Quantifying effects of oxidant air pollutants on agricultural crops

Estimating risks of air pollution damage to agricultural crops requires identifying crop location and size, likely doses, models for translating dose to response, and measures of response appropriate for economic analysis. Assessment of risk requires compatible data sets for each of these variables. Analysis of air pollution mixtures suggests that oxidant crop damage is caused by three compounds: ozone, nitrogen oxides, and peroxyacetylnitrates. The phytotoxicity of ozone, the most prevalent photochemical oxidant, has been studied more extensively than the other two oxidants, and its effects on vegetation are best understood. Response of vegetation to air pollutants was first characterized by foliar or visible injury. Subsequent research indicated that foliar injury did not translate directly into reduced plant growth or yield, which can be measured. Response to air pollutants may be influenced by physical, biological, and environmental factors. Inherent genetic resistance is probably the most important single factor affecting plant response, although environmental factors influencing stomatal aperture may also be important. For several crops open-top chamber studies and cross sectional analyses of field data provide adequate information to develop dose-response functions. All of these studies have both strengths and weaknesses. Although a number of different models exist for selected crops, there is no single biological or statistical criterion which identifies the best or most accurate model.     

Using air pollution based community clusters to explore air pollution health effects in children

To study respiratory health effects of long-term exposure to ambient air pollutant mixture, we observed 7058 school children 5-16 years of age living in the four Chinese cities of Lanzhou, Chongqing, Wuhan, and Guangzhou. These children were enrolled from elementary schools located in eight districts, one urban district and one suburban district in each of the above cities. Ambient levels of PM(2.5), PM(10-2.5), total suspended particles (TSP), SO(2), and NO(x) were measured in these districts from 1993 to 1996. Based on a cluster analysis of arithmetic mean concentrations of PM(2.5), PM(10-2.5), (TSP-PM(10)), SO(2), and NO(x), we classified these children into four ordinal categories of exposure to ambient air pollutant mixtures. We tested for exposure-response relationships using logistic regression models, controlling for relevant covariates. We observed monotonic, positive relationships of exposure to the pollutant mixture with prevalence rates of cough with phlegm and wheeze. Other outcomes were not associated with the exposure in a monotonic exposure-response pattern. Even so, odds ratios for cough, phlegm, bronchitis, and asthma in the higher exposure district clusters were all higher than in the lowest exposure district cluster. We found evidence that exposure to the pollutant mixtures had adverse effects on children living in the four Chinese cities.     

Ecological effects of sulfur dioxide,fluorides, and minor air pollutants: recent trends and research needs

The regulation of the emissions of 'traditional' primary air pollutants (fluorides, sulfur dioxide) has changed the pattern of exposure of ecological systems, with greatly reduced exposure close to sources, but with a smaller effect in some remote areas. Measurements show that recovery is occurring at some sites, in fresh water chemistry (reduced acidity) and in sensitive biota (sustainable fish populations). However, the pattern of change in exposure has not always been simply related to emission reductions. An understanding of responses to recent changes will improve our predictions of the response to future emission changes, both locally and globally. As exposure to 'traditional' pollutants is reduced, the potential for other pollutants to have effects becomes more evident. In the aqueous phase, we need to understand the role of soluble and suspended organics, but this also means explicit recognition of the possibility of phase exchange, and the role of photolytic reactions on plant, soil, and water surfaces. Do highly reactive free radicals in the atmosphere, formed by the action of sunlight on volatile organic compounds, have direct effects on plants? Organic compounds and heavy metals may be bioactive as gases and particles, but for many potentially toxic compounds, the experimental evidence for biotic response is very limited. To evaluate the potential effects of pollutants, we need to understand the pathways by which airborne pollutants enter and react within ecosystems. For vegetation, we have to consider bidirectional fluxes, and distinguish among uptake through stomata, through leaf surfaces, or through roots. There are several challenges for the future. (1) Can we devise experiments that permit exposure of vegetation to gases, particles, and/or aqueous pollutants at 'realistic' concentrations? (2) Can we include the potential interactions with photolytically derived free radicals, and the dynamics of exchange? (3) How do we allow for responses to pollutant mixtures, or the simultaneous exposure to pollutants in gas, particle, and aqueous phases? The recognition of the importance of the dynamic exchange of pollutants between phases will be the key to the development of effective experimental approaches to evaluating cause-effect relationships between pollutant mixtures and ecosystem responses.     

Cancer risk assessment of selected hazardous air pollutants in Seattle

The risk estimates calculated from the conventional risk assessment method usually are compound specific and provide limited information for source-specific air quality control. We used a risk apportionment approach, which is a combination of receptor modeling and risk assessment, to estimate source-specific lifetime excess cancer risks of selected hazardous air pollutants. We analyzed the speciated PM(2.5) and VOCs data collected at the Beacon Hill in Seattle, WA between 2000 and 2004 with the Multilinear Engine to first quantify source contributions to the mixture of hazardous air pollutants (HAPs) in terms of mass concentrations. The cancer risk from exposure to each source was then calculated as the sum of all available species' cancer risks in the source feature. We also adopted the bootstrapping technique for the uncertainty analysis. The results showed that the overall cancer risk was 6.09 x 10(-5), with the background (1.61 x 10(-5)), diesel (9.82 x 10(-6)) and wood burning (9.45 x 10(-6)) sources being the primary risk sources. The PM(2.5) mass concentration contributed 20% of the total risk. The 5th percentile of the risk estimates of all sources other than marine and soil were higher than 110(-6). It was also found that the diesel and wood burning sources presented similar cancer risks although the diesel exhaust contributed less to the PM(2.5) mass concentration than the wood burning. This highlights the additional value from such a risk apportionment approach that could be utilized for prioritizing control strategies to reduce the highest population health risks from exposure to HAPs.     

Traffic and outdoor air pollution levels near highways in Baghdad,Iraq

In Iraq, the number of passenger cars, trucks and buses, local generators, and heavy construction equipment rose to a considerable extent since 2003, causing high environmental problems. Many types of pollutants were monitored and recorded for 24 h during March 2016. The study attempts to explore and establish a relationship between the volume of activity and the movement of motor vehicles of various compounds and contaminants resulting from their exhaust pipes, such as sulfur dioxide, particulate matters, oxides of nitrogen, VOCs, and unburned hydrocarbons. The study focused in and around Mohammad Al-Qasim highway adjacent to the University of Technology, Baghdad. The results showed the need for urgent treatments addressed by the environmental authorities in the city. The study results demonstrated that these contaminants are increased during periods of the beginning and end of working hours for government departments. Some types of sulfur compounds (H₂S and SO₂) concentrations were at serious health-threatening levels, which is a result of the high sulfur content in the Iraqi fuel. The concentrations of NOx and VOC were high, also, which could make the studied area vulnerable to the risk of smog formation. The Iraqi government should make greater efforts to protect the environment and human in this country from the transportation pollution risks.     

Immunotoxic effects of environmental pollutants in marine mammals

Due to their marine ecology and life-history, marine mammals accumulate some of the highest levels of environmental contaminants of all wildlife. Given the increasing prevalence and severity of diseases in marine wildlife, it is imperative to understand how pollutants affect the immune system and consequently disease susceptibility. Advancements and adaptations of analytical techniques have facilitated marine mammal immunotoxicology research. Field studies, captive-feeding experiments and in vitro laboratory studies with marine mammals have associated exposure to environmental pollutants, most notable polychlorinated biphenyls (PCBs), organochlorine pesticides and heavy metals, to alterations of both the innate and adaptive arms of immune systems, which include aspects of cellular and humoral immunity. For marine mammals, reported immunotoxicology endpoints fell into several major categories: immune tissue histopathology, haematology/circulating immune cell populations, functional immune assays (lymphocyte proliferation, phagocytosis, respiratory burst, and natural killer cell activity), immunoglobulin production, and cytokine gene expression. Lymphocyte proliferation is by far the most commonly used immune assay, with studies using different organic pollutants and metals predominantly reporting immunosuppressive effects despite the many differences in study design and animal life history. Using combined field and laboratory data, we determined effect threshold levels for suppression of lymphocyte proliferation to be between < 0.001–10 ppm for PCBs, 0.002–1.3 ppm for Hg, 0.009–0.06 for MeHg, and 0.1–2.4 for cadmium in polar bears and several pinniped and cetacean species. Similarly, thresholds for suppression of phagocytosis were 0.6–1.4 and 0.08–1.9 ppm for PCBs and mercury, respectively. Although data are lacking for many important immune endpoints and mechanisms of specific immune alterations are not well understood, this review revealed a systemic suppression of immune function in marine mammals exposed to environmental contaminants. Exposure to immunotoxic contaminants may have significant population level consequences as a contributing factor to increasing anthropogenic stress in wildlife and infectious disease outbreaks.     

Comparison of indoor and outdoor air quality at two staff quarters in Hong Kong

The indoor and outdoor air quality of two staff quarters of Hong Kong Polytechnic University at Tsim Sha Tsui East (TSTE) and Shatin (ST) were investigated. The air sampling was carried out in winter for about two months starting from January to February of 1996. Fifteen flats from each staff quarter were randomly selected for indoor/outdoor air pollutant measurements. The pollutants measured were NO_x, NO, NO₂, SO₂, CO, and O₃. The variations of pollutant concentrations between indoor and outdoor air were investigated on weekday mornings, weekday evenings, weekend mornings, and weekend evenings. All indoor/outdoor pollutant concentrations measured did not exceed the ASHRAE/NAAQS standard. The carbon monoxide concentrations indoors were systemically higher than those outdoors at the TSTE and the ST quarters, both on weekdays and Sunday, which indicates there are CO sources indoors. Except for CO, the indoor levels of other pollutants (NO_x, NO, NO₂, SO₂, and O₃) are lower than those outdoors. There was a significant correlation (P < 0.05) between indoor and outdoor concentrations for SO₂ and O₃ at both the TSTE and the ST quarters. Except for O₃, the mean concentrations of all the pollutants in the TSTE quarters, both indoor and outdoor, were higher than that of the ST quarters in all sampling periods. All indoor and outdoor O₃ levels were lower at the TSTE quarters than those at the ST quarters. The O₃ ratios of TSTE/ST were 0.72 outdoor and 0.79 indoor. This can be explained by the NO titration reaction through NO conversion to NO₂.     

The influence of ventilation on indoor/outdoor air contaminants in an office building

The air quality in a newly built preschool was investigated in a longitudinal study. Typical air contaminants emanating from building materials were determined, their variation over time (0–18 months) was measured, and the influence of the ventilation system (81%–91% recirculation of return air) on contaminant concentrations was studied. Volatile organic compounds were sampled by adsorption on porous polymer, analysed by a GC/FID system, and identified by MS. A spatial build-up in concentration (ppb or μg/m³ levels) is evident for all the organic compounds, as well as for CO₂, from the outdoor air, through the ventilation system, and through the rooms to the exhaust air. The longitudinal comparison over time shows that all the organic compounds decline in concentration mainly within the first 6 months of occupancy: 1-butanol 4–14 times, toluene and pentanal + hexanal 2–4 times, while formaldehyde remained at a constant low level of 90 ppb (110 μg/m³). It is difficult to believe that the problems of poor air quality in 100 preschools in Stockholm are caused by the organic compounds alone unless interactions occur. A preschool building needs to be gassed off during the first 6 months after its construction with no recirculation of return air allowed (outdoor air rate approx 4–5 ach). During at least 1–2 additional years, it is desired that the recirculation rate of return air is restricted, perhaps to 50%.     

Seasonal variation of 210Pb activity concentration in outdoor air of Milan (Italy)

Weekly measurements of 210Pb activity concentration on aerosol particles were performed at ground level in outdoor air in Milan (Italy) during the years 2000-2001. The experimental method was based on the delayed alpha spectrometry of in-grown 210Po activity detected on airborne particles collected on a filter support. On the same filter the 214Pb activity concentration was also measured during the sampling. 210Pb weekly concentration values showed a great variability and the average monthly values exhibited a seasonal pattern characterised by maxima in winter and minima in spring-summer. The same seasonal trend was also observed in 214Pb concentration values. 210Pb average yearly values were 0.70 and 0.82 mBq/m3 in 2000 and 2001, respectively, in good agreement with literature data registered at continental sites of similar latitude and longitude. The activity ratio 210Pb/214Pb was used to evaluate the residence time of fine aerosols in the urban air of Milan, which was 1-2 days.     

Natural outdoor environments and mental and physical health: Relationships and mechanisms

BackgroundEvidence is growing for the beneficial impacts of natural outdoor environments on health. However, most of the evidence has focused on green spaces and little evidence is available on health benefits of blue spaces and about possible mediators and modifiers of such impacts. We investigated the association between natural outdoor environments (separately for green and blue spaces) and health (general and mental) and its possible mediators and modifiers.MethodsCross-sectional data from adults interviewed in Catalonia (Spain) between 2010 and 2012 as part of the Catalonia Health Survey were used. The collected data included sociodemographic characteristics, self-perceived general health, mental health, physical activity and social support. Indicators of surrounding greenness and access to natural outdoor environments within 300 m of the residence and degree of urbanization were derived for residential addresses. Associations were estimated using logistic regression and negative binominal models.ResultsGreen spaces were associated with better self-perceived general health and better mental health, independent of degree of urbanization. The associations were more consistent for surrounding greenness than for access to green spaces. The results were consistent for different buffers, and when stratifying for socioeconomic status. Slightly stronger associations were found for women and residents of non-densely populated areas. No association was found between green spaces and social contacts and physical activity. The results for blue spaces were not conclusive.ConclusionGreen spaces are associated with better general and mental health across strata of urbanization, socioeconomic status, and genders. Mechanisms other than physical activity or social support may explain these associations.     

Temporal variation of 212Pb concentration in outdoor air of Milan and a comparison with 214Bi

Continuous measurement of hourly concentrations of 212Pb attached to aerosol particles was carried out during the whole year 2000 in the outdoor air of Milan (Italy). An improved experimental method based on on-line alpha spectroscopy during atmospheric particulate matter sampling allowed the contemporary determination of 212Pb and 214Bi through the deconvolution of the alpha energy spectral distribution analysis. The 212Pb hourly concentrations were about 100 times lower than 214Bi but showed a similar characteristic diurnal time trend. However, the influence of meteorological parameters such as rain and wind was more evident in 212Pb than in 214Bi concentrations. The 212Pb average annual concentration was 0.090 +/- 0.060 Bq/m3 with daily mean concentration varying from 0.013 to 0.333 Bq/m3.     

Possible health effects of energy conservation: Impairment of indoor air quality due to reduction of ventilation rate

Efforts to reduce the energy needs to heat or cool dwellings have the potential to create new health hazards. Increases in indoor levels of radon and its progeny from the reduction in air exchange rates add a substantial radioactive burden to the general population. Other indoor pollutants reaching critical concentrations in homes with low air exchange rates are CO and NO₂ from unvented combustion in gas stoves and heaters, tobacco smoke, and asbestos fibers. In addition, insulation materials and certain types of furniture may contribute the toxicant formaldehyde diffusing from foam injected walls or chipboard. Risk estimations using linear dose-response relationships show risk factors per kWh saved which are orders of magnitude greater than for a kWh produced by large power plants using coal, oil, gas, or uranium.     

Estimating the total exposure to air pollutants for different population age groups in Hong Kong

Given that Hong Kong is one of the most densely populated cities in the world, the exposure of the Hong Kong people is one of the interesting research areas. In this study, an indirect approach was used to estimate the exposure to nitrogen dioxide (NO2), respiratory dust (PM10) and carbon monoxide (CO) pollutants experienced by different age groups of people in Hong Kong. The average concentrations of the 20 major microenvironments obtained from our measurement survey data, together with the people activity pattern data obtained from 7-day recall questionnaires, were used to predict frequency distributions to exposure assessment. Our results showed that Hong Kong people spent more than 86% of their time indoors. Homes were shown to be the one of the major exposure sites to NO2, CO and PM10 for all age groups. Our results also indicate that the 24-h NO2 exposure for individuals, irrespective of age, spending more than 2 h in commuting daily, was observed to be exceeding the 24-h NO2 exposure standards. This study was one of the pioneering studies with valuable contribution for modeling the estimates of exposures to NO2, PM10 and CO of different age groups in Hong Kong.     

Recent progress in developing and using personal monitors to measure human exposure to air pollutants

Within the last two years, great progress has been made in the field of personal air quality monitors. Improvements in pump design, miniaturization, adsorption techniques, and new collection principles have produced about a dozen sensitive monitors capable of being used by the general public to measure their normal everyday exposure to many toxic or carcinogenic compounds. This article reviews recent progress in this field, particularly as it relates to U.S. Environmental Protection Agency programs.     

Future climate and adverse health effects caused by fine particulate matter air pollution: case study for Poland

Ground level air pollution, especially fine particulate matter (PM_2.5), has been associated with a number of adverse health effects. The dispersion of PM_2.5 through the atmosphere depends on several mutually connected anthropogenic, geophysical and meteorological parameters, all of which are affected by climate change. This study examines how projected climate change would affect population exposure to PM_2.5 air pollution in Poland. Population exposure to PM_2.5 in Poland was estimated for three decades: the 1990s, 2040s and 2090s. Future climate conditions were projected by Regional Climate Model RegCM (Beta), forced by the general atmospheric circulation model ECHAM5. The dispersion of PM_2.5 was simulated with chemical transport model CAMx version 4.40. Population exposure estimates of PM_2.5 were 18.3, 17.2 and 17.1 μg/m³ for the 1990s, 2040s and 2090s, respectively. PM_2.5 air pollution was estimated to cause approximately 39,800 premature deaths in the population of Poland in the year 2000. Our results indicate that in Poland, climate change may reduce the levels of exposure to anthropogenic particulate air pollution in future decades and that this reduction will reduce adverse health effects caused by the air pollution.     

Assessing the genotoxicity of urban air pollutants in Varanasi City using Tradescantia micronucleus (Trad-MCN) bioassay

In the present study Tradescantia micronucleus (Trad-MCN) bioassay was performed to assess the genotoxicity of air pollutants in Varanasi City. The experiment was performed during October 2006 to April 2007. For Tradescantia micronucleus (Trad-MCN) bioassay four sites were selected, three in the city having different traffic characteristics and one control site virtually free from traffic intervention. Twenty young Tradescantia pallida inflorescences were collected from each sampling site during the study period and micronuclei frequencies were determined in early tetrads of pollen mother cells and expressed as MCN/100 tetrads. During the same period the concentration of different air pollutants were also measured. Tradescantia micronucleus (Trad-MCN) bioassay showed that the plants kept in areas having higher traffic emissions evidence higher micronuclei frequencies than samples kept at control site. The study indicates that in situ biomonitoring using higher plants may be useful for characterizing genotoxic air pollutants in areas even without any sophisticated instrument.     

Adverse effects in wild fish living downstream from pharmaceutical manufacture discharges

A set of biochemical and histological responses was measured in wild gudgeon collected upstream and downstream of urban and pharmaceutical manufacture effluents. These individual end-points were associated to fish assemblage characterisation. Responses of biotransformation enzymes, neurotoxicity and endocrine disruption biomarkers revealed contamination of investigated stream by a mixture of pollutants. Fish from sampled sites downstream of the industrial effluent exhibited also strong signs of endocrine disruption including vitellogenin induction, intersex and male-biased sex-ratio. These individual effects were associated to a decrease of density and a lack of sensitive fish species. This evidence supports the hypothesis that pharmaceutical compounds discharged in stream are involved in recorded endocrine disruption effects and fish population disturbances and threaten disappearance of resident fish species. Overall, this study gives argument for the utilisation of an effect-based monitoring approach to assess impacts of pharmaceutical manufacture discharges on wild fish populations.     

Evaluation of health benefits for improving indoor air quality in workplace

In contrast to a majority of reported damage-cost literature being focused on outdoor pollution, this paper describes the development of a protocol that links population exposure data with reported epidemiological concentration-response coefficients. A change in indoor particulate level is expressed as a change in total exposure levels, which is then linked with a corresponding change in ambient particulate concentrations before evaluating the associated health benefits. In this study, the development of protocol is illustrated by using a typical office building environment and daily time activity patterns of office occupants in Hong Kong. Our results indicate that some benefit gains for the owners-employers and the society would be anticipated if certain filter set configurations had been adopted. However, the amount of benefit gains for the owners-employers is shown to be increased with the average salary level of employees and the duration of their stay in offices.     

The effects of woodburning on the indoor residential air quality

Data from suburban residences in the Boston metropolitan area reveal a potential adverse impact on indoor air quality from woodburning in woodstoves and fireplaces. Ambient pollutant concentrations at each residence were compared to corresponding pollutant levels indoors at three locations (kitchen, bedroom, and activity room). Individual gaseous pollutant samples were averaged on an hourly basis while 24-h integrated samples of particulate matter were obtained. Ten gaseous pollutants were sampled along with total suspended particulates (TSP). Chemical analyses further determined ten components of TSP including trace metals, benzo-a-pyrene(B)aP, respirable suspended particulates (RSP), and water soluble sulfates and nitrates. Monitoring lasted two weeks at each residence and was conducted under occupied, real-life, conditions. Observed, elevated indoor concentrations of TSP, RSP, and BaP are attributed to woodburning. Data indicate that average indoor TSP concentrations during woodburning periods were about three times corresponding levels during nonwoodburning periods. The primary 24-h national ambient air quality standard (NAAQS) for TSP was exceeded once indoors during fireplace use, and the secondary, 24-h TSP NAAQS, was also exceeded indoors by RSP concentrations. Indoor BaP concentrations during woodstove use averaged five times more than during nonwoodburning periods. At this stage, results are only indicative, but the potential impact from elevated indoor concentrations of TSP, RSP, and BaP, attributed to woodburning, may have long-term health implications.