Table 3.
Populations projected to be exposed to wildfire smoke (millions of persons).
| NCA region | Wildfire smoke exposure 1–3 times out of 20 years | Wildfire smoke exposure 4–6 times out of 20 years | Wildfire smoke exposure 7 or more times out of 20 years | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Age 0–4 | Age | All ages | Age 0–4 | Age | All ages | Age 0–4 | Age | All ages | |
| RCP4.5 in 2050 | |||||||||
| Northeast | 0.81 | 1.64 | 8.60 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 |
| Southeast | 0.39 | 0.95 | 4.32 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 |
| Midwest | 0.16 | 0.29 | 1.68 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 |
| Northern Great Plains | 0.12 | 0.33 | 1.40 | 0.00 | 0.00 | 0.02 | 0.00 | 0.00 | 0.00 |
| Southern Great Plains | 0.06 | 0.12 | 0.62 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 |
| Southwest | 0.78 | 2.31 | 8.89 | 0.07 | 0.21 | 0.77 | 0.00 | 0.01 | 0.03 |
| Northwest | 0.48 | 1.13 | 5.28 | 0.01 | 0.03 | 0.13 | 0.00 | 0.00 | 0.00 |
| Total | 2.81 | 6.77 | 30.79 | 0.08 | 0.25 | 0.92 | 0.00 | 0.01 | 0.03 |
| RCP4.5 in 2090 | |||||||||
| Northeast | 0.60 | 0.96 | 5.89 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 |
| Southeast | 0.36 | 0.75 | 3.71 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 |
| Midwest | 0.14 | 0.16 | 1.32 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 |
| Northern Great Plains | 0.10 | 0.27 | 1.14 | 0.00 | 0.00 | 0.01 | 0.00 | 0.00 | 0.00 |
| Southern Great Plains | 0.08 | 0.15 | 0.76 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 |
| Southwest | 0.91 | 2.25 | 9.66 | 0.06 | 0.17 | 0.66 | 0.00 | 0.00 | 0.01 |
| Northwest | 0.38 | 0.76 | 3.87 | 0.01 | 0.02 | 0.06 | 0.00 | 0.00 | 0.01 |
| Total | 2.58 | 5.29 | 26.36 | 0.07 | 0.19 | 0.74 | 0.00 | 0.00 | 0.01 |
| RCP8.5 in 2050 | |||||||||
| Northeast | 0.82 | 1.69 | 8.75 | 0.00 | 0.01 | 0.03 | 0.00 | 0.00 | 0.00 |
| Southeast | 0.34 | 0.87 | 3.82 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 |
| Midwest | 0.20 | 0.35 | 2.10 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 |
| Northern Great Plains | 0.14 | 0.38 | 1.64 | 0.00 | 0.01 | 0.03 | 0.00 | 0.00 | 0.00 |
| Southern Great Plains | 0.04 | 0.07 | 0.37 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 |
| Southwest | 0.89 | 2.63 | 10.17 | 0.08 | 0.27 | 0.93 | 0.00 | 0.01 | 0.02 |
| Northwest | 0.61 | 1.43 | 6.71 | 0.01 | 0.04 | 0.15 | 0.00 | 0.00 | 0.00 |
| Total | 3.05 | 7.42 | 33.56 | 0.10 | 0.32 | 1.14 | 0.00 | 0.01 | 0.03 |
| RCP8.5 in 2090 | |||||||||
| Northeast | 0.89 | 1.34 | 8.67 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 |
| Southeast | 0.92 | 1.85 | 9.43 | 0.00 | 0.00 | 0.01 | 0.00 | 0.00 | 0.00 |
| Midwest | 0.17 | 0.18 | 1.54 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 |
| Northern Great Plains | 0.11 | 0.27 | 1.18 | 0.00 | 0.01 | 0.04 | 0.00 | 0.00 | 0.00 |
| Southern Great Plains | 0.31 | 0.59 | 3.08 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 |
| Southwest | 0.91 | 2.16 | 9.50 | 0.10 | 0.28 | 1.13 | 0.00 | 0.01 | 0.04 |
| Northwest | 0.21 | 0.41 | 2.14 | 0.01 | 0.01 | 0.06 | 0.00 | 0.00 | 0.00 |
| Total | 3.52 | 6.82 | 35.53 | 0.11 | 0.31 | 1.24 | 0.00 | 0.01 | 0.05 |
Note: NCA, National Climate Assessment; RCP, representative concentration pathway. Spatially explicit projections of exposure to wildfire smoke were developed by integrating data from 5 global climate models (GCMs) under RCP8.5 and RCP4.5 in the mid- (2040–2059) and late- (2080–2099) 21st century with county-specific projections of U.S. populations for 2050 and 2090. Corresponding county- and state-level data are depicted in Figure 4 and Table S7, respectively, and county-level data for each GCM is shown in Figure S4. Populations are based on Integrated Climate and Land Use Scenarios (ICLUS) v2 county-level age group projections for the referenced year (i.e., 2050, 2090) (see Table S8 for corresponding projections holding population at 2010 levels and distribution).