Indoor Black Carbon Research Articles

Implications of fuel poverty for indoor black carbon concentrations from space heating

Despite the global transition towards cleaner energy sources observed over the last decade, disparities in access persist worldwide. The dependence on biomass for household heating exacerbates fuel poverty, as economically vulnerable households face challenges in obtaining certified firewood and often resort to using contaminated biomass as a substitute, either partially or completely. We examined black carbon (BC) particle concentrations —a marker for combustion— during wood stove operation through a five-day case study in a typical Chilean household. BC increased rapidly following the ignition of the stove, with the combustion of dry Eucalyptus globulus logs yielding a substantially lower peak (5.29 μg/m3) than when using unclean biomass: 35.75 μg/m3 with demolition wood and painted furniture, and 87.11 μg/m3 with the addition of a blend of particleboard with polystyrene foam. During the latter two events, BC particles remained indoors for about 20 h before the concentrations reverted to pre-spike levels. The slow decay in BC concentrations was further influenced by the infiltration of outdoor air. The mean indoor BC concentrations were comparable to or even exceeded those observed on busy roads in major cities worldwide. These results highlight the risks associated with limited access to clean fuels for indoor heating, alongside inadequate insulation. This study sheds light on the problem of fuel poverty and its adverse effects on health and well-being.

Residential radon decay products are associated with cough and phlegm in patients with COPD

Radon decay products attach to particulate matter (referred to as particle radioactivity, PR) has been shown to be potential to promote airway damage after inhalation. In this study, we investigated associations between PR with respiratory symptoms and health-related quality of life (HRQL) in patients with COPD. 141 male patients with COPD, former smokers, completed the St. George's Respiratory Questionnaire (SGRQ) after up to four 1-week seasonal assessments (N=474) of indoor (home) and ambient (central site) particulate matter ≤ 2.5 µm in diameter (PM2.5) and black carbon (BC). Indoor PR was measured as α-activity (radiation) on PM2.5 filter samples. The ratio of indoor/ambient sulfur in PM2.5 (a ventilation surrogate) was used to estimate α-PR from indoor radon decay. SGRQ responses assessed frequent cough, phlegm, shortness of breath, wheeze, and chest attacks in the past 3 months. Multivariable linear regression with generalized estimating equations accounting for repeated measures was used to explore associations, adjusting for potential confounders. Median (IQR) indoor α-PR was 1.22 (0.62) mBq/m3. We found that there were positive associations between α-PR with cough and phlegm. The strongest associations were with estimated α-PR of indoor origin for cough (31.1 % increase/IQR, 95 %CI: 8.8 %, 57.8 %), and was suggestive for phlegm (13.0 % increase/IQR, 95 %CI: −2.5 %, 31.0 %), similar adjusting for indoor BC or PM2.5. α-PR of indoor origin was positively associated with an increase in SGRQ Symptoms score [1.2 units/IQR; 95 %CI: −0.3, 2.6] that did not meet conventional levels of statistical significance. Our results suggested that exposure to indoor radon decay products measured as particle radioactivity, a common indoor exposure, is associated with cough, and suggestively associated with phlegm and worse HRQL symptoms score in patients with COPD.

Measurement of black carbon exposure in urban classrooms during rush hours

Traffic-related air pollutants are predominantly emitted in urban environments; therefore, analyzing their impact on indoor air quality (IAQ) is important. Effectively managing IAQ is vital, given the extensive duration individuals, particularly students, spend indoors. This study conducted a quantitative assessment of black carbon (BC) and indoor and outdoor particulate matter (PM2.5, particles with diameter ≤2.5 μm) concentrations in five South Korean classrooms to determine the root cause and effects of traffic-related air pollutants on indoor environments. The research specifically focused on indoor BC levels during rush hours, that is, periods marked by increased traffic volume. The analysis revealed that the mean indoor and outdoor BC concentrations in the five classrooms were measured at 1.03 (95% CI: 0.69, 1.36) and 1.38 (95% CI: 0.79, 1.96) μg/m3, respectively, while the mean PM2.5 concentrations were measured at 17.07 (95% CI: 12.92, 13.62) and 29.89 (95% CI: 10.88, 48.89) μg/m3, respectively. The indoor-to-outdoor (I/O) ratio of BC in the five classrooms during the occupied period was 0.77 (95% CI: 0.69, 0.84) and 0.62 (95% CI: 0.51, 0.72) for PM2.5. During the unoccupied period, the I/O ratio of BC was 0.68 (95% CI: 0.63, 0.72) and 0.53 (95% CI: 0.42, 0.63) for PM2.5. The rise in urban traffic increased the BC outdoor level by 47% and the PM2.5 concentration by 13%. Classrooms situated closer to roadways had higher BC levels than those located at a greater distance. During rush hours, the BC concentration in the classroom closest to the major road was 2.03 (95% CI: 1.78, 2.27) μg/m3, while the furthest classroom recorded a concentration of 0.88 (95% CI: 0.79, 0.96) μg/m3. During commuting times, classroom BC concentrations increased by up to 5.86 μg/m3 owing to student door-opening activities, increasing the I/O ratio by approximately 20%. Consequently, the average BC concentration in classrooms during rush hours was approximately double that recorded during non-rush hours (0.73 μg/m3). These findings are instrumental in developing strategies to enhance IAQ in educational settings and guiding urban planning decisions regarding the location of schools.

Measuring and modeling of residential black carbon concentrations in two megacities, China

Indoor exposure to black carbon (BC) may differ greatly from ambient concentrations measured at stationary monitoring stations. This study characterized the variation between measured indoor and outdoor levels of BC and developed models to predict BC exposures within residences. Indoor and outdoor PM2.5 filter samples were collected for five consecutive days from 66 residences in Beijing (BJ) and Nanjing (NJ), China, across two seasons. City-specific indoor BC models were developed using liner mixed effect models and assessed by R2 and root mean square error (RMSE). The mean (SD) of indoor BC concentrations in BJ and NJ were 3.0 μg/m3 (0.6 μg/m3) and 3.2 μg/m3 (0.5 μg/m3), respectively. Both the indoor and outdoor BC concentrations were significantly higher during heating season than non-heating season. In general, indoor levels of BC were strongly associated with outdoor measurements (BJ: rs = 0.74, p < 0.001; NJ: rs = 0.76, p < 0.001), but were often lower. The critical determinants influencing indoor BC exposures varied by city, including outdoor BC concentration, window opening time, presence of indoor smoking, and the volume of the room where the indoor monitor was placed. The final models accounted for 66.4%–86.5 % (RMSE: 0.070–0.106) of the variance in residential-indoor BC exposures. By incorporating the key BC exposure determinants identified here, this modelling approach can improve the estimates of BC exposure and better link BC exposure to health risk assessment.

Indoor and ambient black carbon and fine particulate matter associations with blood biomarkers in COPD patients

BackgroundSystemic inflammation contributes to cardiovascular risk and chronic obstructive pulmonary disease (COPD) pathophysiology. Associations between systemic inflammation and exposure to ambient fine particulate matter (PM ≤ 2.5 μm diameter; PM2.5), and black carbon (BC), a PM2.5 component attributable to traffic and other sources of combustion, infiltrating indoors are not well described. MethodsBetween 2012 and 2017, COPD patients completed in-home air sampling over one-week intervals, up to four times (seasonally), followed by measurement of plasma biomarkers of systemic inflammation, C-reactive protein (CRP) and interleukin-6 (IL-6), and endothelial activation, soluble vascular adhesion molecule-1 (sVCAM-1). Ambient PM2.5, BC and sulfur were measured at a central site. The ratio of indoor/ambient sulfur in PM2.5, a surrogate for fine particle infiltration, was used to estimate indoor BC and PM2.5 of ambient origin. Linear mixed effects regression with a random intercept for each participant was used to assess associations between indoor and indoor of ambient origin PM2.5 and BC with each biomarker. Results144 participants resulting in 482 observations were included in the analysis. There were significant positive associations between indoor BC and indoor BC of ambient origin with CRP [%-increase per interquartile range (IQR);95 % CI (13.2 %;5.2–21.8 and 11.4 %;1.7–22.1, respectively)]. Associations with indoor PM2.5 and indoor PM2.5 of ambient origin were weaker. There were no associations with IL-6 or sVCAM-1. ConclusionsIn homes of patients with COPD without major sources of combustion, indoor BC is mainly attributable to the infiltration of ambient sources of combustion indoors. Indoor BC of ambient origin is associated with increases in systemic inflammation in patients with COPD, even when staying indoors.

Indoor (residential) and ambient particulate matter associations with urinary oxidative stress biomarkers in a COPD cohort

ObjectivesOxidative stress contributes to chronic obstructive pulmonary disease (COPD) pathophysiology. Associations between indoor (residential) exposure to particulate matter ≤2.5 μm in diameter (PM2.5) and one of its components, black carbon (BC), and oxidative stress are ill-defined. MethodsBetween 2012 and 2017, 140 patients with COPD completed in-home air sampling over one week intervals, followed by collection of urine samples to measure oxidative stress biomarkers, malondialdehyde (MDA), a marker of lipid peroxidation, and 8-hydroxy-2′ -deoxyguanosine (8-OHdG), a marker of oxidative DNA damage. Ambient (central site) BC and PM2.5 were measured, and the ratio of indoor/ambient sulfur in PM2.5, a surrogate for residential ventilation and particle infiltration, was used to estimate indoor BC and PM2.5 of outdoor origin. Mixed effects linear regression models with a participant-specific random intercept were used to assess associations with oxidative biomarkers, adjusting for personal characteristics. ResultsThere were positive associations (% increase per IQR; 95 % CI) of directly measured indoor BC with total MDA (6.96; 1.54, 12.69) and 8-OHdG (4.18; −0.67, 9.27), and similar associations with both indoor BC of outdoor origin and ambient BC. There were no associations with directly measured indoor PM2.5, but there were positive associations between indoor PM2.5 of outdoor origin and total MDA (5.40; −0.91, 12.11) and 8-OHdG (8.02; 2.14, 14.25). ConclusionsIn homes with few indoor combustion sources, directly measured indoor BC, estimates of indoor BC and PM2.5 of outdoor origin, and ambient BC, were positively associated with urinary biomarkers of oxidative stress. This suggests that the infiltration of particulate matter from outdoor sources, attributable to traffic and other sources of combustion, promotes oxidative stress in COPD patients.

Black carbon emissions in the rural Indian households: Sources, exposure, and associated threats

In this study, we present the indoor Black Carbon (BC) measurements with the help of Aethalometer (AE‐33) from various sites in Eastern India in a typical kitchen room situated in a rural area. Analysis was done on how various cooking activities performed in the home affected the indoor level of BC. The activities resulting in elevated indoor concentrations included three different periods of cooking breakfast, lunch, and dinner with three different kinds of kitchen structures open, semi‐open and closed kitchen. Close kitchen resulted in the highest BC concentrations, while open kitchen resulted in the lowest level. The burning of low‐grade fuels resulted in the largest increases in indoor BC concentration. We calculated the average BC concentrations for three distinct kitchens, with open kitchens emitting 260.14 μgm−3, semi‐open kitchens emitting 441.14 μgm−3, and closed kitchens emitting 477.25 μgm−3. The biomass burning % was high during the entire research. Because BC mass concentration was found to be high in indoor sampling, as a result, the health risk assessment is also considered to be high in all types of kitchens. As people spend a significant amount of time at home, especially in a future where remote work is anticipated to be easier, finding the activities, sources, and health effects that increase indoor pollution is vital to lowering indoor exposure.

Black Carbon and PM2.5 impact analysis in an urban school

Poor outdoor air quality increases air pollutants indoors. Indoor and outdoor air pollutants adversely affect human health, especially in children, who are particularly vulnerable. In this study, indoor and outdoor BC (Black Carbon) and PM2.5 were measured in an elementary school classroom located in an urban city in South Korea. Indoor and outdoor concentrations (BC and PM2.5) were monitored for 7 days (140 hours) during the winter of December 2021. In addition, the classroom schedule was surveyed to identify the occupancy conditions. The reason for air pollution in the urban school was traffic. Classroom BC and PM2.5 concentrations were affected by outdoor and indoor factors. The primary outdoor factor was infiltration, and the impact was larger for BC than for PM2.5. The primary indoor factor was occupant behavior and the impact was more significant for PM2.5 than for BC.

Modification of associations between indoor particulate matter and systemic inflammation in individuals with COPD

RationaleLittle is known about personal characteristics and systemic responses to particulate pollution in patients with COPD. ObjectivesAssess whether diabetes, obesity, statins and non-steroidal anti-inflammatory medications (NSAIDs) modify associations between indoor black carbon (BC) and fine particulate matter ≤2.5 μm in diameter (PM2.5) on systemic inflammation and endothelial activation. Methods144 individuals with COPD without current smoking and without major in-home combustion sources were recruited at Veterans Affairs Boston Healthcare System. PM2.5 and BC were measured in each participant's home seasonally for a week (up to 4 times; 482 observations) and plasma biomarkers of systemic inflammation [C-reactive protein (CRP); interleukin-6 (IL-6)] and endothelial activation [soluble vascular adhesion molecule-1 (sVCAM-1)] measured. Linear mixed effects regression with a random intercept was used, and effect modification assessed with multiplicative interaction terms and stratum specific estimates. ResultsMedian (25%ile, 75%ile) indoor BC and PM2.5 were 0.6 (0.5,0.7) μg/m3 and 6.8 (4.8,10.4) μg/m3, respectively. Although p-values for effect modification were not statistically significant, there were positive associations (%-increase/interquartile range; 95% CI) between CRP and BC greater among non-statin (18.4%; 3.14–36.0) than statin users (10.8%; 1.9–20.4). There were also positive associations greater among non-statin users between PM2.5 and CRP. For IL-6, associations with BC and PM2.5 were also greater among non-statin users. Associations between CRP and BC were greater (17.7%; 4.1–33.0) in persons with diabetes than without diabetes (10.0%; 0.43–20.4) with similar effects of PM2.5. There were no consistent associations that differed based on obesity. Effect modification was not observed for NSAID use, or with any factor considered with sVCAM-1. ConclusionsAssociations between indoor BC and PM2.5 and CRP were greater in patients with diabetes and those not taking statins, and with IL-6 if not taking statins. These results suggest that these characteristics may modify the systemic response to indoor BC and PM2.5 in persons with COPD.

Daily personal exposure to black carbon in different microenvironments in Hanoi, Vietnam

Daily personal exposure to black carbon (BC) in different microenvironments in Hanoi, Vietnam was quantified for the first time. In this study, a portable instrument, microAethe® model AE51, was used to continuously measure BC concentrations in various microenvironments within buildings and transportation modes. Overall average daily personal exposure to BC from those microenvironments was 5.46 µg/h. The highest BC exposure was during commuting 13.48 µg/h and 5.74 µg/h for the motorcyclist and car driver, respectively. In building environments, the highest BC exposure was 3.98 µg/h in a coffee shop with smoking; the lowest BC exposure was 1.54 µg/h in a hospital department; while BC exposure in an office was 1.92 µg/h. The level of BC exposure in an apartment was strongly influenced by building ventilation modes. They were 3.58 µg/h and 2.15 µg/h with doors/windows open and closed, respectively. Our finding confirmed that commuting contributes disproportionately to the total BC exposure due to the high level of BC during traffic/travel. Building ventilation and air conditioning can significantly affect indoor BC levels and should be considered as a measure to reduce BC exposure within buildings in Hanoi.

Determinants of indoor carbonaceous aerosols in homes in the Northeast United States.

Little is known about sources of residential exposure to carbonaceous aerosols, which include black carbon (BC), the elemental carbon core of combustion particles, and organic compounds from biomass combustion (delta carbon). Assess the impact of residential characteristics on indoor BC and delta carbon when known sources of combustion (e.g., smoking) are minimized. Between November 2012-December 2014, 125 subjects (129 homes) in Northeast USA were recruited and completed a residential characteristics questionnaire. Every 3months, participants received an automated sampler to measure fine particulate matter (PM2.5) in their home during a weeklong period (N = 371 indoor air samples) and were also questioned about indoor exposures. The samples were analyzed using a transmissometer at 880 nm (reflecting BC) and at 370 nm. The difference between the two wavelengths estimates delta carbon. Outdoor BC and delta carbon were measured using a central site aethalometer. Geometric mean indoor concentrations of BC and delta carbon (0.65 µg/m³ and 0.19 µg/m³, respectively), were greater than central site concentrations (0.53 µg/m³ and 0.02 µg/m³, respectively). Multivariable analysis showed that greater indoor concentrations of BC were associated with infrequent candle use, multi-family homes, winter season, lack of air conditioning, and central site BC. For delta carbon, greater indoor concentrations were associated with apartments, spring season, and central site concentrations. In addition to outdoor central site concentrations, factors related to the type of housing, season, and home exposures are associated with indoor exposure to carbonaceous aerosols. Recognition of these characteristics should enable greater understanding of indoor exposures and their sources.

Impact of daily household activities on indoor PM2.5 and Black Carbon concentrations in Malta

In this study we present the outdoor and indoor particulate matter (PM) and Black Carbon (BC) measurements in a typical terraced house, located in an urban area in the island of Malta. The influence of different household activities on the indoor PM2.5 and BC levels were also analysed. The activities resulting in elevated indoor concentrations included sweeping, cooking (not grilling and frying), grilling and frying and burning of candle and incense sticks. Sweeping resulted in the highest PM2.5 concentration (283.14 μg m−3) while frying resulted in the lowest level (104.14 μg m−3). Burning of paraffin wax candles resulted in the largest increases in indoor BC concentration (62.2 μg m−3) while the lowest peaks corresponded to cooking and frying. We estimated average PM2.5 and BC emission rates for each indoor activity reaching 22.19 μg s−1 during sweeping and 2.46 μg s−1 during burning of paraffin candles and incense sticks and were sensitive to different ventilation rates. Given that people spend substantial time in the home environment, especially with a future where remote work is likely to be further facilitated, identifying the activities and sources which lead to elevated indoor pollutants is crucial to limit indoor exposure.

Exposure to fine, ultrafine particles and black carbon in two preschools in nur-sultan city of kazakhstan.

Children in preschools were studied as an exceptionally vulnerable group to lung diseases due to their immature immune system. Few data are available in the literature addressing the exposure of children in preschools to ultrafine (>10nm) particles. Exposure of children to fine, ultrafine (10nm-1µm) particles and black carbon particles present inside and near two preschools in Nur-Sultan, Kazakhstan, during Fall 2019 was investigated. For Preschool I, the average daily (6h) indoor (outdoor) PM1 , PM2.5 , and PM10 concentrations over three-week measurements were 15.0 (SD 12.5)µg/m3 , 34.6 (SD 35.1)µg/m3 , and 47.2 (SD 45.2)µg/m3 , respectively. Average indoor UFP concentrations (>10.0nm) including candle burning events were 5.20×103 (SD 8.80×103 )particles/cm3 , with the background UFP concentration to be 3.30×103 (SD 1.80×103 )particles/cm3 . In Preschool II, the average UFP concentration (>30.0nm) in the morning and afternoon was 3.94×103 (SD 5.34×102 ) and 3.36×103 (SD 1.90×103 )particles/cm3 , respectively. Indoor black carbon (BC) concentrations were correlated with the outdoor smoking activity. The major sources of the indoor particles in the preschools were dust resuspension, candle burning, and infiltrated outdoor particles.

Indoor black carbon and brown carbon concentrations from cooking and outdoor penetration: insights from the HOMEChem study.

Particle emissions from cooking are a major contributor to residential indoor air pollution and could also contribute to ambient concentrations. An important constituent of these emissions is light-absorbing carbon, including black carbon (BC) and brown carbon (BrC). This work characterizes the contributions of indoor and outdoor sources of BC and BrC to the indoor environment by concurrently measuring real-time concentrations of these air pollutants indoors and outdoors during the month-long HOMEChem study. The median indoor-to-outdoor ratios of BC and BrC during the periods of no activity inside the test house were 0.6 and 0.7, respectively. The absorption Ångström exponent was used to characterize light-absorbing particle emissions during different activities and ranged from 1.1 to 2.7 throughout the campaign, with the highest value (indicative of BrC-dominated emissions) observed during the preparation of a simulated Thanksgiving Day holiday style meal. An indoor BC exposure assessment shows that exposure for an occupant present in the kitchen area was ∼4 times higher during Thanksgiving Day experiments (primarily due to candle burning) when compared to the background conditions.

Comparison of measured residential black carbon levels outdoors and indoors with fixed-site monitoring data and with dispersion modelling

Epidemiologic studies on health effects of air pollution usually rely on time-series of ambient monitoring data or on spatially modelled levels. Little is known how well these estimate residential outdoor and indoor levels. We investigated the agreement of measured residential black carbon (BC) levels outdoors and indoors with fixed-site monitoring data and with levels calculated using a Gaussian dispersion model. One-week residential outdoor and indoor BC measurements were conducted for 15 families living in central Stockholm. Time-series from urban background and street-level monitors were compared to these measurements. The observed weekly concentrations were also standardized to reflect annual averages, using urban background levels, and compared spatially to long-term levels as estimated by dispersion modelling. Weekly average outdoor BC level was 472 ng/m3 (range 261–797 ng/m3). The corresponding fixed-site urban background and street levels were 313 and 1039 ng/m3, respectively. Urban background variation explained 50% of the temporal variation in residential outdoor levels averaged over 24 h. Modelled residential long-term outdoor levels were on average comparable with the standardized measured home outdoor levels, and explained 49% of the spatial variability. The median indoor/outdoor ratio across all addresses was 0.79, with no difference between day and night time. Common exposure estimation approaches in the epidemiology of health effects related to BC displayed high validity for residencies in central Stockholm. Urban background monitored levels explained half of the outdoor day-to-day variability at residential addresses. Long-term dispersion modelling explained half of the spatial differences in outdoor levels. Indoor BC concentrations tended to be somewhat lower than outdoor levels.

Indoor PM2.5 Alpha-Radioactivity is Associated with Biomarkers of Oxidative Stress in COPD Patients

Introduction: Radon decays into progeny that attach to indoor air pollution particles and form unattached clusters. After inhalation, we hypothesize that these serve as vectors for radioisotopes that emit radiation (including α-radioactivity) that promote oxidative damage in patients with COPD.Methods: We recruited 140 patients (97% men, mean (SD) age 72.8 (8.3)) with COPD at VA Boston 5/2013-3/2017 who ran a micro-environmental PM2.5 sampler in their home for 1 week up to 4 times a year (n=414 samples). Samples were analyzed for PM2.5 and black carbon (BC). In 2019, α-radioactivity was measured on each PM2.filter. Since 210Pb (t½=22 years), a Rn progeny, is a parent of 210Po (t½=138 days, α-radiation emitter), α-radioactivity reflects formation of 210Po from 210Pb. Based on the 210Pb decay constant and sampled air volume, α-radioactivity during sampling was estimated. Urinary concentrations of oxidative stress biomarkers, 8-hydroxy-2’-deoxyguanosine (8-OHdG) and malondialdehyde (MDA) were assessed. Mixed effects models with a random intercept for each subject were used to examine associations adjusting for age, race, season, urine collection time, BMI, creatinine, diabetes, heart disease, ambient temperature, humidity, and indoor BC and PM2.5.Results: Median (IQR) PM2.5 α-radioactivity=1.5 (0.64) mBq/m3 (equivalent to 0.056 (0.024) pCi/L); PM2.5=6.9 (5.7) µg/ m3; BC=0.58 (0.27) µg/m3. There was a positive association between natural log (α-radioactivity) and 8-OHdG [5.2% increase (95% CI: 0.9-9.7%) per IQR] and MDA [2.0% increase (95% CI: -2.6-6.8%) per IQR]. Results for 8-OHdG were similar adjusting for PM2.5 (5.4%; 95% CI: 1.1-10.0%) and BC (4.6%; 95% CI: 0.1-9.2%). Results for MDA were similar adjusting for PM2.5 (1.9%; 95% CI: -2.8-6.8%) and were reduced adjusting for BC [0.5%; 95% CI: -4.2-5.4%).Conclusions: Indoor PM2.5 α-radioactivity reflecting 210Pb was positively associated with increased DNA oxidation (8-OHdG) and lipid peroxidation (MDA) in participants with COPD.Funding: ES029637, ES019853, USEPA grant RD-835872

Carcinogenic effects of indoor black carbon and particulate matters (PM2.5 and PM10) in rural households of India

Biomass is one of the prime domestic energy sources in the kitchens and about 60% of households are still using biomass and kerosene for cookingin India. These traditional cooking practices are incompetent as the use of biomass in traditional cookstove produces an enormous amount of carbonaceous aerosols that lead to indoor and outdoor air pollution. Emissions of various pollutants like black carbon (BC), PM10 and PM2.5 from burning of biomass cause serious health impacts like respiratory illness, lung cancer, watering of eyes, coughing, asthma and heart problems especially in women due to higher rate of inhalation of these fine particulate matters during the cooking period. Quantification of BC, PM2.5 and PM10 emissions from a different type of biomass in various types of kitchen arrangements and its associated impacts are poorly examined in India. Hence, daily concentrations of BC, PM2.5 and PM10 were monitored from different types of biomass user's households during January 2018 to December 2019 to assess indoor air quality by using aethalometer and nephelometer (pDR-1500) in three districts (Sitapur, Patna and Murshidabad) of Indo-Gangetic Plains (IGP) where approximately, 96% of rural families rely on biomass cooking. The highest mass concentrations were observed in biomass user's households and cow-dung cake users due to low calorific value. About 30.13% of PM10 and 35.89% of PM2.5 data exceeded the national ambient air quality standard on a daily basis in biomass user's households. A cancer risk assessment was also conducted in terms of mass concentration of these pollutants. The lifespan danger from exposure to BC was 4.33 × 10-7 in indoor for non-ventilated kitchens, 2.63 × 10-7 in indoor for ventilated kitchens, 3.98 × 10-7 in outdoor for separated kitchen, 3.22 × 10-7 for semi-open kitchen and 1.78 × 10-7 for open kitchen. The vulnerability assessment for cancer mortality under exposure of pollution was estimated to be highest for the age group of more than 50years whereas lowest for the age group of 0-4years for all kinds of kitchens in the study area.

The association between short-term residential black carbon concentration on blood pressure in a general population sample.

Exposure to black carbon indoors may be associated with blood pressure; however, evidence is limited to vulnerable subpopulations and highly exposed individuals. Our objective was to explore the relationship between indoor black carbon at various exposure windows on resting blood pressure in a general population sample. Black carbon was measured in the home of 76 individuals aged 10-71 in New Orleans, Louisiana. Exposure was measured every 1minute for up to 120hours using an AE51 microaethalometer. Systolic blood pressure and diastolic blood pressure were measured at the conclusion of exposure monitoring. In adjusted models, at all exposure windows, increasing black carbon was associated with increased systolic blood pressure. The period 0-72hours prior to blood pressure measurement showed the strongest effect; a 1μg/m3 increase in black carbon was associated with a 7.55mmHg (P=.02) increase in systolic blood pressure. The relationship was stronger in participants reporting doctor-diagnosed hypertension (β=6.47 vs β=3.27). Black carbon was not associated with diastolic blood pressure. Increasing black carbon concentration indoors is positively associated with increasing systolic blood pressure with the most relevant exposure window being 0-72hours prior to blood pressure measurement. Individuals with hypertension may be a more susceptible population.

Effects of particulate matter gamma radiation on oxidative stress biomarkers in COPD patients.

Inhalation of particulate matter (PM) radioactivity is an important pathway of ionizing radiation exposure. We investigated the associations between short-term exposures to PM gamma radioactivity with oxidative stress in COPD patients. Urinary concentrations of 8-hydroxy-2'-deoxyguanosine (8-OHdG) and malondialdehyde (MDA) of 81 COPD patients from Eastern Massachusetts were measured 1-4 times during 2012-2014. Daily ambient and indoor PM gamma activities (gamma-3 through gamma-9) were calculated based on EPA RadNet data and indoor-outdoor infiltration ratios. Linear mixed-effects models were used to examine the associations between biomarkers with PM gamma activities for moving averages from urine collection day to 7 days before. Our results indicate that ambient and indoor PM gamma activities were positively associated with 8-OHdG, with stronger effects for exposure windows closer to urine collection day. For per interquartile range increase in indoor PM gamma activities averaged over urine collection day and 1 day before, 8-OHdG increased from 3.41% (95% CI: -0.88, 7.88) to 8.87% (95% CI: 2.98, 15.1), adjusted for indoor black carbon. For MDA, the timing of greatest effects across the exposure week varied but was nearly all positive. These findings provide insight into the toxigenic properties associated with PM radioactivity and suggest that these exposures promote systemic oxidative stress.

Variations and characteristics of particulate matter, black carbon and volatile organic compounds in primary school classrooms

Abstract The effect of human activities on the characteristics and variations of indoor air pollutants is poorly understood, in particular for the classroom environment due to the limited reports at present. In this study, an observational campaign (17 days) was carried out in two selected classrooms (one equipped with air purifier) in a primary school of Hangzhou, China. Highly time-resolved particulate matter (PM) and black carbon (BC) were measured using Aerodynamic Particle Sizer (APS) and Aethalometer, and the diurnal variations of PM2.5, PM10, PM20 and BC were characterized in detail. It was found that the student activities occurred throughout the daytime and could result in rapid changes in air pollutants. For example, the daytime student activities (e.g., chasing and running) strongly enhanced the PM level and changed PM diurnal pattern, in particular for coarse particles (2.5–10 μm) with short-term spikes at intervals, which was not observed under vacant conditions. The indoor BC did not show clear diurnal patterns, regardless of working days and weekends. Through absorption exponent analysis, it was inferred that the source of indoor BC was stable at most of the time, and possibly related to traffic emission. Besides, three volatile organic compounds (VOCs) samples were collected from the two classrooms, and the laboratory analysis results showed that oxygenated VOCs was a major contributor to indoor VOCs. Through inter-comparison analysis of indoor and outdoor samples, it was further found that the VOC profile of classrooms has a similar pattern with outdoor environments. Finally, the most abundant VOC species of classroom environment were identified, and their potential sources were estimated.