whole-body cryostimulation (WBC) refers to the therapeutic application of extremely cold dry air for a short period of time. The method has beneficial results in various diseases as well as the recovery of athletes. The effects of WBC in healthy individuals have not been extensively investigated. We aim to explore differences in the effects of WBC on blood pressure (BP), oxygen saturation (SpO2), and heart rate (HR) in healthy adults (not athletes) as well as differences according to gender and smoking status. Fifty adults (male/female: 32/18) smokers/nonsmokers: 26/24) were included in the study. WBC was performed in a cryochamber at -85°C for 3 min. Systolic BP (SBP) and diastolic BP (DBP), HR, and SpO2 were measured before and immediately after WBC. Males and females differed significantly in SBP after WBC (138.1±13.0 vs 128.5±17.0mmHg, respectively, p=0.029), SpO2 after WBC (96.6±1.8 vs 98.3±1.5%, respectively, p=0.001) and HR after WBC (60.1±9.6 vs 70.2±7.7bpm, respectively, p<0.001). In males, SpO2 remained unchanged before and after WBC, whereas in women SpO2 increased by 1.0±1.4% (p=0.038) (Table 2). HR after WBC displayed a downward trend by -9.8±5.9% in males compared to an upward trend by 3.6±15.1 in females (p<0.001). Nonsmokers displayed higher increase in SBP after WBC (4.3±9.0% in smokers compared to 13.3±13.2% in nonsmokers, p=0.007). Smokers presented an increase by 1.0±1.6% in SpO2, while in nonsmokers, SpO2 decreased by 0.8±2.1% following WBC (p=0.001). Our results suggest that WBC affects the cardiovascular and the respiratory system differently in males versus females and smokers versus nonsmokers. More studies are needed in order to fully explore the effects of WBC in these population groups in order to design individualized treatment protocols.

Towards influence of Arabian Sea SST anomalies on the withdrawal date of Meiyu over the Yangtze-Huaihe River basin

Prediction of Meiyu withdrawal date (MWD) over the Yangtze-Huaihe River basin (YHRB) around mid-July has aroused extensive concern recently because of the profound socioeconomic and academic importance. However, relatively few researches have been carried out to identify the potential predictability source that can physically contribute to the Meiyu retreat over the YHRB, which exhibits profound year-to-year variations. This study identifies that the later-than-normal Meiyu withdrawal is preceded by the significant tropical June Arabian Sea (AS) surface sea surface (SST) warming on the interannual timescale. Analyses of possible mechanisms suggest that a striking quasi-barotropic “north-low–south-high” meridional seesaw pattern (i.e. PJ-like pattern) over the Northeast Asian–western North Pacific sector in July favors the transport and convergence of warm-moist water vapor and cold-dry air mass over the YHRB, inducing abundant in situ precipitation and thereby maintaining the Meiyu rainband. Under such a background, the Meiyu termination over the YHRB is delayed. Moreover, dynamical diagnoses and numerical model simulations indicate that the warmer-than-normal AS, which persists from June to the following July, can induce a notable localized low-level cyclonic anomaly via a Rossby-wave-like Matsuno–Gill-type atmospheric response. This cyclonic anomaly can further stimulate a large-scale atmosphere bridge stretching across South Asia and propagating poleward into Northeast Asia, which modulates the aforementioned downstream MWD-related atmospheric conditions continuously. Therefore, AS SST warming can remotely regulate and maintain the July Meiyu rainband through inducing a major direct forcing for the later Meiyu withdrawal over the YHRB, namely the East Asian coastal “north-low-south-high” meridional teleconnection. These results indicate and demonstrate the possible source of predictability for Meiyu withdrawal. This work may help improve forecasting of the withdrawal timing of Meiyu over the YHRB through more accurate predictions of SST over the AS region.

Relationships Between Jianghuai Meiyu Anomaly and the Collaborative Evolution of Wave Trains in the Upper and Lower Troposphere in Mid-July of 2020

Based on the ECMWF reanalysis dataset (ERA5), SST , OLR and the daily precipitation data, the relationship between the Meiyu anomaly in the Yangtze-Huaihe river basin (YHB) and the collaborative evolution of wave trains in the upper and lower troposphere in the mid-July of 2020 is analyzed. The results show that the key circulation background for the long-lasting Meiyu season in the summer of 2020 is the coexistence and collaborative evolution of the Silk-Road (SR) wave train in the upper troposphere and the – + Pacific-Japan (PJ) wave train in the middle-lower troposphere, which is in favor of the movement towards each other of the South Asia high (SAH) and the western Pacific subtropical high (WPSH), resulting in the upper-level divergence over the YHB where is the right side of the jet entrance area. The WPSH strengthens and extends westward, transporting abundant water vapor to the YHB from the Western Pacific and South China Sea. Meanwhile, the meridional circulation develops at the middle and high latitudes, which is in favor of cold-dry air and warm-moist air strongly interact over the YHB, leading to the long-lasting Meiyu season. The coordinative evolution of the SR and PJ wave trains not only affects the persistence and intensity of precipitation in the YHB, but also can be regarded as a precursor signal for the occurrence of persistent heavy rainfall to some extent. The wave-activity flux dispersing eastward along the upper-level jet is beneficial to the development and maintenance of the SR wave train, and the poleward dispersing wave-activity flux is related to the development and maintenance of the PJ wave train. Additionally, along with the weakening El Nino in 2019, the anomalous convection caused by the warm SST in the Western Pacific warm pool is conducive to the formation and maintenance of the PJ wave train. The abnormal convection caused by the warm SST in the Indian Ocean and the east coast of the tropical Atlantic may affect the SR wave train. These are also one of the reasons for the long Meiyu season in 2020.

Study on the diagnosis of idiopathic rhinitis by cold dry air provocation

Objective:This study aimed to compare the nasal response of cold dry air（CDA） provocation in patients with idiopathic rhinitis（IR） and healthy individuals, and further assess its ability in diagnosing IR. Method:CDA provocation was performed among 15 healthy volunteers and 17 IR patients from Beijing Tongren Hospital Outpatient Department. Nasal symptom scores, total nasal volume（TNV）, total nasal resistance（TNR） and minimal cross-sectional area（MCA） were checked before and after the provocation. Logistic regression analysis and Receiver Operating Characteristic（ROC） curves were used in data evaluation. Result:Subjects in the IR group showed significantly larger changes after CDA provocation in total nasal symptom score（TNSS）, total nasal resistance（TNR）, minimal cross-sectional area（MCA） and total nasal volume（TNV）, compared with healthy volunteers. We built a predictive model for IR, Y=0.394×ΔTNSS-0.061 ×ΔTNV（%）+0.014×ΔTNV（%） -2.318, whose area under curve was 0.919 based on multi-factor logistic regression and ROC curve. According to the Youden index, the cut-off criteria was set to be Y >0.49, when its sensitivity and specificity were 82.4% and 84.6%, respectively. Conclusion:Aggravated nasal symptoms and decreased nasal ventilation could be seen after CDA provocation in the IR population. The CDA provocation provides a possible method for assisting the diagnosis of IR, and we'll expand the sample size in future research to verify its clinical application value.

Role of temperature in influenza outbreaks

Respiratory tract infections are among the most common types of infections, globally. Seasonal variations have been associated with substantial roles in influencing respiratory mortality and morbidity. The effects of seasonal variations of respiratory tract infections are evidenced by the monthly increase in the use of healthcare services and hospital admissions during colder seasons. Influenza outbreaks are associated with worse health problems, which increase the morbidity and mortality rate of high-risk populations. Comparing tropical and colder regions, temperatures are high during summer and lower during winter. Additionally, relative humidity is comparatively higher in winter than in summer. In winters, the indoor humidity is low due to heating facilities, which suggests that cold air outside and dry air inside that occurs during the winter favors the transmission of the influenza virus and thus, triggering a flu infection season.

Low-dose capsaicin (0.01 mM) nasal spray is equally effective as the current standard treatment for idiopathic rhinitis: A randomized, double-blind, placebo-controlled trial

Low-dose capsaicin (0.01 mM) nasal spray is equally effective as the current standard treatment for idiopathic rhinitis: A randomized, double-blind, placebo-controlled trial

Impact of INSAT-3D/3DR Radiance Data Assimilation in Predicting Tropical Cyclone Titli Over the Bay of Bengal

This is the first study concerning the assimilation of the INSAT-3D/3DR radiance in the Hurricane Weather Research and Forecasting (HWRF) model and assesses its credibility to improve track, intensity, and precipitation forecasts of tropical cyclone (TC) Titli that occurred over the Bay of Bengal (BoB), which showed rapid intensification (RI) and weakening through its lifetime. The inbuilt Gridpoint Statistical Interpolation (GSI) method is used with a 3-D variational (3DVAR) configuration. Three sets of numerical experiments such as control (CNTL) (no assimilation), Global Telecommunication System (GTS) (observations from GTS network), and INSAT-3D/3DR (INSAT-3D/3DR sounder radiance data and GTS observations) were carried out with seven different initializations. The radiance analysis reproduced the initial vortex and the prominent synoptic scale features associated with TC Titli. The average root-mean-square errors (RMSE) of the analysis were relatively lower in the INSAT-3D/3DR compared to the CNTL and GTS. The HWRF performance is enhanced for track simulation, with improvements in mean landfall position errors by 40%–70% and 26%–52% for the INSAT-3D/3DR and GTS runs, respectively. The assimilation of radiance data has a positive impact on the simulation of warm core and thermodynamic structures, which has led to a more accurate intensity prediction (by 30–47%) over the CNTL. The assimilation run could realistically simulate the RI and weakening phases of the TC. A cold dry air intrusion is also observed when associated with the weakening. The study highlights the need to incorporate INSAT-3D/3DR radiances for improved TC predictions over the BoB basin.

Systematic Errors in South Asian Monsoon Precipitation: Process-Based Diagnostics and Sensitivity to Entrainment in NCAR Models

AbstractIn simulations of the boreal summer Asian monsoon, generations of climate models show a persistent climatological wet bias over the tropical western Indian Ocean and a dry bias over South Asia. Here, focusing on the monsoon developing stages (May–June), process-based diagnostics are first applied to a suite of NCAR models and reanalysis products. Two primary factors are identified for the initiation and maintenance of the wet bias over the northwestern Indian Ocean (NWIO; 5°–15°N, 52°–67°E): (i) excessive tropospheric moisture and (ii) restrained horizontal advection of the 1000–800-hPa levels cold–dry air couplet that originates offshore of Somalia. Second, guided by the diagnostics, we hypothesized that insufficient dilution of convective updrafts is one possible candidate for model bias and performed a series of enhanced entrainment sensitivity experiments with NCAR CAM4. Over the NWIO, the results suggest that globally increasing the maximum entrainment rateεmaxleads to a drier free troposphere, arrests the vertical extension of clouds, and weakens moisture–convection and cloud–radiation feedbacks; each factor contributes to a reduced wet bias. Moreover, a higherεmaxleads to a reduced dry bias over South Asia through changes in the local circulation features. In CAM4, improved precipitation climatology due to increasedεmaxsuggests that insufficient dilution is one factor, but not the only one, that contributes to systematic errors. Rather, realistic representation of boundary layer processes in climate models arising out of local ocean–atmosphere interaction processes off Somalia’s coast deserves attention in reducing the NWIO wet bias.

Rigorous Tritium Wet Scrubber Column Modeling and Design

The rigorous steady-state equilibrium stage Tritium Wet Scrubber Column model has been developed. The model includes the six water isotopologues H2O, HDO, HTO, D2O, DTO, and T2O; heat balance; and packing pressure drop. Heat balance is particularly important in wet scrubber calculations due to evaporative cooling of air with less than 100% relative humidity. Evaporative cooling is generally beneficial, but freezing is possible with very cold dry air, making it important to understand operating limits. The pros and cons of precooling and saturation of the airstream are discussed. The Tritium Wet Scrubber Column model has been applied to scrubbing airstreams containing tritiated light water vapor and for tritiated heavy water vapor in CANDU® heavy water applications. Deuterium and tritium are recovered at slightly different efficiencies, and because of differences in the latent heat of vaporization for H2O and D2O, liquid and vapor compositions affect the column heat balance. Case studies are presented for tritiated light water vapor air detritiation and also for tritiated heavy water vapor air detritiation to provide guidance for design. Further, practical aspects of the wet scrubber column construction and operation are discussed.

Future Projection of Extreme Heavy Snowfall Events With a 5‐km Large Ensemble Regional Climate Simulation

AbstractWe have recently experienced several heavy snowfall events, but still do not sufficiently understand how global warming will impact changes in local extreme snowfall events. The analysis relevant to the extreme events requires ensemble experiments with high‐resolution regional climate modeling. In this study, we use a large number of ensemble warming projections downscaled dynamically to 5‐km grids to examine the differences in distribution and mechanism in extreme snowfall events over Japan between present and future climates. Japan has two typical snowfall patterns, the winter monsoon and the south coast cyclone patterns. The domain‐averaged amount of extreme snowfall in the south coast cyclone pattern regions appear to decrease with the rise in temperatures. Meanwhile, the winter monsoon pattern regions showed little change as the increases in extreme snowfall in the mountainous areas are canceled out by the decrease in the coastal areas. Based on the existing mechanism of normal snowfall, the increase in mountain snow is caused by a temporary intensification of cold air outbreaks. The amount of the cold air blowing from Japan Sea clearly increases only during the days preceding the extreme snowfall event, and as the cold dry air obtains more latent heat over the ocean, the precipitable water vapor increases. The winter monsoon then transports this air over land where the intensification of precipitation results from orographic updraft. This sequence of processes beginning with cold air outbreaks may have a stronger control over extreme snowfall phenomena on the warmer field.

Intensifying effects of El Niño events on winter precipitation extremes in southeastern China

This paper studies the impacts of El Nino-Southern Oscillation (ENSO) on wintertime extreme precipitation in China from 1961 to 2017, and possibly different influences of two El Nino types are also examined. We find that ENSO poses profound influences on extreme precipitation in many portions of China. El Nino (La Nina) intensifies (weakens) the winter precipitation extremes in southeastern China (SEC) and slightly weakens (intensifies) those in central-north China, mainly by changing the frequency rather than the intensity of extreme precipitation. Further analysis suggests that the East Asian winter monsoon tends to be weaker during El Nino winters, suppressing the southward invasion of cold dry air. Via the weakened Walker circulation, El Nino also triggers anomalously descending motion and anticyclone over the western North Pacific (WNP), which exhibits southwesterly anomalies over SEC and is thus conducive to the transport of sufficient moisture into that area. The changes over WNP are also accompanied by ascending motions over East Asia via a local meridional circulation alike the Pacific–Japan pattern. Meanwhile, El Nino induces a southward-displaced East Asian jet stream, as characterized by intensified westerly over southern China, corresponding to anomalously ascending motion there. Together, these changes facilitate the updrafts of circulations and the condensation of water vapor, thus increasing the occurrence of extreme precipitation events in SEC. Moreover, we find that different Nino types exhibit distinct subregional influences. In particular, the canonical eastern Pacific El Nino significantly increases the frequency of extreme precipitation in South China, whereas the Modoki central Pacific El Nino mainly impacts that in East China.

Paradoxical Response to Cold Dry Air Provocation according to the Season in Allergic Rhinitis Patients

Background and Objectives We investigated the seasonal variation of nonspecific hyperreactivity by performing the cold dry air (CDA) provocation test in both summer and winter in patients with rhinitis. Subjects and Method We performed the CDA provocation test in 57 patients with allergic rhinitis (AR) or non-allergic rhinitis (NAR). Depending on the season and the type of rhinitis, we divided patients into four groups (Summer AR group, n=17; Winter AR group, n=15; Summer NAR group, n=18 and Winter NAR group, n=7) and compared the changes in nasal symptoms, total nasal volume (TNV), and minimal cross-sectional area (MCA) measured by acoustic rhinometry after CDA provocation in each group. Results When the CDA provocation was performed for AR patients in summer, nasal symptoms improved slightly, which was significantly different from those shown in winter (Summer AR vs. Winter AR, p=0.012). In addition, there was a significant difference in symptom change between AR and NAR patients in the summer (Summer AR vs. Summer NAR, p=0.033). There was no significant difference in TNV or MCA changes after CDA provocation depending on the type of rhinitis and season (p＞0.05). Conclusion When performing CDA provocation in AR patients in summer, the examiner should pay attention to the possible paradoxical response. Key words: Acoustic rhinometry ㆍ Allergic rhinitis ㆍ Nasal provocation tests

Cold dry air provocation is a reliable diagnostic tool in nonallergic rhinitis.

No diagnostic criteria have been available for nonallergic rhinitis (NAR) to this point in time. Nonspecific nasal hyperresponsiveness (NHR), which could be efficiently assessed by cold dry air (CDA) provocation, is an essential feature of NAR. Thus, this study's purpose was to assess the diagnostic value of CDA provocation in discriminating patients with NAR from healthy individuals. CDA provocation was performed among 13 healthy volunteers and 15 NAR patients. Nasal symptom scores, total nasal volume (TNV), total nasal resistance (TNR) and minimal cross-sectional area (MCA) were checked before and after the provocation. Non-paramedic tests and receiver operating characteristic (ROC) curves were used in data evaluation. Subjects in the NAR group showed significantly larger changes after CDA provocation in total nasal symptom score (TNSS) and nasal congestion score compared with healthy volunteers, while the change for rhinorrhea score was comparable. Similarly, significant differences in the change of MCA and TNV were witnessed between both groups. We built a predictive model for NAR, Y = minus 3.285 plus 2.520 times the difference of TNR (%) plus 1.027 times the difference of TNSS minus 6.542 times the difference of TNV (%), whose area under curve was 0.93. According to the Youden index, the criterion was set to be Y greater than -0.52, when its sensitivity and specificity were 93.3% and 84.6%, respectively. With superior patient-friendliness, safety and efficacy, we successfully performed the first NAR predictive model in the Chinese population, based on a short protocol of CDA provocation, by means of both subjective scores and objective tests (acoustic rhinometry and rhinomanometry).

Physiologic Model for Seasonal Patterns in Flu Transmission.

Seasonal patterns in flu transmission have observational validity in temperate climates. However, there is no consensus mechanism explaining the increased incidence of flu during the winter. The physiologic effects of cold weather and dry air on the upper respiratory system may contribute to immune dysfunction and increased susceptibly to flu-causing pathogens. Low temperature limits the absolute humidity of air. Persistent exposure to dry air leads to airway desiccation and failure of the mucociliary system. The resultant physiologic and histopathologic changes that occur in the airway increase susceptibility to flu-causing pathogens. Laryngoscope, 130:309-313, 2020.

Airway obstruction and bronchial reactivity from age 1 month until 13 years in children with asthma: A prospective birth cohort study.

BackgroundStudies have shown that airway obstruction and increased bronchial reactivity are present in early life in children developing asthma, which challenges the dogma that airway inflammation leads to low lung function. Further studies are needed to explore whether low lung function and bronchial hyperreactivity are inherent traits increasing the risk of developing airway inflammation and asthmatic symptoms in order to establish timely primary preventive initiatives.Methods and findingsWe investigated 367 (89%) of the 411 children from the at-risk Copenhagen Prospective Studies on Asthma in Childhood 2000 (COPSAC2000) birth cohort born to mothers with asthma, who were assessed by spirometry and bronchial reactivity to methacholine from age 1 month, plethysmography and bronchial reversibility from age 3 years, cold dry air hyperventilation from age 4 years, and exercise challenge at age 7 years. The COPSAC pediatricians diagnosed and treated asthma based on symptom load, response to inhaled corticosteroid, and relapse after treatment withdrawal according to a standardized algorithm. Repeated measures mixed models were applied to analyze lung function trajectories in children with asthma ever or never at age 1 month to 13 years. The number of children ever versus never developing asthma in their first 13 years of life was 97 (27%) versus 270 (73%), respectively. Median age at diagnosis was 2.0 years (IQR 1.2–5.7), and median remission age was 6.2 years (IQR 4.2–7.8). Children with versus without asthma had reduced lung function (z-score difference, forced expiratory volume, −0.31 [95% CI −0.47; −0.15], p < 0.001), increased airway resistance (z-score difference, specific airway resistance, +0.40 [95% CI +0.24; +0.56], p < 0.001), increased bronchial reversibility (difference in change in forced expiratory volume in the first second [ΔFEV1], +3% [95% CI +2%; +4%], p < 0.001), increased reactivity to methacholine (z-score difference for provocative dose, −0.40 [95% CI −0.58; −0.22], p < 0.001), decreased forced expiratory volume at cold dry air challenge (ΔFEV1, −4% [95% CI −7%; −1%], p < 0.01), and decreased forced expiratory volume after exercise (ΔFEV1, −4% [95% CI −7%; −1%], p = 0.02). Both airway obstruction and bronchial hyperreactivity were present before symptom debut, independent of disease duration, and did not improve with symptom remission. The generalizability of these findings may be limited by the high-risk nature of the cohort (all mothers had a diagnosis of asthma), the modest study size, and limited ethnic variation.ConclusionsChildren with asthma at some point at age 1 month to 13 years had airway obstruction and bronchial hyperreactivity before symptom debut, which did not worsen with increased asthma symptom duration or attenuate with remission. This suggests that airway obstruction and bronchial hyperreactivity are stable traits of childhood asthma since neonatal life, implying that symptomatic disease may in part be a consequence of these traits but not their cause.

Characteristics of Dry Cold Air Intrusion in a Typical Strong Storm

Taking a typical strong storm in Guizhou on April 5, 2017 for example, the diagnosis analysis used the water vapor cloud and the initial field of EC thin grid, including physical quantity, surface and upper air meteorological observation, as well as radar observation data. For the environment parameter analysis, small CAPE value tended to underestimate storm intensity on potential forecast stage, strong vertical wind shear revealed the strong dry cold air was the important intensity factors of the storm. The water vapor cloud map can be used to monitor the most important features, the dry zone, the wet zone and the boundary between them. When dry intrusion is found, it can be used as one of the bases for the development of heavy rain. Dry cold air intrusion on high-level was traced by water vapor images. And in this process, the analyses revealed the role of dry cold air’s influence on intensity of the storm.

Pengeringan biji jagung menggunakan pengkondisi udara

This study aims to determine the effect of air velocity on the rate of drying corn. Corn seeds were placed after the evaporator of an air conditioner, so that the air came out of the evaporator entered the drying chamber. The water in the corn was evaporated and sucked by dry cold air and then it was condensed in the evaporator. The results show that the mass of corn seeds decreases with the time; the drying rate also decreases with the time and mass-based drying rates at low air speeds are faster than at high air speed. The air conditioner can be used for drying seeds.

Association of outdoor temperature with lung function in a temperate climate.

Acute exposure to cold dry air is a trigger of bronchoconstriction, but little is known about how daily outdoor temperature influences lung function.We investigated associations of temperature from a model using satellite remote sensing data with repeated measures of lung function among 5896 participants of the Framingham Heart Study Offspring and Third Generation cohorts residing in the Northeastern US. We further tested if temperature modified previously reported associations between pollution and lung function. We constructed linear mixed-effects models, and assessed departures from linearity using penalised splines.In fully adjusted linear models, 1-, 2- and 7-day average temperatures were all associated with lower lung function: each 5°C higher previous-week temperature was associated with a 20 mL lower (95% CI -34---6) forced expiratory volume in 1 s. There was significant effect modification by season: negative associations of temperature and lung function were present in winter and spring only. Negative associations between previous-day fine particulate matter and lung function were present during unseasonably warm but not unseasonably cool days, with a similar pattern for other pollutants.We speculate that temperature-related differences in lung function may be explained by behavioural changes on relatively warm days, which may increase outdoor exposures.