Predictors of Indoor Radon Concentrations in Pennsylvania, 1989–2013

http://dx.doi.org/10.1289/ehp.1409014



Table 1. Radon concentrations (Bq/m3) by test and building characteristics, stratified by test location.
Variable Category Basement* First floor*
n (%) Median (IQR)  Range  n (%) Median (IQR)  Range 
aNot available for buildings located in Philadelphia or Pittsburgh. Community socioeconomic deprivation was assigned at the township, borough, or census-tract level, based on six indicators derived from the 2000 U.S. Census: combined less than high school education, not in the labor force, in poverty, on public assistance, civilian unemployment, and does not own a car; a higher score represents a more deprived community. bNo Marcellus activity (other counties): Adams, Bedford, Bucks, Carbon, Chester, Cumberland, Dauphin, Delaware, Erie, Franklin, Fulton, Juniata, Lancaster, Lebanon, Mifflin, Montgomery, Montour, Northumberland, Perry, Pike, Schuylkill, Snyder, Union, and York; low Marcellus activity counties: Allegany, Beaver, Blair, Cambria, Cameron, Centre, Clarion, Columbia, Crawford, Elk, Forest, Huntingdon, Indiana, Jefferson, Lackawanna, Lawrence, Luzerne, McKean, Mercer, Potter, Somerset, Sullivan, Venango, Warren, and Wayne; high Marcellus activity counties: Armstrong, Bradford, Butler, Clinton, Clearfield, Fayette, Greene, Lycoming, Susquehanna, Tioga, Washington, Westmoreland, and Wyoming. cRestricted to 2005–2013 and buildings within 20 km of a drilled well at the time of the radon test. dRestricted to 2005–2013. *Categories of all variables shown had statistically significantly different ln-radon concentrations by ANOVA.
All results Total 705,798 (100) 118.4 (59.2–262.7) 0–69,057 160,937 (100) 55.5 (29.6–111.0) 0–111,481
U.S. EPA action level < 148 Bq/m3 408,184 (57.8) 66.6 (40.7–99.9) 0–147.9 131,245 (81.6) 44.4 (25.9–74) 0–147.9
≥ 148 Bq/m3 297,614 (42.2) 310.8 (207.2–580.9) 148–69,057 29,692 (18.5) 262.7 (188.7–447.7) 148–111,481
Well water use No 591,565 (83.8) 111.0 (58.1–236.8) 0–69,057 138,804 (86.3) 51.8 (27.8–103.6) 0–111,481
Yes 114,233 (16.2) 185.0 (81.4–458.8) 0–55,463 22,133 (13.8) 74.0 (37.0–164.7) 0–14,822
Building type 2-Story 298,672 (42.3) 114.7 (61.1–114.7) 0–55,463 73,340 (45.6) 53.65 (29.6–103.6) 0–111,481
3-Story 69,008 (9.8) 166.5 (77.6–166.5) 2.2–33,973 8,837 (5.5) 70.3 (33.3–162.8) 0.7–7,478
Apartment 1,999 (0.3) 82.0 (44.4–173.9) 3.7–5,254 1,042 (0.7) 33.3 (18.5–68.5) 0.7–1,395
Bi-level 12,599 (1.8) 131.3 (62.9–294.2) 1.1–25,937 2,628 (1.6) 77.7 (37.0–166.5) 1.9–9,476
Cape Cod 15,801 (2.2) 127.7 (70.3–257.2) 0–29,637 3,837 (2.4) 59.2 (29.6–103.6) 0–29,711
Commercial 1,773 (0.3) 77.7 (42.6–157.3) 3.7–4,449 871 (0.5) 40.7 (22.2–83.9) 0.7–6,915
Contemporary 4,156 (0.6) 136.0 (66.6–296) 3.7–25,530 1,968 (1.2) 51.8 (25.9–108.8) 3.7–2,760
Public/school 370 (0.1) 94.7 (47.2–203.5) 13.6–5,176 202 (0.1) 51.8 (27.1–96.2) 3.7–636
Ranch 63,946 (9.1) 151.7 (79.6–323.2) 0.9–69,057 14,764 (9.2) 66.6 (37.0–136.9) 0–10,286
Split level 17,788 (2.5) 107.3 (59.2–218.3) 1.5–41,607 5,822 (3.6) 59.2 (33.3–107.3) 0–8,251
Townhouse 42,691 (6.1) 68.5 (40.7–125.8) 0.2–32,751 16,920 (10.5) 37.0 (22.2–66.6) 0–22,459
Trailer 183 (0.03) 88.8 (51.8–192.4) 18.5–2,531 139 (0.1) 33.3 (18.5–33.3) 3.7–662
Unknown 176,812 (25.1) 122.1 (55.5–297.9) 0–35,668 30,567 (19.0) 62.9 (29.6–153.0) 0–16,119
Test type Activated charcoal 237,932 (33.7) 129.5 (55.5–325.6) 0–69,057 54,957 (34.2) 59.2 (25.9–142.5) 0–50,294
Alpha track 7,074 (1.0) 161.1 (81.4–333.0) 0.7–14,796 1,844 (1.2) 99.9 (42.7–221.4) 0.4–3,441
Charcoal liquid scintillation 44,936 (6.4) 162.8 (70.3–392.2) 0–32,751 4,934 (3.1) 77.7 (33.3–186.9) 3.7–16,119
Continuous 209,994 (29.8) 114.7 (59.2–236.8) 0.2–41,544 14,647 (9.1) 48.1 (25.9–92.5) 0.1–111,481
Electret ion chamber 205,862 (29.2) 111.0 (62.9–214.6) 0–62,974 84,555 (52.5) 53.65 (29.6–99.9) 0–29,711
Test duration 1–7 days 693,864 (98.3) 118.4 (59.2–262.7) 0–69,057 157,912 (98.2) 55.5 (29.6–111.0) 0–111,481
≥ 8 days 11,934 (1.7) 148.0 (74.0–310.8) 0–69,057 3,025 (1.8) 81.4 (37.0–181.3) 0–3,593
Season Winter 169,921 (24.1) 114.7 (59.2–247.9) 0–55,463 37,886 (23.5) 48.1 (25.9–96.2) 0–50,294
Spring 198,485 (28.1) 114.7 (59.2–229.4) 0–62,974 46,432 (28.9) 51.8 (27.8–98.1) 0–22,496
Summer 174,007 (24.7) 133.2 (66.6–299.7) 0–41543.6 40,320 (25.1) 66.6 (33.3–136.9) 0–111,481
Autumn 163,385 (23.2) 118.4 (59.2–292.3) 0–69,057 36,886 (22.6) 59.2 (29.2–129.5) 0–29,711
Average temperature in month of test (°C) < 0 84,259 (11.9) 3.3 (1.6–8.0) 0.004–930 17,294 (10.8) 1.6 (0.8–3.7) 0–276
0 to < 10 232,372 (32.9) 3.3 (1.6–7.7) 0–1,866 53,651 (33.3) 1.6 (0.8–3.4) 0–3,013
10 to < 18.3 189,693 (26.9) 3.4 (1.7–7.3) 0–1,499 43,018 (26.7) 1.5 (0.8–3.0) 0–607
≥ 18.3 199,474 (28.3) 3.0 (1.6–6.2) 0–1,702 46,974 (29.2) 1.4 (0.7–2.6) 0–608
Average rainfall in month of test (cm) < 7.1 236,239 125.8 (62.9–281.9) 0–69,056 53,693 59.2 (29.6–121.0) 0–50,294
7.2–10.8 232,866 116.6 (59.2–251.6) 0–62,974 55,928 55.5 (29.6–107.3) 0–111,481
≥ 10.9 236,693 116.6 (59.2–255.3) 0–41,607 51,316 53.7 (27.8–107.3) 0–22,496
Community socioeconomic deprivation quartilea 1 (< –4.9) 169,327 (24.5) 118.4 (59.2–262.7) 0–35,897 46,100 (29.4) 59.2 (29.6–118.4) 0–50,294
2 (–4.9 to –3.3) 172,068 (24.9) 133.2 (66.6–306.0) 0–55,463 37,389 (23.8) 62.9 (33.3–129.5) 0–29,711
3 (–3.2 to –1.1) 177,619 (25.7) 129.5 (66.6–284.9) 0–69,057 36,734 (23.4) 59.2 (29.6–114.7) 0–18,537
4 (≥ –1.0) 173,407 (25.0) 103.6 (53.7–222.0) 0–35,668 36,742 (23.4) 44.4 (24.1–92.5) 0–111,481
Minor civil division Township 488,168 (69.2) 130.7 (64.8–299.7) 0–55,463 116,311 (72.3) 59.2 (29.6–122.1) 0–50,294
Borough 133,990 (19.0) 112.9 (59.2–233.1) 0–69,057 25,643 (15.9) 51.8 (25.9–103.6) 0–22,496
City 83,638 (11.9) 79.6 (44.4–148.0) 0–31,361 18,983 (11.8) 40.7 (22.2–70.7) 0–111,481
County categoryb
No Marcellus activity Other counties 379,223 (53.7) 120.3 (59.2–273.8) 0–62,974 112,252 (69.8) 55.5 (29.6–111.0) 0–50,294
Low Marcellus activity < 100 drilled wells by 2013 174,216 (24.7) 114.7 (62.9–233.1) 0–30,621 22,734 (14.1) 55.5 (27.4–118.4) 0–22,496
High Marcellus activity ≥ 100 drilled wells by 2013 57,814 (8.2) 129.5 (70.3–260.9) 0–30,858 5,753 (3.6) 62.9 (33.3–129.5) 2.6–111,481
Reading Prong Berks, Lehigh, and Northampton 62,635 (8.9) 192.4 (85.1–425.5) 0–69,057 9,632 (6.0) 96.2 (44.4–210.9) 0–14,822
Philadelphia Philadelphia 31,910 (4.5) 62.9 (37.0–105.5) 0–31,361 10,566 (6.6) 37.0 (22.2–62.9) 0–2,331
Drilled well within 20 km of building No 637,317 (90.3) 118.4 (59.2–266.4) 0–69,057 156,731 (97.4) 55.5 (29.6–111.0) 0–50,294
Yes 68,481 (9.7) 124.0 (70.3–244.2) 0–38,658 4,206 (2.6) 59.2 (33.3–120.3) 3.7–111,481
Drilled-well exposure quartilec
1 < 0.19 well/km2 17,086 (25.0) 120.3 (70.3–225.7) 3.7–23,465 1,086 (25.8) 70.3 (37.0–133.2) 3.7–2,742
2 0.19 to 0.61 well/km2 17,099 (25.0) 125.8 (70.3–255.3) 18.5–29,637 1,073 (25.5) 59.2 (29.6–114.7) 18.5–8,251
3 0.62 to 1.4 well/km2 17,126 (25.0) 125.8 (70.3–247.9) 18.5–30,858 1,046 (24.9) 55.5 (29.6–107.3) 14.8–3,559
4 > 1.4 well/km2 17,170 (25.1) 125.8 (70.3–247.9) 18.5–19,769 1,001 (23.8) 59.2 (37.0–122.1) 18.5–111,481
Producing-well exposure quartiled
1 < 2.55 m3/day/km2 83,971 (24.3) 111.0 (55.5–247.9) 2.6–40,928 13,052 (31.2) 51.8 (26.3–99.9) 0–8,131
2 2.55 to 294.4 m3/day/km2 86,196 (24.9) 120.3 (61.1–266.4) 7.4–35,897 10,826 (25.9) 59.2 (30.9–118.4) 0–29,711
3 294.5 to 4312.6 m3/day/km2 86,989 (25.1) 125.8 (62.9–281.2) 11.1–62,974 10,034 (24.0) 59.2 (33.3–122.1) 3.7–12,119
4 > 4312.7 m3/day/km2 89,143 (25.7) 133.2 (70.3–288.6) 11.1–30,858 7,879 (18.9) 61.1 (33.3–124.0) 5.6–111,481