Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “METEOROLOGY”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 91 records · Page 5Linked to original sources
PubMed2006

Quercus pollen season dynamics in the Iberian peninsula: response to meteorological parameters and possible consequences of climate change.

The main characteristics of the Quercus pollination season were studied in 14 different localities of the Iberian Peninsula from 1992-2004. Results show that Quercus flowering season has tended to start earlier in recent years, probably due to the increased temperatures in the pre-flowering period, detected at study sites over the second half of the 20th century. A Growing Degree Days forecasting model was used, together with future meteorological data forecast using the Regional Climate Model developed by the Hadley Meteorological Centre, in order to determine the expected advance in the start of Quercus pollination in future years. At each study site, airborne pollen curves presented a similar pattern in all study years, with different peaks over the season attributable in many cases to the presence of several species. High pollen concentrations were recorded, particularly at Mediterranean sites. This study also proposes forecasting models to predict both daily pollen values and annual pollen emission. All models were externally validated using data for 2001 and 2004, with acceptable results. Finally, the impact of the highly-likely climate change on Iberian Quercus pollen concentration values was studied by applying RCM meteorological data for different future years, 2025, 2050, 2075 and 2099. Results indicate that under a doubled CO(2) scenario at the end of the 21st century Quercus pollination season could start on average one month earlier and airborne pollen concentrations will increase by 50 % with respect to current levels, with higher values in Mediterranean inland areas.

Air Pollutants↗
PubMed1995

Analysis of meteorologic variables and seasonal aeroallergen pollen counts in Denver, Colorado.

BACKGROUND: The observation of low levels of weed pollens following a freeze and an early autumn snowfall in Denver, Colorado led to this analysis of meteorologic variables and pollen counts. OBJECTIVE: The purpose of this study was to examine, in depth, the relationship between observed pollen counts and a selection of independent meteorologic variables. METHODS: We prospectively studied in 1991 daily high and low temperature, relative humidity, precipitation, barometric pressure, percent sunshine, wind velocity and direction, tree, grass, and weed pollen, as well as dates of the first frost/freeze. Similar data were retrospectively analyzed for 1987-1990. RESULTS: Correlation coefficients for the prospective data were as high as .611 for high temperature and cottonwood and .718 for high temperature and maple (P < .001). High and low temperature showed strong correlations with the combined weed counts (.598 and .628, respectively, P < .001). CONCLUSIONS: Denver weed pollens appear impacted more by temperature and less by precipitation and humidity, while the converse is true for tree and grass pollen. However, weed pollen, especially sage, may appreciably rebound after freezing temperatures. While separate meteorologic variables may have high correlations with specific pollen counts in a given year, such effect is not consistent and varies from year to year.

Allergens↗
PubMed1994

Correlation between meteorological conditions and mutagenicity of airborne particulate samples in a tropical monsoon climate area from Kaohsiung City, Taiwan.

Kaohsiung is a city of 1.5 million located in the southern part of Taiwan. It has a serious air pollution problem mainly attributable to much industrial and commercial activity. In order to estimate the effects of traffic, season, and meteorological conditions on the mutagenicity of Kaohsiung City's urban ambient particulate matter, 624 airborne particulate samples were collected on a weekly basis from 12 locations for an entire year. The mutagenic potential of acetone extracts of air samples was evaluated by the Salmonella/microsomal test with S. typhimurium TA98 in the presence and absence of S9 mixtures. The air samples from November 1990 showed the highest direct and indirect mutagenicity among the 12 months, whereas those from June and July 1991 had the lowest direct and indirect mutagenic activity, respectively. The mutagenicity showed a good correlation with amounts of the acetone extractable matter of airborne particulates. The meteorological conditions, monthly mean precipitation, and wind speed also showed a good correspondence with mutagenicity. Wind direction and temperature had a moderate relationship. The major mutagenic fractions of air samples that had the highest mutagenic activity in a month were purified using Sephadex LH-20 column chromatography, and the contents of PAHs, 1-NP, and DNPs were analyzed by HPLC. The characteristic concentration ratios of PAHs indicated that, for the main pollution sources of airborne particulates from Kaohsiung city, the mobile sources were more important than the stationary ones. The total amounts of 1-NP and DNPs in airborne particulates seemed to correspond to their mutagenicity. Although the total amounts of 1-NP and DNPs in the air samples correlated with their mutagenicity, the major mutagenic chemicals in the airborne particulate samples from Kaohsiung City need further investigation.

Air Pollutants↗
PubMed1995

A year-round study on functional relationships of airborne fungi with meteorological factors.

Air sampling was conducted in Waterloo, Canada throughout 1992. Functional relationships between aeromycota and meteorological factors were analysed. The meteorological factors were, in descending order of importance: mean temperature, minimum temperature, maximum temperature, mean wind speed, relative humidity (RH), rain, maximum wind speed and snow. The most important airborne fungal propagules in descending order were total fungal spores, unidentified Ascomycetes, Cladosporium, Coprinus, unidentified Basidiomycetes, Alternaria and unidentified fungi. Most airborne fungal taxa and highly significant relationship with temperature, but Aspergillus/Penicillium, hyphal fragments were positively associated with wind speed. In comparison with other airborne fungal taxa, Leptosphaeria and unidentified Ascomycetes were more closely correlated with rain and RH during the growing season.

Air Microbiology↗
PubMed2002

Effects of meteorological conditions on spore plumes.

Fungal spores are an ever-present component of the atmosphere, and have long been known to trigger asthma and hay fever symptoms in sensitive individuals. The atmosphere around Tulsa has been monitored for airborne spores and pollen with Burkard spore traps at several sampling stations. This study involved the examination of the hourly spore concentrations on days that had average daily concentrations near 50,000 spores/m(3) or greater. Hourly concentrations of Cladosporium, Alternaria, Epicoccum, Curvularia, Pithomyces, Drechslera, smut spores, ascospores, basidiospores, other, and total spores were determined on 4 days at three sites and then correlated with hourly meteorological data including temperature, rainfall, wind speed, dew point, air pressure, and wind direction. On each of these days there was a spore plume, a phenomenon in which spore concentrations increased dramatically over a very short period of time. Spore plumes generally occurred near midday, and concentrations were seen to increase from lows around 20,000 total spores/m(3) to highs over 170,000 total spores/m(3) in 2 h. Multiple regression analysis of the data indicated that increases in temperature, dew point, and air pressure correlated with the increase in spore concentrations, but no single weather variable predicted the appearance of a spore plume. The proper combination of changes in these meteorological parameters that result in a spore plume may be due to the changing weather conditions associated with thunderstorms, as on 3 of the 4 days when spore plumes occurred there were thunderstorms later that evening. The occurrence of spore plumes may have clinical significance, because other studies have shown that sensitization to certain spore types can occur during exposure to high spore concentrations.

Air Microbiology↗
PubMed2002

Simulation of rice biomass accumulation by an extended logistic model including influence of meteorological factors.

The biomass (X) of a biological population, described by growth models, depends only on time (t), i.e., X = f(t). Some parameters in these models are frequently taken as constants, but they may vary with growth processes under different ecological conditions. An extended logistic model including changes in the influence of meteorological factors is developed to simulate biomass accumulation processes of rice sown on different dates. The model may be generally described as X = f (p, t), in which p stands for meteorological factors. The model can be used to generalize population growth processes in experiments carried out under different environments. It is shown that the model may account for 96.6% of the variance of rice biomass on the basis of sowing dates, developmental stage, solar radiation and temperature in the Yangtze River valley in China.

Biomass↗
PubMed2004

Evaporation of intercepted precipitation from fruit litter of Liquidambar styraciflua L. (sweetgum) in a clearing as a function of meteorological conditions.

Interception of precipitation by fruit litter is a poorly understood component of the hydrologic cycle in forested ecosystems. Even less well understood is the effect of meteorological conditions on the evaporation of precipitation intercepted by forest litter. This study sought to examine the influence of meteorological conditions on the evaporation of intercepted precipitation by fruit litter from Liquidambar styraciflua L. (sweetgum) by deriving and calibrating a regression model to estimate evaporation from the fruit litter that may be of potential use to forest and watershed managers. Data on evaporative losses from the fruit litter used to derive and calibrate the statistical model were acquired through a larger field experiment conducted from mid November 2002 through April 2003. Results from the forward stepwise least squares multiple regression model demonstrated that evaporative losses from the fruit litter were estimated with a high degree of accuracy based on the amount of water stored, solar radiation inputs, and vapor pressure deficit (adjusted R(2)=0.836, F=82.28, P<0.00001). The amount of water stored in the fruit litter explained the highest proportion of variance in the regression model. Storm to storm comparisons also highlighted the importance of solar radiation and wind speed in determining evaporation from the fruit litter. The regression model potentially may be used in conjunction with a canopy interception model to predict interception losses from L. styraciflua dominated forests and plantations.

Ecosystem↗
PubMed1999

Conidia of Alternaria in the atmosphere of the city of Cordoba, Spain in relation to meteorological parameters.

In this study, we have analyzed the presence of conidia belonging to different species of the genus Alternaria in the atmosphere of the city of Cordoba, using a Hirst sampler. The results show that spores of this genus are present all year, with a clear seasonal pattern which shows two peaks, one in spring and the other in fall. A total of 26,822 conidia/m3 have been sampled, which implies a daily mean of 74.3 conidia/m3. Statistical analyses comparing the data with meteorological parameters show a positive correlation with maximum, minimum and mean temperatures, and a negative correlation with rain. Nevertheless, meteorological parameters seem to affect the number of conidia differently according to the season of the year. Regression analyses carried out in order to obtain a predictive pattern show that the best fit is between the 7-day running mean of the number of conidia and a week's accumulated mean temperature.

Air Microbiology↗
PubMed2005

Meteorological normalisation and non-parametric smoothing for quality assessment and trend analysis of tropospheric ozone data.

Despite extensive efforts to ensure that sampling and installation and maintenance of instruments are as efficient as possible when monitoring air pollution data, there is still an indisputable need for statistical post processing (quality assessment). We examined data on tropospheric ozone and found that meteorological normalisation can reveal (i) errors that have not been eliminated by established procedures for quality assurance and control of collected data, as well as (ii) inaccuracies that may have a detrimental effect on the results of statistical tests for temporal trends. Moreover, we observed that the quality assessment of collected data could be further strengthened by combining meteorological normalisation with non-parametric smoothing techniques for seasonal adjustment and detection of sudden shifts in level. Closer examination of apparent trends in tropospheric ozone records from EMEP (European Monitoring and Evaluation Programme) sites in Finland showed that, even if potential raw data errors were taken into account, there was strong evidence of upward trends during winter and early spring.

Air Pollutants↗
PubMed2006

Study of meteorological aspects and urban concentration of SO2 in atmospheric environment of La Plata, Argentina.

This article presents and discusses SO(2) (ppbv) concentration measurements combined with meteorological data (mainly wind speed and direction) for a five-year campaign (1996 to 2000), in a site near an oil refinery plant close to the city of La Plata and surroundings (aprox. 740.000 inh.), considered one of the six most affected cities by air pollution in the country. Since there is no monitoring network in the area, the obtained results should be considered as medium term accumulated data that enables to determine trends by analyzing together gas concentrations and meteorological parameters. Preliminary characterization of the behaviour of the predominant winds of the region in relation with potential atmospheric gas pollutants from seasonal wind roses is possible to carry out from the data. These results are complemented with monthly averaged SO(2) measurements. In particular, for year 2000, pollutant roses were determined which enable predictions about contamination emission sources. As a general result we can state that there is a clear increase in annual SO(2) concentration and that the selected site should be considered as a key site for future survey monitoring network deployment. Annual SO(2) average concentration and prevailing seasonal winds determined in this work, together with the potential health impact of SO(2) reveals the need for a comprehensive and systematic study involving particulate matter an other basic pollutant gases.

Air Pollutants↗
PubMed2006

Assessing respiratory morbidity through pollution status and meteorological conditions for Delhi.

The study focuses on assessing the status of respiratory morbidity in Delhi over a four years period from 2000-2003. An attempt was made to investigate the role of important pollutants (SO(2), NO(2), SPM and RSPM) and various meteorological factors (temperature minimum & maximum, relative humidity at 0830 and 1730 hrs. and wind speed) in being responsible for respiratory admissions on account of COPD, asthma and emphysema. The study showed that winter months had greater exposure risk as pollutants often get trapped in the lower layers of atmosphere resulting in high concentrations. Statistical analysis revealed that two pollutants have significant positive correlation with the number of COPD cases viz., SPM (r = 0.474; p < 0.01) and RSPM (r = 0.353; p < 0.05), while a meteorological factor temperature (minimum) has a significant negative correlation (r = -0.318; p < 0.05) with COPD. Stepwise multiple regression analysis was performed for COPD as dependent variable and R(2) value of 0.33 was obtained indicating that SPM and RH(1730) were able to explain 33 percent variability in COPD. The partial correlation of SPM and RH(1730) on COPD was higher than any other combination and therefore they can be regarded as important contributing variables on COPD.

Air Pollutants↗
PubMed2005

Characteristics of roadside air pollution in Korean metropolitan city (Daegu) over last 5 to 6 years: temporal variations, standard exceedances, and dependence on meteorological conditions.

The present study performed a roadside data analysis to provide baseline data for exploring associations between environmental exposure to four gaseous pollutants and health effects on residents living near roadways. The yearly roadside concentrations of CO and SO2 showed a well-defined decreasing trend, whereas those of NO2 and O3 exhibited the reverse trend. In most cases, the diurnal trends of the roadside concentrations were well-defined for all seasons, plus the daytime concentrations were higher than the nighttime concentrations. In contrast to the other target pollutants, the daytime O3 concentrations observed at the roadside sites were lower than those observed at the residential site, likely due to high-levels of fresh NO from traffic emissions that rapidly react with O3, thereby reducing the O3 roadside level. The Sunday roadside concentrations of CO, NO2, and SO2 were similar to or somewhat lower than the weekday concentrations. Conversely, for O3 the Sunday roadside concentrations were similar to or somewhat higher than the weekday concentrations. The higher O3 concentrations on Sunday may be due to the reduced titration from a decrease in NOx emissions under VOC-limited conditions (low VOC/NOx conditions). The monthly averages of O3 concentrations exhibited the reverse seasonal variation to the other target compounds, with peak O3 concentrations between April and June, and the second peak between August and October. It is also suggested that for O3, the 8-h standard is more stringent than the 1-h standard, while for NO2 and SO2, the 1-h standard is more stringent than the 24-h standard. The multiple regression equations obtained from the relationship between the concentrations and five meteorological parameters indicated that the number and type of meteorological variables in the equations varied according to the pollutant, monitoring station, or season.

Air Pollutants↗
PubMedDate not supplied

Predicting malaria seasons in Kenya using multitemporal meteorological satellite sensor data.

This article describes research that predicts the seasonality of malaria in Kenya using remotely sensed images from satellite sensors. The predictions were made using relationships established between long-term data on paediatric severe malaria admissions and simultaneously collected data from the Advanced Very High Resolution Radiometer (AVHRR) on the National Oceanic and Atmospheric Administrations (NOAA) polar-orbiting meteorological satellites and the High Resolution Radiometer (HRR) on the European Organization for the Exploitation of Meteorological Satellites' (EUMETSAT) geostationary Meteosat satellites. The remotely sensed data were processed to provide surrogate information on land surface temperature, reflectance in the middle infra-red, rainfall, and the normalized difference vegetation index (NDVI). These variables were then subjected to temporal Fourier processing and the fitted Fourier data were compared with the mean percentage of total annual malaria admissions recorded in each month. The NDVI in the preceding month correlated most significantly and consistently with malaria presentations across the 3 sites (mean adjusted r2 = 0.71, range 0.61-0.79). Regression analyses showed that an NDVI threshold of 0.35-0.40 was required for more than 5% of the annual malaria cases to be presented in a given month. These thresholds were then extrapolated spatially with the temporal Fourier-processed NDVI data to define the number of months, in which malaria admissions could be expected across Kenya in an average year, at an 8 x 8 km resolution. The resulting maps were compared with the only existing map (Butler's) of malaria transmission periods for Kenya, compiled from expert opinion. Conclusions are drawn on the appropriateness of remote sensing techniques for compiling national strategies for malaria intervention.

Data Collection↗
PubMed2001

Meteorological simulations of boundary-layer structure during the 1996 Paso del Norte Ozone Study.

Meteorological simulations centered around the border cities of El Paso and Ciudad Juárez have been performed during an ozone episode that occurred on August 13, 1996 during the 1996 Paso del Norte Ozone Study field campaign. Simulations were performed using the HOTMAC boundary-layer meteorological model using a 1, 2, 4 and 8-km horizontal grid size nested mesh system. Investigation of the vertical structure and evolution of the atmospheric boundary layer for the August 12-14 time period is emphasized in this paper due to its suspected importance in precipitating the ozone episode [Sci Total Environ (2001)]. This period was characterized by a slowly-evolving high pressure system over the region, a persistent upper-level jet at 2500-3500 m above ground level (agl), deep daytime mixed layer heights of 3500 m depth and unusually deep nighttime stable layers extending up to 2500 m above the ground. The fact that the boundary-layer growth stalled on the morning of August 13 relative to that on August 12 has been suggested as a possible reason for the ozone episode on the 13th. In addition, relatively weak surface-level winds were measured on August 13. Using both model results and experimental data we hypothesize explanations for the slower mixed-layer growth on the morning of the 13th and the stronger surface-level winds found on the 12th and 14th.

Air Movements↗
PubMed2002

The influence of meteorological conditions on the behavior of pollutants concentrations in São Paulo, Brazil.

The observed behavior of pollution concentrations to the prevailing meteorological conditions has been studied for the period from June 13 to September 2, 1994, for the Metropolitan Area of Sao Paulo (MASP). The synoptic conditions, which prevailed during the period, have been identified. The behavior of these large-scale systems namely the relative positions, the nature and the types of the anticyclone or cold front (CF) has been investigated, and for each identified synoptic situation, trace elements concentrations have been determined. During the CF synoptic condition, the elements presented low concentrations associated with intense ventilation, precipitation and high relative humidity. It is seen that for both the synoptic conditions namely the South Atlantic Subtropical High and Polar High, high values of concentrations prevailed due to weak ventilation, low relative humidity and absence of precipitation. The micro and mesoscale meteorological conditions have also been studied for a day with low and a day with high concentration of particulate pollutants. Finally, applying receptor modeling to the fine aerosol mass concentration data set, five categories of emission sources in the MASP were identified: vehicles, garbage incineration, vegetation, suspend soil dust and burning of fuel oil.

Aerosols↗
PubMed2005

Relationship between different size classes of particulate matter and meteorology in three European cities.

Evidence on the correlation between particle mass and (ultrafine) particle number concentrations is limited. Winter- and spring-time measurements of urban background air pollution were performed in Amsterdam (The Netherlands), Erfurt (Germany) and Helsinki (Finland), within the framework of the EU funded ULTRA study. Daily average concentrations of ambient particulate matter with a 50% cut off of 2.5 microm (PM2.5), total particle number concentrations and particle number concentrations in different size classes were collected at fixed monitoring sites. The aim of this paper is to assess differences in particle concentrations in several size classes across cities, the correlation between different particle fractions and to assess the differential impact of meteorological factors on their concentrations. The medians of ultrafine particle number concentrations were similar across the three cities (range 15.1 x 10(3)-18.3 x 10(3) counts cm(-3)). Within the ultrafine particle fraction, the sub fraction (10-30 nm) made a higher contribution to particle number concentrations in Erfurt than in Helsinki and Amsterdam. Larger differences across the cities were found for PM2.5(range 11-17 microg m(-3)). PM2.5 and ultrafine particle concentrations were weakly (Amsterdam, Helsinki) to moderately (Erfurt) correlated. The inconsistent correlation for PM2.5 and ultrafine particle concentrations between the three cities was partly explained by the larger impact of more local sources from the city on ultrafine particle concentrations than on PM2.5, suggesting that the upwind or downwind location of the measuring site in regard to potential particle sources has to be considered. Also, relationship with wind direction and meteorological data differed, suggesting that particle number and particle mass are two separate indicators of airborne particulate matter. Both decreased with increasing wind speed, but ultrafine particle number counts consistently decreased with increasing relative humidity, whereas PM2.5 increased with increasing barometric pressure. Within the ultrafine particle mode, nucleation mode (10-30 nm) and Aitken mode (30-100 nm) had distinctly different relationships with accumulation mode particles and weather conditions. Since the composition of these particle fractions also differs, it is of interest to test in future epidemiological studies whether they have different health effects.

Air Pollutants↗
PubMed2002

Pollutional and meteorological factors are closely related to complaints of non-allergic, non-infectious perennial rhinitis patients: a time series model.

BACKGROUND: Epidemiological studies in the past have focused on meteorological conditions, pollution and pollen and their relationship with symptoms of bronchial hyper-reactivity, however, there are no epidemiological studies which examine a wide range of such factors and determine their role in nasal hyper-reactivity. OBJECTIVE: To investigate whether environmental factors can influence symptomatology in non-allergic non-infectious perennial rhinitis (NANIPER) patients, who suffer primarily from nasal hyper-reactivity symptoms. METHODS: We studied 16 non-smoking NANIPER patients and seven non-smoking controls during a 218-day study period (March-October) by means of daily symptom scores and visual analogue scales for the subsets patency, secretions and sneezing, and compared them to seven primary factors which affected 'symptoms' and 10 secondary factors which affected primary factors only. RESULTS: The mean symptom scores in the NANIPER and control groups were 2.17 and 0.13, respectively. In NANIPER, the highest correlations of primary factors with symptomatology were found for symptom scores and sneezing with minimum daytime temperature (r = -0.62 and -0.45, respectively), ozone and NO concentrations. Patency and secretions were associated with minimum daytime temperature (r = -0.39 and 0.32, respectively). Time series analysis, however, correcting for several confounders such as autocorrelated symptomatology, showed that minimum daytime temperature and daytime relative humidity made an independent contribution to symptoms. In the control group, correlations were much lower, though present. Time series analysis was not possible. CONCLUSIONS: We conclude that in a mild climate with relatively low levels of pollution, minor pollution and meteorological disturbances result in substantial changes in nasal reactivity symptoms in NANIPER patients, but not controls, irrespective of other factors such as allergy or infection.

Adolescent↗
PubMed2003

The influence of meteorological conditions and stringent emission control on high TSP episodes in Istanbul.

Istanbul has faced serious air pollution problems since the mid-80s. This is mainly due to particulate air pollution coming from poor quality lignite in areas, which are heavily populated and industrialized. As a consequence of severe air pollution problems, stringent control on the emissions in the city started in the year of 1994. In this work, in order to study the relationship between emissions and meteorological conditions, an assessment of air pollution episodes and air pollution potential in the city is presented for the terms at the changed emission schedule as the influence of an emission reduction strategy. The influence of meteorological conditions on the TSP (total suspended particulates) levels is considered for two consecutive winter periods. On this occasion, the city has faced different TSP levels and episode characteristics depending on stringent emission reductions covering the banned, poor-quality lignite and fuel switching. For this purpose, climatological conditions and air quality analyses were performed.

Air Pollutants↗