Outdoor Particulate Matter Concentrations Research Articles

Effects of atmospheric particulate pollution on lung function of athletes

There is a knowledge gap on how ground-level particulate pollution affects labor productivity in emerging nations due to a lack of study, especially when it comes to outdoor work settings like couriers in the express delivery industry. Combining findings from two research projects, this paper examines the socioeconomic consequences of particulate matter and ground-level particulate pollution. Special panel dataset from China's express delivery companies are used, we study how particulate pollution affects courier productivity. The instrumental variable of our analysis was built by particulate pollution data from upwind towns. Moreover, a comparable rise in particulate levels during the 30 days caused a significant 23.7% decline in worker productivity. This draws attention to a neglected area of the economic effects of particulate pollution, especially in underdeveloped countries. Our results also highlight the wider health hazards connected to outdoor activities in high-pollution locations, drawing comparisons on outdoor exercisers and particulate matter concentrations. The critical need for coordinated policy attention addressing both ground-level Particulate and particle matters in developing nations is highlighted by the increased risk of lung function impairment among outdoor exercisers owing to excessive particulate matter concentrations. The interrelated risks that air pollution poses to public health and economic productivity are clarified by this Comprehensive viewpoint.

Outdoor Health Risk of Atmospheric Particulate Matter at Night in Xi'an, Northwestern China.

The deterioration of air quality via anthropogenic activities during the night period has been deemed a serious concern among the scientific community. Thereby, we explored the outdoor particulate matter (PM) concentration and the contributions from various sources during the day and night in winter and spring 2021 in a megacity, northwestern China. The results revealed that the changes in chemical compositions of PM and sources (motor vehicles, industrial emissions, coal combustion) at night lead to substantial PM toxicity, oxidative potential (OP), and OP/PM per unit mass, indicating high oxidative toxicity and exposure risk at nighttime. Furthermore, higher environmentally persistent free radical (EPFR) concentration and its significant correlation with OP were observed, suggesting that EPFRs cause reactive oxygen species (ROS) formation. Moreover, the noncarcinogenic and carcinogenic risks were systematically explained and spatialized to children and adults, highlighting intensified hotspots to epidemiological researchers. This better understanding of day-night-based PM formation pathways and their hazardous impact will assist to guide measures to diminish the toxicity of PM and reduce the disease led by air pollution.

Energy-focused predictive control for particulate matter concentration and thermal comfort indoors in Delhi

This paper presents a novel, model-based approach for energy-focused indoor particulate matter (PM) concentration control and indoor temperature management for a residential house. A physics-based model is developed to predict PM concentration and temperature indoors as a function of outdoor PM concentration, outdoor temperature, indoor emission, indoor heat generation, and flow rates of air handling unit (AHU), portable air filter (PAF), and air conditioning (AC) systems. The optimized settings of the ventilation systems AHU, PAF, and AC are determined employing a nonlinear model predictive control (MPC) algorithm. A case study in Delhi, one of the most polluted cities in the world, is conducted. Extensive simulation studies under seasonal changes in outdoor conditions and varying indoor emissions demonstrate the ability of the MPC controller to maintain PM concentration and temperature indoors within or close to the desired levels, while optimizing energy consumption.

The Representativeness of Outdoor Particulate Matter Concentrations for Estimating Personal Dose and Health Risk Assessment of School Children in Lisbon.

This study investigated the suitability of outdoor particulate matter data obtained from a fixed monitoring station in estimating the personal deposited dose. Outdoor data were retrieved from a station located within the urban area of Lisbon and simulations were performed involving school children. Two scenarios were applied: one where only outdoor data were used assuming an outdoor exposure scenario, and a second one where an actual exposure scenario was adopted using the actual microenvironment during typical school days. Personal PM10 and PM2.5 dose (actual exposure scenario) was 23.4% and 20.2% higher than the ambient (outdoor exposure scenario) PM10 and PM2.5 doses, respectively. The incorporation of the hygroscopic growth in the calculations increased the ambient dose of PM10 and PM2.5 by 8.8% and 21.7%, respectively. Regression analysis between the ambient and personal dose showed no linearity with R2 at 0.07 for PM10 and 0.22 for PM2.5. On the other hand, linear regression between the ambient and school indoor dose showed no linearity (R2 = 0.01) for PM10 but moderate (R2 = 0.48) for PM2.5. These results demonstrate that ambient data must be used with caution for the representativeness of a realistic personal dose of PM2.5 while for PM10 the ambient data cannot be used as a surrogate of a realistic personal dose of school children.

Development of air purifier operation guidelines using grey box models for the concentrations of particulate matter in elementary school classrooms.

Considering the hazardous effects of particulate matter (PM) exposure on students and teachers and the high PM concentration issue in South Korea, air purifiers have recently been installed in most classrooms to improve air quality. However, some on-site challenges, such as operational costs and noise, have been issues with the continuous operation of air purifiers. Therefore, a guideline is needed to dynamically predict the indoor PM concentration based on the changes in outdoor PM concentration and activate the air purifiers only when necessary. This study develops a grey-box model that uses measured data and physical differential equations to perform the given objective and verifies its accuracy using ASTM D5157. Modeling and analysis results have obtained information that can form the basis for developing guidelines to address PM issues in schools: The air purifier should be operated during periods where the predicted values exceed the limit in closed windows and the air purifier is not operating. It was also confirmed that the need for the operation of the air purifier varies between schools and classrooms under the same outdoor PM concentration. Indoor PM concentration increased significantly after students' simultaneous mass movement, necessitating air purifiers' operation before and after the events. The prefilter of the heater also aided in the removal of coarse PM. Additionally, the limitations and future development directions of the model were discussed.

Estimating the mortality attributable to indoor exposure to particulate matter of outdoor origin in mainland China

Previous estimations on the premature deaths attributable to indoor ambient particulate matter (PM) with aerodynamic diameter < 2.5 μm (PM2.5) of outdoor origin only considered the indoor PM2.5 concentration, which always neglected the impact from the distribution of particle size and the PM deposition in human airways. To tackle this issue, we first calculated the premature deaths due to PM2.5 was approximately 1,163,864 persons in mainland China in 2018 by using the global disease burden approach. Then, we specified the infiltration factor of PM with aerodynamic diameter < 1 μm (PM1) and PM2.5 to estimate the indoor PM pollution. Results showed that average concentrations of indoor PM1 and PM2.5 of outdoor origin were 14.1 ± 3.9 μg/m3 and 17.4 ± 5.4 μg/m3, respectively. The indoor PM1/PM2.5 ratio of outdoor origin was estimated to be 0.83 ± 0.18, which was 36 % higher than the ambient PM1/PM2.5 ratio (0.61 ± 0.13). Furthermore, we calculated the premature deaths from the indoor exposure of outdoor origin was approximately 734,696, accounting for approximately 63.1 % of total deaths. Our results are 12 % higher than previous estimations neglecting the impact from the distribution disparities of PM between indoor and outdoor. Regarding the cause-specific diseases, indoor PM2.5 exposure of outdoor origin accounted for 293,379 deaths to ischemic heart disease, followed by 158,238 deaths to chronic obstructive pulmonary disease, 134,390 deaths to stroke, 84,346 cases to lung cancer, 52,628 deaths to lower respiratory tract infection, and 11,715 deaths to type 2 diabetes. In addition, we for the first time estimated the indoor PM1 of outdoor origin has led to approximately 537,717 premature deaths in mainland China. Our results have well demonstrated the health impact may be approximately 10 % higher when considering the effects from infiltration and respiratory tract uptake and physical activity levels, comparing to the treatment that only used outdoor PM concentration.

Impacts of PM on Indoor Air Quality of Airport Terminal Buildings in a Core City of North China Plain

With the economic growth and globalization, a great deal of airports are being or planned to be constructed or retrofitted in China. The air quality in airport terminal buildings has not been studied as in-depth as airport ambient air quality. Due to its unique architectural and operational characteristics, the airport terminal buildings have individual performance of indoor air quality. The contribution of outdoor particulate matter (PM) to indoor environment and passengers’ exposure to indoor PM is not well understood. The indoor (i.e., terminal buildings) and outdoor PM concentrations with particle sizes from 0.25 to 32 μm of Tianjin Binhai International Airport (IATA: TSN) were monitored continuously during two cases in winter and summer 2020. Higher indoor PM concentrations occurred in winter as well as in the arrival halls of TSN. During winter case, the indoor sources contributed more to the indoor environment than the outdoor sources, whereas the opposite was found during summer case. Sharp variation of indoor PM number concentrations existed in particles within the range of 0.25–0.40 μm in size, with a peak number concentration at particle size of about 0.30 μm. PM with smaller particle sizes were more likely to enter the indoor environment from outdoor. The comprehensive exposure in the TSN terminal buildings was higher than those in the transportation microenvironments, residences and other buildings. Significant diurnal variations of Respiratory deposition dose (RDD) were observed under various exposure durations. Our results highlight the need for further monitoring and improving the air quality in the terminal buildings.

Air pollution with NO2, PM2.5, and elemental carbon in relation to risk of breast cancer– a nationwide case-control study from Denmark

Air pollution with particulate matter is an established lung carcinogen. Studies have suggested an association with breast cancer, but the evidence is inconsistent. MethodsFrom nationwide registers, we identified all breast cancer cases (n = 55 745) in Denmark between 2000 and 2014. We matched one control for each case on age and year of birth. We used a multi-scale dispersion model to estimate outdoor concentrations of particulate matter <2.5 μm (PM2.5), elemental carbon (EC) and nitrogen dioxide (NO2) as time-weighted average over all addresses up to 20 years prior to diagnosis. We calculated odds ratios (OR) and 95% confidence intervals (CI) by conditional logistic regression with adjustment for marital status, educational level, occupational status, personal income, region of origin, medication and area-level socio-economic indicators. ResultsA 10 μg/m3 higher PM2.5 was associated with an OR for breast cancer of 1.21 (95% CI: 1.11–1.33). The corresponding ORs for EC (per 1 μg/m3) and NO2 (per 10 μg/m3) were 1.03 (95% CI: 1.00–1.07) and 1.03 (95% CI: 1.01–1.06), respectively. In multi–pollutant models, the OR for PM2.5 changed only little, whereas ORs for EC or NO2 approached the null. In an analysis of persons below 55 years, PM2.5 was associated with an OR of 1.32 (95% CI: 1.09–1.60) per 10 μg/m3 increase. ConclusionWe found evidence of an association between the investigated air pollutants and breast cancer, especially PM2.5. There were indications that the association differed by age at diagnosis. We were not able to include all potential confounders and thus, results should be interpreted with caution.

Properties of Particulate Matter in the Air of the Wieliczka Salt Mine and Related Health Benefits for Tourists.

This study aimed to evaluate the mass concentration of size-resolved (PM1, PM2.5, PM4, PM10, PM100) particulate matter (PM) in the Wieliczka Salt Mine located in southern Poland, compare them with the concentrations of the same PM fractions in the atmospheric air, and estimate the dose of dry salt aerosol inhaled by the mine visitors. Measurements were conducted for 2 h a day, simultaneously inside (tourist route, passage to the health resort, health resort) and outside the mine (duty-room), for three days in the summer of 2017 using DustTrak DRX devices (optical method). The highest average PM concentrations were recorded on the tourist route (54–81 µg/m3), while the lowest was in the passage to the health resort (49–62 µg/m3). At the same time, the mean outdoor PM concentrations were 14–20 µg/m3. Fine particles constituting the majority of PM mass (68–80%) in the mine originated from internal sources, while the presence of coarse particles was associated with tourist traffic. High PM deposition factors in the respiratory tract of children and adults estimated for particular mine chambers (0.58–0.70), the predominance of respirable particles in PM mass, and the high content of NaCl in PM composition indicate high health benefits for mine visitors.

Vertical distribution characteristics of outdoor particulate matter concentration in high-rise buildings during working days and non-working days

With the acceleration urbanization in China, it is great significance to understand the distribution characteristics of outdoor particulate matter concentration in high-rise buildings during working days and non-working days. In this paper, a high-rise building of different heights (1, 7, 11, 17, 23, 27) in a university in Xi'an is tested and analyzed. The test times are 8:00, 14:00 and 21:00 respectively. The results showed that the change trend of the particulate matter concentration with the increase of vertical height is the same at all times of the non-working day. While the change trend of particulate matter concentration with the increase of vertical height is basically the same at other times except 8:00 on the working day. In addition, the concentration of particulate matter on working days increased significantly compared to non-working days, with the largest increase at 14:00. On non-working days, PM1.0/PM10 and PM2.5/PM10 both showed a trend of first increasing, then decreasing, and then increasing in different time periods. On weekdays, PM1.0/PM10 and PM2.5/PM10 all showed a trend of falling first and then rising in different time periods. This article provides a reference for the development of high-rise buildings and the effective control of particulate matter concentration in high-rise buildings.

Behavioral interventions to reduce particulate matter exposure in patients with COPD.

Introduction:Chronic obstructive pulmonary disease (COPD) is commonly affected by particulate matter (PM) exposure. In this study, we aimed to evaluate whether behavioral interventions to reduce PM exposure improve clinical outcomes in patients with COPD.Methods:A multicenter randomized controlled trial will be conducted involving 120 participants recruited from 3 hospitals in the capital region of the Republic of Korea. Patients aged 40 to 80 years with a diagnosis of COPD and a forced expiratory volume at 1 s <80% of the predicted value are eligible for inclusion. The participants will be randomized to either the intervention group or the usual care group (2:1). The behavioral interventions will comprise the following activities: checking air quality forecast; operating indoor air cleaners and regular check-ups of filters; ventilating the home regularly by opening windows; adhering to inhaler treatment; and refraining from going out on high air pollution days. “Internet-of-things”-based, gravimetric, and light-scattering methods will be used to measure indoor and outdoor PM concentrations. To estimate the degree of individual PM exposure, a time-activity diary and land use regression modeling will be used. The efficacy of the behavioral interventions on the following outcomes will be analyzed: amount of PM exposure, changes in forced expiratory volume at 1 s from the baseline, changes in respiratory symptoms and quality of life, risks of exacerbation, hospitalization, and death.Discussion:Given the harmful effect of air pollutants, individual-level interventions to reduce exposure may be significant. However, there is a lack of evidence on how effective such interventions are to date. This study will be able to provide physicians and patients with evidence-based strategies to reduce PM exposure in daily life.Trial registration number:NCT04878367

The influence of outdoor PM2.5 concentration at workplace on nonaccidental mortality estimates in a Canadian census-based cohort.

Associations between mortality and exposure to ambient air pollution are usually explored using concentrations of residential outdoor fine particulate matter (PM2.5) to estimate individual exposure. Such studies all have an important limitation in that they do not capture data on individual mobility throughout the day to areas where concentrations may be substantially different, leading to possible exposure misclassification. We examine the possible role of outdoor PM2.5 concentrations at work for a large population-based mortality cohort. Using the 2001 Canadian Census Health and Environment Cohort (CanCHEC), we created a time-weighted average that incorporates employment hours worked in the past week and outdoor PM2.5 concentration at work and home. We used a Cox proportional hazard model with a 15-year follow-up (2001 to 2016) to explore whether inclusion of workplace estimates had an impact on hazard ratios for mortality for this cohort. Hazard ratios relying on outdoor PM2.5 concentration at home were not significantly different from those using a time-weighted estimate, for the full cohort, nor for those who commute to a regular workplace. When exploring cohort subgroups according to neighborhood type and commute distance, there was a notable but insignificant change in risk of nonaccidental death for those living in car-oriented neighborhoods, and with commutes greater than 10 km. Risk analyses performed with large cohorts in low-pollution environments do not seem to be biased if relying solely on outdoor PM2.5 concentrations at home to estimate exposure.

Assessment of pre-filter systems to control indoor inflow of particulate matter

Ventilation systems are installed to introduce outdoor fresh air into indoor environments in an effort to improve indoor air quality. However, as the concentrations of outdoor particulate matter are increasing, additional measures are required to reduce these concentrations in the incoming outdoor air in ventilation systems. This study used a multi-step process to investigate these issues. First, we determined the current status of indoor fine particulate matter (PM2.5) concentrations based on the filter grade of an installed ventilation system. Second, a pre-filter system with guaranteed filtering performance and usability was installed in the outdoor air duct of a ventilation system to compensate for its shortcomings; then, the reduction of indoor PM2.5 concentration was evaluated. To determine whether the filtering performance of the ventilation system was sufficient, the relationships between the indoor–outdoor PM2.5 concentrations and indoor/outdoor PM2.5 concentration ratio were established based on the World Health Organization standard concentrations. The quality of the pre-filter system was tested by installing it in two separate houses that were using the same ventilation system. The results show that based on the filter grade of the European Standards, a fine filter (F grade) or a filter of a higher grade should be used for conventional ventilation systems. By installing a pre-filter system in the conventional ventilation system, the indoor PM2.5 concentration was reduced by 31% and 69% depending on the maintenance of the ventilation system.

A model for population exposure to PM2.5: Identification of determinants for high population exposure in Seoul

Outdoor concentrations of particulate matter with an aerodynamic diameter of <2.5 μm (PM2.5) are often used as a surrogate for population exposure to PM2.5 in epidemiological studies. However, people spend most of their daily activities indoors; therefore, the relationship between indoor and outdoor PM2.5 concentrations should be considered in the estimation of population exposure to PM2.5. In this study, a population exposure model was developed to predict seasonal population exposure to PM2.5 in Seoul, Korea. The input data for the population exposure model comprised 3984 time-location patterns, outdoor PM2.5 concentrations, and the microenvironment-to-outdoor PM2.5 concentrations in seven microenvironments. A probabilistic approach was used to develop the Korea simulation exposure model. The determinants for the population exposure group were identified using a multinomial logistic regression analysis. Population exposure to PM2.5 varied significantly among the three seasons (p < 0.01). The mean ± standard deviation of population exposures to PM2.5 was 21.3 ± 4.0 μg/m3 in summer, 9.8 ± 2.7 μg/m3 in autumn, and 29.9 ± 10.6 μg/m3 in winter. Exposure to PM2.5 higher than 35 μg/m3 mainly occurred in winter. Gender, age, working hours, and health condition were identified as significant determinants in the exposure groups. An “unhealthy” health condition was the most significant determinant. The high PM2.5 exposure group was characterized as a higher proportion of males of a lower age with longer working hours. The population exposure model for PM2.5 could be used to implement effective interventions and evaluate the effectiveness of control policies to reduce exposure.

Indoor air quality of 5,000 households and its determinants. Part A: Particulate matter (PM2.5 and PM10–2.5) concentrations in the Japan Environment and Children's Study

Exposure to particulate matter (PM) is one of the important risk factors for morbidity and mortality. Although PM concentrations have been assessed using air quality monitoring stations or modelling, few studies have measured indoor PM in large-scale birth cohorts. The Japan Environment and Children's Study (JECS) measured indoor and outdoor air quality in approximately 5000 households when the participating children were aged 1.5 and 3 years. PM was collected using portable pumps for 7 days (total of 24 h), inside and outside each home. Prediction models for indoor PM concentrations were built using data collected at age 1.5 years and post-validated against data collected at age 3 years. Median indoor/outdoor PM2.5 and PM10–2.5 concentrations at age 1.5 years [3 years] were 12.9/12.7 [12.5/11.3] μg/m3 and 5.0/6.3 [5.1/6.1] μg/m3, respectively. Random forest regression analysis found that the major predictors of indoor PM2.5 were indoor PM10–2.5, outdoor PM2.5, indoor smoking, observable smoke and indoor/outdoor temperature. Indoor PM2.5, outdoor PM10–2.5, indoor humidity and opening room windows were important predictors of indoor PM10–2.5 concentrations. Indoor benzene, acetaldehyde, ozone and nitrogen dioxide concentrations were also found to predict indoor PM2.5 and PM10–2.5 concentrations, possibly due to the formation of secondary organic aerosols. These findings demonstrate the importance of reducing outdoor PM concentrations, avoiding indoor smoking, using air cleaner in applicable and diminishing sources of VOCs that could form secondary organic aerosols, and the resulting models can be used to predict indoor PM concentrations for the rest of the JECS cohort.

Using Crowd-Sourced Data to Assess the Temporal and Spatial Relationship between Indoor and Outdoor Particulate Matter.

Using hourly measures across a full year of crowd-sourced data from over 1000 indoor and outdoor pollution monitors in the state of California, we explore the temporal and spatial relationship between outdoor and indoor particulate matter (PM) concentrations for different particle sizes. The scale of this study offers new insight into both average penetration rates and drivers of heterogeneity in the outdoor-indoor relationship. We find that an increase in the daily outdoor PM concentration of 10% leads to an average increase of 4.2-6.1% in indoor concentrations. The penetration of outdoor particles to the indoor environment occurs rapidly and almost entirely within 5 h. We also provide evidence showing that penetration rates are associated with building age and climatic conditions in the vicinity of the monitor. Since people spend a substantial amount of each day indoors, our findings fill a critical knowledge gap and have significant implications for government policies to improve public health through reductions in exposure to ambient air pollution.

Epigenome-wide analysis of long-term air pollution exposure and DNA methylation in monocytes: results from the Multi-Ethnic Study of Atherosclerosis

ABSTRACT Air pollution might affect atherosclerosis through DNA methylation changes in cells crucial to atherosclerosis, such as monocytes. We conducted an epigenome-wide study of DNA methylation in CD14+ monocytes and long-term ambient air pollution exposure in adults participating in the Multi-Ethnic Study of Atherosclerosis (MESA). We also assessed the association between differentially methylated signals and cis-gene expression. Using spatiotemporal models, one-year average concentrations of outdoor fine particulate matter (PM2.5) and oxides of nitrogen (NOX) were estimated at participants’ homes. We assessed DNA methylation and gene expression using Illumina 450k and HumanHT-12 v4 Expression BeadChips, respectively (n = 1,207). We used bump hunting and site-specific approaches to identify differentially methylated signals (false discovery rate of 0.05) and used linear models to assess associations between differentially methylated signals and cis-gene expression. Four differentially methylated regions (DMRs) located on chromosomes 5, 6, 7, and 16 (within or near SDHAP3, ZFP57, HOXA5, and PRM1, respectively) were associated with PM2.5. The DMRs on chromosomes 5 and 6 also associated with NOX. The DMR on chromosome 5 had the smallest p-value for both PM2.5 (p = 1.4×10−6) and NOX (p = 7.7×10−6). Three differentially methylated CpGs were identified for PM2.5, and cg05926640 (near TOMM20) had the smallest p-value (p = 5.6×10−8). NOX significantly associated with cg11756214 within ZNF347 (p = 5.6×10−8). Several differentially methylated signals were also associated with cis-gene expression. The DMR located on chromosome 7 was associated with the expression of HOXA5, HOXA9, and HOXA10. The DMRs located on chromosomes 5 and 16 were associated with expression of MRPL36 and DEXI, respectively. The CpG cg05926640 was associated with expression of ARID4B, IRF2BP2, and TOMM20. We identified differential DNA methylation in monocytes associated with long-term air pollution exposure. Methylation signals associated with gene expression might help explain how air pollution contributes to cardiovascular disease.

Indoor and Outdoor Particulate Matter Concentrations in the Vicinity of Plastic Waste Processing Industries

While plastic recycling has gained conclusive acceptance by various stakeholders as a preferable products’ end-of-life management, plastic waste processing industries may contribute to serious air pollutants emission and impair human health, especially if it is in uncontrolled conditions. Apart from toxic gas pollutants, this industry may also emit significant concentration of particulates matter or dust, notably via physical (shredding, sorting, and washing) and melt (re-granulation and reprocessing) processes. Meanwhile, in Sungai Petani, Kedah, Malaysia, public anguish is increasing in recent years due to mushrooming plastic waste recycling industries in its residential area. Thus, a study was conducted to analyse the day- and night-time ambient air PMio levels and their relationship with selected meteorological parameters (ambient temperature, relative humidity and wind speed) at two different locations (Cinta Sayang Resort Villa, CSRV and Metro Specialist Hospital, HM) in Sungai Petani, Kedah, Malaysia. The mean ambient PMio levels of Cinta Sayang Resort Villa (CSRV) and Metro Specialist Hospital (HM) were found exceeding the New Malaysia Ambient Air Quality Standard at 150 (μg/m3 (24-hours), which were 568.082 + 266.441 (μg/m3 615.046 + 355.672 (μg/m3, respectively. Distribution of PMio concentrations betwen day and night-time were found to be statistically insignificant at both sites. Meteorological parameters have also contributed to the trend of PMio concentrations at both sites especially at HM. Inverse correlation with PMio at CSRV was explained by the absence of moisture (or rain) at the site while the positive correlation observed at HM was due to the hot temperature-strong wind association at the site. Temperature was found to be the manipulating factor for PMio at HM, via linear regression model developed at PMouth = - 4352.426 + 170.557 x Th with F(1, 8) = 15.224 at p < .005, accounting for 65.6% of the variation Thus, proper attention should be given to the particulates matter emitted in Sungai Petani, believed to be influenced by the uncontrolled emission from the plastic recycling industries.

Comparative Analysis of Indoor and Outdoor Particulate Matter Concentrations and Air Quality in Ogbomoso, Nigeria

Background.Airborne particulates are an issue in many urban regions around the world and their detrimental impact on human health has increasingly become a public health concern.Objectives.The aim of the present study was to examine particle pollution in an urban settlement in Nigeria. This study examines the extent, spatial variation, and sources of indoor and outdoor particulate matter (PM) concentrations in Ogbomoso, Nigeria.Methods.The survey research method was adopted. Sampling included 385 buildings across selected precincts and different residential zones in the town of Ogbomoso. Particulate matter analytes (PM1, PM2.5 and PM10) within/around each building were measured with a particle counter and details on domestic utilities/practices were obtained with a questionnaire. Analysis of variance was used to determine inter-zonal variations in PM levels and simple linear regression was used to analyze the relationship between indoor and outdoor air quality.Results.Indoor and outdoor respirable particle (PM2.5) concentrations were lower than the World Health Organization (WHO) Interim Target limit of 75 μg/m3, while concentrations of inhalable particles (PM10) were higher than the set limit of 150 μg/m3 for daily averages. Coarse particles dominated, with an accumulative PM2.5/PM10 ratio of 0.24. The inter-zonal analysis of PM concentrations revealed that indoor and outdoor PM levels varied significantly by residential zone (p = 0.0005; p = 0.01, respectively). Regression analysis showed a significant but weak relationship between indoor and outdoor PM levels (r = +0.221), while the coefficient of determination (R2 = 0.049) showed that only about 5% of the variation in indoor air quality was associated with outdoor air quality. Particle pollution inducers were identified in the residents' waste disposal methods and adopted fuels/energy sources, with firewood and charcoal linked with increased concentrations of particulate matter.Conclusions.Air quality was relatively poor in the study area given observed particulate matter concentrations. Cleaner fuels, effective waste management systems and improved roads are needed to foster better air quality in the study area.Competing Interests.The authors declare no competing financial interests

Gestational exposures to outdoor air pollutants in relation to low birth weight: A retrospective observational study

Findings for impacts of outdoor air pollutants on birth outcomes were controversial. We performed a retrospective observational study in 2527 preschoolers of Shanghai, China and investigated associations of duration-averaged concentrations of outdoor sulphur dioxide (SO2), nitrogen dioxide (NO2), and particulate matter with an aerodynamic diameter ≤ 10 μm (PM10) in different months and trimesters of gestation, with preterm birth (PB), low birth weight (LBW), term low birth weight (T-LBW), and small for gestational age (SGA). Daily concentrations of outdoor air pollutants were collected in each residence-located district. Parents reported health information. In the multivariate logistic regression analyses, exposures to outdoor NO2 were consistently associated with the higher odds of LBW and T-LBW. These associations were generally stronger for early months than for later months of the gestation. Adjusted odds ratios generally were larger in multi-pollutant model than in single-pollutant model. Exposure to NO2 in the first month of the gestation was significantly associated with T-LBW (adjusted OR, 95%CI: 1.91, 1.02–3.58 for increment of interquartile range (18.5 μg/m3); p-value = 0.044) in multi-pollutant model. This association was stronger in girls, renters, and children whose mothers ≥30 years-old, with household dampness-related exposures, and with parental smoking during pregnancy. Our results indicate that exposure to NO2 during gestation perhaps is a risk factor for LBW and T-LBW, and effects of NO2 exposures could be greater during early periods than during later periods of gestation.