PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Particulate Matter”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

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

At least 739 records · Page 41Linked to original sources
PubMed1997

Mutagenicity and chemical analysis of airborne particulate matter collected in Pisa.

The genotoxic effects of airborne particulate samples collected from two urban areas during various traffic intensity levels were evaluated using the yeast Saccharomyces cerevisiae (D7 strain) and Salmonella typhimurium (TA98 and TA100 strains). Standard protocols were used, in compliance with recent legislation. Airborne particulate data reveal that genotoxic effects were more evident in the samples collected in the area with intense moving traffic than in the area with limited traffic. Particulate, benzene, toluene, NO2, CO, and heavy metal determinations in these two areas show that their concentrations are related to the intensity of traffic.

Air Pollutants↗
PubMed2006

Airborne particulate matter from primarily geologic, non-industrial sources at levels below National Ambient Air Quality Standards is associated with outpatient visits for asthma and quick-relief medication prescriptions among children less than 20 years old enrolled in Medicaid in Anchorage, Alaska.

In Anchorage, Alaska, particulates with aerodynamic diameter < or = 10 micro m (PM(10)) arise primarily from natural, geologic sources, and particulates with aerodynamic diameter < or = 2.5 micro m (PM(2.5)) arise primarily from automobile emissions. The current study used a population-based time-series analysis design to evaluate the effects of daily and weekly PM(10) and PM(2.5) on respiratory health outcomes among children <20 years of age residing in Anchorage enrolled in Medicaid. All generated estimating equations models were adjusted for season, year, weekends, temperature, wind speed, and precipitation. Relative to the days with PM(10) mass concentration < or = 13 micro g/m(3), a significant 9.3% increase (RR: 1.093, 95% CI: 1.004-1.191) in the rate of outpatient visits for asthma occurred during days with PM(10) of 20-33 micro g/m(3). No further dose-response occurred for days with PM(10) > or = 34 micro g/m(3). A significant 18.1% increase (RR: 1.181, 95% CI: 1.010-1.381) in the rate of quick-relief medication prescriptions occurred during days with PM(10) of 34-60 micro g/m(3), and a 28.8% increase (RR: 1.288, 95% CI: 1.026-1.619) occurred during days with PM(10) > or = 61 micro g/m(3). Similar results for outpatient asthma visits and quick-relief medication occurred in weekly models. There were no significant associations with PM(2.5) in either daily or weekly models. These subtle but statistically significant associations suggest that non-industrial, geologic sources of PM(10) may have measurable health effects at levels below current national standards.

Adolescent↗
PubMed2006

Deposition measurement of particulate matter in connection with corrosion studies.

A new passive particle collector (inert surrogate surface) that collects particles from all directions has been developed. It was used to measure particle deposition at 35 test sites as part of a project that examined corrosion of materials in order that variation in particulate material could be used in development of dose-response functions in a modern multi-pollutant environment. The project, MULTI-ASSESS, was funded by the EU to examine the effects of air pollution on cultural heritage. Passive samplers were mounted rain-protected, and both in wind-protected and wind-exposed positions, to match the exposure of the samples for corrosion studies. The particle mass and its chemical content (nitrate, ammonium, sulfate, calcium, sodium, chloride, magnesium and potassium) were analysed. The loss of light reflectance on the surrogate surface was also measured. Very little ammonium and potassium was found, and one or more anions are missing in the ion balance. There were many strong correlations between the analysed species. The mass of analysed water-soluble ions was fairly constant at 24% of the total mass. The particle mass deposited to the samplers in the wind-protected position was about 25% of the particles deposited to an openly exposed sampler. The Cl-/Na+ ratios indicate a reaction between HNO(3) and NaCl. The deposited nitrate flux corresponds to the missing chloride. The Ca2+ deposition equals the SO4(2-) deposition and the anion deficiency. The SO4(2-) deposition most likely originates from SO2 that has reacted with basic calcium-containing particles either before or after they were deposited. The particle depositions at the urban sites were much higher than in nearby rural sites. The deposited mass correlated surprisingly well with the PM(10) concentration, except at sites very close to traffic.

Air Pollutants↗
PubMed2006

Ambient particulate matter exhibits direct inhibitory effects on oxidative stress enzymes.

A primary mechanistic hypothesis by which ambient air particles have a significant negative impact on human health is via the induction of pulmonary inflammatory responses mediated through the generation of reactive oxygen species (ROS). Development of a biosensor for the assessment of particulate ROS activity would be a significant advance in air pollution monitoring. The objective of this study was to evaluate whether air particulates interact directly with protective enzymes involved in oxidative stress responses. We performed enzyme activity assays on four enzymes involved in oxidative stress responses (Cu/Zn superoxide dismutase, Mn superoxide dismutase, glutathione peroxidase, and glutathione reductase) in the presence of particles of varying toxicities and found distinctive inhibition patterns. On the basis of these findings, we suggest a strategy for an enzyme bioassay that could be used to assess the potential of particles to generate ROS-induced responses.

Air Pollutants↗
PubMed2004

Particulate matter air pollution stimulates monocyte release from the bone marrow.

Particulate air pollution (PM(10)) stimulates alveolar macrophages (AMs) to release immature granulocytes from the bone marrow (BM) into the circulation. This study was designed to determine the effect of PM(10) (ambient EHC-93 or inert carbon [CC]) instillation exposure on the monocyte release from the BM and the role of AM in this response. Monocyte precursors were labeled in the BM of rabbits in vivo by an intravenous injection of 5'-bromo-2'-deoxyuridine, and the effects of PM(10) were determined by instillation either particles or supernatants of AM exposed to particles into the lungs. Instillation of EHC-93 (500 microg/ml) or supernatants from AM incubated with EHC-93 (100 microg/ml) increased circulating band cell counts (p < 0.05) and shortened the transit time of monocytes through the BM (35.5 +/- 2.2 to 25.0 +/- 1.5 hours or 36.2 +/- 2.6 to 25.7 +/- 1.8 hours, p < 0.05) compared with the control subject. CC (1%) instillation also shortened the monocyte BM transit time to 28.4 +/- 1.9 hours (p < 0.05), but supernatants of AM incubated with CC did not. We conclude that exposure to atmospheric PM(10) stimulates the production of mediators by AM, and these cytokines accelerate the monocyte release from the BM.

Air Pollutants↗
PubMed2002

[Calculating emissions of exhaust particulate matter from motor vehicles with PART5 model].

PART5, a vehicle particulate emission factor model developed by USEPA, was modified and then used to obtain the emission factors of exhaust PM10 and PM2.5 from on-road automobiles, trucks and motorcycles in Beijing. The total exhaust PM10 and PM2.5 emissions from motor vehicles in 1995 and 1998 were calculated separately. The contribution ratios of different types of vehicles to the total vehicular emissions, and the share of different exhaust particulate components including Pb, direct SO4(2-), soluble organic fraction (SOF) and remaining carbon portion (RCP), were also estimated. It was shown that the emission factors of exhaust PM10 and PM2.5 from gasoline motor vehicles, motorcycles and heavy-duty diesel vehicles in Beijing were 1.7-8.6 times, 2.1-3.5 times and 1.3-1.5 times, respectively, of the USA average emission levels during the same period. The total exhaust PM10 and PM2.5 from vehicles were 2445 tons and 1890 tons in 1995 in Beijing, and increased to 3359 tons and 2694 tons in 1998, which increase by 37.4% and 42.5%, respectively.

Air Pollution↗
PubMed2006

Fine organic particulate matter dominates indoor-generated PM2.5 in RIOPA homes.

Residential indoor and outdoor fine particle (PM(2.5)) organic (OC) and elemental carbon (EC) concentrations (48 h) were measured at 173 homes in Houston, TX, Los Angeles County, CA, and Elizabeth, NJ as part of the Relationship of Indoor, Outdoor and Personal Air (RIOPA) study. The adsorption of organic vapors on the quartz fiber sampling filter (a positive artifact) was substantial indoors and out, accounting for 36% and 37% of measured OC at the median indoor (8.2 microg C/m(3)) and outdoor (5.0 microg C/m(3)) OC concentrations, respectively. Uncorrected, adsorption artifacts would lead to substantial overestimation of particulate OC both indoors and outdoors. After artifact correction, the mean particulate organic matter (OM=1.4 OC) concentration indoors (9.8 microg/m(3)) was twice the mean outdoor concentration (4.9 microg/m(3)). The mean EC concentration was 1.1 microg/m(3) both indoors and outdoors. OM accounted for 29%, 30% and 29% of PM(2.5) mass outdoors and 48%, 55% and 61% of indoor PM(2.5) mass in Los Angeles Co., Elizabeth and Houston study homes, respectively. Indirect evidence provided by species mass balance results suggests that PM(2.5) nitrate (not measured) was largely lost during outdoor-to-indoor transport, as reported by Lunden et al. This results in dramatic changes with outdoor-to-indoor transport in the mass and composition of ambient-generated PM(2.5) at California homes. On average, 71% to 76% of indoor OM was emitted or formed indoors, calculated by (1) Random Component Superposition (RCS) model and (2) non-linear fit of OC and air exchange rate data to the mass balance model. Assuming that all particles penetrate indoors (P=1) and there is no particle loss indoors (k=0), a lower bound estimate of 41% of indoor OM was indoor-generated (mean). OM appears to be the predominant species in indoor-generated PM(2.5), based on species mass balance results. Particulate OM emitted or formed indoors is substantial enough to alter the concentration, composition and behavior of indoor PM(2.5). One interesting effect of increased indoor OM concentrations is a shift in the gas-particle partitioning of polycyclic aromatic hydrocarbons (PAHs) from the gas to the particle phase with outdoor-to-indoor transport.

Aerosols↗
PubMed2004

The Salmonella mutagenicity of urban airborne particulate matter (PM2.5) from eight sites of the Emilia-Romagna regional monitoring network (Italy).

ARPA Emilia Romagna created, in 1997, a regional network for the continuous monitoring of the mutagenicity of PM(2.5) by short-term mutagenicity bioassays to guarantee a constant surveillance on the entire regional territory. The continuous monitoring of the PM mutagenicity provides essential information for a better understanding of the impact of air pollution on the health of the population, and allows one to better judge the efficiency of national and local efforts for urban air quality improvement (use of "green" petrol and ecodiesel, days during which traffic is prohibited, etc.). This article presents the results relating to the Network's activity between September 2000 and December 2002, on PM(2.5) fraction. The organic extracts of PM(2.5) were tested for mutagenicity using Salmonella tester strains TA98 and TA100 with and without metabolic activation (S9). The data obtained on the genotoxicity of air particulate extracts have revealed a constant presence of mutagenic substances adsorbed on particulate matter-with a prevalence of direct-acting mutagens than of promutagens-in a typical seasonal trend featuring higher levels in autumn-winter and lower in warmer periods of the year. In this work the evolution of PM(2.5) mutagenicity was compared with the particles, carbon monoxide (CO) and nitrogen dioxide (NO(2)) concentrations (monthly average); these comparisons revealed a quite good level of agreement on a local basis.

Air Pollutants↗
PubMed2006

Numerical modeling of particulate matter dispersion from Kerman Cement Plant, Iran.

A three dimensional diffusion model has been developed for computing the concentration of PM10 from Kerman Cement Plant, Iran. This model incorporates source-related factors, meteorological factors, surface roughness, and settling particles to estimate pollutant concentration from continuous sources. The study focused on the local environmental impact of Kerman Cement Plant. The performance of the model was found to be in good agreement with measured data; the average absolute percent deviation is 25.53%. In addition, the result of this modeling shows that the PM10 concentration in the ambient air at distances of about 600-1,400 m from the stacks is higher than the WHO guidelines of an annual average of 260 microg/m(3).

Humans↗
PubMed2006

Implications for occupational exposure to particulate matter.

The demonstrated effects of lower levels of ambient particles on cardiovascular and respiratory system morbidity and mortality were initially surprising in light of current concepts of occupational particle exposure and acute and chronic cardiopulmonary effects. Specifically, the exposure levels, as defined by the weight of the particles per liter of breathing air, at which recognized disease occurs under workplace conditions are considerably higher than the observed levels of ambient particles associated with serious adverse health effects. The possible reasons for this difference have not been adequately addressed. To further address this question, a re-examination of workplace exposure-response relationships is needed, which may include emphasis on measuring exposures to fine and ultrafine particles rather than to total particle mass concentration alone.

Air Pollutants↗