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Use of satellite observations for long-term exposure assessment of global concentrations of fine particulate matter.

van Donkelaar A, Martin RV, Brauer M, Boys BL - Environ. Health Perspect. (2014)

Bottom Line: In contrast, the North American proportion above the WHO Air Quality Guideline of 10 μg/m3 fell from 62% in 1998-2000 to 19% in 2010-2012.We found significant agreement between satellite-derived estimates and ground-based measurements outside North America and Europe (r = 0.81; n = 210; slope = 0.68).The low bias in satellite-derived estimates suggests that true global concentrations could be even greater.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Nova Scotia, Canada.

ABSTRACT

Background: More than a decade of satellite observations offers global information about the trend and magnitude of human exposure to fine particulate matter (PM2.5).

Objective: In this study, we developed improved global exposure estimates of ambient PM2.5 mass and trend using PM2.5 concentrations inferred from multiple satellite instruments.

Methods: We combined three satellite-derived PM2.5 sources to produce global PM2.5 estimates at about 10 km × 10 km from 1998 through 2012. For each source, we related total column retrievals of aerosol optical depth to near-ground PM2.5 using the GEOS-Chem chemical transport model to represent local aerosol optical properties and vertical profiles. We collected 210 global ground-based PM2.5 observations from the literature to evaluate our satellite-based estimates with values measured in areas other than North America and Europe.

Results: We estimated that global population-weighted ambient PM2.5 concentrations increased 0.55 μg/m3/year (95% CI: 0.43, 0.67) (2.1%/year; 95% CI: 1.6, 2.6) from 1998 through 2012. Increasing PM2.5 in some developing regions drove this global change, despite decreasing PM2.5 in some developed regions. The estimated proportion of the population of East Asia living above the World Health Organization (WHO) Interim Target-1 of 35 μg/m3 increased from 51% in 1998-2000 to 70% in 2010-2012. In contrast, the North American proportion above the WHO Air Quality Guideline of 10 μg/m3 fell from 62% in 1998-2000 to 19% in 2010-2012. We found significant agreement between satellite-derived estimates and ground-based measurements outside North America and Europe (r = 0.81; n = 210; slope = 0.68). The low bias in satellite-derived estimates suggests that true global concentrations could be even greater.

Conclusions: Satellite observations provide insight into global long-term changes in ambient PM2.5 concentrations. Satellite-derived estimates and ground-based PM2.5 observations from this study are available for public use.

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Decadal (2001–2010) mean PM2.5 concentrations over Europe. The top panel displays satellite-derived values. The lower right panel contains ground-based values in operation at least 3 years during this period. The lower left panel provides a scatterplot and statistics (slope = 0.78; r = 0.73; n = 512; 1‑σ error = 1 μg/m3 + 21%) of the two data sets, sampled on the same years but noncoincidently on a daily basis. The 1:1 line is solid. The line of best fit is dash–dot. The observed 1-σ error is dotted. Numeric data for GBD regional means are provided in Table 1. A common, logarithmic color scale is used for Figures 1–4.
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f2: Decadal (2001–2010) mean PM2.5 concentrations over Europe. The top panel displays satellite-derived values. The lower right panel contains ground-based values in operation at least 3 years during this period. The lower left panel provides a scatterplot and statistics (slope = 0.78; r = 0.73; n = 512; 1‑σ error = 1 μg/m3 + 21%) of the two data sets, sampled on the same years but noncoincidently on a daily basis. The 1:1 line is solid. The line of best fit is dash–dot. The observed 1-σ error is dotted. Numeric data for GBD regional means are provided in Table 1. A common, logarithmic color scale is used for Figures 1–4.

Mentions: Figure 2 (top panel) shows decadal mean satellite-derived PM2.5 concentrations over Europe. PM2.5 is generally higher in Eastern Europe than in Western Europe. The Po Valley in Italy is characterized by the highest regional concentrations, with average PM2.5 for some local locations exceeding 35 μg/m3 from 2001 through 2010. Figure 2 also shows available long-term mean ground-level observations, which are mostly for the latter part of this period. We find slightly weaker agreement with satellite-derived estimates for Europe than for North America, with slope = 0.78, r = 0.73 and 1-σ error = 1 μg/m3 + 21%. The weaker agreement likely results from the shorter temporal sampling of 3 years over this region, as illustrated in Supplemental Material, Tables S1 and S2. A cluster of ground-level monitors in southern Poland with annual mean concentrations > 35 μg/m3 contributes to the disagreement. PM2.5 concentrations in southern Poland near Katowice are higher in wintertime compared with other seasons (Rogula-Kozlowska et al. 2014), when satellite observations are more frequent.


Use of satellite observations for long-term exposure assessment of global concentrations of fine particulate matter.

van Donkelaar A, Martin RV, Brauer M, Boys BL - Environ. Health Perspect. (2014)

Decadal (2001–2010) mean PM2.5 concentrations over Europe. The top panel displays satellite-derived values. The lower right panel contains ground-based values in operation at least 3 years during this period. The lower left panel provides a scatterplot and statistics (slope = 0.78; r = 0.73; n = 512; 1‑σ error = 1 μg/m3 + 21%) of the two data sets, sampled on the same years but noncoincidently on a daily basis. The 1:1 line is solid. The line of best fit is dash–dot. The observed 1-σ error is dotted. Numeric data for GBD regional means are provided in Table 1. A common, logarithmic color scale is used for Figures 1–4.
© Copyright Policy - public-domain
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4314252&req=5

f2: Decadal (2001–2010) mean PM2.5 concentrations over Europe. The top panel displays satellite-derived values. The lower right panel contains ground-based values in operation at least 3 years during this period. The lower left panel provides a scatterplot and statistics (slope = 0.78; r = 0.73; n = 512; 1‑σ error = 1 μg/m3 + 21%) of the two data sets, sampled on the same years but noncoincidently on a daily basis. The 1:1 line is solid. The line of best fit is dash–dot. The observed 1-σ error is dotted. Numeric data for GBD regional means are provided in Table 1. A common, logarithmic color scale is used for Figures 1–4.
Mentions: Figure 2 (top panel) shows decadal mean satellite-derived PM2.5 concentrations over Europe. PM2.5 is generally higher in Eastern Europe than in Western Europe. The Po Valley in Italy is characterized by the highest regional concentrations, with average PM2.5 for some local locations exceeding 35 μg/m3 from 2001 through 2010. Figure 2 also shows available long-term mean ground-level observations, which are mostly for the latter part of this period. We find slightly weaker agreement with satellite-derived estimates for Europe than for North America, with slope = 0.78, r = 0.73 and 1-σ error = 1 μg/m3 + 21%. The weaker agreement likely results from the shorter temporal sampling of 3 years over this region, as illustrated in Supplemental Material, Tables S1 and S2. A cluster of ground-level monitors in southern Poland with annual mean concentrations > 35 μg/m3 contributes to the disagreement. PM2.5 concentrations in southern Poland near Katowice are higher in wintertime compared with other seasons (Rogula-Kozlowska et al. 2014), when satellite observations are more frequent.

Bottom Line: In contrast, the North American proportion above the WHO Air Quality Guideline of 10 μg/m3 fell from 62% in 1998-2000 to 19% in 2010-2012.We found significant agreement between satellite-derived estimates and ground-based measurements outside North America and Europe (r = 0.81; n = 210; slope = 0.68).The low bias in satellite-derived estimates suggests that true global concentrations could be even greater.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Nova Scotia, Canada.

ABSTRACT

Background: More than a decade of satellite observations offers global information about the trend and magnitude of human exposure to fine particulate matter (PM2.5).

Objective: In this study, we developed improved global exposure estimates of ambient PM2.5 mass and trend using PM2.5 concentrations inferred from multiple satellite instruments.

Methods: We combined three satellite-derived PM2.5 sources to produce global PM2.5 estimates at about 10 km × 10 km from 1998 through 2012. For each source, we related total column retrievals of aerosol optical depth to near-ground PM2.5 using the GEOS-Chem chemical transport model to represent local aerosol optical properties and vertical profiles. We collected 210 global ground-based PM2.5 observations from the literature to evaluate our satellite-based estimates with values measured in areas other than North America and Europe.

Results: We estimated that global population-weighted ambient PM2.5 concentrations increased 0.55 μg/m3/year (95% CI: 0.43, 0.67) (2.1%/year; 95% CI: 1.6, 2.6) from 1998 through 2012. Increasing PM2.5 in some developing regions drove this global change, despite decreasing PM2.5 in some developed regions. The estimated proportion of the population of East Asia living above the World Health Organization (WHO) Interim Target-1 of 35 μg/m3 increased from 51% in 1998-2000 to 70% in 2010-2012. In contrast, the North American proportion above the WHO Air Quality Guideline of 10 μg/m3 fell from 62% in 1998-2000 to 19% in 2010-2012. We found significant agreement between satellite-derived estimates and ground-based measurements outside North America and Europe (r = 0.81; n = 210; slope = 0.68). The low bias in satellite-derived estimates suggests that true global concentrations could be even greater.

Conclusions: Satellite observations provide insight into global long-term changes in ambient PM2.5 concentrations. Satellite-derived estimates and ground-based PM2.5 observations from this study are available for public use.

Show MeSH
Related in: MedlinePlus