Exhaust Gas Research Articles

Parametric study on configuration geometry effect on thrust performance of annular ED nozzles

A numerical investigation is conducted to uncover the parametric influence of configuration geometry on the thrust performance of annular expansion deflection (ED) nozzles. Based on the classic design principle of Taylor’s ED nozzle configuration, the influences of six geometric elements, covering the expansion channel region, the near-pintle region, and the shroud region, including 13 nozzle configurations, are examined in detail. The flow characteristics in each nozzle are demonstrated, according to which the connections between the geometric changes and nozzle thrust performance are elucidated. The present results show that the nozzle flow pattern is closely related to the nozzle configuration geometry. In the open operation mode of the ED nozzle, the wide expansion channel has very little restriction on the axial expansion of the exhaust gas. The high axial velocity brings strong shock strength and total pressure loss, which are unfavorable to the nozzle thrust performance. The large curvature of the shroud expansion section contributes greatly to the exhaust gas deflection, which increases the mass flow rate of the supersonic core flow zone through the nozzle exit plane, and therefore favors the thrust performance. In the closed operation mode, geometric differences in the expansion channel region have little effect on the supersonic gas, which fills almost the entire nozzle. The shroud region still affects the axial deflection of the gas and its large curvature is associated with superior thrust performance. These investigations suggest that the annular ED nozzles with narrow expansion channels and large shroud curvatures are superior in thrust performance.

Changes in the Dominant Contributions of Nitrate Formation and Sources During Haze Episodes: Insights From Dual Isotopic Evidence

AbstractInorganic nitrate (NO3−), a crucial component of fine particulate matter (PM2.5), has not shown a consistent decrease, despite an obvious decrease of nitrogen oxide (NOx) and PM2.5. The atmospheric oxidation process for nitrate formation has been deemed a key factor in pollution; however, the changes of sources and oxidation pathways during a particular haze episode require further investigation. Here, daily dual isotopes (δ15N and δ18O) were used to quantify the sources and oxidation pathways of nitrate formation in Qingdao, a port city in Northern China, from September 2017 to February 2018. This study also includes a detailed introduction to two haze episodes. δ15N and δ18O results show that both fractions of nocturnal oxidation for nitrate formation and NOx from coal combustion were lower in warmer season and higher in colder season. The fractions increased with increasing PM2.5 under low PM2.5 concentration while the fractions were not significantly changed under higher PM2.5 concentration, dominated by nocturnal oxidation (70.6% ± 9.7%) and coal combustion (66.1% ± 18.2%), respectively. The haze episode 1 was attributed to smoke transported over long distances, which provided a large amount of aerosol particles to absorb more locally formed gaseous HNO3 or N2O5. In this episode, meteorological and air quality factors, nitrate sources, and formation mechanism did not obviously change. Haze episode 2 was caused by unfavorable meteorological factors that enhanced local nitrate accumulation. As pollution worsened, the oxidation pathway shifted from OH oxidation to N2O5 hydrolysis, and the primary source changed from coal combustion to more vehicle exhaust.

Long-Term Trends and Ecological Risks of Heavy Metal Accumulation in Cultivated Land of Songnen Plain, China

Heavy metal pollution in agricultural soils poses a serious threat to food security. Therefore, it is crucial to conduct risk assessments and issue early warnings about high levels of metal contamination for the sustained prosperity of agriculture. To assess the risks, identify the sources, quantify the amounts, and determine the extent of pollution from seven heavy metals, as well as to provide early warnings, 78 soil samples were collected from farmed lands in the Songnen Plain of Jilin Province. The average concentrations of Zn, Cu, Mn, Pb, Cd, Ni, and As were found to be 2.05, 1.5, 0.2, 1.09, 2.68, 1.53, and 1.17 times higher than the background values of Chinese soils, respectively. Source analysis indicated that toxic Pb originates from vehicle exhaust emission, while Cd, Cu, and Ni are attributed to industrial activities. Zn and As are likely associated with agricultural practices, and Mn predominantly stems from natural environmental sources. The geo-accumulation index suggests relatively high, accumulation levels for Zn, Cu, Mn, and Pb. Meanwhile, the single-factor pollution index indicates elevated pollution levels of Zn, Cu, and Cd. Potential ecological risk assessment reveals that certain areas within Changchun and Baicheng cities exhibit higher ecological risks. Notably, Cd has the highest potential ecological risk index (RI) of the seven heavy metals and warrants special attention. By analyzing annual pollutant accumulations, predictions can be made about the heavy metal content in four cities within the Songnen Plain, enabling the issuance of early warnings regarding soil heavy metal risks. The findings suggest that without proactive measures to mitigate heavy metal accumulation in soils, Changchun and Songyuan will reach severe pollution levels by 2031 and 2029, respectively.

Research on the Correlation Mechanism Between Complex Slopes of Mountain City Roads and the Real Driving Emission of Heavy-Duty Diesel Vehicles

This research proposed the method of using cumulative positive and negative elevation increment indicators based on road segment to identify the slope characteristics of mountain city roads. Furthermore, it proposed the adoption of these indicators, combined with driving dynamics and emission theory, to analyze the correlation mechanism between the road slope and the actual driving fuel consumption and emissions. Three routes with different slope characteristics were selected in the mountain city of Chongqing, and six road driving tests were conducted using a Class N2 heavy-duty diesel vehicle. Finally, a comprehensive and in-depth study on fuel consumption and emission characteristics was carried out. The results show that the cumulative positive and negative elevation increment indicators based on road segment can correctly identify the complex slope characteristics of mountain city roads. Moreover, using the above indicators, the research method based on the theory of driving dynamics and emission successfully revealed the correlation mechanism between the slope of mountain city roads and the fuel consumption and emissions. Overall, the changes in fuel consumption factor and pollutants CO, NOX, and PN are positively correlated with the change in slope. The increase in slope leads to a rise in load, thereby increasing the required power, fuel consumption, and rich combustion conditions, ultimately leading to an increase in pollutants. It should be noted that driving dynamics also affect fuel consumption and emissions, leading to the specific rate of change between slope and fuel consumption not being consistent and a significant increase in the PN (Particulate Number) on some road sections. In addition, exhaust gas temperature may have a certain impact on emissions.

Replacing Car Trips with a Cargo Bike Sharing Service: What Features Do Users Value Most?

While cargo bikes are becoming an increasingly popular alternative to larger, more polluting vehicles in both the logistics and private mobility sectors, there has been comparatively little research on their use for private mobility. The potential of shared cargo bikes to replace car trips has been examined in some studies, but no previous research has investigated the critical factors that make it a valued alternative. By studying users’ willingness to pay, this paper examines the perceived value of a free cargo bike sharing service for users. The research is based on a survey of 321 users of the Fietje cargo bike sharing service in Bremen, conducted in 2022. In this sample, 38 to 55% of shared cargo bikes trips would otherwise have been performed by car. The paper identifies the transport of objects and children as critical features that provide value to users and create the potential to replace car trips. The results also draw attention to the fact that a cargo bike sharing service is likely to be a more effective tool for reducing car use if it is free. Introducing a fee would increase car trips by 14 to 18% of the total trips enabled by the service.

Direct measurement of brake wear particles from a light-duty vehicle under real-world driving conditions

Abstract As tailpipe emissions have decreased, there is a growing focus on the relative contribution of non-exhaust sources of vehicle emissions. Addressing these emissions is key to better evaluating and reducing vehicles’ impact on air quality and public health. Tailoring solutions for different non-exhaust sources, including brake emissions, is essential for achieving sustainable mobility. Studying emissions from vehicles in real-world scenarios provides a better understanding of their environmental impact compared to laboratory testing alone. This study presents findings on the direct measurement of brake particles and the characterization of this source of particulate matter in real-world conditions using a mobile laboratory. In situ measurements of particle concentration and size distribution showed good agreement with previous laboratory studies, indicating the suitability of the approach to investigate break particle emissions during real-world operation. The study demonstrates that particle size distributions can vary based on the temperature of the brake disk, which is influenced by the initial braking speed, with significant variations observed between speeds of 60, 80, 100, and 120 km/h. Particles with sizes between 6 and 523 nm were released into the air from the brake system, although it is likely that larger particles were also emitted but not captured due to the upper detection limit of the Engine Exhaust Particle Sizer. During harsh braking events, such as decelerations of 4.2 m/s2 from 120 km/h, a concentration of up 106 (#/cm3) was measured for particles under 8 nm. Moreover, scanning electron microscope analysis revealed that nanoparticles are present in the form of agglomerates, whose shape can change depending on the formation process. Elements present in the particles comprised mainly iron, copper, and aluminium, indicating wear of the brake pad materials and disk components.

Mechanistic Insights into CO2 Adsorption of Li4SiO4 at High Temperature

The development of materials with high adsorption capacity for capturing CO2 from industrial exhaust gases has proceeded rapidly in recent years. Li4SiO4 has attracted attention due to its low cost, high capture capacity, and good cycling stability for direct high-temperature CO2 capture. Thus far, the CO2 adsorption mechanism of Li4SiO4 is poorly understood, and detailed phase transformations during the CO2 adsorption process are missing. Here, aided by in situ X-ray diffraction and in situ Raman spectroscopy, we find that Li4SiO4 reacts with CO2 to form Li2SiO3 and Li2CO3 in CO2 atmosphere at 973 K, with no detectable involvement of crystalline Li2O during the adsorption process. Moreover, we observe a formation of stepped structures in the Li4SiO4 surface after CO2 adsorption by scanning electron microscopy. To illustrate the formation of stepped structures, we propose a modified double-shell mechanism, suggesting a possible two-dimensional nucleation and growth of Li2CO3. This work provides a deeper understanding of the CO2 adsorption mechanism and paves a way for further optimization of Li4SiO4-based adsorbents.

Occupational exposure and sarcoidosis: a case-control study in three countries.

Preceding studies of environmental and occupational risk factors of sarcoidosis yielded inconsistent findings. We aimed to ascertain the occupational risk factors for sarcoidosis in a case-control study. A total of 237 sarcoidosis patients with a histologically confirmed diagnosis were matched with 474 controls for sex and age (median 49, interquartile range 37; 60 years) recruited from the university hospitals and outpatient centres in Belarus, Kazakhstan and the Russian Federation. Ever and cumulative (considering years and hours per week) exposure to 24 occupational factors were analysed using logistic regression. In the overall sample of 711 subjects, 50% were females and any occupational exposure was more prevalent in cases compared to controls (60% versus 40%, P < 0.001). Current daily smoking as opposed to ex-smoking was associated with the lower risk of the outcome. Adjusted for smoking, age, sex and a few other exposures, ever-exposure to hay in agriculture (odds ratio (OR) 3.64 (95% confidence interval (CI) 1.26; 10.50)), engine exhausts (OR 2.94 (95% CI 1.14; 7.54)) and printing equipment (OR 1.66 (95% 1.03; 2.68)) was associated with sarcoidosis. The effect was also positive for cumulative exposure to hay in agriculture (OR 2.02 (95% CI 1.00; 4.07)), stone dust (OR 1.07 (95% CI 1.01; 1.14)) and engine exhausts (OR 1.18 (95% CI 1.03; 1.38)) and was stronger in never-smokers and subjects 40 years and older. Widespread occupational exposures may increase the risk of sarcoidosis, but further research is needed to elucidate the complex interplay of environmental and occupational factors in the epidemiology of sarcoidosis.

Significant NO2 Formation in Truck Exhaust Plumes and Its Association with Ambient O3: Evidence from Extensive Plume-Chasing Measurements.

Vehicle nitrogen oxides (NOx) significantly increase nitrogen dioxide (NO2) exposure in traffic-related environments. The NO2/NOx ratios are crucial for accurate NO2 modeling and are closely linked to public health concerns. In 2020, we used a mobile platform to follow test trucks (plume-chasing) that were installed with a portable emission measuring system (PEMS) on two restricted driving tracts. Six hundred eighteen exhaust plumes were collected through the PEMS-chasing measurements from seven trucks. The NOx emission factors (EFs), and the NO2/NOx ratios, were calculated at distinct stages (i.e., tailpipe and on-road). A significant reduction in NOx EFs (>64%) was observed with normal operating after-treatment devices, except for trucks equipped with diesel particulate filter (DPF). Disparities in tailpipe NO2/NOx ratios were also found, attributed to the after-treatment technologies. The NO2/NOx ratios measured from plume-chasing were significantly higher (3-4 times, p < 0.001) than the tailpipe measurements, providing field evidence of substantial NO2 formation in exhaust plumes. We developed a quantitative relationship between NO2/NOx ratios from tailpipe and plume-chasing measurements and demonstrated a robust correlation (R2 > 0.90). Since the NO2 formation in the exhaust plume is not explicitly accounted for in NO2 modeling, the quantitative relationship (O3-NO2/NOx) could improve the estimation of NO2 exposure when local emission inventory (tailpipe emissions) is available.

Non-Stoichiometric BaxMn0.7Cu0.3O3 Perovskites as Catalysts for CO Oxidation: Optimizing the Ba Content

In this work, a series of BaxMn0.7Cu0.3O3 samples (x: 1, 0.9, 0.8, and 0.7, BxMC) was synthesized, characterized, and used as catalysts for CO oxidation reaction. All formulations were active for CO oxidation in the tested conditions. A correlation between the electrical conductivity, obtained by impedance spectroscopy, and the reducibility of the samples, obtained by H2-TPR, was observed. The Ba0.8Mn0.7Cu0.3O3 composition (B0.8MC) showed the best catalytic performance (comparable to that of the 1% Pt/Al2O3 reference sample) during tests conducted under conditions similar to those found in the exhaust gases of current gasoline engines. The characterization data suggest the simultaneous presence of a high Mn(IV)/Mn(III) surface ratio, oxygen vacancies, and reduced copper species, these two latter being key properties for ensuring a high CO conversion percentage as both are active sites for CO oxidation. The reaction temperature and the reactant atmosphere composition seem to be the most important factors for achieving a good catalytic performance, as they strongly determine the location and stability of the reduced copper species.

Impact of Drive Days and No-DriveDays on Atmospheric Carbon Monoxide (CO) concentration

Automobile emissions rise in tandem with population growth. Increases in motorised vehicles lead to high urban traffic congestion, air pollution and health effects such as asthma, cardiorespiratory illness, headaches and cardiorespiratory disorders. The carbon monoxide (CO) released by vehicles acts as a greenhouse gas and is correlated with climate change. The study aims to evaluate and compare CO levels and vehicle counts on Drive Days (DD) and No-Drive Days (NDD) and to analyse the correlation between CO Concentration and vehicle count. The vehicles were counted, and CO concentrations were monitored using a CO meter over a five-year period. The research focused on observing No-Drive Days at Bishop Heber College, where commuters are encouraged to avoid motorised vehicles and to use eco-friendly transport. The number of vehicles has reduced significantly from DDs to NDDs ranging from 36% to 90.3%. On the DD, the CO concentrations were higher than the maximum permissible level signifying the need to take measurements. However, the CO levels have reduced on NDDs with a mean of 1.52 mg/m3 well below the maximum permissible level. The investigation concluded that a decrease in vehicle numbers decreased the atmospheric CO concentration. The organisation and execution of No-Drive Days, as well as participant support greatly influence the level of success and sustainability of such initiatives.

The Role of Lifestyle and Environmental Factors in the Pathogenesis of Multiple Myeloma.

The study evaluated the impact of lifestyle and environmental exposure on the etiology of multiple myeloma (MM). A multicenter case-control study was conducted in 20 hematology centers and in 5 outpatient clinics in Poland. The questionnaire on exposure to potential risk factors including sociodemographic data, lifestyle, and environmental factors was completed. A total of 274 patients with newly diagnosed MM and 208 patients from primary healthcare centers in the control group were enrolled in the study. Regarding lifestyle, sports practiced systematically for at least half a year play a protective role in the development of myeloma (OR = 0.40, 95% CI, 0.28-0.58, p < 0.001). Among environmental factors harmful exposures that increase the likelihood of the development of MM include pesticides (OR = 3.29, p < 0.001), asphalt (OR = 2.42, p = 0.026), coal dust (OR = 2.27, p = 0.004), organic vapors (OR = 2.11, p = 0.001), metal dust (OR = 2.07, p = 0.023), exhaust fumes (OR = 2.03, p < 0.01), and chemicals (OR = 1.80, p < 0.01). The pathogenesis of MM is complex with the impact of modifiable factors. Lifestyle, with physical activity, seems to play a key role.

Assessment of the Possibility of Using Exhaust Gas Composition in Predicting the Tech-nical Condition of the Engine

Assessment of the Possibility of Using Exhaust Gas Composition in Predicting the Tech-nical Condition of the Engine

Thermoelectric Energy Harvesting for Exhaust Waste Heat Recovery: A System Design.

Thermal energy harvesting for high-speed moving objects is particularly promising in providing an efficient and sustainable energy source to enhance operational capabilities and endurance. Thermoelectric (TE) technology, by exploiting temperature gradients between a heat source and ambient temperature, can provide a continuous power supply to such systems, reducing the reliance on conventional batteries and extending operation times. However, the integrated thermoelectric generator (TEG) system design research is far behind materials development. In this study, both experimental and numerical studies of TEG systems are designed and conducted to recover thermal energy. An integrated proof-of-concept platform is developed to simulate an exhaust gas emission system and demonstrate the designed TEG system performance. Triangular plate-fin heat exchangers are designed to collect heat from exhaust pipelines such as engine exhaust gas. While longitudinal trapezoidal fin cylindrical heatsink is designed for dissipating heat via forced convection, particularly for high-speed moving objects, the heatsink design is optimized using finite element analysis (FEA) simulations to maximize the temperature gradient and electrical output power. As a result, under a temperature gradient (ΔT) of 190 °C with commercial bismuth telluride-based TE modules, a maximum system output power of 40 W is achieved experimentally. Furthermore, a computational simulation is conducted to showcase the feasibility of the current system design under high-speed moving vehicle conditions. This study provides an advanced TEG system design bridging the TE device and integrated system transition and represents a potential advancement in the pursuit of high-speed moving objects such as autonomous and longer-lasting aerial platforms.

Compressed Air Vehicle

ct - This paper presents an experimental study of an engine driven by compressed air. The compressed air engine is a modified 100 cc internal combustion engine. The engine is modified from a 4-working stroke to a 2- working stroke engine (power and exhaust) by modification of cam-gear system. A temperature decrease from room temperature to 15 °C was observed at exhaust. The project was successfully manufactured and tested. Experimental analysis were carried out on this modified engine to find out its performance characteristics like brake power, indicated power, torque etc. It should be noted that pressure higher than that currently employed can result in increased engine performance in terms of output power, torque and speed. Nevertheless, the main advantage of this engine is that no hydrocarbon fuel is required that means no combustion process is taking place, thus the compressed air vehicle will play important role in reducing air pollution. Another benefit is that it uses air as fuel which is available abundantly in atmosphere. This study presents the atmospheric air which can be used in vehicles as the main or auxiliary source of power system. Key Words: Compressed air, Alternative Sources of Energy, clean &amp; highly efficient, light weight, Non-polluting.

EFFECTIVE REMOVAL OF EXHAUST VALVE DEPOSITS USING HIGHER ALCOHOL WITH GUTTER OIL IN SINGLE CYLINDER DIESEL ENGINE

This study examined a CIDI engine's exhaust valve. while excessive silt builds up on the exhaust system walls, especially while driving in an urban area, or when there are leaks in the vacuum or exhaust pipes, the valve has a tendency to become stuck. To determine the amount of deposition buildup on the exhaust valve, the engine was operated at a constant speed and load. Regarding this, to find out how three tested fuels—DF, DF90GO10, and DF70GO15Pn15—affect long-term endurance tests, a single-cylinder diesel engine was chosen and tested for 200 hours on each fuel sample. The results of the analysis showed that the exhaust valve's running surface was severely damaged. The results demonstrated that DF90WCO10 generated comparatively more deposits, especially on the exhaust valve. Additionally, the deposits formed on important engine parts, including intake/exhaust valves, when DF90WCO10 was employed had a completely different elements composition and structure than when DF and DF70GO15Pn15 were used. In contrast to both fuels, it was found that adding n-pentanol as a ternary mix produced less deposits. Overall, the inclusion rate of waste cooking oil showed that deposits were more common, especially on the valves, and that they were also more likely to be brittle and moist.

Experimental investigation of benzyl alcohol premixing effect on 5E concepts of compression ignition engine powered with lemongrass oil – diesel blend using response surface methodology

The corrected abstract is as follows.This article aims to study the benzyl alcohol premixing effect on the 5E concept of compression ignition engines powered with a lemongrass oil-diesel blend. The central composite approach is used to create the experimental matrix for the load (50–100%) and benzyl alcohol premixing ratio (0–20%). The experiment uses a computerized compression ignition, water-cooled, single-cylinder, naturally aspirated, four-stroke engine. The statistical model is tested using analysis of variance and confirmed at the 95% confidence level. Quadratic and linear models are created, and regression equations provide surface plots to analyse load–premixing ratio interaction on output response. Premixing of benzyl alcohol at 20% at maximum loads confirms 31.09%, 14.95%, 31.09%, 39.91%, 17.26%, 11.06%, 7.59%, 36.61%, and 4.34% higher enviroeconomic loss, thermal efficiency, brake-specific carbon dioxide, brake-specific nitrogen monoxide, cooling water exergy, sustainability index, volumetric efficiency, and exhaust gas temperature. It also has lower exergoeconomic loss, thermoeconomic loss, brake-specific energy consumption, brake-specific carbon monoxide, smoke opacity, brake-specific hydrocarbon fuel exergy, exhaust gas exergy, destructed exergy, and entropy generation by 23.64%, 30.4%, 17.50%, 13.6%, 81.30%, 18.1%, 27.77%, and 27.77%, respectively. It is necessary to control nitrogen monoxide using exhaust gas recirculation or selective catalytic reduction technology in future work.

Implications of photochemical losses of VOCs: An integrated approach for source apportionment, ozone formation potential and health risk assessment.

The increasing ozone (O3) concentration has received significant attention recently, yet the health risks posed by volatile organic compounds (VOCs) cannot be ignored. Accurately identifying the primary sources of VOCs contributing to health risks and O3 formation has been challenging due to their high reactivity with oxidants in ambient air. This study conducted field measurements of VOCs seasonally and diurnally in an urban area of central Taiwan, aiming to elucidate the effects of photochemical loss of VOCs on the source apportionment of O3, as well as health risks of VOCs under different levels of O3. The results revealed that O3 formation was sensitive to VOCs, which was diagnosed using the regional threshold of the observed VOCs/NOX ratio and was further supported by a significant positive correlation between O3 concentrations and initial O3 formation potential. The dispersion normalized positive matrix factorization model, applied to initial mixing ratios of VOCs, identified six VOC sources, with the synthetic rubber industry and solvent usage being prominent contributors to O3 formation potential. A source-attributed health risk assessment approach was developed that incorporates the effects of photochemical losses and observed mixing ratios of VOCs, enabling a more accurate evaluation of health risks from different sources. Non-carcinogenic risks associated with VOC sources remained within acceptable thresholds, while the carcinogenic risks posed by vehicle exhaust and solvent usage were above acceptable levels, particularly on O3 non-polluted days. This study highlights the importance of establishing concurrent control strategies for VOCs and O3 to effectively mitigate air pollution and improve public health.

A novel biodegradable nanoparticle as a robust biodiesel antioxidant, and fuel additive for improvement of diesel engine performance and exhaust emission

A novel biodegradable nanoparticle as a robust biodiesel antioxidant, and fuel additive for improvement of diesel engine performance and exhaust emission

Factors associated with asthma symptoms in Colombian subpopulations aged 1 to 17 and 18 to 59: Secondary analysis of the study "Prevalence of asthma and other allergic diseases in Colombia 2009-2010".

Asthma, a chronic inflammatory lung disease, is one of the leading causes of disability, demands on health resources, and poor quality of life. It is necessary to identify asthma-related risk factors to reduce the presence and development of symptoms. This study aimed to explore the association of multiple possible factors with asthma symptoms in two subpopulations, children, adolescents, and adults, in six cities in Colombia. This was an observational analytical case-control study based on a cross-sectional study conducted as a secondary analysis of the prevalence of asthma and other allergic diseases in Colombia during 2009 and 2010. Weighted logistic regressions were conducted for each population. Out of the 5978 subjects in the cross-sectional survey, 747 were identified as cases, and 3109 were identified as controls. The prevalence of asthma was 30.8% in the child and adolescent population and 14.7% in the adult population. Among the various factors studied, those associated with asthma symptoms in children/adolescents were: a family history of asthma (OR 2.4; 95% CI 1.3-4.7) and rhinitis (OR 2.0; 95% CI 1.1-3.6); acetaminophen consumption at least once a month (OR 3.6; 95% CI 2.1-6.2); and the presence of birds at home (OR 2.0; 95% CI 1.1-3.8). Regarding food consumption: fruit consumption (OR 3.8; 95% CI 1.1-12.7). In adults, the factors that showed significant association were: a family history of allergic diseases (rhinitis OR 3.3; 95% CI 2.3-4.6), atopic eczema (OR 4.4; 95% CI 2.8-7.0), or asthma (OR 1.8;95% CI 1.3-2.6); acetaminophen consumption at least once a month (OR 2.0; 1.5-2.8); the presence of dogs at home (OR 1.4;95% CI 1.03-1.8), exposure to second-hand smoke (OR 1.7; 95% CI 1.2-2.2), and exposure to exhaust fumes during the day (OR 1.7; 95% CI 1.04-2.7). Our findings suggest that different cultural, environmental, and family factors are associated with asthma symptoms in children and adolescents, and these associations are evident in both males and females.