The Use of Standardized Diesel Exhaust Particles in Alzheimer's Disease Research.

The mechanisms underlying how urban air pollution exposure conveys Alzheimer's disease risk and affects plaque pathology is largely unknown. Because particulate matter, the particle component of urban air pollution, varies across location, pollution source, and time, a single model representative of all ambient particulate matter is unfeasible for research investigating the role of ar pollution in central nervous system diseases. More specifically, the investigation of several models of particulate matter with enrichment of source-specific components are essential to employ, in order to more fully understand what characteristics of particulate matter affects Alzheimer's disease, including standardized diesel exhaust particles.

Air quality standards for the concentration of particulate matter 2.5, global descriptive analysis.

OBJECTIVE: To compare ambient air quality standards for the mass concentration of aerosol particles smaller than approximately 2.5 µm (PM2.5) and exposure to these particles in national and regional jurisdictions worldwide. METHODS: We did a review of government documents and literature on air quality standards. We extracted and summarized the PM2.5 concentration limits effective before July 2020, noting whether standards were enforced, voluntary or target. We compared averaging methods and permitted periods of time that standards may be exceeded. We made a descriptive analysis of PM2.5 standards by population, total area and population density of jurisdictions. We also compared data on actual PM2.5 air quality against the standards. FINDINGS: We obtained data on standards from 62 jurisdictions worldwide, including 58 countries. Of the world's 136.06 million km2 land under national jurisdictions, 71.70 million km2 (52.7%) lack an official PM2.5 air quality standard, and 3.17 billion people live in areas without a standard. The existing standards ranged from 8 to 75 µg/m3, mostly higher than the World Health Organization guideline annual limit of < 10 µg/m3. The weakest PM2.5 standards were often exceeded, while the more stringent standards were often met. Several jurisdictions with the highest population density demonstrated compliance with relatively stringent standards. CONCLUSION: The metrics used in PM2.5 ambient air quality standards should be harmonized worldwide to facilitate accurate assessment of risks associated with PM2.5 exposure. Population density alone does not preclude stringent PM2.5 standards. Modernization of standards can also include short-term standards to unmask PM2.5 fluctuations in high-pollution areas.

Household and personal air pollution exposure measurements from 120 communities in eight countries: results from the PURE-AIR study.

BACKGROUND: Approximately 2·8 billion people are exposed to household air pollution from cooking with polluting fuels. Few monitoring studies have systematically measured health-damaging air pollutant (ie, fine particulate matter [PM2·5] and black carbon) concentrations from a wide range of cooking fuels across diverse populations. This multinational study aimed to assess the magnitude of kitchen concentrations and personal exposures to PM2·5 and black carbon in rural communities with a wide range of cooking environments. METHODS: As part of the Prospective Urban and Rural Epidemiological (PURE) cohort, the PURE-AIR study was done in 120 rural communities in eight countries (Bangladesh, Chile, China, Colombia, India, Pakistan, Tanzania, and Zimbabwe). Data were collected from 2541 households and from 998 individuals (442 men and 556 women). Gravimetric (or filter-based) 48 h kitchen and personal PM2·5 measurements were collected. Light absorbance (10-5m-1) of the PM2·5 filters, a proxy for black carbon concentrations, was calculated via an image-based reflectance method. Surveys of household characteristics and cooking patterns were collected before and after the 48 h monitoring period. FINDINGS: Monitoring of household air pollution for the PURE-AIR study was done from June, 2017, to September, 2019. A mean PM2·5 kitchen concentration gradient emerged across primary cooking fuels: gas (45 µg/m3 [95% CI 43-48]), electricity (53 µg/m3 [47-60]), coal (68 µg/m3 [61-77]), charcoal (92 µg/m3 [58-146]), agricultural or crop waste (106 µg/m3 [91-125]), wood (109 µg/m3 [102-118]), animal dung (224 µg/m3 [197-254]), and shrubs or grass (276 µg/m3 [223-342]). Among households cooking primarily with wood, average PM2·5 concentrations varied ten-fold (range: 40-380 µg/m3). Fuel stacking was prevalent (981 [39%] of 2541 households); using wood as a primary cooking fuel with clean secondary cooking fuels (eg, gas) was associated with 50% lower PM2·5 and black carbon concentrations than using only wood as a primary cooking fuel. Similar average PM2·5 personal exposures between women (67 µg/m3 [95% CI 62-72]) and men (62 [58-67]) were observed. Nearly equivalent average personal exposure to kitchen exposure ratios were observed for PM2·5 (0·79 [95% 0·71-0·88] for men and 0·82 [0·74-0·91] for women) and black carbon (0·64 [0·45-0·92] for men and 0·68 [0·46-1·02] for women). INTERPRETATION: Using clean primary fuels substantially lowers kitchen PM2·5 concentrations. Importantly, average kitchen and personal PM2·5 measurements for all primary fuel types exceeded WHO's Interim Target-1 (35 µg/m3 annual average), highlighting the need for comprehensive pollution mitigation strategies. FUNDING: Canadian Institutes for Health Research, National Institutes of Health.

Air pollution control strategies directly limiting national health damages in the US.

Exposure to fine particulate matter (PM2.5) from fuel combustion significantly contributes to global and US mortality. Traditional control strategies typically reduce emissions for specific air pollutants and sectors to maintain pollutant concentrations below standards. Here we directly set national PM2.5 mortality cost reduction targets within a global human-earth system model with US state-level energy systems, in scenarios to 2050, to identify endogenously the control actions, sectors, and locations that most cost-effectively reduce PM2.5 mortality. We show that substantial health benefits can be cost-effectively achieved by electrifying sources with high primary PM2.5 emission intensities, including industrial coal, building biomass, and industrial liquids. More stringent PM2.5 reduction targets expedite the phaseout of high emission intensity sources, leading to larger declines in major pollutant emissions, but very limited co-benefits in reducing CO2 emissions. Control strategies limiting health damages achieve the greatest emission reductions in the East North Central and Middle Atlantic states.

Potential gains in life expectancy by attaining daily ambient fine particulate matter pollution standards in mainland China: A modeling study based on nationwide data.

BACKGROUND: Ambient fine particulate matter pollution (PM2.5) is one leading cause of disease burden, but no study has quantified the association between daily PM2.5 exposure and life expectancy. We aimed to assess the potential benefits in life expectancy by attaining the daily PM2.5 standards in 72 cities of China during 2013-2016. METHODS AND FINDINGS: We applied a two-stage approach for the analysis. At the first stage, we used a generalized additive model (GAM) with a Gaussian link to examine the city-specific short-term association between daily PM2.5 and years of life lost (YLL); at the second stage, a random-effects meta-analysis was used to generate the regional and national estimations. We further estimated the potential gains in life expectancy (PGLE) by assuming that ambient PM2.5 has met the Chinese National Ambient Air Quality Standard (NAAQS, 75 µg/m3) or the ambient air quality guideline (AQG) of the World Health Organization (WHO) (25 µg/m3). We also calculated the attributable fraction (AF), which denoted the proportion of YLL attributable to a higher-than-standards daily mean PM2.5 concentration. During the period from January 18, 2013 to December 31, 2016, we recorded 1,226,849 nonaccidental deaths in the study area. We observed significant associations between daily PM2.5 and YLL: each 10 µg/m3 increase in three-day-averaged (lag02) PM2.5 concentrations corresponded to an increment of 0.43 years of life lost (95% CI: 0.29-0.57). We estimated that 168,065.18 (95% CI: 114,144.91-221,985.45) and 68,684.95 (95% CI: 46,648.79-90,721.11) years of life lost can be avoided by achieving WHO's AQG and Chinese NAAQS in the study area, which corresponded to 0.14 (95% CI: 0.09-0.18) and 0.06 (95% CI: 0.04-0.07) years of gain in life expectancy for each death in these cities. We observed differential regional estimates across the 7 regions, with the highest gains in the Northwest region (0.28 years of gain [95% CI: 0.06-0.49]) and the lowest in the North region (0.08 [95% CI: 0.02-0.15]). Furthermore, using WHO's AQG and Chinese NAAQS as the references, we estimated that 1.00% (95% CI: 0.68%-1.32%) and 0.41% (95% CI: 0.28%-0.54%) of YLL could be attributable to the PM2.5 exposure at the national level. Findings from this study were mainly limited by the unavailability of data on individual PM2.5 exposure. CONCLUSIONS: This study indicates that significantly longer life expectancy could be achieved by a reduction in the ambient PM2.5 concentrations. It also highlights the need to formulate a stricter ambient PM2.5 standard at both national and regional levels of China to protect the population's health.

Visible Particulate Contamination Control for Injectable Products: A Life-Cycle Approach.

Visible particulate matter contamination is responsible for the rejection or recall of numerous batches of injectable product each year. The result is wasted time, effort, money, product and the limited availability of medically necessary drug and biologic products. Recently published compendial standards have alleviated some of the confusion surrounding suitable test methods and acceptance criteria for visible particulates; however, the complexities of visual inspection methods across a wide range of injectable product types packaged in diverse and sometimes complex container systems has complicated the approach to visible particulate control in injectable products. The solution is a life-cycle approach to visible particulate contamination control that addresses the prevention, inspection, identification, and remediation of visible particulate contamination. More importantly, the life-cycle approach to visible particulate control is aligned with current United States Food and Drug Administration's good manufacturing practices and can serve as an effective tool for demonstrating regulatory compliance for inspections, audits, and regulatory submissions.

An Australian incremental guideline for particulate matter (PM2.5) to assist in development and planning decisions.

OBJECTIVES: Many large-scale developments in Australia, such as road infrastructure, are subject to community concern due to their ongoing emission of particulate matter that may lead to adverse health impacts. The assessment of these impacts is guided by planning and health policies, but these policies have limitations. The objective of this paper is to provide an approach to setting an incremental guideline that can be used by regulators and health professionals to assess the impact of particulate matter from a development on a population, specifically the impact of particulate matter less than or equal to 2.5 micrometres in diameter (PM2.5). Type of program or service: Environmental health policy. METHODS: The calculation of PM2.5 concentrations and life days lost using concentration response functions and life tables. RESULTS: We calculated annual incremental concentrations of PM2.5 for a 1 in 1 000 000 increased risk of mortality, a 1 in 100 000 increased risk of mortality and a 1 in 10 000 increased risk of mortality along with associated life days lost. These values can be used to assess the acceptability of PM2.5 health impacts from a development. LESSONS LEARNT: An incremental annual PM2.5 concentration of up to 0.02 µg/m³ could be considered negligible, while concentrations between 0.02 and 1.7 µg/m³ could be considered acceptable/tolerable, with concentrations greater than 1.7 µg/m³ considered unacceptable.

Use of IoT sensing and occupant surveys for determining the resilience of buildings to forest fire generated PM2.5.

Wildfires and associated emissions of particulate matter pose significant environmental and health concerns. In this study we propose tools to evaluate building resilience to extreme episodes of outdoor particulate matter using a combination of indoor and outdoor IoT measurements, coupled with survey-based information of occupants' perception and behaviour. We demonstrated the application of the tools on two buildings with different modes of ventilation during the Chico Camp fire event. We characterized the resilience of the buildings on different temporal and spatial scales using the well-established I/O ratio and a newly proposed E-index that evaluates indoor concentration in the context of adopted 24-hour exposure thresholds. Indoor PM2.5 concentration during the entire Chico Camp Fire event was 21 µg/m3 for 4th Street (Mechanically Ventilated) and 36 µg/m3 for Wurster Hall (Naturally Ventilated). The cumulative median I/O ratio during the fire event was 0.27 for 4th Street and 0.67 for Wurster Hall. Overall E-index for 4th Street was 0.82, suggesting that the whole building was resilient to outdoor air pollution while overall E-index was 1.69 for Wurster Hall suggesting that interventions are necessary. The survey revealed that occupant perception of workplace air quality aligns with measured PM2.5 in the two buildings. The results also highlight that a large portion of occupants wore face masks, even though the PM2.5 concentration was below WHO threshold level. The results of our study demonstrate the utility of the proposed IoT-enabled and survey tools to assess the degree of protection from air pollution of outdoor origin for a single building or across a portfolio of buildings. The proposed survey tool also provides direct links between the PM2.5 levels and occupants' perception and behavior.

Ambient air quality changes after stubble burning in rice-wheat system in an agricultural state of India.

Ground-based ambient air monitoring was conducted to assess the contribution of crop residue burning of wheat (Triticum aestivum) and rice (Oriza sativa) at different locations in three districts (Kaithal, Kurukshetra, and Karnal) of the agricultural state of Haryana in India for two successive years (2016 and 2017). The Air Quality Index (AQI) and concentration of primary pollutants (SOx, NOx, and PM2.5) were determined in rice and wheat crop season, for burning and non-burning periods. During crop residue burning periods, concentrations of SOx, NOx, and PM2.5 were exceeded the NAAQS values by 78%, 71%, and 53%, respectively. A significant increase in SOx (4.5 times), NOx (3.8 times), and PM2.5 concentration (3.5 times) was observed in stubble burning periods as compared to pre-burning (p < 0.05). A positive and significant correlation among the three pollutant concentrations was observed (p < 0.01). The AQI of KA site in Karnal district fell in severely polluted category during 2016 for rice as well as wheat residue burning period, and of KK site in Kaithal during wheat residue burning in year 2017. Results of present study indicate a remarkable increase in pollutant concentration (SOx, NOx, and PM2.5) during the crop residue burning periods. To the best of our knowledge, the outcomes of present study in this region have not been reported in earlier reports. Hence, there is an urgent need to curb air pollution by adopting sustainable harvesting technologies and management of residues.

PM2.5 Cooperative Control with Fuzzy Cost and Fuzzy Coalitions.

Haze control cost is hard to value by a crisp number because it is often affected by various factors such as regional uncertain meteorological conditions and topographical features. Furthermore, regions may be involved in different coalitions for haze control with different levels of effort. In this paper, we propose a PM2.5 cooperative control model with fuzzy cost and crisp coalitions or fuzzy coalitions based on the uncertain cross-border transmission factor. We focus on the Beijing­Tianjin­Hebei regions of China and obtain the following major findings. In the case of haze control in the Beijing­Tianjin­Hebei regions of China, local governments in the global crisp coalition can achieve their emission reduction targets with the lowest aggregated cost. However, Hebei fails to satisfy its individual rationality if there is no cost sharing. Therefore, the Hukuhara­Shapley value is used to allocate the aggregated cost among these regions so that the grand coalition is stable. However, the Beijing­Tianjin­Hebei regions cannot achieve their emission reduction targets in the global fuzzy coalition without government subsidies.

Applying the concept of "number needed to treat" to the formulation of daily ambient air quality standards.

The World Health Organization sets up the Ambient Air Quality Guidelines mainly based on short-term and long-term health effects of air pollution. Previous studies, however, have generally revealed a non-threshold concentration-response relationship between air pollution and health, making it difficult to determine a concentration, below which no obvious health effects can be observed. Here we proposed a novel approach based on the concept of "number needed to treat", specifically, we calculated the reduction in air pollution concentrations needed to avoid one death corresponding to different hypothetical concentration standards; the one with the smallest value would be the most practical concentration standard. As an example, we applied this approach to the daily standard of ambient PM2.5 (particulate matter with aerodynamic diameter ≤2.5 µm) in four Chinese cities. The calculation was based on the association between daily mortality and ambient PM2.5, which was examined by a generalized additive model with adjustment of important covariates. Significant associations were observed between PM2.5 and mortality. Our analyses suggested that it is appropriate to have 50 µg/m3 as the daily standard of ambient PM2.5 for the study area, compared to the current standard of which were directly adopted from the national standard of 75 µg/m3. This novel approach should be considered when planning and/or revising the ambient air quality guidelines/standards.

The quantitative assessment of the public excess disease burden advanced by inhalable particulate matter under different air quality standard targets in Tianjin, China.

Currently, the quantitative assessment of the public excess risk for the update of the air quality guidelines only considered the mortality and morbidity without disease burden indicators. To provide evidences for the update of air quality guidelines and the policy analysis of air control, a simple framework to identify the excess disease burden of PM10 was used in this study. Daily data on PM10, meteorological factors, and deaths were collected in this 10-year (2001-2010) time series study in Tianjin, China. The excess disease burden advanced by PM10 was assessed when the PM10 levels exceeded the expected levels. Generalized additive model was used to estimate the associations of PM10 with mortality and years of life lost (YLL). Our study found that the exposure of PM10 was associated with the increasing of mortality and YLL in different diseases. The excess deaths and YLL of different diseases advanced by PM10 when the PM10 levels exceeded the expected levels were high and showed a decreasing trend from 2001 to 2010. The annual deaths and YLL standardized per million population advanced by PM10 when the annual PM10 levels exceeded the China national ambient air quality secondary standard targets (70 µg/m3) and WHO guideline (20 µg/m3) were 126 persons, 2670 person years and 260 persons, 5449 person years, respectively. This study may provide a simple framework to identify the excess disease burden of PM and provide basic and intuitive evidences to update the air quality guidelines. Furthermore, these findings may also provide decisionmakers with intuitive quantitative information for policymaking and emphasize health considerations in air quality policy discussions.

The economic benefits of fulfilling the World Health Organization's limits for particulates: A case study in Algeciras Bay (Spain).

Algeciras Bay is an important industrial and port zone in the south of Spain whose pollution by particulate matter surpasses the threshold levels recommended by the World Health Organization (WHO) in its 2005 Guide on Air Quality. This study analyses the mortality avoided and the economic benefit which would be derived from a reduction of the pollution of PM2.5 and PM10 to the levels recommended by the WHO in Algeciras Bay in the period 2005-2015. The analysis carried out shows that the industrial zones, such as Los Barrios and San Roque, are those which have greater levels of pollution and in which the relative risk is greater. The calculations for Algeciras Bay between 2000 and 2015 show 182 deaths which would be avoided if the particulate matter pollution were reduced to the levels recommended by the WHO. Likewise, the economic valuation which this impact has on health is carried out through two concepts: the cost of illness and the Value of Statistical Life (VSL). The result shows that the economic benefit that would come out with the cost of illness valuation is 5,329,110€ and from the VSL is 414,787,113€. Implications: PM2.5 has a greater concentration in industrial localities and is linked to the industrial activity. When the particulate matter pollution is reduced to the levels recommended by the WHO in an industrialised area such as Algeciras (Spain), 182 deaths which would be avoided. The result shows that the economic benefit that would come out with the cost of illness valuation is 5,329,110€ and from the value of statistical life is 414,787,113€.

Applying Integrated Exposure-Response Functions to PM2.5 Pollution in India.

Fine particulate matter (PM2.5, diameter ≤2.5 µm) is implicated as the most health-damaging air pollutant. Large cohort studies of chronic exposure to PM2.5 and mortality risk are largely confined to areas with low to moderate ambient PM2.5 concentrations and posit log-linear exposure-response functions. However, levels of PM2.5 in developing countries such as India are typically much higher, causing unknown health effects. Integrated exposure-response functions for high PM2.5 exposures encompassing risk estimates from ambient air, secondhand smoke, and active smoking exposures have been posited. We apply these functions to estimate the future cause-specific mortality risks associated with population-weighted ambient PM2.5 exposures in India in 2030 using Greenhouse Gas-Air Pollution Interactions and Synergies (GAINS) model projections. The loss in statistical life expectancy (SLE) is calculated based on risk estimates and baseline mortality rates. Losses in SLE are aggregated and weighted using national age-adjusted, cause-specific mortality rates. 2030 PM2.5 pollution in India reaches an annual mean of 74 µg/m³, nearly eight times the corresponding World Health Organization air quality guideline. The national average loss in SLE is 32.5 months (95% Confidence Interval (CI): 29.7⁻35.2, regional range: 8.5⁻42.0), compared to an average of 53.7 months (95% CI: 46.3⁻61.1) using methods currently applied in GAINS. Results indicate wide regional variation in health impacts, and these methods may still underestimate the total health burden caused by PM2.5 exposures due to model assumptions on minimum age thresholds of pollution effects and a limited subset of health endpoints analyzed. Application of the revised exposure-response functions suggests that the most polluted areas in India will reap major health benefits only with substantial improvements in air quality.

Are current Chinese national ambient air quality standards on 24-hour averages for particulate matter sufficient to protect public health?

With rapid economic development and urbanization in recent decades, China has experienced the worsening of ambient air quality. For better air quality management to protect human health, Chinese government revised national ambient air quality standards (NAAQS) for particulate matter (PM) in 2012 (GB3095-2012). To assess the effectiveness of current NAAQS for PM on public health in Chinese population, we conducted a meta-analysis on published studies examining the mortality risk of short-term exposure to PM with aerodynamic diameters less than 10 and 2.5µm (PM10 and PM2.5) in China. The reported 24-hour concentrations of PM10 and PM2.5 in studies ranged from 43.5 to 150.1µg/m3 and 37.5 to 176.7µg/m3. In the pooled excess, mortality risk estimates of short-term exposure to PM. In specific, per 10µg/m3 increase in PM10, we observed increases of 0.40% (95%CI: 0.33%, 0.47%), 0.57% (95%CI: 0.44%, 0.70%) and 0.49% (95%CI: 0.40%, 0.58%) in total, respiratory and cardiovascular mortality, per 10µg/m3 increase in PM2.5, we observed increases of 0.51% (95%CI: 0.38%, 0.63%), 0.62% (95%CI: 0.52%, 0.73%) and 0.75% (95%CI: 0.54%, 0.95%) in total, respiratory and cardiovascular mortality. Finally, we derived 125µg/m3 for PM10 and 62.5µg/m3 for PM2.5 as 24-hour recommendation values based on the pooled estimates. Our results indicated that current Chinese NAAQS for PM could be sufficient in mitigating the excess mortality risk from short-term exposure to ambient PM. However, future research on long-term exposure cohort studies in Chinese population is also essential in revising annual averages for PM in Chinese NAAQS.

Development of an indicator for characterizing particle size distribution and quality of stormwater runoff.

Stormwater particles washed from road-deposited sediments (RDS) are traditionally characterized as either turbidity or total suspended solids (TSS). Although these parameters are influenced by particle sizes, neither of them characterizes the particle size distribution (PSD), which is of great importance in pollutant entrainment and treatment performance. Therefore, the ratio of turbidity to TSS (Tur/TSS) is proposed and validated as a potential surrogate for the bulk PSD and quality of stormwater runoff. The results show an increasing trend of Tur/TSS with finer sizes of both RDS and stormwater runoff. Taking heavy metals (HMs, including Cu, Pb, Zn, Cr, and Ni) as typical pollutants in stormwater runoff, the concentrations (mg/kg) were found to vary significantly during rainfall events and tended to increase significantly with Tur/TSS. Therefore, Tur/TSS is a valid parameter to characterize the PSD and quality of stormwater. The high negative correlations between Tur/TSS and rainfall intensity demonstrate that stormwater with higher Tur/TSS generates under low intensity and, thus, characterizes small volume, finer sizes, weak settleability, greater mobility, and bioavailability. Conversely, stormwater with lower Tur/TSS generates under high intensity and, thus, characterizes large volume, coarser sizes, good settleability, low mobility, and bioavailability. These results highlight the need to control stormwater with high Tur/TSS. Moreover, Tur/TSS can aid the selection of stormwater control measures with appropriate detention storage, pollution loading, and removal effectiveness of particles.

Characteristics of Major Air Pollutants in China.

Following the rapid development of China's economy, air pollution has become more and more serious. Air pollution in China presents complex pollution characterized by high PM2.5 and O3 concentration. This study presents an overview of the status of air quality and emission in China and discusses the temporal and spatial distribution of major pollutants (PM10, PM2.5, SO2, NOX, and O3). The results show that the reduced emissions have improved the air quality in China. However, the Chinese National Ambient Air Quality Standard (CNAAQS) for PM10 and PM2.5 still be exceeded in many cities of China in 2015. A total of 77.5% (for PM2.5) and 65.4% (for PM10) of the monitoring cities were found to be exceeded CNAAQS. The average annual O3 concentration was increasing during 2013-2015, and 16% of the total cities in 2015 did not meet the CNAAQS, indicating that O3 pollution should be paid more attention. For NO2 and SO2, the exceedances of CNAAQS are rare. PM2.5, PM10, and SO2 concentrations are higher in northern than in southern regions. High NO2 occurred in Beijing-Tianjin-Hebei and Yangtze River delta region. Secondary particles formation and motor vehicle exhaust were the main sources of PM2.5 in megacities. Dust was the main source for PM10. The formation of O3 is VOC-limited in urban areas of China and NOX-limited in nonurban areas.