Human reactions to a mixture of indoor air volatile organic compounds

A controlled experimental study of human reactions to a mixture of 22 volatile organic compounds often found in indoor air was performed in a climate chamber. Twenty-one healthy subjects were compared with a group of 14 subjects suffering from the ‘sick building syndrome’ (SBS subjects), i.e. having symptoms related to the indoor environment (irritated mucous membranes, headache, etc.) as defined by WHO in 1982. In groups of 4 these subjects were exposed during two successive periods to either 0 and 0 mg m⁻³, 25 and 0 mg m⁻³, or 0 and 25 mg m⁻³; 25 mg m⁻³ is equivalent to the highest concentrations expected in a new building. The study was double blinded, and a latin square design was used to balance out effects of day in the week and season. Both groups reacted subjectively to the air reporting worse odor, worse indoor air quality as defined by the subject, and more irritated mucous membranes in eye, throat and nose than in the clean environment. A tendency to a stronger response was seen among the SBS subjects. Objective measures indicated among others an exposure related reduction in lung function among SBS subjects. Both groups had an increased number of polymorphonuclear leucocytes in tear fluid as a result of exposure. This was not seen for nasal secretions. Psychological performance tests indicated an exposure related diminished ability to learn. In conclusion, the experiment indicates that exposure to volatile organic compounds in low concentrations as seen in new houses causes both subjective complaints and objective signs in normal healty subjects; but more so in subjects from the sick building syndrome.     

On the spatial and temporal variations in atmospheric concentrations of hexachlorobenzene and hexachlorocyclohexane isomers at several locations in the province of Ontario,Canada

Hexachlorobenzene (HCB), as well as α- and γ-hexachlorocyclohexane (HCH) have been measured at seven sites in Ontario, Canada during the years 1985–1989. While two of the locations were close to a suspected source of the organochlorines, five were sites that reflected the non-urban airshed loadings which are considered to be regionally representative of the Great Lakes. At the non-urban locations, the γ-HCH (lindane) and α-HCH concentrations ranged from 15 to 190 pg m⁻³ (mean of 47 pg m⁻³) and 50 to 660 pg m⁻³ (mean of 240 pg m⁻³), respectively. The HCB concentrations varied from 20 to 310 pg m⁻³ (mean of 94 pg m⁻³). At the suspected source locations, the α:γ HCH ratio was less than unity while at locations distant from known or suspected sources, the α:γ ratio was usually greater than 7. At the non-urban locations, the highest concentrations of the α- and γ-HCH isomers were observed during the summer and the lowest concentrations were seen during the winter. The concentration of HCB, however, remained relatively constant throughout the year.     

Design of an environmental chamber for high voltage testing in simulated dust and sand storms

This paper describes the design and the construction of an environmental chamber which enables the breakdown voltage of practically used electrodes to be determined during sand/dust storm conditions. The dust particles used were ⩽ 150 μm in dia. and ranged from a few mgm⁻³ to a few gm⁻³ in concentration. Studies were done using switching as well as lightning impulse voltages of up to 1 MV in addition to the high a.c. voltages of up to 200 kV. Using this facility, it was found that the presence of sand/dust particles can greatly affect the breakdown voltages of air gaps. This effect is dependent on the electrode shape, the gap length, and the type of applied voltage. Typical results are shown in this paper.     

Levels of airborne man-made mineral fibres in U.K. dwellings. I—Fibre levels during and after installation of insulation

This paper gives the details of airborne levels of man-made mineral fibres (MMMF) found during installation of loft insulation in 12 dwellings. About 250 samples of air were collected and analyzed by transmission electron microscopy (TEM).Respirable fibre levels measured in static samples collected in the lofts during installation generally were < 0.1 f ml⁻¹. In living spaces respirable fibre levels were< 0.006 f ml⁻¹. Personal samples on the installers gave < 1 f ml⁻¹, with the exception of a fine glass fibre blanket. A few selected samples were also analyzed by phase contrast optical microscopy (PCOM) which showed lower values than those recorded by TEM. Static gravimetric concentrations in the lofts were in the 0.3–6.5 mg m⁻³ range, and in the living spaces 0.11–0.44 mg m⁻³, but in both environments most of this dust was not MMMF.     

Chlorinated organic compounds in the troposphere over the western North Atlantic Ocean measured by aircraft

Results of 32 individual flights during 1985, 1986 and 1988 using a King Air research aircraft over the western North Atlantic Ocean and the Adirondack Mountains are presented. Measurements were made for selected trace organic compounds including α- and γ-isomers of hexachlorocyclohexane (HCH), the summed isomers of α- and γ-chlordane, dieldrin and polychlorinated biphenyls (PCBs). The concentrations of compounds at altitudes of 300–10,000 ft indicate that these compounds were well mixed in the atmosphere and that for the most part, ground-level and higher-altitude concentrations were similar in magnitude. There was a high degree of variability due to time, meteorological events and location. Concentrations over the Adirondack Mountains in 1985 were the highest measured with means of 0.198 ng m⁻³ for HCB, 0.388 ng m⁻³ for α-HCH, 0.509 ng m⁻³ for γ-HCH, 0.340 ng m⁻³ for dieldrin, 0.480 ng m⁻³ for chlordane and 0.951 ng m⁻³ for total PCBs. Concentrations over the western North Atlantic south-east of Bermuda in summer 1988 wer lower, with means of 0.093 ng m⁻³ for HCB, 0.142 ng m⁻³ for α-HCH, 0.012 ng m⁻³ for γ-HCH, 0.016 ng m⁻³ for dieldrin 0.020 ng m⁻³ for chlordane and 0.600 ng m⁻³ for PCBs. During 1988 concentrations of most of the compounds were similar in the atmosphere of the coastal zone, 50–100 km off the U.S., to those measured near Bermuda. Chlordane, and to a lesser extent dieldrin, showed a decrease in concentration away from North America.     

Monitoring GHG from manure stores on organic and conventional dairy farms

Organic farming methods are claimed to be more environmentally friendly than conventional methods and the EU MIDAIR project had an overall aim to compare emissions from organic dairy farming with conventional methods of milk production. Manure stores are the second largest source of methane emissions (after enteric fermentation) on European dairy farming.The aim of this project was to measure green house gas (GHG) emissions from manures in covered and uncovered slurry stores and farm yard manure (FYM) heaps. The chosen method for measuring these emissions was the tracer ratio method, using sulphur hexafluoride (SF₆) as the tracer gas, the limitations of this method prevented successful measurements being made on some of the stores and a modified method was used on the covered stores. The difference in concentration of the upwind and downwind samples and interfering sources were limiting factors. FYM emission measurements were successful only when the manure was stored indoors.Methane emissions were successfully measured over a 12 month period from the uncovered slurry stores. Emission rates from the uncovered slurry stores on the conventional farm and the organic farm ranged from 14.4 to 49.6 and from 12.4 to 42.3 g C m⁻³ d⁻¹, respectively, with the mean CH₄ emission rates of 35 and 26 g C m⁻³ d⁻¹. On both farms, nitrous oxide emissions were close to zero.Methane emissions measured from the indoor organic FYM in summer were 17.1 g C m⁻³ d⁻¹ and the nitrous oxide emission was 411 mg N m⁻³ d⁻¹.The covered slurry stores were in such close proximity to other GHG sources that the tracer ratio method was unsuitable and the air-injection method was adopted. The measured emissions from covered slurry stores of CH₄, CO₂ and NH₃ were, respectively, 14.9 g C m⁻³ d⁻¹, 12.9 g C m⁻³ d⁻¹ and 18.6 mg NH₃ m⁻² d⁻¹ of slurry in February and 12.0 g C m⁻³ d⁻¹, 9.5 g C m⁻³ d⁻¹ and 335 mg NH₃ m⁻² d⁻¹ slurry in March. No nitrous oxide production could be measured.     

Characterization of pollen deposition in a forest environment

Measurements of the dry deposition of pollen were made during the months of May and June 1987 in northern Wisconsin, using a smooth surrogate surface. Samples were taken on a raft located on Little Rock Lake and at a nearby field monitoring station. Rain samples were also collected at the field station. The wet SO₄²⁻ flux was 102.7 mg m⁻², compared with a dry SO₄²⁻ flux of 118 mg m⁻² at the field monitoring site and 45 mg m⁻² at the lake site.The SO₄²⁻ content of pollen ranged from 0.2 to 0.8% of the weight of the pollen, and NO₃⁻ concentrations were an order of magnitude lower. Between 9 and 22% of the pollen weight was available as total organic carbon (TOC) upon addition to water.The addition of pollen to distilled water produced an acid reaction, due to organic acids and not inorganic acidity.     

Polynuclear aromatic hydrocarbon degradation by heterogeneous reactions with N2O5 on atmospheric particles

The degradation of particulate polynuclear aromatic hydrocarbons (PAH) on atmospheric soot particles in the presence of gas phase dinitrogen pentoxide (N₂O₅) was explored. Dilute diesel and wood soot particles containing PAH were reacted with∼10ppm of N₂O₅ in a 200 ℓ continuous stirred tank reactor (CSTR). To provide a stable source of particles for reaction in the CSTR, diesel or wood soot particles were injected at night into a 25 m³ Teflon outdoor chamber. The large chamber served as a reservoir for the feed aerosol, and the aerosol could then be introduced at a constant flow rate into the CSTR. PAH-N₂O₅ heterogeneous rate constants for wood soot at 15°C ranged from2 × 10⁻¹⁸to5 × 10⁻¹⁸ cm³ molecules⁻¹ s⁻¹. For diesel soot the rate constants at 16°C were higher and ranged from5 × 10⁻¹⁸to30 × 10⁻¹⁸ cm³ molecules⁻¹ s⁻¹. Comparisons with other studies suggest that sunlight is the most important factor which influences PAH decay. This is followed by ozone, NO₂, N₂O₅ and nitric acid. The rate constants of nitro-PAH formation from a parent PAH and N₂O₅ were of the order of1 × 10⁻¹⁹−1 × 10⁻¹⁸ molecules⁻¹s⁻¹. The uncertainty associated with all of these rate constants is± a factor of 3. Given, however, the small magnitude of the rate constants and the low levels of N₂O₅ present in the atmosphere, we concluded that PAH heterogeneous reactions with gas phase N₂O₅ degrade particle-bound PAH or to form nitro-PAH from PAH arenot very important. (Direct application of the specific rate constants derived in this study to ambient atmospheres should not be undertaken unless the ambient particle size distributions and chemical composition of the particles are similar to the ones reported in this study.)     

The variability of biogenic sulfur flux from a temperate salt marsh on short time and space scales

Three emission chambers were deployed simultaneously to measure rates of emission of dimethyl sulfide, methane thiol and carbonyl sulfide within or across vegetation zones in a New Hampshire salt marsh. Short term (a few hours) variation in fluxes of all S gases from replicate sites were small within a monospecific stand of either Spartina alterniflora or S. patens. The quantity of emergent biomass and the type of vegetation present were the primary factors regulating the rate of emission. Dimethyl sulfide fluxes from the S. alterniflora soils ranged from 800 to 18,000 nmol m⁻² h⁻¹ compared to emissions of 25–120 nmol m⁻² h⁻¹ from S. patens. This difference was probably due to the presence of the dimethyl-sulfide precursor dimethylsulfoniopropionate which is an osmoregulator in S. alterniflora but not in S. patens. Methane thiol emissions from S. alterniflora were 20–280 nmol m⁻² h⁻¹ and they displayed a similar diel trend as dimethyl sulfide, although at much lower rates, suggesting that methane thiol is produced primarily by leaves. Methane thiol emissions from S. patens were 20–70 nmol m⁻² h⁻¹. Net uptake of carbonyl sulfide of 25–40 nmol m⁻² h⁻¹ occurred in stands of S. alterniflora while net efflux of 10–36 nmol m⁻² h⁻¹ of carbonyl sulfide occurred in stands of S. patens. In general, ranges of emissions of sulfur gases were similar to most other published values.     

Patterns of daily exposure to TSP and CO in the Garhwal Himalaya

Daily integrated exposure to TSP and CO was assessed by personal and stationary sampling of air in six microenvironments. Time-budget surveys were conducted to determine how much time four population groups (adult women, children, adult men and youths) spend in these microenvironments. Burning of biofuels in traditional unvented cookstoves is the most important anthropogenic source of pollutants in the study area—a rural and hilly region in the Garhwal Himalaya.Concentrations of pollutants measured at the time of cooking were found to be very high but comparable to those measured in the Indian plains (5.6 mg m⁻³ and 21 ppm for TSP and CO, respectively). The daily exposure of adult women to TSP and CO was estimated to be 37 mg h m⁻³ and 110 ppm h, respectively. Daily exposure, within each of the four population groups, was found to be very uniform across individuals for both the pollutants. Patterns of concentrations and daily exposure, as influenced by the time of the day, season and altitude are discussed.     

Excess particulate and gaseous bromine at a remote coastal location

Samples were collected at remote sites on the Isle of Harris, off the northwest coast of Scotland, to determine levels of particulate Br and gaseous Br trapped on base-impregnated filters. Lead and Na were also measured so that an estimate of the Br contribution from sea salt and vehicular pollution could be made. Particulate Br levels of more than double this estimated amount were recorded, with ‘excess’ Br concentrations of up to 54 ng m⁻³ being measured. Gaseous Br (believed to be mainly in the form of HBr) was found in similar, or somewhat higher, concentrations as particulate Br, with a mean of 28 ng Br m⁻³, compared with the mean particulate level of 21 ng m⁻³. It is conjectured that a similar situation exists at these sites as has been observed in the Arctic spring, where it appears that biochemically produced organobromine gases are photolyzed, with the subsequent removal of O₃ and formation of both particulate Br and gaseous HBr. This may represent an important global source of reactive Br and a potential O₃ sink in the marine troposphere.     

Monthly and seasonal trends of total suspended particulate matter and smoke concentration in industrial and residential areas in Cairo

Total suspended particulate (TSP) matter and smoke were investigated at Shoubra El-Kheima industrial area and El-Dokki residential area located in Cairo. TSP gave the highest monthly mean concentration in 2 years' study at Shoubra El-Kheima (895 μg m⁻³), nearly 12 times the geometrical mean of air quality standard (75 μg m⁻³). The corresponding figure at the residential area is 544 μg m⁻³, which is 7.3 concentrations during spring and lower during summer. Smoke concentration in the industrial area was nearly 1.4 and 1.2 times its concentration in the residential area during the 2 study years. Smoke concentration was found to be light to moderate during 86% of the days and heavy to extremely heavy during 14% of the days at the industrial area. The corresponding percentages for the residential area were 90% and 10% for light to moderate and heavy to extremely heavy, respectively.     

Biogenic and anthropogenic organic compounds in eolian particulates in the East Mediterranean region—I. Occurrence and origin

Lipids of biogenic and anthropogenic origin were determined in aerosol samples, collected seasonally, in a coastal area on the north of the island of Crete. Lipid classes such as n-alkanes, hopanes, polycyclic aromatic hydrocarbons, fatty alcohols, fatty acids, fatty acid salts and α,ω-dicarboxylic acids were characterized by GC/MS and GC/FID analysis, in terms of their contents of homologous compound series. The concentrations ranged between 56 and 215 ng m⁻³ for n-alkanes, 10 and 52 ng m⁻³ for polycyclic aromatic hydrocarbons, 2 and 31 ng m⁻³ for fatty alcohols, 13 and 279 ng m⁻³ for fatty acids, 24 and 220 ng m⁻³ for fatty acid salts and 0.4 and 7.5 ng m⁻³ for α, ω-dicarboxylic acid salts. The prevailing winds were influencing the composition of the eolian particles. Generally, aerosols sampled during south wind events predominantly contained lipids originating from higher plants, while when north and northwest winds prevailed the major components were of marine origin. The absence of unsaturated fatty acids in all aerosol samples is related to the presence of α,ω-dicarboxylic acids, which are believed to be their photo-oxidation products.     

孤东水库水体富营养化评价及其生态控制研究

对孤东水库水生物状况进行系统调查和水体富营养状态进行评价,在此基础上,提出了生态修复技术,通过理论计算与试验确定草食性和滤食性鱼类的投放量,并进行了围格试验.结果表明,孤东水库菹草优势度达80%,浮游植物量为22,32mg/L,单位面积上的总磷浓度是0.310 g/(m<'2>·a),水体处于富营养化状态,通过保持孤东水库鲢、鳙鱼的水体生物量在19-25 g/m<'3>左右,在9月藻类繁殖高峰期,生物量由14.6 mg/L降为3 mg/L.总磷、总氮和高锰酸盐指数年均值分别由生态控制前的0.06 mg/L、3.06 mg/L和4.42 mg/L降为0.03 mg/L、1.58 mg/L和3.73 mg/L,水库水质改善效果明显,同时下游水厂的单方水药耗也由生态控制前的42g/rn3降至25g/m<'3>.试验证明,通过采用合理投放草食性和滤食性鱼类的生态修复技术,可以有效控制水库富营养化状态,并取得显著的社会、经济效益.     

Characteristics of airborne particles inside southern California museums

The concentrations and chemical composition of suspended particulate matter were measured in both the fine and total size modes inside and outside five southern California museums over summer and winter periods. The seasonally averaged indoor/outdoor ratios for particulate matter mass concentrations ranged from 0.16 to 0.96 for fine particles and from 0.06 to 0.53 for coarse particles, with the lower values observed for buildings with sophisticated ventilation systems which include filters for particulate matter removal. Museums with deliberate particle filtration systems showed indoor fine particle concentrations generally averaging less than 10 μg m⁻³. One museum with no environmental control system showed indoor fine particle concentrations averaging nearly 60 μg m⁻³ in winter and coarse particle concentrations in the 30–40 μg m⁻³ range. Analyses of indoor vs outdoor concentrations of major chemical species indicated that indoor sources of organic matter may exist at all sites, but that none of the other measured species appear to have major indoor sources at the museums studied. Significant fractions of the dark-colored fine elemental (black) carbon and soil dust particles present in outdoor air are able to penetrate to the indoor atmosphere of the museums studied, and may constitute a soiling hazard to works of art displayed in museums.     

Spatial and temporal patterns in summertime sulfate aerosol acidity and neutralization within a metropolitan area

A study of sulfate aerosol acidity in Metropolitan Toronto was conducted during the summer of 1986. Fine-fraction aerosol (<2.5-μm) were collected using Teflon membrane filters and analyzed for major ionic species (H⁺, NH⁺₄, NO⁻₃, SO²⁻₄). Samples were collected for 6 weeks at three study sites: one in the Center City and the others 13 km (WNW) and 20 km (NE) away. There were very strong correlations among the three sites with respect to measured aerosol species (r² > 0.9 for 24-h data). However, spatial variations in the magnitude of aerosol acidity were observed during sulfate episodes. For example, the peak concentrations for all sites occurred on 25–26 July 1986. While the 24-h data for sulfate were quite uniform at the three sites (34, 34 and 35 μg m⁻³), H⁺ concentrations were 9.4, 8.3 and 6.0 μg m⁻³ (as H₂SO₄) for the NE, WNW and Center City sites, respectively. For most of the summertime episodes, the downtown area also had lower aerosol acidity compared to the two sites in suburban areas.     

Vapor adsorption artifact in the sampling of organic aerosol: Face velocity effects

The concentration (μgC m⁻³) of aerosol organic carbon as determined by collection with quartz fiber filters was found to exhibit a significant decrease with increasing filter face velocity. A similar face velocity dependence was found for organic carbon on back-up quartz fiber filters behind either quartz fiber front filters (QQ combination) or Teflon membrane front filters (TQ combination). Additionally, the concentration of organic carbon on the back-up filter in the TQ combination was always greater than on the back-up filter in the QQ combination. The most likely explanation for these observations is the adsorption or organic vapors onto the filter medium itself. The amount of organic carbon adsorbed onto the quartz fiber front filter can be approximated by measuring the amount of organic carbon on a quartz fiber back-up filter behind a Teflon front filter with both filter combinations sampling at the same face velocity. Making the correction in such a manner removes most of the face velocity dependence inthe resultant concentrations. For 24 h sampling in Portland, Oregon, at a face velocity of 40 cm s⁻¹, the correction exceeded 50% for uncorrected organic carbon concentrations of 2 μgC m⁻³ but decreased to 15% at 16 μgC m⁻³.     

Concentration of monoterpenes in a maple forest in Quebec

Measurements of monoterpene concentrations are reported for a maple forest in Quebec near the St Lawrence River. The upper limit of the total biogenic hydrocarbon concentrations obtained is 4.4 ppbV (24 μg m⁻³), similar to those found for coniferous forests. The main monoterpenes determined were: limonene, α-pinene, sabinene, camphene and myrcene.