Exposures to and origins of carbonaceous PM2.5 in a cookstove intervention in Northern Ghana

Polycyclic aromatic hydrocarbons in breast milk of nursing mothers: Correlates with household fuel and cooking methods used in Uganda, East Africa

Maternal breast milk, which is a complete food for the infant's growth, development, and health, contains fats and lipids making it susceptible to accumulation of lipophilic compounds like polycyclic aromatic hydrocarbons (PAHs). This study aimed at analyzing correlates of measured levels of PAHs in breast milk of nursing mothers to frequently used household fuels and cooking methods in Uganda, and estimate the potential health risks of PAHs to infants through breastfeeding. Sixty breast milk samples were collected from healthy and non-smoking mothers who had lived in Kampala capital city (urban area) and Nakaseke district (rural area) for at least five years. Sample extracts were analyzed for PAHs using a gas chromatograph coupled with a triple quadrupole mass spectrometer. ∑₁₃PAHs in samples from Kampala ranged from 3.44 to 696 ng/g lw while those from Nakaseke ranged from 0.84 to 87.9 ng/g lw. PAHs with 2-3 rings were more abundant in the samples than PAHs with 4-6 rings. At least 33 % of the variance in the levels of ∑₁₃PAHs in the breast milk samples was attributable to the fuel type and cooking methods used. Nursing mothers who used charcoal for cooking accumulated higher levels of ∑₁₃PAHs in their breast milk samples compared to those who used firewood. Levels of ∑₁₃PAHs in breast milk of mothers increased depending on the cooking methods used in the order; boiling< grilling< deep-frying. In all samples, hazard quotients for PAHs were <1 and estimated incremental cancer risks were all between 10^-6 and 10^-4, indicating that the health risks to infants due to the ingestion of PAHs in breast milk was tolerable. Further studies with large datasets on PAHs and their derivatives and, larger samples sizes are needed to confirm these findings.

Exposure Contrasts of Pregnant Women during the Household Air Pollution Intervention Network Randomized Controlled Trial

BACKGROUND

Exposure to PM 2.5 arising from solid fuel combustion is estimated to result in ∼ 2.3 million premature deaths and 91 million lost disability-adjusted life years annually. Interventions attempting to mitigate this burden have had limited success in reducing exposures to levels thought to provide substantive health benefits.

OBJECTIVES

This paper reports exposure reductions achieved by a liquified petroleum gas (LPG) stove and fuel intervention for pregnant mothers in the Household Air Pollution Intervention Network (HAPIN) randomized controlled trial.

METHODS

The HAPIN trial included 3,195 households primarily using biomass for cooking in Guatemala, India, Peru, and Rwanda. Twenty-four-hour exposures to PM 2.5 , carbon monoxide (CO), and black carbon (BC) were measured for pregnant women once before randomization into control (n = 1,605 ) and LPG (n = 1,590 ) arms and twice thereafter (aligned with trimester). Changes in exposure were estimated by directly comparing exposures between intervention and control arms and by using linear mixed-effect models to estimate the impact of the intervention on exposure levels.

RESULTS

Median postrandomization exposures of particulate matter (PM) with aerodynamic diameter ≤ 2.5 μ m (PM 2.5 ) in the intervention arm were lower by 66% at the first (71.5 vs. 24.1   μ g / m 3 ), and second follow-up visits (69.5 vs. 23.7   μ g / m 3 ) compared to controls. BC exposures were lower in the intervention arm by 72% (9.7 vs. 2.7   μ g / m 3 ) and 70% (9.6 vs. 2.8   μ g / m 3 ) at the first and second follow-up visits, respectively, and carbon monoxide exposure was 82% lower at both visits (1.1 vs. 0.2  ppm ) in comparison with controls. Exposure reductions were consistent over time and were similar across research locations.

DISCUSSION

Postintervention PM 2.5 exposures in the intervention arm were at the lower end of what has been reported for LPG and other clean fuel interventions, with 69% of PM 2.5 samples falling below the World Health Organization Annual Interim Target 1 of 35   μ g / m 3 . This study indicates that an LPG intervention can reduce PM 2.5 exposures to levels at or below WHO targets. https://doi.org/10.1289/EHP10295.

Chemical Investigation of Household Solid Fuel Use and Outdoor Air Pollution Contributions to Personal PM2.5 Exposures

In communities with household solid fuel use, transitioning to clean stoves/fuels often results in only moderate reductions in fine particulate matter (PM2.5) exposures; the chemical composition of those exposures may help explain why. We collected personal exposure (men and women) and outdoor PM2.5 samples in villages in three Chinese provinces (Shanxi, Beijing, and Guangxi) and measured chemical components, including water-soluble organic carbon (WSOC), ions, elements, and organic tracers. Source contributions from chemical mass balance modeling (biomass burning, coal combustion, vehicles, dust, and secondary inorganic aerosol) were similar between outdoor and personal PM2.5 samples. Principal component analysis of organic and inorganic components identified analogous sources, including a regional ambient source. Chemical components of PM2.5 exposures did not differ significantly by gender. Participants using coal had higher personal/outdoor (P/O) ratios of coal combustion tracers (picene, sulfate, As, and Pb) than those not using coal, but no such trend was observed for biomass burning tracers (levoglucosan, K+, WSOC). Picene and most levoglucosan P/O ratios exceeded 1 even among participants not using coal and biomass, respectively, indicating substantial indirect exposure to solid fuel emissions from other homes. Contributions of community-level emissions to exposures suggest that meaningful exposure reductions will likely require extensive fuel use changes within communities.

Health impacts of a randomized biomass cookstove intervention in northern Ghana

BACKGROUND

Household air pollution (HAP) from cooking with solid fuels has adverse health effects. REACCTING (Research on Emissions, Air quality, Climate, and Cooking Technologies in Northern Ghana) was a randomized cookstove intervention study that aimed to determine the effects of two types of "improved" biomass cookstoves on health using self-reported health symptoms and biomarkers of systemic inflammation from dried blood spots for female adult cooks and children, and anthropometric growth measures for children only.

METHODS

Two hundred rural households were randomized into four different cookstove groups. Surveys and health measurements were conducted at four time points over a two-year period. Chi-square tests were conducted to determine differences in self-reported health outcomes. Linear mixed models were used to assess the effect of the stoves on inflammation biomarkers in adults and children, and to assess the z-score deviance for the anthropometric data for children.

RESULTS

We find some evidence that two biomarkers of oxidative stress and inflammation, serum amyloid A and C-reactive protein, decreased among adult primary cooks in the intervention groups relative to the control group. We do not find detectable impacts for any of the anthropometry variables or self-reported health.

CONCLUSIONS

Overall, we conclude that the REACCTING intervention did not substantially improve the health outcomes examined here, likely due to continued use of traditional stoves, lack of evidence of particulate matter emissions reductions from "improved" stoves, and mixed results for HAP exposure reductions.

CLINICAL TRIAL REGISTRY

ClinicalTrials.gov (National Institutes of Health); Trial Registration Number: NCT04633135 ; Date of Registration: 11 November 2020 - Retrospectively registered. URL: https://clinicaltrials.gov/ct2/show/NCT04633135?term=NCT04633135&draw=2&rank=1.

Modeling approaches and performance for estimating personal exposure to household air pollution: A case study in Kenya

This study assessed the performance of modeling approaches to estimate personal exposure in Kenyan homes where cooking fuel combustion contributes substantially to household air pollution (HAP). We measured emissions (PM_2.5 , black carbon, CO); household air pollution (PM_2.5 , CO); personal exposure (PM_2.5 , CO); stove use; and behavioral, socioeconomic, and household environmental characteristics (eg, ventilation and kitchen volume). We then applied various modeling approaches: a single-zone model; indirect exposure models, which combine person-location and area-level measurements; and predictive statistical models, including standard linear regression and ensemble machine learning approaches based on a set of predictors such as fuel type, room volume, and others. The single-zone model was reasonably well-correlated with measured kitchen concentrations of PM_2.5 (R²  = 0.45) and CO (R²  = 0.45), but lacked precision. The best performing regression model used a combination of survey-based data and physical measurements (R²  = 0.76) and a root mean-squared error of 85 µg/m³ , and the survey-only-based regression model was able to predict PM2.5 exposures with an R² of 0.51. Of the machine learning algorithms evaluated, extreme gradient boosting performed best, with an R² of 0.57 and RMSE of 98 µg/m³ .

Impact of the wood-burning Justa cookstove on fine particulate matter exposure: A stepped-wedge randomized trial in rural Honduras

TRIAL DESIGN

We evaluated the impact of a biomass stove intervention on fine particulate matter (PM2.5) concentrations using an individual-level, stepped-wedge randomized trial.

METHODS

We enrolled 230 women in rural Honduran households using traditional biomass stoves and randomly allocated them to one of two study arms. The Justa stove, the study intervention, was locally-sourced, wood-burning, and included an engineered combustion chamber and chimney. At each of 6 visits over 3 years, we measured 24-hour gravimetric personal and kitchen PM2.5 concentrations. Half of the households received the intervention after Visit 2 and half after Visit 4. We conducted intent-to-treat analyses to evaluate the intervention effect using linear mixed models with log-transformed kitchen or personal PM2.5 (separately) as the dependent variable, adjusting for time. We also compared PM2.5 concentrations to World Health Organization (WHO) guidelines.

RESULTS

Arms 1 and 2 each had 115 participants with 664 and 632 completed visits, respectively. Median 24-hour average personal PM2.5 exposures were 81 μg/m3 (25th-75th percentile: 50-141 μg/m3) for the traditional stove condition (n=622) and 43 μg/m3 (25th-75th percentile: 27-73 μg/m3) for the Justa stove condition (n=585). Median 24-hour average kitchen concentrations were 178 μg/m3 (25th-75th percentile: 69-440 μg/m3; n=629) and 53 μg/m3 (25th-75th percentile: 29-103 μg/m3; n=578) for the traditional and Justa stove conditions, respectively. The Justa intervention resulted in a 32% reduction in geometric mean personal PM2.5 (95% confidence interval [CI]: 20-43%) and a 56% reduction (95% CI: 46-65%) in geometric mean kitchen PM2.5. During rainy and dry seasons, 53% and 41% of participants with the Justa intervention had 24-hour average personal PM2.5 exposures below the WHO interim target-3 guideline (37.5 μg/m3), respectively.

CONCLUSION

The Justa stove intervention substantially lowered personal and kitchen PM2.5 and may be a provisional solution that is feasible for Latin American communities where cleaner fuels may not be available, affordable, or acceptable for some time. Clinicaltrials.gov: NCT02658383.

Impacts of stove/fuel use and outdoor air pollution on chemical composition of household particulate matter

Biomass combustion for cooking and heating releases particulate matter (PM_2.5 ) that contributes to household air pollution. Fuel and stove types affect the chemical composition of household PM, as does infiltration of outdoor PM. Characterization of these impacts can inform future exposure assessments and epidemiologic studies, but is currently limited. In this study, we measured chemical components of PM_2.5 (water-soluble organic matter [WSOM], ions, black carbon, elements, organic tracers) in rural Chinese households using traditional biomass stoves, semi-gasifier stoves with pelletized biomass, and/or non-biomass stoves. We distinguished households using one stove type (traditional, semi-gasifier, or LPG/electric) from those using multiple stoves/fuels. WSOM concentrations were higher in households using only semi-gasifier or traditional stoves (31%-33%) than in those with exclusive LPG/electric stove (13%) or mixed stove use (12%-22%). Inorganic ions comprised 14% of PM in exclusive LPG/electric households, compared to 1%-5% of PM in households using biomass. Total PAH content was much higher in households that used traditional stoves (0.8-2.8 mg/g PM) compared to those that did not (0.1-0.3 mg/g PM). Source apportionment revealed that biomass burning comprised 27%-84% of PM_2.5 in households using biomass. In all samples, identified outdoor sources (vehicles, dust, coal combustion, secondary aerosol) contributed 10%-20% of household PM_2.5 .

Effectiveness of a Household Energy Package in Improving Indoor Air Quality and Reducing Personal Exposures in Rural China

We evaluated whether an energy package comprising a low-polluting semigasifier cookstove with chimney, water heater, and pelletized biomass fuel would improve air pollution in China. We measured the stove use, 48-h air pollution exposures (PM_2.5, black carbon), and kitchen concentrations (PM_2.5, black carbon, carbon monoxide, nitrogen oxides) for 205 women, along with ambient PM_2.5. Over half (n = 125) were offered the energy package after baseline assessment, forming "treated" and "untreated" groups, and we repeated the measurements up to 3 occasions over 18-months. Kitchen carbon monoxide did not change, and nitrogen oxides increased in summer but decreased in winter for both groups. Summer geometric mean exposures and kitchen concentrations of PM_2.5 and black carbon decreased by 24-67% in women who received the energy package, but greater reductions (48-70%) were observed in untreated homes, likely due to increased use of gas stoves. After adjusting for differences in outdoor PM_2.5, receiving the energy package was associated with decreased winter exposures to PM_2.5 (-46%; 95% CI: -70, -2) and black carbon (-55%; -74, -25) and the summer increases were smaller (PM_2.5: 8%; -22, 51 and black carbon: 37%; -12, 113). However, PM_2.5 exposures remained 1.5-3 times higher than those of health-based international air pollution targets.

Kitchen Area Air Quality Measurements in Northern Ghana: Evaluating the Performance of a Low-Cost Particulate Sensor within a Household Energy Study

Household air pollution from the combustion of solid fuels is a leading global health and human rights concern, affecting billions every day. Instrumentation to assess potential solutions to this problem faces challenges—especially related to cost. A low-cost ($159) particulate matter tool called the Household Air Pollution Exposure (HAPEx) Nano was evaluated in the field as part of the Prices, Peers, and Perceptions cookstove study in northern Ghana. Measurements of temperature, relative humidity, absolute humidity, and carbon dioxide and carbon monoxide concentrations made at 1-min temporal resolution were integrated with 1-min particulate matter less than 2.5 microns in diameter (PM2.5) measurements from the HAPEx, within 62 kitchens, across urban and rural households and four seasons totaling 71 48-h deployments. Gravimetric filter sampling was undertaken to ground-truth and evaluate the low-cost measurements. HAPEx baseline drift and relative humidity corrections were investigated and evaluated using signals from paired HAPEx, finding significant improvements. Resulting particle coefficients and integrated gravimetric PM2.5 concentrations were modeled to explore drivers of variability; urban/rural, season, kitchen characteristics, and dust (a major PM2.5 mass constituent) were significant predictors. The high correlation (R2 = 0.79) between 48-h mean HAPEx readings and gravimetric PM2.5 mass (including other covariates) indicates that the HAPEx can be a useful tool in household energy studies.

Exposures to Carbon Monoxide in a Cookstove Intervention in Northern Ghana

Biomass burning for home energy use is a major environmental health concern. Improved cooking technologies could generate environmental health benefits, yet prior results regarding reduced personal exposure to air pollution are mixed. In this study, two improved stove types were distributed over four study groups in Northern Ghana. Participants wore real-time carbon monoxide (CO) monitors to measure the effect of the intervention on personal exposures. Relative to the control group (those using traditional stoves), there was a 30.3% reduction in CO exposures in the group given two Philips forced draft stoves (p = 0.08), 10.5% reduction in the group given two Gyapa stoves (locally made rocket stoves) (p = 0.62), and 10.2% reduction in the group given one of each (p = 0.61). Overall, CO exposure for participants was low given the prevalence of cooking over traditional three-stone fires, with 8.2% of daily samples exceeding WHO Tier-1 standards. We present quantification methods and performance of duplicate monitors. We analyzed the relationship between personal carbonaceous particulate matter less than 2.5 microns (PM2.5) and CO exposure for the dataset that included both measurements, finding a weak relationship likely due to the diversity of identified air pollution sources in the region and behavior variability.

Attributing Air Pollutant Exposure to Emission Sources with Proximity Sensing

Biomass burning for home energy use contributes to negative health outcomes and environmental degradation. As part of the REACCTING study (Research on Emissions, Air quality, Climate, and Cooking Technologies in Northern Ghana), personal exposure to carbon monoxide (CO) was measured to gauge the effects of introducing two different cookstove types over four intervention groups. A novel Bluetooth Low-Energy (BLE) Beacon system was deployed on a subset of those CO measurement periods to estimate participants’ distances to their most-used cooking areas during the sampling periods. In addition to presenting methods and validation for the BLE Beacon system, here we present pollution exposure assessment modeling results using two different approaches, in which time-activity (proximity) data is used to: (1) better understand exposure and behaviors within and away from homes; and (2) predict personal exposure via microenvironment air quality measurements. Model fits were improved in both cases, demonstrating the benefits of the proximity measurements.

Updated Emission Factors from Diffuse Combustion Sources in Sub-Saharan Africa and Their Effect on Regional Emission Estimates

Diffuse emission sources outside of kitchen areas are poorly understood, and measurements of their emission factors (EFs) are sparse for regions of sub-Saharan Africa. Thirty-one in-field emission measurements were taken in northern Ghana from combustion sources common to rural regions worldwide. Sources sampled included commercial cooking, trash burning, kerosene lanterns, and diesel generators. EFs were calculated for carbon monoxide (CO), carbon dioxide (CO₂), as well as carbonaceous particulate matter, specifically elemental carbon (EC) and organic carbon (OC). EC and OC emissions were measured from kerosene lighting events (EF_EC = 25.1 g/kg-fuel SD = 25.7, EF_OC = 9.5 g/kg-fuel SD = 10.0). OC emissions from trash burning events were large and highly variable (EF_OC = 38.9 g/kg-fuel SD = 30.5). Combining our results with other recent in-field emission factors for rural Ghana, we explored updated emission estimates for Ghana using a region specific emissions inventory. Large differences are calculated for all updated source emissions, showing a 96% increase in OC and 78% decrease in EC compared to prior estimates for Ghana's emissions. Differences for carbon monoxide were small when averaged across all updated source types (-1%), though the household wood use and trash burning categories individually show large differences.

Promoting LPG usage during pregnancy: A pilot study in rural Maharashtra, India

Household air pollution from the combustion of biomass and coal is estimated to cause approximately 780,000 premature deaths a year in India. The government has responded by promoting uptake of liquefied petroleum gas (LPG) by tens of millions of poor rural families. Many poor households with new LPG stoves, however, continue to partially use traditional smoky chulhas. Our primary objective was to evaluate three strategies to transition pregnant women in rural Maharashtra to exclusive use of LPG for cooking. We also measured reductions in kitchen concentrations of PM2.5 before and after our interventions. Our core intervention was a free stove, 2 free LPG cylinders (one on loan until delivery), and repeated health messaging. We measured stove usage of both the traditional and intervention stoves until delivery. In households that received the core intervention, an average of 66% days had no indoor cooking on a chulha. In an adjacent area, we evaluated a conditional cash transfer (CCT) based on usage of LPG in addition to the core intervention. Results were less successful, due to challenges implementing the CCT. Pregnant women in a third nearby area received the core intervention plus a maximum of one 14.2 kg cylinder per month of free fuel. In their homes, 90% of days had no indoor cooking on a chulha. On average, exclusive LPG use decreased kitchen concentrations of PM2.5 by approximately 85% (from 520 to 72 μg/m3). 85% of participating households agreed to pay the deposit on the 2nd cylinder. This high purchase rate suggests they valued how the second cylinder permitted continuous LPG supply. A program to increase access to second cylinders may, thus, be a straightforward way to encourage use of clean fuels in rural areas.

Prices, peers, and perceptions (P3): study protocol for improved biomass cookstove project in northern Ghana

Background

Despite their potential health and social benefits, adoption and use of improved cookstoves has been low throughout much of the world. Explanations for low adoption rates of these technologies include prices that are not affordable for the target populations, limited opportunities for households to learn about cookstoves through peers, and perceptions that these technologies are not appropriate for local cooking needs. The P3 project employs a novel experimental design to explore each of these factors and their interactive effects on cookstove demand, adoption, use and exposure outcomes.

Methods

The P3 study is being conducted in the Kassena-Nankana Districts of Northern Ghana. Leveraging an earlier improved cookstove study that was conducted in this area, the central design of the P3 biomass stove experiment involves offering stoves at randomly varying prices to peers and non-peers of households that had previously received stoves for free. Using household surveys, electronic stove use monitors, and low-cost, portable monitoring equipment, we measure how prices and peers’ experience affect perceptions of stove quality, the decision to purchase a stove, use of improved and traditional stoves over time, and personal exposure to air pollutants from the stoves.

Discussion

The challenges that public health and development communities have faced in spreading adoption of potentially welfare-enhancing technologies, like improved cookstoves, have highlighted the need for interdisciplinary, multisectoral approaches. The design of the P3 project draws on economic theory, public health practice, engineering, and environmental sciences, to more fully grasp the drivers and barriers to expanding access to and uptake of cleaner stoves. Our partnership between academic institutions, in the US and Ghana, and a local environmental non-governmental organization creates unique opportunities to disseminate and scale up lessons learned.

Trial registration

ClinicalTrials.gov NCT03617952 7/31/18 (Retrospectively Registered).

Electronic supplementary material

The online version of this article (10.1186/s12889-018-6116-z) contains supplementary material, which is available to authorized users.

Assessment of the Cambodian National Biodigester Program

The National Biodigester Program (NBP) was established in 2006 to build and maintain household biodigesters in Cambodia. In its first six years, the program installed almost 20,000 biodigesters and established an in-country network of local financiers, construction companies, skilled masons, bioslurry specialists and after-care technicians accessible to rural users in 14 of 24 Cambodian provinces. Since its initial success, the program's adoption rates have stalled despite increasing government support and high rates of user satisfaction. Building on an initial evaluation of the NBP in 2013, this updated assessment identifies multiple changes in its second implementation phase that have undermined the initial momentum of the program. Abrupt interruptions in institutional support, deteriorating supply side services (access to construction agents, masons, repair services) and reduced access to credit for farmers have eroded the service network that the first implementation phase established. Structural changes in the rural economy may also contribute to declining demand. Government support to another biodigester program which offers a lower investment price, but does not provide after-sales services has also undercut the long-term implementation strategy of the NBP. The paper finds that despite these programmatic changes, the installed biodigesters continue to perform according to expectation and to be maintained and valued by their users, but the future viability of the program remains uncertain.

Impact of improved cookstoves on women's and child health in low and middle income countries: a systematic review and meta-analysis

OBJECTIVES

Improved biomass cookstoves may help reduce the substantial global burden of morbidity and mortality due to household air pollution (HAP) that disproportionately affects women and children in low and middle income countries (LMICs).

DESIGN

Systematic review and meta-analysis of (quasi-)experimental studies identified from 13 electronic databases (last update: 6 April 2018), reference and citation searches and via expert consultation.

SETTING

LMICs PARTICIPANTS: Women and children INTERVENTIONS: Improved biomass cookstoves MAIN OUTCOME MEASURES: Low birth weight (LBW), preterm birth, perinatal mortality, paediatric acute respiratory infections (ARIs) and COPD among women.

RESULTS

We identified 53 eligible studies, including 24 that met prespecified design criteria. Improved cookstoves had no demonstrable impact on paediatric lower ARIs (three studies; 11 560 children; incidence rate ratio (IRR)=1.02 (95% CI 0.84 to 1.24)), severe pneumonia (two studies; 11 061 children; IRR=0.88 (95% CI 0.39 to 2.01)), LBW (one study; 174 babies; OR=0.74 (95% CI 0.33 to 1.66)) or miscarriages, stillbirths and infant mortality (one study; 1176 babies; risk ratio (RR) change=15% (95% CI -13 to 43)). No (quasi-)experimental studies assessed preterm birth or COPD. In observational studies, improved cookstoves were associated with a significant reduction in COPD among women: two studies, 9757 participants; RR=0.74 (95% CI 0.61 to 0.90). Reductions in cough (four studies, 1779 participants; RR=0.72 (95% CI 0.60 to 0.87)), phlegm (four studies, 1779 participants; RR=0.65 (95% CI 0.52 to 0.80)), wheezing/breathing difficulty (four studies; 1779 participants; RR=0.41 (95% CI 0.29 to 0.59)) and conjunctivitis (three studies, 892 participants; RR=0.58 (95% CI 0.43 to 0.78)) were observed among women.

CONCLUSION

Improved cookstoves provide respiratory and ocular symptom reduction and may reduce COPD risk among women, but had no demonstrable child health impact.

REGISTRATION

PROSPERO: CRD42016033075.

Study on sandstorm PM10 exposure assessment in the large-scale region: a case study in Inner Mongolia

The current exposure-effect curves describing sandstorm PM₁₀ exposure and the health effects are drawn roughly by the outdoor concentration (OC), which ignored the exposure levels of people's practical activity sites. The main objective of this work is to develop a novel approach to quantify human PM₁₀ exposure by their socio-categorized micro-environment activities-time weighed (SCMEATW) in strong sandstorm period, which can be used to assess the exposure profiles in the large-scale region. Types of people's SCMEATW were obtained by questionnaire investigation. Different types of representatives were trackly recorded during the big sandstorm. The average exposure levels were estimated by SCMEATW. Furthermore, the geographic information system (GIS) technique was taken not only to simulate the outdoor concentration spatially but also to create human exposure outlines in a visualized map simultaneously, which could help to understand the risk to different types of people. Additionally, exposure-response curves describing the acute outpatient rate odds by sandstorm were formed by SCMEATW, and the differences between SCMEATW and OC were compared. Results indicated that acute outpatient rate odds had relationships with PM₁₀ exposure from SCMEATW, with a level less than that of OC. Some types of people, such as herdsmen and those people walking outdoors during a strong sandstorm, have more risk than office men. Our findings provide more understanding of human practical activities on their exposure levels; they especially provide a tool to understand sandstorm PM₁₀ exposure in large scale spatially, which might help to perform the different categories population's risk assessment regionally.