Patterns and predictors of personal exposure to indoor air pollution from biomass combustion among women and children in rural China

Indoor air pollution (IAP) from domestic biomass combustion is an important health risk factor, yet direct measurements of personal IAP exposure are scarce. We measured 24-h integrated gravimetric exposure to particles < 2.5 μm in aerodynamic diameter (particulate matter, PM?.?) in 280 adult women and 240 children in rural Yunnan, China. We also measured indoor PM?.? concentrations in a random sample of 44 kitchens. The geometric mean winter PM?.? exposure among adult women was twice that of summer exposure [117 μg/m3 (95% CI: 107, 128) vs. 55 μg/m3 (95% CI: 49, 62)]. Children's geometric mean exposure in summer was 53 μg/m3 (95% CI: 46, 61). Indoor PM?.? concentrations were moderately correlated with women's personal exposure (r=0.58), but not for children. Ventilation during cooking, cookstove maintenance, and kitchen structure were significant predictors of personal PM?.? exposure among women primarily cooking with biomass. These findings can be used to develop exposure assessment models for future epidemiologic research and inform interventions and policies aimed at reducing IAP exposure. PRACTICAL IMPLICATIONS: Our results suggest that reducing overall PM pollution exposure in this population may be best achieved by reducing winter exposure. Behavioral interventions such as increasing ventilation during cooking or encouraging stove cleaning and maintenance may help achieve these reductions.     

Exposure to household air pollution from biomass cookstoves and blood pressure among women in rural Honduras: A cross‐sectional study

Growing evidence links household air pollution exposure from biomass cookstoves with elevated blood pressure. We assessed cross‐sectional associations of 24‐hour mean concentrations of personal and kitchen fine particulate matter (PM_2.5), black carbon (BC), and stove type with blood pressure, adjusting for confounders, among 147 women using traditional or cleaner‐burning Justa stoves in Honduras. We investigated effect modification by age and body mass index. Traditional stove users had mean (standard deviation) personal and kitchen 24‐hour PM_2.5 concentrations of 126 μg/m³ (77) and 360 μg/m³ (374), while Justa stove users’ exposures were 66 μg/m³ (38) and 137 μg/m³ (194), respectively. BC concentrations were similarly lower among Justa stove users. Adjusted mean systolic blood pressure was 2.5 mm Hg higher (95% CI, 0.7‐4.3) per unit increase in natural log‐transformed kitchen PM_2.5 concentration; results were stronger among women of 40 years or older (5.2 mm Hg increase, 95% CI, 2.3‐8.1). Adjusted odds of borderline high and high blood pressure (categorized) were also elevated (odds ratio = 1.5, 95% CI, 1.0‐2.3). Some results included null values and are suggestive. Results suggest that reduced household air pollution, even when concentrations exceed air quality guidelines, may help lower cardiovascular disease risk, particularly among older subgroups.     

Comparison of next-generation portable pollution monitors to measure exposure to PM2.5 from household air pollution in Puno,Peru

Assessment of personal exposure to PM_2.5 is critical for understanding intervention effectiveness and exposure-response relationships in household air pollution studies. In this pilot study, we compared PM_2.5 concentrations obtained from two next-generation personal exposure monitors (the Enhanced Children MicroPEM or ECM; and the Ultrasonic Personal Air Sampler or UPAS) to those obtained with a traditional Triplex Cyclone and SKC Air Pump (a gravimetric cyclone/pump sampler). We co-located cyclone/pumps with an ECM and UPAS to obtain 24-hour kitchen concentrations and personal exposure measurements. We measured Spearmen correlations and evaluated agreement using the Bland-Altman method. We obtained 215 filters from 72 ECM and 71 UPAS co-locations. Overall, the ECM and the UPAS had similar correlation (ECM ρ = 0.91 vs UPAS ρ = 0.88) and agreement (ECM mean difference of 121.7 µg/m³ vs UPAS mean difference of 93.9 µg/m³) with overlapping confidence intervals when compared against the cyclone/pump. When adjusted for the limit of detection, agreement between the devices and the cyclone/pump was also similar for all samples (ECM mean difference of 68.8 µg/m³ vs UPAS mean difference of 65.4 µg/m³) and personal exposure samples (ECM mean difference of −3.8 µg/m³ vs UPAS mean difference of −12.9 µg/m³). Both the ECM and UPAS produced comparable measurements when compared against a cyclone/pump setup.     

Maternal exposure to carbon monoxide and fine particulate matter during pregnancy in an urban Tanzanian cohort

Low birthweight contributes to as many as 60% of all neonatal deaths; exposure during pregnancy to household air pollution has been implicated as a risk factor. Between 2011 and 2013, we measured personal exposures to carbon monoxide (CO) and fine particulate matter (PM_2.5) in 239 pregnant women in Dar es Salaam, Tanzania. CO and PM_2.5 exposures during pregnancy were moderately high (geometric means 2.0 ppm and 40.5 μg/m³); 87% of PM_2.5 measurements exceeded WHO air quality guidelines. Median and high (75th centile) CO exposures were increased for those cooking with charcoal and kerosene versus kerosene alone in quantile regression. High PM_2.5 exposures were increased with charcoal use. Outdoor cooking reduced median PM_2.5 exposures. For PM_2.5, we observed a 0.15 kg reduction in birthweight per interquartile increase in exposure (23.0 μg/m³) in multivariable linear regression; this finding was of borderline statistical significance (95% confidence interval 0.30, 0.00 kg; P = 0.05). PM_2.5 was not significantly associated with birth length or head circumference nor were CO exposures associated with newborn anthropometrics. Our findings contribute to the evidence that exposure to household air pollution, and specifically fine particulate matter, may adversely affect birthweight.     

Exposure to household air pollution from biomass‐burning cookstoves and HbA1c and diabetic status among Honduran women

Household air pollution from biomass cookstoves is estimated to be responsible for more than two and a half million premature deaths annually, primarily in low and middle‐income countries where cardiometabolic disorders, such as Type II Diabetes, are increasing. Growing evidence supports a link between ambient air pollution and diabetes, but evidence for household air pollution is limited. This cross‐sectional study of 142 women (72 with traditional stoves and 70 with cleaner‐burning Justa stoves) in rural Honduras evaluated the association of exposure to household air pollution (stove type, 24‐hour average kitchen and personal fine particulate matter [PM_2.5] mass and black carbon) with glycated hemoglobin (HbA1c) levels and diabetic status based on HbA1c levels. The prevalence ratio (PR) per interquartile range increase in pollution concentration indicated higher prevalence of prediabetes/diabetes (vs normal HbA1c) for all pollutant measures (eg, PR per 84 μg/m³ increase in personal PM_2.5, 1.49; 95% confidence interval [CI], 1.11‐2.01). Results for HbA1c as a continuous variable were generally in the hypothesized direction. These results provide some evidence linking household air pollution with the prevalence of prediabetes/diabetes, and, if confirmed, suggest that the global public health impact of household air pollution may be broader than currently estimated.     

Chimney stoves modestly improved Indoor Air Quality measurements compared with traditional open fire stoves: results from a small‐scale intervention study in rural Peru

Nearly half of the world's population depends on biomass fuels to meet domestic energy needs, producing high levels of pollutants responsible for substantial morbidity and mortality. We compare carbon monoxide (CO) and particulate matter (PM_2.5) exposures and kitchen concentrations in households with study‐promoted intervention (OPTIMA‐improved stoves and control stoves) in San Marcos Province, Cajamarca Region, Peru. We determined 48‐h indoor air concentration levels of CO and PM_2.5 in 93 kitchen environments and personal exposure, after OPTIMA‐improved stoves had been installed for an average of 7 months. PM_2.5 and CO measurements did not differ significantly between OPTIMA‐improved stoves and control stoves. Although not statistically significant, a post hoc stratification of OPTIMA‐improved stoves by level of performance revealed mean PM_2.5 and CO levels of fully functional OPTIMA‐improved stoves were 28% lower (n = 20, PM_2.5, 136 μg/m³ 95% CI 54–217) and 45% lower (n = 25, CO, 3.2 ppm, 95% CI 1.5–4.9) in the kitchen environment compared with the control stoves (n = 34, PM_2.5, 189 μg/m³, 95% CI 116–261; n = 44, CO, 5.8 ppm, 95% CI 3.3–8.2). Likewise, although not statistically significant, personal exposures for OPTIMA‐improved stoves were 43% and 17% lower for PM_2.5 (n = 23) and CO (n = 25), respectively. Stove maintenance and functionality level are factors worthy of consideration for future evaluations of stove interventions.     

Household air pollution and personal exposure to nitrated and oxygenated polycyclic aromatics (PAHs) in rural households: Influence of household cooking energies

Residential solid fuels are widely consumed in rural China, contributing to severe household air pollution for many products of incomplete combustion, such as polycyclic aromatic hydrocarbons (PAHs) and their polar derivatives. In this study, concentrations of nitrated and oxygenated PAH derivatives (nPAHs and oPAHs) for household and personal air were measured and analyzed for influencing factors like smoking and cooking energy type. Concentrations of nPAHs and oPAHs in kitchens were higher than those in living rooms and in outdoor air. Exposure levels measured by personal samplers were lower than levels in indoor air, but higher than outdoor air levels. With increasing molecular weight, individual compounds tended to be more commonly partitioned to particulate matter (PM); moreover, higher molecular weight nPAHs and oPAHs were preferentially found in finer particles, suggesting a potential for increased health risks. Smoking behavior raised the concentrations of nPAHs and oPAHs in personal air significantly. People who cooked food also had higher personal exposures. Cooking and smoking have a significant interaction effect on personal exposure. Concentrations in kitchens and personal exposure to nPAHs and oPAHs for households using wood and peat were significantly higher than for those using electricity and liquid petroleum gas (LPG).     

Characterization and exposure assessment of household fine particulate matter pollution in China

Household fine particulate matter (PM_2.5) pollution greatly impacts residents' health. To explore the current national situation of household PM_2.5 pollution in China, a study was conducted based on literature published from 1998 to 2018. After extracting data from the literature in conformity with the requirements, the nationwide household-weighted mean concentration of household PM_2.5 (HPL) was calculated. Subgroup analyses of spatial, geographic, and temporal differences were also done. The estimated overall HPL in China was 132.2 ± 117.7 μg/m³. HPL in the rural area (164.3 ± 104.5 μg/m³) was higher than that in the urban area (123.9 ± 122.3 μg/m³). For HPLs of indoor sampling sites, the kitchen was the highest, followed by the bedroom and living room. There were significant differences of geographic distributions. The HPLs in the South were higher than the North in four seasons. The inhaled dose of household PM_2.5 among school-age children differed from provinces with the highest dose up to 5.9 μg/(kg·d). Countermeasures should be carried out to reduce indoor pollution and safeguard health urgently.     

Reduction in personal exposures to particulate matter and carbon monoxide as a result of the installation of a Patsari improved cook stove in Michoacan Mexico

The impact of an improved wood burning stove (Patsari) in reducing personal exposures and indoor concentrations of particulate matter (PM(2.5)) and carbon monoxide (CO) was evaluated in 60 homes in a rural community of Michoacan, Mexico. Average PM(2.5) 24-h personal exposure was 0.29 mg/m(3) and mean 48-h kitchen concentration was 1.269 mg/m(3) for participating women using the traditional open fire (fogon). If these concentrations are typical of rural conditions in Mexico, a large fraction of the population is chronically exposed to levels of pollution far higher than ambient concentrations found by the Mexican government to be harmful to human health. Installation of an improved Patsari stove in these homes resulted in 74% reduction in median 48-h PM(2.5) concentrations in kitchens and 35% reduction in median 24-h PM(2.5) personal exposures. Corresponding reductions in CO were 77% and 78% for median 48-h kitchen concentrations and median 24-h personal exposures, respectively. The relationship between reductions in median kitchen concentrations and reductions in median personal exposures not only changed for different pollutants, but also differed between traditional and improved stove type, and by stove adoption category. If these reductions are typical, significant bias in the relationship between reductions in particle concentrations and reductions in health impacts may result, if reductions in kitchen concentrations are used as a proxy for personal exposure reductions when evaluating stove interventions. In addition, personal exposure reductions for CO may not reflect similar reductions for PM(2.5). This implies that PM(2.5) personal exposure measurements should be collected or indoor measurements should be combined with better time-activity estimates, which would more accurately reflect the contributions of indoor concentrations to personal exposures. PRACTICAL IMPLICATIONS: Installation of improved cookstoves may result in significant reductions in indoor concentrations of carbon monoxide and fine particulate matter (PM(2.5)), with concurrent but lower reductions in personal exposures. Significant errors may result if reductions in kitchen concentrations are used as a proxy for personal exposure reductions when evaluating stove interventions in epidemiological investigations. Similarly, time microenvironment activity models in these rural homes do not provide robust estimates of individual exposures due to the large spatial heterogeneity in pollutant concentrations and the lack of resolution of time activity diaries to capture movement through these microenvironments.     

Size distribution and lung-deposited doses of particulate matter from household exposure to biomass smoke

Exposure to high concentrations of particulate matter (PM) is associated with a number of adverse health effects. However, it is unclear which aspects of PM are most hazardous, and a better understanding of particle sizes and personal exposure is needed. We characterized particle size distribution (PSD) from biomass-related pollution and assessed total and regional lung-deposited doses using multiple-path deposition modeling. Gravimetric measurements of kitchen and personal PM_2.5 (<2.5 µm in size) exposures were collected in 180 households in rural Puno, Peru. Direct-reading measurements of number concentrations were collected in a subset of 20 kitchens for particles 0.3-25 µm, and the continuous PSD was derived using a nonlinear least-squares method. Mean daily PM_2.5 kitchen concentration and personal exposure was 1205 ± 942 µg/m³ and 115 ± 167 µg/m³, respectively, and the mean mass concentration consisted of a primary accumulation mode at 0.21 µm and a secondary coarse mode at 3.17 µm. Mean daily lung-deposited surface area (LDSA) and LDSA during cooking were 1009.6 ± 1469.8 µm²/cm³ and 10,552.5 ± 8261.6 µm²/cm³, respectively. This study presents unique data regarding lung deposition of biomass smoke that could serve as a reference for future studies and provides a novel, more biologically relevant metric for exposure-response analysis compared to traditional size-based metrics.     

Indoor air pollution from particulate matter emissions in different households in rural areas of Bangladesh

Indoor air pollution from the combustion of traditional biomass fuels (wood, cow dung, and crop wastes) is a significant public health problem predominantly for poor populations in many developing countries. It is particularly problematic for the women who are normally responsible for food preparation and cooking, and for infants/young children who spend time around their mothers near the cooking area. Airborne particulate matter (PM) samples were collected from cooking and living areas in homes in a rural area of Bangladesh to investigate the impact of fuel use, kitchen configurations, and ventilation on indoor air quality and to apportion the source contributions of the measured trace metals and BC concentrations. Lower PM concentrations were observed when liquefied petroleum gas (LPG) was used for cooking. PM concentrations varied significantly depending on the position of kitchen, fuel use and ventilation rates. From reconstructed mass (RCM) calculations, it was found that the major constituent of the PM was carbonaceous matter. Soil and smoke were identified as components from elemental composition data. It was also found that some kitchen configurations have lower PM concentrations than others even with the use of low-grade biomass fuels. Adoption of these kitchen configurations would be a cost-effective approach in reducing exposures from cooking in these rural areas.     

Measuring the exposure of infants and children to indoor air pollution from biomass fuels in The Gambia

Indoor air pollution (IAP) from biomass fuels contains high concentrations of health damaging pollutants and is associated with an increased risk of childhood pneumonia. We aimed to design an exposure measurement component for a matched case-control study of IAP as a risk factor for pneumonia and severe pneumonia in infants and children in The Gambia. We conducted co-located simultaneous area measurement of carbon monoxide (CO) and particles with aerodynamic diameter <2.5 microm (PM(2.5)) in 13 households for 48 h each. CO was measured using a passive integrated monitor and PM(2.5) using a continuous monitor. In three of the 13 households, we also measured continuous PM(2.5) concentration for 2 weeks in the cooking, sleeping, and playing areas. We used gravimetric PM(2.5) samples as the reference to correct the continuous PM(2.5) for instrument measurement error. Forty-eight hour CO and PM(2.5) concentrations in the cooking area had a correlation coefficient of 0.80. Average 48-h CO and PM(2.5) concentrations in the cooking area were 3.8 +/- 3.9 ppm and 361 +/- 312 microg/m3, respectively. The average 48-h CO exposure was 1.5 +/- 1.6 ppm for children and 2.4 +/- 1.9 ppm for mothers. PM(2.5) exposure was an estimated 219 microg/m3 for children and 275 microg/m3 for their mothers. The continuous PM(2.5) concentration had peaks in all households representing the morning, midday, and evening cooking periods, with the largest peak corresponding to midday. The results are used to provide specific recommendations for measuring the exposure of infants and children in an epidemiological study. PRACTICAL IMPLICATIONS: Measuring personal particulate matter (PM) exposure of young children in epidemiological studies is hindered by the absence of small personal monitors. Simultaneous measurement of PM and carbon monoxide suggests that a combination of methods may be needed for measuring children's PM exposure in areas where household biomass combustion is the primary source of indoor air pollution. Children's PM exposure in biomass burning homes in The Gambia is substantially higher than concentrations in the world's most polluted cities.     

Application of land use regression to regulatory air quality data in Japan

A land use regression (LUR) model has been used successfully for predicting traffic-related pollutants, although its application has been limited to Europe and North America. Therefore, we modeled traffic-related pollutants by LUR then examined whether LUR models could be constructed using a regulatory monitoring network in Shizuoka, Japan. We used the annual-mean nitrogen dioxide (NO₂) and suspended particulate matter (SPM) concentrations between April 2000 and March 2006 in the study area. SPM accounts for particulate matter with an aerodynamic diameter less than 8 μm (PM₈). Geographic variables that are considered to predict traffic-related pollutants were classified into four groups: road type, traffic intensity, land use, and physical component. Using geographical variables, we then constructed a model to predict the monitored levels of NO₂ and SPM. The mean concentrations of NO₂ and SPM were 35.75 μg/m³ (standard deviation of 11.28) and 28.67 μg/m³ (standard deviation of 4.73), respectively. The final regression model for the NO₂ concentration included five independent variables. R² for the NO₂ model was 0.54. On the other hand, the regression model for the SPM concentration included only one independent variable. R² for the SPM model was quite low (R² = 0.11). The present study showed that even if we used regulatory monitoring air quality data, we could estimate NO₂ moderately well. This result could encourage the wide use of LUR models in Asian countries.     

Household air pollution and personal exposure risk of polycyclic aromatic hydrocarbons among rural residents in Shanxi,China

Polycyclic aromatic hydrocarbons (PAHs) are a group of pollutants of widespread concerns. Gaseous and size‐segregated particulate‐phase PAHs were collected in indoor and outdoor air in rural households. Personal exposure was measured and compared to the ingestion exposure. The average concentrations of 28 parent PAHs and benzo(a)pyrene (BaP) were 9000 ± 8390 and 131 ± 236 ng/m³ for kitchen, 2590 ± 2270 and 43 ± 95 ng/m³ for living room, and 2800 ± 3890 and 1.6 ± 0.7 ng/m³ for outdoor air, respectively. The mass percent of high molecular weight (HMW) compounds with 5–6 rings contributed 1.3% to total 28 parent PAHs. Relatively higher fractions of HMW PAHs were found in indoor air compared to outdoor air. Majorities of particle‐bound PAHs were found in the finest PM_0.25, and the highest levels of fine PM_0.25‐bound PAHs were in the kitchen using peat and wood as energy sources. The 24‐h personal PAH exposure concentration was 2100 ± 1300 ng/m³. Considering energies, exposures to those using wood were the highest. The PAH inhalation exposure comprised up to about 30% in total PAH exposure through food ingestion and inhalation, and the population attributable fraction (PAF) for lung cancer in the region was 0.85%. The risks for inhaled and ingested intakes of PAHs were 1.0 × 10^?5 and 1.1 × 10^?5, respectively.     

Burden of disease attributed to anthropogenic air pollution in the United Arab Emirates: Estimates based on observed air quality data

This study quantifies the national burden of disease attributed to particulate matter (PM) and ozone (O₃) in ambient air in the United Arab Emirates (UAE), a rapidly growing nation in which economic development and climatic conditions pose important challenges for air quality management. Estimates of population exposure to these air pollutants are based on observed air quality data from fixed-site monitoring stations. We divide the UAE into small grid cells and use spatial-statistical methods to estimate the ambient pollutant concentrations in each cell based on the observed data. Premature deaths attributed to PM and O₃ are computed for each grid cell and then aggregated across grid cells and over a year to estimate the total number of excess deaths attributable to ambient air pollution. Our best estimate is that approximately 545 (95% CI: 132-1224) excess deaths in the UAE in the year 2007 are attributable to PM in ambient air. These excess deaths represent approximately 7% (95% CI: 2-17%) of the total deaths that year. We attribute approximately 62 premature deaths (95% CI: 17-127) to ground-level O₃ for the year 2007. Uncertainty in the natural background level of PM, due to the frequent dust storms occurring in the region, has significant impacts on the attributed mortality estimates. Despite the uncertainties associated with the integrated assessment framework, we conclude that anthropogenic ambient air pollution, in particular PM, causes a considerable public health impact in the UAE in terms of premature deaths. We discuss important uncertainties and scientific hypotheses to be investigated in future work that might help reduce the uncertainties in the burden of disease estimates.     

Indoor exposure to particulate matter and the incidence of acute lower respiratory infections among children: A birth cohort study in urban Bangladesh

Approximately half of all children under two years of age in Bangladesh suffer from an acute lower respiratory infection (ALRI) each year. Exposure to indoor biomass smoke has been consistently associated with an increased risk of ALRI in young children. Our aim was to estimate the effect of indoor exposure to particulate matter (PM_2.5) on the incidence of ALRI among children in a low‐income, urban community in Bangladesh. We followed 257 children through two years of age to determine their frequency of ALRI and measured the PM_2.5 concentrations in their sleeping space. Poisson regression was used to estimate the association between ALRI and the number of hours per day that PM_2.5 concentrations exceeded 100 μg/m³, adjusting for known confounders. Each hour that PM_2.5 concentrations exceeded 100 μg/m³ was associated with a 7% increase in incidence of ALRI among children aged 0–11 months (adjusted incidence rate ratio (IRR) 1.07, 95% CI 1.01–1.14), but not in children 12–23 months old (adjusted IRR 1.00, 95% CI 0.92–1.09). Results from this study suggest that reducing indoor PM_2.5 exposure could decrease the frequency of ALRI among infants, the children at highest risk of death from these infections.     

Lower tract respiratory infection in children younger than 5 years of age and adverse pregnancy outcomes related to household air pollution in Bariloche (Argentina) and Temuco (Chile)

The main objective of this study was to evaluate the association between household air pollution with lower tract respiratory infection (LRTI) in children younger than 5 years old and adverse pregnancy outcomes. This retrospective cohort study took place in two cities in Patagonia. Using systemic random sampling, we selected households in which at least one child <5 years had lived and/or a child had been born alive or stillborn. Trained interviewers administered the questionnaire. We included 926 households with 695 pregnancies and 1074 children. Household cooking was conducted indoors in ventilated rooms and the use of wood as the principal fuel for cooking was lower in Temuco (13% vs. 17%). In exposed to biomass fuel use, the adjusted OR for LRTI was 1.87 (95% CI 0.98–3.55; P = 0.056) in Temuco and 1.12 (95% CI 0.61–2.05; P = 0.716) in Bariloche. For perinatal morbidity, the OR was 3.11 (95% CI 0.86–11.32; P = 0.084) and 1.41 (95% CI 0.50–3.97; P = 0.518), respectively. However, none of the effects were statistically significant (P > 0.05). The use of biomass fuel to cook in traditional cookstoves in ventilated dwellings may increase the risk of perinatal morbidity and LRTI.     

Effects of pollution from personal computers on perceived air quality, SBS symptoms and productivity in offices

In groups of six, 30 female subjects were exposed for 4.8 h in a low-polluting office to each of two conditions--the presence or absence of 3-month-old personal computers (PCs). These PCs were placed behind a screen so that they were not visible to the subjects. Throughout the exposure the outdoor air supply was maintained at 10 l/s per person. Under each of the two conditions the subjects performed simulated office work using old low-polluting PCs. They also evaluated the air quality and reported Sick Building Syndrome (SBS) symptoms. The PCs were found to be strong indoor pollution sources, even after they had been in service for 3 months. The sensory pollution load of each PC was 3.4 olf, more than three times the pollution of a standard person. The presence of PCs increased the percentage of people dissatisfied with the perceived air quality from 13 to 41% and increased by 9% the time required for text processing. Chemical analyses were performed to determine the pollutants emitted by the PCs. The most significant chemicals detected included phenol, toluene, 2-ethylhexanol, formaldehyde, and styrene. The identified compounds were, however, insufficient in concentration and kind to explain the observed adverse effects. This suggests that chemicals other than those detected, so-called 'stealth chemicals', may contribute to the negative effects. PRACTICAL IMPLICATIONS: PCs are an important, but hitherto overlooked, source of pollution indoors. They can decrease the perceived air quality, increase SBS symptoms and decrease office productivity. The ventilation rate in an office with a 3-month-old PC would need to be increased several times to achieve the same perceived air quality as in a low-polluting office with the PC absent. Pollution from PCs has an important negative impact on the air quality, not only in offices but also in many other spaces, including homes. PCs may have played a role in previously published studies on SBS and perceived air quality, where PCs were overlooked as a possible pollution source in the indoor environment. The fact that the chemicals identified in the office air and in the chamber experiments were insufficient to explain the adverse effects observed during human exposures illustrates the inadequacy of the analytical chemical methods commonly used in indoor air quality investigations. For certain chemicals the human senses are much more sensitive than the chemical methods routinely used in indoor air quality investigations. The adverse effects of PC-generated air pollutants could be reduced by modifications in the manufacturing process, increased ventilation, localized PC exhaust, or personalized ventilation systems.     

Real-time air monitoring of occupational exposures to particulate matter among hairdressers in Maryland: A pilot study

Hairdressers are exposed to particulate matter (PM), a known air pollutant linked to adverse health effects. Still, studies on occupational PM exposures in hair salons are sparse. We characterized indoor air PM concentrations in three salons primarily serving an African/African American (AA) clientele, and three Dominican salons primarily serving a Latino clientele. We also assessed the performance of low-cost sensors (uRAD, Flow, AirVisual) by comparing them to high-end sensors (DustTrak) to conduct air monitoring in each salon over 3 days to quantify work shift concentrations of PM_2.5, respirable PM (RPM), and PM₁₀. We observed high spatial and temporal variability in 30-min time-weighted average (TWA) RPM concentrations (0.18–5518 μg/m³). Readings for the uRAD and AirVisual sensors were highly correlated with the DustTrak (R² = 0.90–0.99). RPM 8-hour TWAs ranged from 18 to 383 µg/m³ for AA salons, and 9–2115 µg/m³ for Dominican salons. Upper 95th percentiles of daily RPM exposures ranged from 439 to 2669 µg/m³. The overall range of 30-min TWA PM_2.5 and PM₁₀ concentrations was 0.13–5497 and 0.36-,541 μg/m³, respectively. Findings suggest that hairdressers could be overexposed to RPM during an 8-hour shift. Additional comprehensive monitoring studies are warranted to further characterize temporal and spatial variability of PM exposures in this understudied occupational population.     

An integrated approach to assess air pollution threats to cultural heritage in a semi-confined environment: The case study of Michelozzo's Courtyard in Florence (Italy)

An example of an integrated approach to assess air pollution threats to cultural heritage in a semi-confined environment is presented in this work, where the monitoring campaign carried out at the Michelozzo's Courtyard (in Palazzo Vecchio, Florence, Italy) is used as a case study. A wide research project was carried out, with the main aim of obtaining the first quantitative data on air quality and microclimate conditions inside the Courtyard, and, if possible, identifying the main causes of degradation and suggesting appropriate conservation strategies. The investigation adopted a holistic approach involving thermographic measurements on the wall paintings, microclimatic analysis, gaseous pollutant monitoring, atmospheric particles characterisation and dry deposition compositional analysis. Attention was focused on the wall painting depicting the city of Hall because of its anomalous and critical conservation conditions, which are visible at a glance, due to the contrast between a wide darker zone around the central subject of the painting and external lighter areas.